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use of barbiturates for anxiolysis chlorpromazine). The next subcategory of phenothiazines has declined in favor of benzodiazepines. This is, in part, due includes the piperidine derivatives, such as thioridazine. The to the greater safety margin of benzodiazepines over barbitu- last subcategory of phenothiazines are the piperazine deriva- rates. The lethal dose of barbiturates is only some 50 times tives (e.g., prochlorperazine). greater than the therapeutic dose, whereas the lethal dose of Most phenothiazines have a strong antiemetic effect, benzodiazepines is one-thousand times greater than the ther- which blocks the chemoreceptor trigger zone (CTZ) within apeutic dose. the medulla. The most famous of these is scopolamine, which is used to treat motion sickness. Many patients who are receiv- Benzodiazepines ing chemotherapy for cancer are prescribed a phenothiazine, Benzodiazepines are effective for treating such anxiety- such as chlorpromazine, for nausea control. related disorders as panic attacks, as well as seizure activity, by attaching to benzodiazepine receptors located in the Limbic Precautions system of the central nervous system. These benzodiazepine Phenothiazines also exert an antagonistic infl uence on receptors are thought to enhance the attraction of gamma- other receptors. The majority of side effects attributed to aminobutyric acid (GABA) to the GABA receptor, which in the phenothiazines can be traced to this broad blockade of turn opens chloride channels in the neuron. Increased chlo- other receptors. For example, phenothiazines block alpha- ride (Cl-) within the cell hyperpolarizes the neuron, making adrenergic receptors in the peripheral circulation. As a direct it more diffi cult to depolarize. consequence of this blockade, when a patient stands up the Benzodiazepines are also used for a number of other cardiovascular system cannot compensate and the patient therapeutic effects including treatment of sleep disorders may experience syncope.72 (hypnotic effect), seizures (see earlier discussion), and More troubling may be the antimuscarinic effects of phe- muscle spasms. However, the majority of benzodiazepines nothiazines. Through its inhibition of smooth muscle, phe- are prescribed for their anxiolytic effect. Short-acting ben- nothiazines cause the patient to experience blurred vision zodiazepines, such as lorazepam, are effective in ending (papillary muscle), dry mouth, constipation, and urinary panic attacks. Long-acting benzodiazepines are effective in retention. treating the agitation and anxiety patients experience when they go through alcohol withdrawal. It should be noted that Extrapyramidal System ethanol (ethyl alcohol) is also a sedative. The therapeutic goal in alcohol detoxifi cation is to fi rst replace the alcohol Coordination of muscles is owed, in part, to the extrapyra- with a benzodiazepine, then to slowly wean the patient off midal system that connects the motor coordination from the of the benzodiazepine. cerebral cortex with the spinal nerves. There are abundant cholinergic and dopaminergic receptors within this system. A naturally occurring imbalance between these two receptors Antidepressant Medication is the pathogenesis of Parkinson’s disease. Phenothiazines Depression is a disturbance in a patient’s mood, not thought, can produce a drug-induced Parkinsonian syndrome. and is characterized by feelings of hopelessness, helpless- Characteristics of the extrapyramidal symptoms (EPS) of ness, and despair. Some psychiatrists attribute these mal- drug-induced Parkinsonian syndrome include a shuffl ing gait, adjusted emotions to a lack of a certain neurotransmitter resting tremors, muscle rigidity with resultant slurred speech, in the brain, specifi cally the monoamines. Monoamines drooling, and a gross motor restlessness called akathisia.73 include norepinephrine and serotonin. Antidepressant med- If left untreated, drug-induced Parkinsonian syndrome ications that have had a positive effect are medications that can lead to involuntary movements of the extremities (a either increase the amount of monoamines in the synaptic tardive dyskinesia). These include fl y-catching motions of junction or decrease the destruction of monoamines by the tongue and a spasm of the neck muscles, called torticol- enzymes, indirectly increasing the amount of monoamines lis, that tilts the head to one side (formerly called wryneck). in the synaptic junction. Pharmacological Therapeutics for Medical Emergencies 707 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Tricyclic Antidepressants Selective Serotonin Re-Uptake Inhibitors The class of antidepressants that block the uptake of sero- Selective serotonin re-uptake inhibitors (SSRI) preferentially tonin, norepinephrine, and dopamine into the neuron are block the re-uptake of serotonin into the neuron and thus, called the tricyclic antidepressants. The fi rst generation of indirectly, increase the amount of neurotransmitter in the syn- tricyclic antidepressants (TCA), including imipramine and aptic cleft. The SSRI drugs are thought to have less impact on amitriptyline, are chemically related to the phenothiazines the parasympathetic nervous system as well as fewer cardio- and have similar mood-altering effects. The second genera- vascular side effects such as orthostatic hypotension. tion of TCA also has the same action but slightly different pharmacokinetics, with different side effects and a longer Monoamine Oxidase Inhibitors duration of action. Monoamine oxidase is an enzyme that metabolizes excess The primary action of TCA is to increase the mono- catecholamines, through a process of oxidation, into inactive amines serotonin, norepinephrine, and epinephrine in the metabolites that can be harmlessly excreted. MAO inhibitors brain’s neuronal synapse. At issue is whether the antidepres- prevent the deactivation of catecholamines from the synap- sant effect is due to increased monoamines or the observed tic gap and therefore indirectly increase the amount of neu- subsequent increase in monoamine receptors in the brain. rotransmitter in the synaptic junction. The MAO inhibitors Regardless, TCA administration results in mood elevation, are similar to TCA in effect, but different in their pharmaco- improved mental alertness, and increased physical activity. dynamics, as they elevate the patient’s mood. The TCA, as a class, are effective in between 50% and 70% Tyramine, the fundamental substance for monoamines of patients taking the medication. such as norepinephrine, is found in such foodstuffs as aged cheeses, fermented sausages (such as bologna, pepperoni, Precautions salami, and summer sausage), sauerkraut, smoked or pickled Tricyclic antidepressants also affect a number of other meats, beer, and red wines. peripheral neural receptors including serotonin, alpha- Typically, tyramine is metabolized in the intestines by adrenergic receptors, and muscarinic receptors. TCA can MAO. When the patient has been placed on an MAO inhibi- block muscarinic receptors in the parasympathetic nervous tor, tyramine-rich foods are absorbed unaltered into the cir- system, resulting in dry mouth (xerostomia), blurred vision, culation. Tyramine taken up by the neurons displaces the and urinary retention.74 monoamines in the neuron’s vesicles, liberating large quanti- Tricyclic antidepressants also increase catecholamine ties of catecholamines. activity in the heart while blocking alpha-adrenergic recep- The resulting increase of catecholamines in the neuronal tors in the peripheral capillary beds. Subsequently, when a synapse leads to profound sympathetic stimulation. Subse- patient stands suddenly the central nervous system cannot quently, tachycardia and hypertension ensues and can lead to refl exively adjust to the sudden change in blood distribution a potentially life-threatening hypertensive crisis. and the patient experiences orthostatic syncope. Mania Toxicity Psychotic depression is discernible by extremes of mood. The depressed patient may elect to attempt suicide by inges- One moment the patient is depressed, voicing hopelessness, tion of the TCA prescription. A TCA overdose can be danger- and the next moment the patient is elated and demonstrates ous at many levels. Alone, TCA blocks sodium channels in self-confi dence beyond reason. Patients exhibiting these the heart, leading to complex cardiac conduction abnormali- behaviors are said to be bipolar (i.e., manic–depressives) and ties including AV block, reentry ventricular dysrhythmia, and must be treated for both extremes in emotion. ventricular tachycardia, including polymorphic ventricular Lithium Salts tachycardia (specifi cally torsades de pointes).75,76 Co-ingestion of depressants, such as alcohol, along The prototypical anti-mania drug is lithium. While lithium with the TCA can lead to a toxic sedation. Similarly, if the salts are very effective, the therapeutic index for lithium patient ingested MAO inhibitors (another antidepressant) is very low. Effects of lithium intoxication include ataxia along with the TCA, the two drugs can produce a signifi cant (drunken staggers), confusion, and convulsions.78 sympathetic overstimulation that manifests as high fever (hyperpyrexia) that mimics heat stroke, marked hyperten- Drugs That Are Used to Treat sion, and convulsions. Treatment of a TCA overdose is aimed at reversing these Childbirth Emergencies negative cardiovascular effects and protecting the airway. Traditionally, medications are used sparingly during pregnancy After controlling the airway, alkalinization of the blood with for fear of possible teratogenic effects. However, under certain sodium bicarbonate (0.5 mg/kg) may be the initial treat- special circumstances it may be necessary to use medication. ment.77 The sodium bicarbonate bolus is usually followed by In those instances, the Paramedic should review the drug’s an intravenous infusion of sodium bicarbonate. pregnancy classifi cation as well as contact medical control. 708 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Eclampsia even on one organ system. Terbutaline, a smooth muscle relax- ant (beta-adrenergic agonist), has been given intravenously Eclampsia, also known as toxemia of pregnancy, is the cul- (0.025 mg/min IV drip) with some success. However, signifi - mination of a syndrome called pre-eclampsia. It is dramati- cant side effects limit its use to emergencies only. cally revealed by the pregnant woman’s convulsion between her third trimester (twentieth week) and immediately post- Oxytocics partum. Pre-eclampsia produces hypertension (rise in the baseline systolic pressure by 31 mmHg), protein in the urine Labor, the forceful contraction of the uterine smooth mus- (albuminuria), and peripheral edema. cles, is induced by the hormone oxytocin which is secreted Treatment of eclampsia has two objectives: stop the con- from the posterior pituitary gland. Oxytocin, which trans- vulsion and preserve the life of the fetus. If left untreated, lated literally means “rapid birth,” is made synthetically and the mother’s eclampsia-induced convulsion can lead to coma can be intravenously administered by Paramedics during a and stress the unborn infant. A higher incidence of placenta pregnancy- related emergency. abruptio has also been noted following eclampsia-induced The onset of action of synthetic oxytocin, such as convulsions. ergonovine or oxytocin itself, is almost immediate (one to six While diazepam is effective in treating the convulsion, minutes) and causes uterine contractions to gradually increase evidence suggests that magnesium sulfate remains superior over one hour. The strong contractions of the uterus tend to for the treatment of eclampsia.79 Whenever magnesium sul- compress blood vessels and slow intrauterine bleeding. fate is administered, careful monitoring of blood pressure, pulse, respirations, and fetal heart sounds (when possible) should occur at least every 15 minutes. Street Smart It is important that Paramedics make the distinction between the mother who is experiencing an eclampsia-induced convulsion and one with a pre-existing seizure disorder. This Stimulation of the mother’s nipple stimulates milk distinction is important when selecting preferred agents for discharge from the breast via release of oxytocin. emergency treatment. If uncontrolled, a convulsion can lead This cause and effect is called the letdown refl ex. to fetal anoxia and brain damage. Therefore, it must be treated immediately with the most effective anticonvulsant agent. Therapeutically, stimulation of the mother’s nipple, by the suckling infant, can also release oxytocin Labor that will cause uterine contractions and help control Complications of pregnancy, such as premature labor, pre- hemorrhage. term delivery, and breech deliveries, make the fi eld deliv- ery of an infant more dangerous. In certain situations, it is desirable to inhibit the labor of a pregnant woman in favor of effecting an immediate transfer of the mother to a better Drugs That Are Used equipped birthing center. Another serious complication of pregnancy is post- to Combat Infection partum hemorrhage. When the products of conception are An infection occurs whenever any microorganism, such as a incompletely removed from the uterus following labor, virus, bacteria, parasite, fungus, or worm (helminth), invades such as incomplete placental detachment, then |
the mother the body and overcomes the host’s native defenses. Without may hemorrhage uncontrollably. In those cases, Paramedics medical intervention, these infections can lead to generalized may institute a life-saving infusion of medication to force sepsis, septic shock, and even death. uterine contraction. The best defense against infection is prevention. Para- medics can utilize a variety of techniques to try and prevent Tocolysis infection. The fi rst assumption of infection control is that Medications that cause uterine relaxation, and thus pathogens (microorganisms capable of producing infec- inhibit labor, are called tocolytics. Some tocolytics, such tion) are omnipresent in the community and within the work as ethyl alcohol (inhibits oxytocin) and aspirin (inhibits environment. To limit their transmission (i.e., prevention), p rostaglandin-induced labor), are impractical in the fi eld. Paramedics use a variety of barrier devices (gloves, goggles, In some cases, a simple bolus of intravenous solution can mask, and gown) as well as aseptic techniques. be temporarily effective. The bolus of intravenous solution Hypothetically, a complete lack of all microorganisms activates antidiuretic hormone from the posterior pituitary (surgical asepsis) would be the most desirable situation for gland and also inhibits oxytocin secretion from the poste- EMS. However, surgical asepsis is only possible via steril- rior pituitary as well. ization and is therefore impractical in the fi eld. More real- Hypothetically, any smooth muscle relaxant should also istically, the Paramedics’ goal should be to attain medical inhibit labor, as few drugs work exclusively in one organ or asepsis (an absence of pathogenic microorganisms) in the Pharmacological Therapeutics for Medical Emergencies 709 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. fi eld. Medical asepsis is obtained through a combination of Some antibiotics are effective against a large number of hygienic measures, such as hand washing, barrier devices, bacteria (i.e., the antibiotic is nonspecifi c) and thus are classi- antiseptics, and disinfectants. fi ed as broad-spectrum antibiotics. Other antibiotics are very Disinfectants are solutions and compounds, such as the effective for only a specifi c bacteria. For example, isoniazid phenols and chlorine compounds, which effectively remove is only effective against mycobacterium tuberculosis, and pathogens from inanimate objects, such as work surfaces and thus is classifi ed as a narrow-spectrum antibiotic. assessment tools. However, they are generally toxic when In many cases, a patient will be placed on a broad-spectrum they come in contact with living tissue. Therefore, disinfec- antibiotic while awaiting laboratory results of cultures obtained tants cannot be used in the treatment of patients unless their from the patient. With the results in hand, more specifi c, or potency is reduced (e.g., through dilution). Weakened, these narrow-spectrum, antibiotic therapy would be prescribed. solutions tend to inhibit, rather than destroy, pathogens and Antibiotics can bring about their antimicrobial effect by are thus called antiseptics. several means, including inhibiting cell wall synthesis, inhib- Antiseptics, as well as disinfectants, can be further iting protein synthesis, or as an antimetabolite. categorized as either bacteriostatic (solutions that slow the growth of pathogens) or bactericidal (solutions that kill off Antibiotics That Inhibit Cell Wall Synthesis the pathogens). Some solutions are effective against a broad Bacteria, unlike native cells, are not isotonic in the intersti- spectrum of pathogens (i.e., fungi, virus, and bacteria) and tial fl uid. The resulting osmotic pressure places a great strain are called germicides. An effective disinfectant must be able upon the bacteria’s cell walls. Any antibiotic that weakens to kill off all bacteria (not spores), fungi, parasites, and most that cell wall (e.g., by inhibiting the synthesis of portions viruses within 10 minutes of application. of the cell wall) will cause the cell wall to structurally fail and the cell to burst (i.e., lysis). Antimicrobials The pharmacodynamics of the fi rst antibiotic (penicillin) works by this mechanism. Subsequent generations of antibiotics, Despite meticulous medical asepsis, infections do still occur. such as the cephalosporins, also depend on this mechanism.80 Medical intervention is necessary to prevent the spread of Allergies to penicillin are common, occurring in about infection. Treatments for infection can be broken down into 5% of the U.S. population.81 Not surprisingly, patients who surgical treatments and medical treatments. Surgical treat- develop an allergy to penicillin drugs often have a cross- ments include the debridement of dead and necrotic tissue, allergy to the cephalosporins as well, since the two are incision and drainage of infection, and excision of infected chemically related. Newer broad-spectrum penicillins, such organs. A discussion of surgical treatment is beyond the as piperacillin, are among some of the most widely used anti- scope of this text. biotics because of their wide safety margin. Unfortunately, Medical treatments for infection include the use of chem- overuse and poor patient compliance has led to the devel- icals (i.e., drugs) for their therapeutic benefi t. Organization opment of penicillin-resistant bacteria, the c reation of super- of these chemotherapeutic agents can be arranged according infections, and subsequently limited the usefulness of these to the pathogen that the drug is most effective against. For inexpensive antibiotics. example, antibiotics are drugs that are effective against bac- teria and antivirals are most effective against viruses. Antibiotics That Inhibit Protein Synthesis Antivirals Inhibition of protein synthesis within the bacteria’s cytoplasmic ribosome by these antibiotics causes the bacteria to misread Viruses, the smallest pathogen, are incapable of independent the genetic code. Unable to properly synthesize the necessary reproduction and, as parasites, require a host cell for replica- proteins for cell reproduction, the bacterium dies. Tetracy- tion. Understanding how important this simple process is to a clines, aminoglycosides, erythromycin, chloramphenicol, and virus’s infectivity, antiviral treatment is focused on preventing clindamycin are all antibiotics that work by this mechanism. the virus from injecting (i.e., uncoating) its RNA into the host cell or inhibiting the synthesis of DNA once the virus is inside. Antibiotics That Are Antimetabolites Unfortunately, due to the close relationship of the virus to the Bacteria, like the host, require certain substrates for the pro- host cell, it is diffi cult to kill one without eliminating the other. duction of proteins and the like. For example, one of those substrates is folate. Folate, which is produced by the bacteria Antibiotics from PABA, is converted into folic acid, an essential cofactor The sheer number of antibiotics available on the market is in amino acid synthesis. The sulfonamide class of antibiotics staggering. To lend order to this collection, antibiotics can competes with bacteria for the enzymes necessary for this be further classifi ed according to their action. Minimally, conversion, thus inhibiting the bacteria’s ability to produce antibiotics should suppress bacterial infections, allowing the amino acids and proteins. Isoniazid (IND), a potent antituber- host’s defenses to overcome the infection (e.g., tetracycline culosis agent, works by a similar mechanism, inhibiting the or erythromycin) or even destroy the invading pathogen (e.g., synthesis of mycolic acids. This, in turn, weakens the myco- aminoglycosides, cephalosporins, and penicillins). bacterium’s cell wall. 710 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Antifungals Chemotherapy is one of the three mainstays of cancer treatment, the other two being radiation and surgery. Chemo- Of the over one million varieties of fungus, over 400 are known therapy is aimed at eliminating the cancer at the cellular level. to cause disease in humans. So many varieties of fungus exist In some instances, the chemotherapy is calculated to reduce that fungus is categorized as one of the fi ve kingdoms of life. a tumor’s mass for surgical removal later. In other cases, the Fungus is identifi able by its rigid cell walls, among other char- chemotherapy is intended to eliminate any remaining cancer acteristics, which makes it particularly resistant to most antibi- cells (micrometastases) after surgery and/or radiation. otics. Fungal infections, called mycoses, are generally treated Drugs that eradicate cancer cells are called antineoplastics. with antibiotics that disrupt the cell wall of the fungus, making These antineoplastic drugs depend upon the rapid division of it more permeable. The cell walls are now “leaky,” essential the dysfunctional cells within a tumor to be effective. To prolif- substrates (such as potassium) leak out, and the cell dies. erate, cancer cells depend on amino acids and nucleic acids in Antiprotozoal order to build DNA and RNA. By understanding this concept, chemotherapies are designed that deprive the cancer cell of Protozoa, a one-celled organism, may be the most abundant these essential substrates (i.e., antimetabolites), block the tran- life form on Earth, creating more “biomass” than any other life scription of RNA to new DNA (called mitotic inhibitors), or form. Of particular concern to Paramedics are the protozoa that prevent cell division entirely (such as the alkylating agents). cause malaria and the protozoa that cause amebic dysentery. All antineoplastic agents are also effective against cell Malaria, carried in mosquito saliva, is a blood-borne division among normal healthy cells, particularly the rapidly infection. dividing epithelial cells of the mucus lining in the intestine, Roughly 40% of the world’s population is at risk for the dermis of the skin, and the hair. Thus, the margin between malaria. In fact, it is estimated that one African child dies the therapeutic and toxic margins of antineoplastic agents is every 30 seconds from malaria.82 extremely narrow and serious side effects frequently occur. Acute dysentery, characterized by large amounts of A common side effect is a decline in the number of white mucus-laden diarrhea and severe abdominal pain, is the con- blood cells. At the peak (nadir) of the chemotherapy’s effec- sequence of intestinal amebic infection. If left untreated, dys- tiveness, the patient’s white blood cell count will be at its lowest entery can lead to profound hypovolemia and shock. (leukopenia) and the patient will be seriously immunocompro- While improved sanitary conditions have decreased the mised. With a limited immunity, opportunistic infections can incidence of these two diseases in the United States, immi- obtain a foothold and the patient can become septic. Often the grants from other countries and tourists traveling abroad can fi rst sign of infection is a fever of unknown origin.83 bring the disease back in the Americas. Similarly, at the nadir of the chemotherapy the patient’s Pregnancy and Protozoa platelet count will also drop. The resulting thrombocytopenia will leave the patient at greater risk for spontaneous hemor- A particular concern of pregnant women is the possibility of con- rhage (e.g., cerebral hemorrhage) and bruising. tracting toxoplasmosis. The causative agent in toxoplasmosis is toxoplasma gondii, a protozoa that is carried in the feces of cats as an oocyst (encapsulated protozoa). Absorbed systemically, the protozoa are transferred to the fetus and can cause blindness, Street Smart loss of hearing, and mental retardation. For this reason, women who are pregnant are advised to not empty cat litter boxes. The nadir of chemotherapy usually occurs in the Antihelmintics middle of the cycle (e.g., on the seventh day of a 14-day cycle). At this time, the patient is at greatest The helminthes (worms) include blood fl ukes, fl atworms, and tapeworms. (Ringworm is a fungal infection.) These worms risk for acquiring infection. Paramedics should can be present in undercooked beef or pork, or transmitted by practice reverse isolation when caring for this patient. common vectors, such as the mosquito, horse fl y, or black fl y. Treatment of worms is aimed at the specifi c helminth that has been identifi ed. Interestingly, a number of the treatments Palliative Care paralyze the worm. When co-administered with laxative, the body then can purge the infestation. In many instances, all a Paramedic can do is offer support and palliative measures to patients with cancer. Palliative measures Drugs Used to Treat Cancer are those treatments |
that are intended to alleviate the unpleas- ant symptoms of chemotherapy with antineoplastic agents. Cancer is the second leading cause of death in the United Common symptoms associated with chemotherapy include States. One in four patients will have a diagnosis of cancer in nausea, vomiting, anorexia, and diarrhea. Use of antiemetics— his or her lifetime. The goal of cancer treatment is to elimi- such as promethazines, phenothiazines, and antihistamines— nate the cancer from the body. may bring the patient much needed relief and comfort. Pharmacological Therapeutics for Medical Emergencies 711 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Paramedics have a limited arsenal of effective chemotherapeutic agents with which to fi ght disease. Despite this apparent disability, thoughtful Paramedics can intervene early in an emergency with this limited number of medications and reduce the morbidity and mortality associated with these diseases. Key Points: • The brain consists of the brainstem (the primitive refl ex arcs in the spinal cord, causing an immediate brain), the cerebellum, and the cerebrum. withdrawal from the stimulus. • Only lipid-soluble drugs are capable of passing into • Neuromodulators are substances that affect the brain tissue. This blood-brain barrier is the result transmission of pain sensations to the brain. of tight slit junctions, gaps in capillaries that allow Endorphins are natural neuromodulators and attach some substances to pass. to opiate receptors. Sodium movement across the • membrane is slowed, thus slowing nerve conduction CNS depressants reduce anxiety, decrease and pain interpretation. excitability, and (at higher doses) produce sleep. Depressants include barbiturates, benzodiazepines, • Opiate analgesics act in the same manner as and alcohol. endorphins. • Depressants work by interfering with ion movement • Opiate analgesics include morphine, fentanyl, across the membrane or occupying receptor sites. codeine, and hydromorphone. Side effects include • respiratory depression, altered mental status, and Anesthesia is lack of sensation. vasodilation. • Analgesia, the fi rst stage of anesthesia, is the lack • Synthetic opiates, including meperidine and of pain. methadone, have less undesirable side effects. • Anesthetic agents can be inhaled or intravenously • Opiate antagonists, such as naloxone, reverse the administered. effects but do not affect an allergic reaction. • Nitrous oxide is an inhaled fi eld anesthetic. • Non-opioid analgesics act at the level of the injury, • IV anesthetics include short-acting benzodiazepines reducing the effects of infl ammation. and short-acting barbiturates. • Salicylate (aspirin) toxicity results in a metabolic • Conscious sedation is a technique used to depress acidosis. a patient’s level of consciousness without loss of • Acetaminophen toxicity can lead to permanent liver protective refl exes. In the fi eld setting, it enables damage. the Paramedic to perform diffi cult or painful procedures. • Anticonvulsant medications affect the sodium • channels in the nerve’s action potential or affect Pain is the most common reason to call EMS. the neurotransmitter GABA, reducing rapid • The pain threshold, the level of stimulus that will electrical discharges. Barbiturates, hydantoins, elicit a pain response, varies from person to person. benzodiazepines, succinimides, and valproic acid prevent or treat seizure activity. • Nociceptors (pain receptors) send messages over myelinated A fi bers (sharp pain) or via unmyelinated • Anti-Parkinson’s medications block acetylcholine or C fi bers (dull or burning pain). A fi bers connect to increase dopamine reception in the brain. 712 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. • The endocrine system utilizes hormones to relay (histamine) can cause bronchoconstriction, chemical messages. Hormones can be given to treat angioedema, and airway swelling, plus hypotension some endocrine diseases. secondary to vasodilation. Antihistamines are • antagonists and compete for the H1 receptors. Diabetes mellitus can cause the medical They prevent further effects but do not reverse emergencies of hypoglycemia or hyperglycemia with the effects already present. Epinephrine reverses or without acidosis. the effects. • Insulin is a protein that must be injected. Various • Gastrointestinal medications include over-the- insulin preparations have different onset and counter antacids designed to buffer stomach acids, duration of effect. emetics that induce vomiting, antiemetics that • Oral hypoglycemic agents act in one or more of the prevent vomiting by affecting the vomiting center in following ways: the brain, antidiarrheal medications, and laxatives that stimulate release of rectal contents, soften the ■ Stimulate beta cells in the pancreas to produce more insulin stool by increased water absorption, or bulk up the stool with insoluble fi bers. ■ Reduce glucagon levels ■ Increase insulin binding to cell receptors • Medications that treat bleeding disorders either ■ Delay absorption of carbohydrates interfere with anticoagulant drugs or replace ■ Lower insulin resistance missing coagulation factors. • Hypoglycemia is treated with sugar replacement • Ineffective or decreased red blood cells may be by mouth or intravenously. Glucagon can be given treated with replacement substances such as iron or intramuscularly to stimulate the release of glycogen vitamins. and its subsequent metabolism to glucose. • • Antipsychotic medications include those that block The cortex of the adrenal glands produces dopamine receptors, those that reduce anxiety, and mineralocorticoids (which affect water and sodium those that enhance the neurotransmitters, called balance), glucocorticoids (which affect infl ammation), monoamines. androgenous steroids, and estrogen. The medulla produces epinephrine and norepinephrine. • Medications that slow labor are called tocolytics. • Many work by beta agonism relaxing the smooth The ovaries are the primary site of estrogen muscle of the uterus. Medications that enhance production. Altering the amount and timing of labor (oxytocics) work by stimulating or imitating estrogen production has a contraceptive effect. the effect of oxytocin from the posterior pituitary. Estrogen also inhibits or enhances the growth of tumors, has a cardioprotective effect, and limits • Drugs used to combat infection are directed toward bone density loss in post-menopausal women. the specifi c agent. • ■ Antibiotics affect bacterial invasions through The pituitary gland produces different hormones inhibiting cell wall synthesis, inhibiting protein in its anterior portion compared to its posterior synthesis, or as an antimetabolite. portion. Antidiuretic hormone from the ■ Antivirals try to prevent viruses from invading posterior portion is given as vasopressin to cause host cells. vasoconstriction and limit water loss. Oxytocin is ■ Antifungals affect the integrity of the rigid cell also a posterior pituitary hormone. wall. • The thyroid gland is responsible for the rate of ■ Antiprotozoans and antihelmintics help the body metabolism. Drugs used to treat thyroid disorders purge the invading organisms. include medications to stimulate the production of • Drugs used to treat cancer are antineoplastics. triiodothyronine (T3) or thyroxine (T4). These affect the metabolism of the rapidly dividing • Anaphylaxis is the most severe inappropriate cancer cell but also affect other rapidly dividing response to an allergen. The chemical mediator cells such as hair follicles. Pharmacological Therapeutics for Medical Emergencies 713 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Review Questions: 1. Describe the mechanism of action of opiate 8. Name two medications given to treat pain relievers. hypoglycemia. 2. How does the opiate antagonist naloxone 9. What is the mechanism of action of work? Does it affect an allergic reaction to an antihistamines? Do these medications reverse opiate drug? the presenting signs? 3. List at least two non-opiate pain relievers, 10. Name two mechanisms of action for state their mechanism of action, and state their antipsychotic medications. What is a potentially toxic effects. reversible side effect of the major antipsychotic 4. Name two ways in which anticonvulsant agents? medications prevent or treat seizures. 11. What is the classifi cation of drugs that slow or 5. What is the mechanism of action of anti- stop labor? Stimulate labor? Parkinson’s drugs? 12. Describe three mechanisms by which 6. What protein is given to reduce glucose levels in antibiotics work. the blood? Can it be taken orally? 7. List the mechanisms used by oral hypoglycemic agents to lower blood glucose levels. Case Study Questions: Please refer to the Case Study at the beginning of the 3. Name at least fi ve questions that the Paramedic chapter and answer the questions below: should ask regarding the patient’s past medical 1. What classifi cations of drugs relieve pain? Alter history. sensation? Modify metabolism? 2. Name at least six questions the Paramedic should ask regarding the history of the present illness (complaint). References: 1. Burt A. Textbook of Neuroanatomy. Philadelphia: W.B. Saunders 5. Whitwam JG, Amrein R. Pharmacology of fl umazenil. Acta Company; 1993. Anaesthesiol Scand Suppl. 1995;108:3–14. 2. Seigel G, ed., et al. Basic Neurochemistry: Molecular, Cellular 6. Ngo AS, Anthony CR, et al. Should a benzodiazepine antagonist and Medical Aspects (Periodicals). Philadelphia: Lippincott be used in unconscious patients presenting to the emergency Williams & Wilkins; 1998. department? Resuscitation. 2007;74(1):27–37. 3. Lopez-Munoz F, Ucha-Udabe R, et al. The history of barbiturates 7. Hamilton M. Researching harm reduction—care and a century after their clinical introduction. Neuropsychiatr Dis contradictions. Subst Use Misuse. 1999;34(1):119–141. Treat. 2005;1(4):329–343. 8. Wobst AH. Hypnosis and surgery: past, present, and future. 4. Lader M, Petursson H. Rational use of anxiolytic/sedative drugs. Anesth Analg. 2007;104(5):1199–1208. Drugs. 1983;25(5):514–528. 714 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 9. Andrade J, Deeprose C. Unconscious memory formation during 29. Ghoneim MM, Dhanaraj J, et al. Comparison of four opioid anaesthesia. Best Pract Res Clin Anaesthesiol. 2007;21(3): 385–401. analgesics as supplements to nitrous oxide anesthesia. Anesth 10. Punjasawadwong Y, Boonjeungmonkol N, et al. Bispectral index Analg. 1984;63(4):405–412. for improving anaesthetic delivery and postoperative recovery. 30. Gillman PK. Monoamine oxidase inhibitors, opioid analgesics Cochrane Database Syst Rev. 2007;4:CD003843. and serotonin toxicity. Br J Anaesth. 2005;95(4):434–441. 11. Szmuk P, Aroyo N, et al. Listening to music during anesthesia 31. McGuire W, Fowlie PW. Naloxone for narcotic-exposed newborn does not reduce the sevofl urane concentration needed to maintain infants. Cochrane Database Syst Rev. 2002;4:CD003483. a constant bispectral index. Anesth Analg. 2008;107(1):77–80. 32. History of aspirin. Available at: http://www.bayeraspirin.com/ 12. Jaslow D, Lemecha D. Prehospital pharmacology: nitrous oxide. pain/asp_history.htm. Accessed December 9, 2008. Emerg Med Serv. 2007;36(2):71–73. 33. Vane JR, Botting RM. The mechanism of action of aspirin. 13. Faddy SC, Garlick SR. A systematic review of the safety of Thromb Res. 2003;110(5-6):255–258. analgesia with 50% nitrous oxide: can lay responders use 34. Temple AR. Pathophysiology of aspirin overdosage toxicity, analgesic gases in the prehospital setting? Emerg Med J. with implications for management. Pediatrics. 1978;62(5 Pt 2 2005;22(12):901–908. Suppl):873–876. 14. Bledsoe BE, Myers JW. Future trends in prehospital pain 35. Proudfoot AT. Toxicity of salicylates. Am J Med. management. JEMS. 2003;28(6):68–71. 1983;75(5A):99–103. 15. Schrading W, Kaplan R, et al. Effect of scavenging on ambient 36. Bailey BO. Acetaminophen hepatotoxicity and overdose. Am Fam levels of nitrous oxide in ambulances. Ann Emerg Med. Physician. 1980;22(1):83–87. 1990;19(8):910–913. 37. Karumanchi SA, Lindheimer MD. Advances in the understanding 16. Zelicof-Paul A, Smith-Lockridge A, et al. Controversies in of eclampsia. Curr Hypertens Rep. 2008;10(4):305–312. rapid sequence intubation in children. Curr Opin Pediatr. 38. |
Craig S. Phenytoin poisoning. Neurocrit Care. 2005;3(2):161–170. 2005;17(3):355–362. 39. Tomsick RS. The phenytoin syndrome. Cutis. 1983;32(6):535–541. 17. Bean A, Jones J. Atropine: re-evaluating its use during paediatric 40. Brewer JM, Waltman PA. Epilepsy and pregnancy: maternal and RSI. Emerg Med J. 2007;24(5):361–362. fetal effects of phenytoin. Crit Care Nurse. 2003;23(2):93–98. 18. Butler,J, Jackson R. Best evidence topic report. Lignocaine as a 41. Gladstone DJ, Bologa M, et al. Course of pregnancy and fetal pretreatment to rapid sequence intubation in patients with status outcome following maternal exposure to carbamazepine and asthmaticus. Emerg Med J. 2005;22(10):732. phenytoin: a prospective study. Reprod Toxicol. 1992;6(3):257–261. 19. Butler J, Jackson R. Towards evidence based emergency 42. Karceski S. Patient page. Epilepsy and pregnancy: are seizure medicine: best BETs from Manchester Royal Infi rmary. medications safe? Neurology. 2008;71(14):e32–33. Lignocaine premedication before rapid sequence induction in 43. Ferrara JM, Stacy N. Impulse-control disorders in Parkinson’s head injuries. Emerg Med J. 2002;19(6):554. disease. CNS Spectr. 2008;13(8):690–698. 20. Robinson N, Clancy M. In patients with head injury undergoing 44. Penson PE, Ford WR, et al. Vasopressors for cardiopulmonary rapid sequence intubation, does pretreatment with intravenous resuscitation. Does pharmacological evidence support clinical lignocaine/lidocaine lead to an improved neurological outcome? practice? Pharmacol Ther. 2007;115(1):37–55. A review of the literature. Emerg Med J. 2001;18(6):453–457. 45. Putcha N, Allon M. Management of hyperkalemia in dialysis 21. Lee C, Porter KM. Prehospital management of lower limb patients. Semin Dial. 2007;20(5):431–439. fractures. Emerg Med J. 2005;22(9):660–663. 46. Kim HJ. Combined effect of bicarbonate and insulin with glucose 22. McManus JG, Jr., Sallee DR, Jr. Pain management in in acute therapy of hyperkalemia in end-stage renal disease the prehospital environment. Emerg Med Clin North Am. patients. Nephron. 1996;72(3):476–482. 2005;23(2):415–431. 47. Allon M, Takeshian A, et al. Effect of insulin-plus-glucose 23. Thomas SH, Shewakramani S. Prehospital trauma analgesia. infusion with or without epinephrine on fasting hyperkalemia. J Emerg Med. 2008;35(1):47–57. Kidney Int. 1993;43(1):212–217. 24. Salerno E. Race, culture, and medications. J Emerg Nurs. 48. Marks V, Teale JD. Drug-induced hypoglycemia. Endocrinol 1995;21(6):560–562. Metab Clin North Am. 1999;28(3):555–577. 25. Gordon DB. Love G. Pharmacologic management of neuropathic 49. Cryer PE. Symptoms of hypoglycemia, thresholds for their pain. Pain Manag Nurs. 2004;5(4 Suppl 1):19–33. occurrence, and hypoglycemia unawareness. Endocrinol Metab 26. Sellin JH. A practical approach to treating patients with chronic Clin North Am. 1999;28(3):495–500, v–vi. diarrhea. Rev Gastroenterol Disord. 2007;7(Suppl 3):S19–S26. 50. Brindley PG, Simmonds M, et al. Best evidence in critical care 27. Shah SB, Hanauer SB. Treatment of diarrhea in patients with medicine. Steroids in sepsis: bulking up the evidence. Can J infl ammatory bowel disease: concepts and cautions. Rev Anaesth. 2008;55(9):648–650. Gastroenterol Disord. 2007;7(Suppl 3):S3–10. 51. Du Plessis JJ. High-dose dexamethasone therapy in head injury: 28. Porter R. The Greatest Benefi t to Mankind: A Medical History of a patient group that may benefi t from therapy. Br J Neurosurg. Humanity. New York: W. W. Norton & Company; 1999. 1992;6(2):145–147. Pharmacological Therapeutics for Medical Emergencies 715 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 52. Reimondo G, Bovio S, et al. Secondary hypoadrenalism. 67. Au N, Rettie AE. Pharmacogenomics of 4-hydroxycoumarin Pituitary. 2008;11(2):147–154. anticoagulants. Drug Metab Rev. 2008;40(2):355–375. 53. Karagiannis A, Mikhailidis DP, et al. Pheochromocytoma: an 68. Agaliotis DP.Hemophilia overview. 2008. Available at: http:// update on genetics and management. Endocr Relat Cancer. www.emedicine.com/med/TOPIC3528.HTM. Accessed 2007;14(4):935–956. November 22, 2008. 54. Jick S, Kaye JA, et al. Further results on the risk of nonfatal 69. Dayalu P, Chou KL. Antipsychotic-induced extrapyramidal venous thromboembolism in users of the contraceptive symptoms and their management. Expert Opin Pharmacother. transdermal patch compared to users of oral contraceptives 2008;9(9):1451–1462. containing norgestimate and 35 microg of ethinyl estradiol. 70. Henretig FM. Special considerations in the poisoned pediatric Contraception. 2007;76(1):4–7. patient. Emerg Med Clin North Am. 1994;12(2):549–567. 55. Spohr FA, Teschendorf P, et al. Vasopressors in cardiopulmonary 71. Thornley B, Rathbone J, et al. Chlorpromazine versus placebo for resuscitation. N Engl J Med. 2008;359(15):1624–1625; author schizophrenia. Cochrane Database Syst Rev. 2003;2:CD000284. reply 1625. 72. Schoenberger JA. Drug-induced orthostatic hypotension. Drug 56. Sillberg VA, Perry JJ, et al. Is the combination of vasopressin and Saf. 1991;6(6):402–407. epinephrine superior to repeated doses of epinephrine alone in the 73. Mehta M, Gharpure V, et al. Acute iron poisoning. 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Bradberry SM, Thanacoody HK, et al. Management of the dysfunction in clinical practice. Eur Rev Med Pharmacol Sci. cardiovascular complications of tricyclic antidepressant 2006;10(5):269–278. poisoning: role of sodium bicarbonate. Toxicol Rev. 61. Fisher MM. Severe histamine mediated reactions to 2005;24(3):195–204. intravenous drugs used in anaesthesia. Anaesth Intensive Care. 78. Nguyen L. Lithium I: the basics. J Emerg Nurs. 2008;34(3):268–269. 1975;3(3):180–197. 79. Duley L, Gulmezoglu AM, et al. Magnesium sulphate and 62. Sheikh A, Shehata YA, et al. Adrenaline (epinephrine) for the other anticonvulsants for women with pre-eclampsia. Cochrane treatment of anaphylaxis with and without shock. Cochrane Database Syst Rev. 2003;2:CD000025. Database Syst Rev. 2008;4:CD006312. 80. Tipper DJ. Mode of action of beta-lactam antibiotics. Pharmacol 63. Allen MD, Greenblatt DJ, et al. Effect of magnesium–aluminum Ther. 1985;27(1):1–35. hydroxide and kaolin–pectin on absorption of digoxin from 81. Prescott WA, Jr., DePestel DD, et al. Incidence of carbapenem- tablets and capsules. J Clin Pharmacol. 1981;21(1):26–30. associated allergic-type reactions among patients with versus 64. Scharman EJ, Hutzler JM, et al. Single dose pharmacokinetics of patients without a reported penicillin allergy. Clin Infect Dis. syrup of ipecac. Ther Drug Monit. 2000;22(5):566–573. 2004;38(8):1102–1107. 65. Krenzelok EP, McGuigan M, et al. Position statement: ipecac 82. Jerrard DA, Broder JS, et al. Malaria: a rising incidence in the syrup. American Academy of Clinical Toxicology; European United States. J Emerg Med. 2002;23(1):23–33. Association of Poisons Centres and Clinical Toxicologists. 83. Gaeta GB, Fusco FM, et al. Fever of unknown origin: a J Toxicol Clin Toxicol. 1997;35(7):699–709. systematic review of the literature for 1995–2004. Nucl Med 66. Corey S. Recent developments in the therapeutic potential of Commun. 2006;27(3):205–211. cannabinoids. P R Health Sci J. 2005;24(1):19–26. 716 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. KEY CONCEPTS: Upon completion of this chapter, it is expected that the reader will understand these following concepts: • Phases of the cardiac cycle • The coronary blood supply to the major portions of the cardiac conduction system compared and contrasted with the regions of the heart. • The heart’s pacemaking control, rate, and rhythm • The purpose of ECG monitoring • The electrophysical and hemodynamic events occurring throughout the entire cardiac cycle correlated with the various ECG waveforms, segments, and intervals Case Study: “Something just happened to Mrs. Fitzpatrick,” said the intern Paramedic. “Her ECG complexes were upright and now they are negative.” His preceptor (teaching Paramedic) asked if he changed leads, but the intern Paramedic denied doing anything to the monitor. After they had checked the patient, the preceptor began reviewing the waveforms on the ECG tracing. 718 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. FPO Principles of Electrocardiography 719 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. OVERVIEW: From the toes to the nose, the heart pumps blood throughout the entire body. Similar to the fi re engine’s water pump, the heart has two components. It has an electrical system that controls the pump’s action and a mechanical system that produces the pump’s output. In the heart, both must work effi ciently and in sequence in order to maintain the rhythmic pumping action that causes the 2 to 3 billion heart beats which occur over the average person’s lifespan. The electricity to run the heart’s electrical system results from an electrochemical process. That electrochemical process occurs in specialized nervous cells in the heart’s conduction system. This conduction system rhythmically stimulates the heart’s muscles, thereby pacing the heart. Since the heart is essential to life, the heart’s muscle cells (the myocardial cells) possess a special property called automaticity. That is, they can also generate electricity but at a much slower rate. This myocardial- induced pacing is a backup system that, although generally less effi cient, can be life-saving. The mechanical process, which creates the movement of blood and generates a pulse, is secondary to the electrical process and is dependent upon the electrical system for rate and rhythm. Damage and disruption to the electrical system can be catastrophic to the individual. Therefore, it is important for Paramedics to constantly assess the heart’s electrical activity. Technology has given Paramedics the tools to observe the heart’s electrical activity and to visually display it on an ECG monitor. Anatomy Myocardium The heart lies within the thoracic cavity, an area in the center Myocardium of the chest. This space, known as the mediastinum, also con- tains the great vessels (the aorta and the trachea). The heart is situated directly behind the sternum and extends slightly farther to the left of sternum than to the right. The base of the heart, where the great vessels enter, is located at the 2nd inter- Epicardium costal space. The apex of the heart is located at approximately (visceral layer of the the 5th intercostal space on the left midclavicular line. Endocardium serous The heart is composed of three layers of tissues pericardium) (Figure 32-1). From outside inward, the fi rst layer of the heart is the two-part pericardium. It has one part which envelops Figure 32-1 Cross-section of the myocardium. the heart and roots of the great vessels, plus another part that is closely adherent to the heart called the epicardium. The cords (such as the chordae tendinae or, as in the case of the epicardium is considered the heart’s outermost part. Between aorta, a thick supportive ring). these two parts is a lubricant called pericardial fl uid which The muscle fi bers of |
the myocardium are specially decreases friction as the heart beats within the pericardial sac. arranged in vertical bundles and fi gure 8 shapes called whorls. The next layer is the thicker myocardium. The myocar- This arrangement allows maximum effi ciency in both push- dium is a muscular layer that actually performs the heart’s ing and squeezing blood out of the heart during each heart work by contracting forcefully and ejecting blood from within beat. The muscles, valves, and rings all attach to a fi brous the heart’s chambers. Controlling this ejection are valves. matrix called the cardiac skeleton. Valves serve to direct blood in one direction from one cham- The innermost layer of the heart is the endocardium. ber to another through the heart. These valves are assisted by The endocardium is a single-layer thick sheet of epithelial muscles (such as the papillary muscles) and thick connective cells that act as a lining, like the sleeve inside a fi re hose. 720 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Unlike the rest of the heart, this layer gets its nutrition (oxy- through ventricular fi lling and ejection, is called a cardiac gen and glucose) directly from the circulating blood volume. cycle. The cardiac cycle is highly dependent upon pressure Unfortunately, because of its direct contact with circulating changes that occur within the heart’s chambers to create for- blood, this layer is prone to infection from any pathogen cir- ward blood fl ow. When the atria are at rest (atrial diastole) culating in the blood (e.g., an infection such as syphilis). This blood fl ows into the atria from the body and lungs. The blood infected condition is called endocarditis. then continues into the ventricles through the open atrioven- Although cardiac muscle fi bers function similarly to tricular valves. Approximately 70% of the blood returning skeletal muscle fi bers, there are several important differences. to the heart passively enters the ventricles at this time. As A specialized cell membrane in the myocardial cell reduces pressure increases in the atria, the atria become stretched. electrical resistance and allows an electrical stimulus to move The stretched atria will then contract (atrial systole), forc- rapidly from cell to cell. The myocardial cells are found in ing approximately 32% more blood into the ventricles than strands, or myofi brils, which form an extensive interrelated would normally be there because of passive ventricular fi ll- network. This network further enhances the rapid movement ing. The active contribution of blood to the ventricle by the of the electrical stimulus from cell to cell and myofi bril to atria is called the atrial kick. This atrial kick ultimately myofi bril, as well as to the myocardial mass as a whole. This increases the amount of blood in the ventricles (the end dia- networking of cells and myofi brils allows simultaneous stim- stolic volume (EDV) or the preload). The greater the preload, ulation of the whole structure so that it functionally acts as the greater the cardiac output. a single unit. A mass of cells that act as a unit is termed a With the ventricles maximally fi lled, the backpressure functional syncytium. The atria act as one syncytium and from the blood in the ventricles causes the atrioventricular the ventricles as another. The cardiac skeleton, made up of valves to close and bulge upward toward the atria. The chor- fi brous connective tissues, serves to isolate one syncytium dae tendinae (Figure 32-2), strong cords attached to papil- from the other. As a result of electrical stimulation, muscles lary muscles, which emanate from the inferior wall, prevent in the atria will contract as a unit (a functional syncytium), the valves from inverting into the atria, which would allow pushing blood from the base of the heart to the apex of the a backfl ow of blood into the atria (regurgitation). With the heart and the ventricles. The muscular ventricles will, in atrioventricular valves closed, the atria begins diastole again turn, function as another functional syncytium, pushing and while the ventricles prepare for systole. squeezing blood from the apex of the heart and out the great As a result of the atrial kick, and because the atrioven- vessels. tricular valves are closed, the pressure within the ventricles rises sharply, distending the ventricular walls. This distention Cardiac Cycle of the ventricles, and the resulting tension, causes the myo- cardium to contract more forcibly—a phenomenon predicted During a single contraction (one heart beat), blood fl ows in Starling’s law. through all four chambers of the heart. This contraction, With the pressure elevated in the ventricles, the ventricu- including an entire sequence of events from atrial fi lling lar muscle fi bers contract forcefully and generate suffi cient Direction of blood flow Atrium Cusp of atrioventricular valve Chordae tendineae Papillary muscle Ventricle Atrioventricular valve open Figure 32-2 The chordae tendinae prevent inversion of the valves during ventricular systole. Principles of Electrocardiography 721 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. pressure to force open the aortic and pulmonary valves and source. The SA node initiates an impulse between 60 to eject blood out of the heart. This process is called ventricu- 100 times per minute. This rate is normally faster than in lar systole. The cardiac output (the volume of blood ejected any other portion of the conduction system. The SA node out of the ventricles) fl ows via the aorta to the body or to the assumes dominance as the pacemaker and is termed the pri- lungs. After the contraction, the ventricles relax and begin a mary or physiologic pacemaker of the heart. The SA node period of ventricular diastole. also has innervations from the sympathetic and the para- The arrangement of the muscle fi bers effi ciently ejects sympathetic nervous systems. The sympathetic nervous blood from the ventricles. However, even under optimal con- system increases automaticity and subsequently the rate of ditions, the ventricles cannot eject 100% of the blood from discharge. The sympathetic nervous system can therefore the ventricles. The percentage of blood pushed and squeezed cause the heart to race. Conversely, the cardiac branch of out of the heart is called the ejection fraction. Normal ejec- the vagus nerve, the 10th cranial nerve and a part of the tion fraction of blood in a healthy heart is 60% to 75% of the parasympathetic nervous system, dampens automaticity end diastolic volume (the preload).1 of the cardiac conduction system. Therefore, stimulation of the vagus nerve can cause the heart to slow down. The Conduction System parasympathetic nerve (the vagus nerve) ends at the AV The heart requires a taskmaster in order to perform its rhyth- node but the sympathetic nerves run the entire length of mical work. Although this taskmaster can be infl uenced by the conduction system from the SA node to the Purkinje other parts of the body, the heart’s primary control is its own fi bers. This is an important fact to remember when discuss- specialized cardiac cells. These cells are designed to carry on ing treatments for heart blocks. the heart’s electrical rhythm. These specialized cells are col- Once the impulse is initiated at the SA node, it spreads lectively called the conduction system (Figure 32-3). across the heart like a wavefront, depolarizing the myocar- The initial portion of the conduction system is the sinoa- dium along the way. The result of this electrical stimulation trial node (SA). This node is located just beneath the epicar- of the myocardium is that the right and left atria contract dium on the posterior wall of the right atrium near to the end immediately and nearly simultaneously (syncyctium) after of the vena cava and at the junction of the sinus of Valsalva the impulse leaves or exits the SA node. The impulse is and the atria. The SA node has fi bers which connect it to the then conducted toward the ventricles via the internodal heart’s right atrial cells. A special pathway exists for the SA pathways. The electrical signal then passes to the atrioven- node to communicate with the left atrium. This path is called tricular node (AV) located in between the atria and the Bachmann’s Bundle. ventricles. The SA cells have the ability to initiate an electri- The electrical impulse cannot normally enter the ven- cal impulse without needing stimulation from an outside tricles except by passing through the AV node. The cardiac skeleton, which serves as a framework for the heart’s valves, also electrically separates the atria from the ventricles. The signal next enters the AV node. The cells of the AV node are designed to conduct the impulse slowly. This electrical delay permits the atria to contract, thereby per- mitting maximal fi lling of the ventricles. This also allows the ventricle to receive the “atrial kick” that occurs when the atria contract. When atrial contraction is complete, the signal moves down the long strip of tissue below the Left atrium AV node connecting the atria and the ventricles, called the Sinoatrial node junctional tissues. The junctional tissues are capable of (pacemaker) Purkinje independently initiating a stimulus if the SA nodal impulse fibers should fail to depolarize them fi rst. The intrinsic rate of the Atrioventricular junctional tissue is approximately 40 to 60 bpm. Therefore, node if the SA node fails to fi re, then junction tissue at the Right AV node is the heart’s secondary pacemaker. Often junc- atrium tional rhythms produce less cardiac output because of the Purkinje fibers loss of the atrial kick that would normally occur if the SA node was the pacemaker.2 Atrioventricular When the impulse reaches the ventricle, it is conducted bundle through a wide, thick group of fi bers called the bundle of Right and left Interventricular His. The bundle of His conducts the impulse to the inter- bundle branches septum ventricular septum where it divides into the right and left bundle branches. The bundle branches lie deep within the Figure 32-3 The electrical conduction system. myocardium just above the endocardium. The left bundle 722 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. branch will further divide into an anterior branch and a pos- Coronary Circulation terior branch to adequately serve the larger, thicker left ven- and Its Relationship to Conduction tricle (Figure 32-4). With the exception of the endocardium, the heart does not uti- At the level of the ventricular cells, the bundle branches lize the blood fl owing through it for its metabolic needs. The further divide to carry the impulse along the Purkinje heart is served by a special set of arteries and veins called the fi bers. Purkinje fi bers, named after Jan E. Purkyne, con- coronary circulation. These blood vessels are called the cor- nect directly with the ventricular myocardium, allowing the onaries because they resemble a crown of thorns positioned ventricles to contract nearly simultaneously as a functional on top of the heart. The coronary arteries arise from the aorta syncytium. in an area adjacent to the aortic valve, an area called the sinus Impulse Formation of Valsalva. They are the fi rst arteries to arise from the aorta but they receive their blood fl ow last. This is because |
the aor- Each part of the conduction system, from the SA node to the tic valve leafl ets occlude the coronary arteries during systole. Purkinje fi bers, is capable of initiating an electrical impulse The result is that the coronary arteries fi ll only after the aorta via automaticity. Such capability serves as a backup plan for valve has closed during diastole. the heart in the event one pacemaker fails. Should this occur, Because of the particular importance of the left ventricle, there is another pacemaker available to take its place. The when the term “wall” is used it describes the portions of the normal rate of the SA node is 60 to 100 impulses per minute. left ventricle. The walls of the left ventricle are broken down Its next closest neighbor, the AV node, can initiate impulses into the following: the inferior wall (that portion that lies next at a rate of 40 to 60 impulses per minute, while the bundle of to the diaphragm) and the anterior wall (that part of the left His initiates impulses at only 20 to 40 times per minute. The ventricle which faces forward). The anterior wall is the larg- slowest rate is that initiated in the Purkinje fi bers, which has a est part of the left ventricle and contains the greatest mass of rate of an agonizing 20 beats per minute or less. muscle in the heart (Figure 32-5). The conduction is arranged to complement the heart’s The anterior wall of the left ventricle gets its blood from the muscular action. The atrial aspect of the conduction system left coronary artery. The left main coronary artery almost imme- moves the impulse from superior to inferior just like the diately divides and gives rise to the left anterior descending contraction of the atria, which is from superior to inferior. coronary artery (LAD) and the left circumfl ex (Cx). Therefore, the upper portion of the conduction system can The LAD provides blood to the SA node, in 45% of the pop- be called the supraventricular (above the ventricles) portion. ulation, and to the majority of the muscle mass in the left Once the impulse enters the ventricles, the conduction system ventricle. Perhaps more importantly, the LAD provides the takes it inferiorly to the apex and then (via the Purkinje fi bers) blood supply to the lower portion of the conduction system, immediately back upward, resulting in an inferior to superior the bundle of His, and the three bundle branches. route. This mimics the ventricular contraction of inferior to However, the most important function of the LAD is to superior. The lower portion of the conduction system can be provide blood fl ow to the largest part of the left ventricle, its referred to as the ventricular portion. anterior wall. In fact, 60% to 70% of the blood that travels to the coronary arteries is provided to the LAD and subse- quently to the anterior wall. AV node AV junction Surface walls Area of the bundle of His Anterior (V1 to V4) Posterior wall, reciprocal changes only ( V1 to V4) Right bundle branch Left bundle branch Inferior wall Lateral wall (leads II, III, aVF) (I, aVL, V5, V6) Figure 32-4 The atrioventricular node provides a pause in electrical conduction for the impulse Figure 32-5 The anterior, lateral, and inferior traveling from the atria to the ventricles. walls of the heart. Principles of Electrocardiography 723 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The circumfl ex coronary artery, a minor branch of the muscular contraction and those designed to initiate and carry left coronary artery, bends around to the left side of the heart impulses. In both circumstances, the activity is based on the and provides blood to the lateral wall of the left ventricle. movement of ions and the electrical changes that the ions The circumfl ex provides about 40% to 50% of the blood fl ow cause as they move. to the anterior wall, with the remainder supplied by the left The events are broken down into phases numbered from anterior descending coronary artery. 0 to 4. In a typical cardiac working cell, which is not part of The right coronary artery (RCA) serves the right atrium the specialized conduction system, the process will begin at and ventricle and the inferior portion or wall of the left ven- phase 0. A resting cardiac cell is normally negatively charged tricle, which lies on the diaphragm. In 55% of the population, on its inside. An electrical stimulus will change the perme- the RCA provides blood to the sinus node, and in 90% of the ability of the cell’s membrane by opening special channels, population it provides blood to the atrioventricular junction, allowing for the movement of sodium into the cell. The infl ux both located in the upper portion of the conduction system. of sodium is very rapid, and the process of allowing the The sinus node and atrioventricular junction are important sodium in is called fast channel response. Sodium is a cation portions of the conduction system as they control the atria () so a large amount of sodium moving into the cell will and therefore are part of the atrial kick. cause the inside to become positive. The coronary veins follow the general pattern of the Phase 1 begins when the fast sodium channels close. arteries except on the posterior wall, where an enlarged vein Chloride, an anion (), also moves into the cell during called the coronary sinus drains blood. The coronary sinus phase 1. With sodium no longer adding its positive charge drains into the vena cava at its juncture with the right atrium. to the inside of the cell, and chloride with its negative charge Other veins, called Thebesian’s veins, drain directly through moving in, the cell again becomes negative. the heart muscle into the heart chambers (Figure 32-6). Phase 2 is the plateau phase of the action potential. In phase 2 calcium, which is another cation (), leaks in slowly. Electrophysiology Calcium movement is termed “slow channel response” The heart creates an impulse via an electrochemical reaction. because of the difference in speed of movement from that of Electrophysiology describes how the heart actually initiates the sodium channels. At the same time calcium is coming in, the impulse by describing the electrochemical reactions that potassium (), another cation, is leaking out. The net change occur at the cellular level. Key to cardiac electrophysiology in electrical charge is zero and the cell remains somewhat is the action potential of each and every myocardial cell. The negative inside, but does not yet return to its resting state. term cardiac action potential is defi ned as the electrochemi- In phase 3 the slow channels (i.e., calcium movement) cal activity of the heart’s individual cells. This activity occurs shut down but potassium continues to move out of the cell somewhat differently in those cells designed for the work of very quickly. As a result, the cell becomes negatively charged. Anastomosis Aorta (junction of Left coronary vessels) artery (behind pulmonary trunk) Superior Superior vena cava vena cava Left atrium Right coronary artery Circumflex artery Great cardiac Right atrium vein Left Right ventricle ventricle Anterior Anterior Marginal artery interventricular cardiac vein artery Posterior Small cardiac Middle interventricular vein Coronary sinus cardiac vein artery Figure 32-6 The coronary circulation. 724 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. However, it does not have the same chemical makeup as it did occurs fastest in cells of the SA node and slowest in cells of when everything began at phase 0. There is too much sodium the Purkinje fi bers. The SA pacemaker cells generally depo- but not enough potassium inside the cell. While the electri- larize more times per minute and thus have a faster pacing cal charges are back to normal, the chemical makeup is not. rate, called the intrinsic rate. For SA cells, the intrinsic rate During this phase, another stimulus could trigger the cell to is 60 to 100 times per minute. depolarize. However, that depolarization would be out of sync The AV node cells would spontaneously depolarize at 40 with the rest of the cell’s repolarization–depolarization cycle. to 60 times per minute except that the SA node is faster (a Phase 4 begins with the cell actively pulling potassium concept called dominance). Impulses are being conducted back into the cell while forcefully expelling sodium. The to the AV node and cause depolarizations. The AV node is movement of these two ions is against their concentration said to be refractory, or unable to respond to a new stimu- gradients. Therefore, the cell must use energy to move these lus. It is not chemically or electrically ready to depolarize chemicals in order to achieve normalcy again. The process again and thus cannot spontaneously depolarize at its own is termed “active transport.” In this case, the movement is intrinsic rate. caused by the sodium–potassium pump powered by adeno- If the SA node were to stop sending impulses to the sine triphosphate (ATP). In phase 4 the cell’s chemical and AV node, the AV node would be electrically and chemically electrical composition is back at its baseline. This state is ready to begin its own spontaneous depolarizations. Thus, the called the resting membrane potential. The charge inside of heart would still receive regular impulses from a pacemaker the cell at this point is approximately 90 mV and is ready to cell but at a slower rate. This mechanism is called an escape be discharged or depolarized. mechanism. When a cell initially changes its charges, it is said to depo- These impulses of the slower pacemaker site (so-called larize. The process of returning to its resting state is called escape impulses) then become the heart’s dominant pace- repolarization. Phase 0 is the rapid depolarization of the cell. maker. The escape mechanism is the backup plan of the heart. Phases 1 to 4 describe the various stages of repolarization. If a faster pacemaker site fails, there is another slower one A pacemaker cell undergoes the same phases of the ready to take its place; a concept expanded on shortly. action potential (Figure 32-7), but the process differs slightly. The activities of phase 4 vary depending on time. Early in the Properties of Cardiac Cells phase, the sodium potassium pump is actively returning the cell to its predepolarization chemical state. Later in phase 4, All muscle cells have the qualities of excitability and con- a new process begins. tractibility. Cardiac muscle cells possess additional properties Pacemaker cells allow a slow movement of sodium and that specifi cally govern the heart’s activity. The fi rst of these calcium into the cell at the same time potassium is leaking out. special qualities is automaticity. This is the cell’s ability to These ion movements cause the cell to gradually become less generate its own action potential. Cardiac cells do not need an negative. At a certain point (or threshold) approximately 60 outside stimulus to depolarize. Enhanced automaticity is nor- mV, the cell spontaneously begins phase 0, the rapid depolar- mally a property of the pacemaker cardiac cells which gener- ization period. The inside charge of the pacemaker cell is not ate the stimulus in a predictable and reliable way. as negative as that of a working cell when phase 0 began. This The next special property of cardiac muscle is conduc- difference causes phase 0 to occur more slowly in the pace- tivity. Conductivity is the transmission of the electrical stim- maker cell. It |
also changes the timing of phases 1 to 3. ulus from cell to cell. The myocardium’s ability to do this is There is variation in how quickly a pacemaker cell allows owed to special intercellular junctions. The rate at which the the leakage of sodium and calcium in and potassium out at stimulus is conducted varies from atrial cells to ventricular phase 4. The faster the leak, the sooner the cell begins phase 0 cells. This rate can be further modifi ed by damage to cells, (spontaneous depolarization). This translates into more depo- age changes, and drugs. larizations per minute or a faster rate. Leakage at phase 4 As is true with other muscles, the myocardium has the ability to respond to a stimulus, a property called excitabil- ity. Healthy cardiac cells respond to the stimulus generated Action Potential of Myocardial Working Cell from the pacemaker cells. When cells have been damaged by a lack of oxygen, they may respond to a much lower stimulus, ECG causing enhanced excitability. In some cases, the hypoxic mV 1 2 injured myocardial cell, for example, may even compete with 0 0 Action potential the pacemaker cells by generating spontaneous impulses via 3 abnormal automaticity.3–6 The resultant aberrant beats are 4 4 called ectopic beats (ectopic is Greek for “out of place”). –100 Inside cell Na° and Cell membrane The fi nal special property is the cardiac cells’s ability K° Na° Ca° K° K° K° Outside cell to contract. Contractility is the cardiac muscle fi bers’ abil- ity to shorten or contract. This is the mechanical response Figure 32-7 Cardiac cell action potentials. to the electrochemical properties of automaticity, excitability, Principles of Electrocardiography 725 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Transmembrane potential and conductivity. In order to have a heart beat as opposed to can indicate a number of abnormal cardiac and extra-cardiac electrical activity, the cardiac cells must be able to contract. conditions, it may also be normal while the patient is in jeop- Without the contraction, a state of electromechanical disso- ardy. The fi rst rule of patient care is: Treat the patient, not the ciation occurs. monitor. Electrocardiographic Principles Leads The ECG machine creates leads. A lead is a view of the Assessment of the heart’s electrical activity forms a basis for heart’s electrical activity from a specifi c vantage point. The cardiac physical assessment. The tools to assess the electrical lead relies on an electrical difference between two elec- activity have been developed over the past 200 years. However, trodes to create a view of the passage of electricity down it is only within the last 50 years that portable equipment has the heart’s conduction system over a period of time; under- been developed allowing for the out-of-hospital monitoring standing this last statement is critical for an understanding of of cardiac electrical activity. electrocardiology. Electrical current in a resting heart was fi rst measured A lead is made up of two electrodes—one electrode is in 1843, DuBois-Raymond then coined the term “action negative and the other is positive. Electricity travels from a potential” based on these measurements. Electrical changes negative electrode toward a positive electrode. As a result associated with a beating heart were fi rst recorded in 1887. of having two electrical polarities—positive and negative— Willem Einthoven developed methods of standardizing and with a distance between the two poles, a dipole is established. calibrating recordings of the electrical activity in 1911 and Because it takes some time, even though it is a fraction of built the fi rst functional ECG machine. Willem Einthoven a second, for the electricity to fl ow between one pole to the was awarded the Nobel Prize in medicine in 1924 for his other, Paramedics are able to determine its direction (vec- contributions.7 tor). Any electrical activity which fl ows toward the positive electrode will be seen as upright or positive defl ection on the ECG monitor screen or recording paper. Any activity travel- Street Smart ing away from the positive electrode will be seen as down- ward or negative defl ection (Figure 32-8). Willem Einthoven’s invention was originally called Standard Leads the “elektrokardiogramm” or EKG. The anglicized Einthoven developed recordings of the heart’s electrical activ- version of the same term is electrocardiogram ity, using both arms and the left leg as electrode placement or ECG. However, the two terms are often used interchangeably. Depolarization Electrode ECG deflection Wave By understanding the concept of syncytium and with + A knowledge of anatomy, the Paramedic knows that electricity _ + propagates (fl ows) down the heart in an activation wavefront. It moves from inside to outside (endocardium to epicardium) + _ and from base to apex to base. The resulting voltage changes + B within the heart are transmitted to the skin. Einthoven’s ECG machine is used to detect the voltage changes that occur between two points on the skin’s surface. These changes _ + + are created by the propagating activation front of the heart’s C depolarization. + The ECG machine, or monitor, records the ECG on a type of graph paper to plot the amount of change or ampli- _ tude on the vertical axis of the graph and time on the hori- D + zontal axis. These recordings are explained more fully in + Chapter 33. Observation and research has shown the norms Electrode for the amplitude/time of the surface ECG. A Paramedic with knowledge of the standard ECG trac- Figure 32-8 A positive defl ection is recorded ings can perform a comparative analysis with abnormal ECG when current is moving toward the unipolar lead tracings and relate those fi ndings to the patient’s clinical and negative when current is moving away from condition. It is important to remember that while the ECG the unipolar lead. 726 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. pathway. Defl ections from baseline are upright—larger than in Lead I but not as large as those in Lead II. Under normal conditions, the largest and clearest picture Right arm Left arm of the electrical signal is seen in Lead II. For this reason, electrode electrode (aVR) (aVL) Lead II is the single best lead to monitor the conduction path- Lead I way of the heart for errors. Waves In order for Paramedics to interpret, describe, and discuss the tracings that occur on the ECG machine due to the Right leg electrode Left leg heart’s electrical activity, a common language is needed. If electrode the Paramedic understands that during diastole the heart’s (aVF) resting membrane potential is negative (approximately () Lead Right arm Right leg Left leg Left arm 90 mV) and accepts that as a baseline, and at the moment of I – + depolarization the transmembrane potential becomes posi- tive behind the wavefront, then the Paramedic is able to trace II – + the path of the electricity cascading over the heart. Einthoven III + – described these defl ections away from the even baseline, or aVR + – – – fl atline, and termed them “waves.” If the depolarization front is moving toward the positive electrode, then its wave will aVL – – – + be upright or positive. If it is moving away from the posi- aVF – – + – tive electrode, then its wave will be downward or negative. Einthoven documented the expected changes in voltage and Figure 32-9 Einthoven’s Triangle derived assigned the waves letter titles beginning with P-Q-R-S-T-U from the standard limb ECG leads. (Table 32-1). In a healthy heart, these waves are directed toward or away from the positive electrode in a predictable manner as they pass along the heart’s conductive pathway. points (Figure 32-9). Using a human silhouette as back- To establish a baseline, the ECG tracing starts when the ground, draw a triangle extending from the left arm at the heart is at rest (diastole) and the transmembrane potential is wrist, right arm at the wrist, and left leg at the ankle. This is negative. The fl at line seen during this period, called the iso- Einthoven’s Triangle. Einthoven’s Triangle visually describes electric line, indicates that the line is not a voltage change the relationship of any two electrode points to any other two occurring. electrode points in the triangle. While not quite an equilat- When the SA node spontaneously depolarizes, it propa- eral triangle, anatomically the two leads are in an equilateral gates a wavefront across the atria that takes approximately triangular arrangement electrically. Einthoven called these 0.08 to 0.1 seconds. This is represented on the surface ECG standard leads and identifi ed them with the Roman numbers in Lead II as a rounded positive defl ection in the normal heart. of I, II, and III. The wavefront now enters the AV node where it is slowed. Lead I measures the voltage change between the right The period of time when the wavefront is retarded, in the arm and the left arm. The negative electrode is on the right electrical sense, in the AV node is seen as a brief isoelectric arm. The positive electrode is on the left arm. The axis of line on the ECG. Lead I is across the chest wall and somewhat corresponds to Exiting the AV node, the depolarization wave continues that of the conduction which occurs leftward and downward. to propagate across the entire ventricular mass in a predict- Under normal conditions, the electrical movement is toward able fashion, The fi rst area to be depolarized, from right to the positive electrode. Defl ections from baseline in Lead I are left, is the septal wall. This momentary swing in the vector generally upright or positive but small. of the electrical fl ow away from the positive electrode in Lead II notes the change between the right arm and left Lead II causes a small negative defl ection in the ECG called a leg. The positive electrode is located on the left leg. This Q wave. Not every depolarization of septal wall results in a arrangement mimics the conduction system alignment of left Q wave in every lead; sometimes the energy is too small to and downward. This arrangement is almost in-line with the be recorded. heart’s natural conductive pathway. As a result, the defl ec- Having transversed the septum, and the bundle of His tions from baseline in Lead II are upright and much larger within, to the apex of the heart, the activation front begins to than in Lead I. depolarize the myocardium in the apex of the heart toward the Lead III measures change between the left arm and left base of the heart and from the inner endocardium to the outer leg. The positive electrode is on the left leg. The axis is also epicardium. This causes a contraction of the left ventricular similar to that of Lead II and the heart’s natural conduction myocardial whorl and starts the ejection of blood from the Principles of Electrocardiography 727 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Lead III Lea d II Table 32-1 Waves on ECG with a Sinus Rhythm by a mirror image of the QRS, it does not occur in this man- in Lead |
II 0 ner. The epicardium repolarizes more rapidly than the inner Name Description bundles of the endocardium, resulting in a near simultane- ous repolarization. This is represented on the ECG as a T Isoelectric line Straight line wave. Represents diastole For the sake of completeness, it is necessary to discuss No voltage difference noted the repolarization of the atria as well. Like the ventricles, Neither (1) nor (–) defl ections the atria’s repolarization is represented by a small positive P wave First defl ection from isoelectric line rounded wave called the tP wave. Under normal circum- stances, the tP wave is obscured on the ECG by the QRS. Represents atrial depolarization However, the tP may be visible during periods of ventricu- Occurs just prior to atrial contraction lar standstill. Practically, differentiating the P wave from the Positive upright and rounded tP wave under those conditions is diffi cult. However, it is pT wave Normally obscured by the QRS assumed that the fi rst wave after the longer period of diastole Represents atrial repolarization is the P wave and therefore the wave immediately following If seen, positive and upright the P wave is the tP wave. On rare occasion there may be another small positive Q wave First defl ection of the QRS complex rounded wave that occurs immediately after the T wave Represents septal depolarization and before the next cardiac cycle. Originally thought to be Downward or negative defl ection caused by a late repolarization of the Purkinje fi bers, it is now Less than one third of the total QRS height thought to be “after-depolarizations.” After-depolarizations May not occur in healthy heart are late depolarizations in the myocardium that occur as a result of altered chemistry (e.g., secondary to drugs) at the R wave Initial or second wave of the QRS complex cellular level that changes the myocardial cell’s automatic- Represents depolarization of bundle of His ity. These errors in automaticity can lead to abnormal or Upright or positive defl ection ectopic beats as a result of stimulating the rest of the myo- Is the initial wave if there is no Q wave cardium during phase 3 or phase 4 of repolarization. These S wave Final wave of QRS complex premature depolarizations of the rest of the myocardium Represents depolarization of the bundle branches can lead to triggered activity such as atrial or ventricular tachycardia. Negative or downward defl ection ECG waves combine in predictable ways to describe T wave Defl ection from baseline ventricular other cardiac events and are the basis for ECG interpretation, Represents repolarization of the ventricle discussed in further detail in Chapter 33. Positive or upright in defl ection QRS complexes are a combination of two or more U wave Small defl ection following after the T wave waves. When a wave repeats itself (e.g., there are two upward defl ections in the QRS, due to errors of condution), then the Represents after-polarizations fi rst wave is considered the prime wave and is represented Positive or upright in defl ection by a capital letter and the second wave is represented by a Not typically seen lowercase letter. For example, a proper notation of a QRS might read RSr. ventricles. The vector of this electrical wavefront down the Intervals and Spaces bundle branches is parallel to the positive lead in Lead II and In some instances, the activity between the waves (i.e., the results in a large positive defl ection on the ECG called the timing) is more representative of cardiac pathology than R wave. the waves themselves. The space between waves is called Following from the bundle branches along the Purkinje a segment and a segment and a wave together are called fi bers, the wavefront continues to propagate to its terminus an interval. Intervals and segments represent electro- in the remaining ventricular myocardium upwards toward physiological events as well as mechanical events within the base of the heart. This abrupt change in the vector of the the heart. wavefront away from the positive lead in Lead II creates a The fi rst interval on the standard ECG is the PR i nterval. negative defl ection that is represented by the S wave. The PR interval represents the retardation of the propaga- Following the depolarization of the ventricular myocar- tion of the depolarization in the atrioventricular node. dium, the heart immediately begins the process of repolar- Normally this interval is a fraction of a second, between ization. Interestingly, while it would seem the repolarization 0.12 and 0.20 seconds, and is measured from the begin- would occur in a retrograde fashion, and thus be represented ning of the P wave to the fi rst defl ection in the QRS. During 728 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. this fraction of a second, atrial kick occurs and maximal approximately the same length as the QRS (0.08 to 0.12 sec- v entricular fi lling occurs. onds) and corresponds with the plateau phase of the action If the PR interval is shortened, it may be indicative of an potential. Therefore, any alteration of the action potential accessory pathway and may lead to pre-excitation syndrome. (e.g., ischemia or drugs such as digitalis) can result in changes Alternatively, a prolonged PR interval (greater than 0.20 sec- in the ST segment. onds) may represent the initial electrophysiologic change The last segment, the TP segment, represents the time of an ischemic AV node that can progress to heart block. when phase 4 of the action potential has occurred and the However, some prolonged PR intervals are a function of the heart has achieved its resting membrane potential. Normally natural changes of aging or a drug effect. In every case, the this results in no electrical movement and is represented by patient’s medical condition must be taken into account when an isoelectric line (Table 32-2 and Figure 32-10). there is a fi nding of an abnormal PR interval. The other interval in the ECG is the QT interval. Whereas Table 32-2 Intervals and Segments the PR interval is indicative of the atrial depolarization and repolarization, the QT interval is indicative of the ventricu- Name Description Signifi cance lar depolarization–repolarization cycle. The QT interval can PR interval P wave plus PR segment Period of time for stimulus also be thought of as indicative of systole. The QT interval to travel across the atria is measured from the fi rst defl ection of the QRS to the end and delay at AV node of the T wave and is normally about 0.40 seconds. However, ST segment Point from J wave to T Beginning of ventricular QT intervals vary according to the heart’s rate. The faster a wave repolarization heart races, the shorter the QT interval becomes. To ascertain QT interval Beginning of QRS Represents ventricular if a QT interval is abnormal, the heart rate must be taken into complex to end of T depolarization and account. Using Bazett’s formula, the measurement is cor- wave repolarization rected to account for the increased automaticity. The result TP segment Point from end of T Represents the isoelectric is referred to as the QT corrected or QTc. Any QT interval wave to start of next line greater than 0.44 seconds is considered abnormal and labeled depolarization a “prolonged QT interval.” Medications, such as Vaughn-Williams Class I drugs, can cause a prolonged QT interval as well as a congenital condition called prolonged QT syndrome (LQTS). Patients ECG intervals with LQTS are prone to ventricular tachycardias—particularly one dysrhythmia called polymorphic ventricular tachycardia or torsades de pointes.8–10 Conversely, some patients may be born with short QT syndrome. Short QT syndrome (less than 0.32 seconds) is the cause of syncope and sudden cardiac death as well. Perhaps the most important segment or interval is the ST ST segment. The ST segment, that period from the end of P segment T the QRS to the beginning of the T wave, represents an iso- 0.08 to < 0.12 < 0.20 electric period in the normal heart; a time when the heart is 0.11 sec sec sec neither depolarizing or repolarizing In the ischemic heart, where there is altered electrophysiology, late depolarization may cause either a depression or an elevation in the ST seg- PR interval Q R S ment. In some cases, the ST segment elevation may represent myocardial infarction in progress, known as an ST elevation 0.12 to < 0.10 sec myocardial infarction (STEMI); more discussions of this 0.20 sec very important ECG fi nding are contained in the following QT interval chapters. < 0.38 sec The ST segment starts at the J point, the point imme- diately following the QRS where the ECG returns to base- Time line and continues to the T wave. The typical ST segment is Figure 32-10 ECG complex intervals. Principles of Electrocardiography 729 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Voltage The measurement of the heart’s electrical activity is a key objective assessment tool for the Paramedic. This chapter has provided a basis for the heart’s electrophysiology and lays the foundation for the following two chapters that discuss monitoring of the cardiac rhythm and 12-lead ECG. Key points: • The heart lies within the thoracic cavity. The base connect it to the heart’s atrial cells. of the heart is located at the 2nd intercostal space A special pathway exists to communicate with and the apex is located at approximately the 5th the left atrium. This path is called Bachmann’s intercostal space on the left midclavicular line. Bundle. The impulse is also conducted toward The heart is composed of three layers. First is the the ventricles via the internodal pathways to the two-part pericardium which envelops the heart atrioventricular node (AV). When the impulse and roots of the great vessels plus continues on as reaches the ventricular side of the AV node, it is the epicardium, or outermost layer of the heart. conducted through a wide, thick group of fi bers The next layer, closer to the center of the organ, called the bundle of His, which divides into the is the myocardium. This is the muscular layer. The right and left bundle branches. The left bundle innermost layer is the endocardium, which lines the branch will further divide into an anterior branch chambers of the heart. Valves serve to direct blood and a posterior branch to adequately serve the in one direction through the heart. larger, thicker left ventricle. At the level of the ventricular cells, the impulse is carried by the • An entire sequence of events from atrial fi lling and Purkinje fi bers. ejection through ventricular fi lling and ejection is called the cardiac cycle. The cycle consists of atrial • The heart’s rate and rhythm are initiated and diastole and systole plus ventricular diastole and controlled by an electrochemical process. Altering systole. the ion content inside of a pacemaking cell triggers • an electrical stimulus. The SA node completes this The heart is served by a special set of arteries and process more quickly than any part of a healthy veins called the coronary circulation. The major conduction system and is therefore considered coronary arteries are the right coronary artery the heart’s pacemaker. The number of times per (RCA) and the left coronary artery (LCA, also called minute that the SA node completes this process is the left main) which divides into the left anterior termed its intrinsic rate. Should the SA node fail, descending artery (LAD) and the left circumfl ex the AV node has a slower intrinsic rate and will act artery |
(LCx). as the backup plan or escape pacemaker. Should • In 55% of the population, the RCA provides blood the AV node fail, the bundle of His or Purkinje to the sinus node. In 90% of the population, it fi bers can function as an escape pacemaker, provides blood to the atrioventricular junction. although at a much slower rate. The LAD provides blood to the SA node in the remaining 45% of the population, to the AV junction • The action potential has fi ve phases numbered in the remaining 10% of the population, and to the 0 to 4. remainder of the conduction system in nearly 100% ■ In phase 0, a resting cardiac cell is normally of people. negatively charged on its inside. A rapid infl ux of sodium occurs, causing the inside to become • The initial portion of the conduction system is the positive. sinoatrial node (SA). The SA node has fi bers which 730 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. ■ Phase 1 begins when the fast sodium channels as a unit from superior to inferior. The ventricles close. Chloride, an anion (), moves into the will function as a unit, pushing and squeezing blood cell. With its negative charge, the cell again from inferior to superior. becomes negative. ■ Phase 2 is a plateau phase. Calcium (another • The electrical impulse cannot normally enter the cation) leaks in slowly. At the same time calcium ventricles except by passing through the AV node. is coming in, potassium (another cation) is The cells of the AV node are designed to conduct the leaking out. The net change in electrical charge impulse slowly, which allows the ventricles to receive is zero and the cell remains somewhat negative the “atrial kick” that occurs when the atria contract. inside, but does not yet return to its resting • The functional properties of cardiac muscle tissue state. are automaticity, excitability, conductivity, and ■ Phase 3 has the slow channels or calcium contractility. movement shut down, although potassium moves out of the cell very quickly. The cell • Using electrodes, the ECG records the voltage becomes very negative but does not have the changes that occur between two points and are same chemical makeup as it did when everything transmitted to the skin. began at phase 0. ■ Phase 4 begins with the cell actively pulling • Electricity travels from a negative point toward a potassium back into the cell while forcefully positive one. The positive electrode is the viewing expelling sodium. electrode. Any electrical activity that points toward the positive electrode will be seen as upright • Cardiac muscle fi bers have a specialized cell or positive on the screen or paper. Any activity membrane that reduces electrical resistance traveling away from the positive electrode will be and allows an electrical stimulus to move rapidly seen as downward or negative. from cell to cell. The cells also form an extensive network that further enhances the rapid movement • The waves evident on the ECG correspond to of the electrical stimulus. This allows the whole electrical events in the body. structure to act as a unit. The atria will contract Review Questions: 1. If a papillary muscle in the right ventricle was properties, describe how the heart’s normal damaged and did not function, what could processes can be disrupted. happen to forward blood fl ow? 5. Would it be possible for the properties of 2. Name two ways in which a very rapid heart rate automaticity, excitability, and conductivity to may interfere with coronary blood fl ow. function but not the property of contractility? 3. Describe what may occur if a person had an Why or why not? What assessment would give accessory pathway around the AV node. you the answer? 4. When heart cells die, they are replaced by 6. If you could design a substance that would slow scar tissue. The scar tissue does not possess the movement of calcium into the cell at the properties of automaticity, conductivity, phase 2 of the cardiac action potential, what excitability, or contractility. Using each of these would happen to the heart rate? Principles of Electrocardiography 731 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Case Study Questions: Please refer to the Case Study at the beginning of the 3. Where is the electrical stimulus when each of chapter and answer the questions below: the following waves, intervals, segments, or 1. Why did the Paramedics check the patient before complexes is occurring? analyzing the monitoring strip? a. P wave 2. What is happening at the cellular level when b. PR interval each of the following waves, intervals, segments, c. QRS complex or complexes is occurring? d. ST segment a. P wave e. T wave b. PR interval 4. What is happening mechanically during c. QRS complex a. the P wave? d. ST segment b. the QRS complex? e. T wave c. the T wave? References: 1. Wayne- Alexander R, Fuster V, King SB, Nash I, O’Rourke RA, 6. Kaminski KA, Bonda TA, Korecki J, Musial WJ. Oxidative Prystowsky EN, Roberts R. Hurst’s the Heart, Vol. 2 (11th ed.). stress and neutrophil activation—the two keystones of ischemia/ New York: McGraw-Hill Professional; 2005. reperfusion injury. Int J Cardiol. 2002;86(1):41–59. 2. Brunekreeft JA, Graauw M, de Milliano PA, Keijer JT. Infl uence 7. Cajavilca C, Varon J. Willem Einthoven: the development of the of left bundle branch block on left ventricular volumes, ejection human electrocardiogram. Resuscitation. 2007;76(3):325–328. fraction and regional wall motion. Neth Heart J. 2007;15(3):89–94. 8. Roden DM. Clinical practice. Long-QT syndrome. N Engl J Med. 3. Sarre A, Maury P, Kucera P, Kappenberger L, Raddatz E. 2008;358(2):169–176. Arrhythmogenesis in the developing heart during 9. Janeira LF. Torsades de pointes and long QT syndromes. Am Fam anoxia-reoxygenation and hypothermia-rewarming: an in vitro Physician. 1995;52(5):1447–1453. model. J Cardiovasc Electrophysiol. 2006;17(12):1350–1359. 10. Kannankeril PJ, Roden DM. Drug-induced long QT and torsade 4. Kutala VK, Khan M, Angelos MG, Kuppusamy P. Role of oxygen de pointes: recent advances. Curr Opin Cardiol. 2007;22(1): in postischemic myocardial injury. Antioxid Redox Signal. 39–43. 2007;9(8):1193–1206. 5. Hoffman JW, Jr., Gilbert TB, Poston RS, Silldorff EP. Myocardial reperfusion injury: etiology, mechanisms, and therapies. J Extra Corpor Technol. 2004;36(4):391–411. 732 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. KEY CONCEPTS: Upon completion of this chapter, it is expected that the reader will understand these following concepts: • Use of ECG as a tool • Correct application of electrodes • Troubleshooting the equipment • Interpretation of rhythms Case Study: Jane Sheehan had called EMS because she felt faint and her heart seemed to be beating too fast. The fi rst response unit had started her on oxygen, obtained vital signs, and was asking questions about the event when the Paramedic unit arrived. The Paramedic received report while placing Ms. Sheehan on a cardiac monitor. The Paramedic quickly interpreted the rhythm, verifi ed that Ms. Sheehan did not have any drug allergies, and then outlined a plan of care for her. The EMTs wondered aloud what the lines on the monitor meant and what part they played in determining a diagnosis and treatment. 734 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. FPO The Monitoring ECG 735 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. OVERVIEW: Paramedics use an electrocardiogram each day to monitor the cardiac rhythm in a signifi cant proportion of their patients. Most cardiac monitors today have developed into comprehensive monitoring tools that measure other parameters including blood pressure, pulse oximetry, and capnography. In this chapter, we will examine the use of the basic cardiac monitor to observe the patient’s cardiac rhythm. The Monitoring ECG In the eyes of the public and many healthcare providers, the distinction between basic life support and advanced life sup- port is the electrocardiogram machine. The electrocardio- gram (ECG) provides Paramedics with information about the electrical activity of the patient’s heart (i.e., the depolariza- tion and repolarization of the heart through the cardiac cycle of systole and diastole). Armed with this additional data, the Paramedic can make better clinical decisions regarding treat- ment and transport. By interpreting the ECG’s rhythm for disorder, the Paramedic can come to suspect electrolyte disturbances that can cause errors of automaticity (conduction abnormalities) or errors of conduction, as well as signs of is-chemic heart disease. Any of these can indicate a potent ial life-t hreatening Figure 33-1 A Paramedic’s cardiac emergency. Furthermore, changes in a rhythm strip may be monitor–defi brillator. indicative of other medical conditions such as head injury, toxic exposure, electrolyte imbalance or other more funda- mental disorders such as hypoxia and hypothermia.1 Continuous monitoring of the patient’s heart rhythm monitor (Figure 33-1). The monitor is analogous to a com- allows the Paramedic to note changes in the patient’s con- puter’s visual display of the machine’s output. dition, as well as the patient’s response to treatments, and thus continue or alter treatment plans accordingly. The ECG Tracing goal of prehospital ECG monitoring is to obtain a clear and Like the original silver string galvanometer used in the accurate view of the heart’s electrical activity quickly and fi rst experiments by Willem Einthoven, the modern ECG dependably. machine senses the current changes, or fl uctuations, between When using an ECG, the Paramedic’s fi rst priority two e lectrodes—one negative and one positive—as a wave should be to monitor the heart for the presence of any life- of depolarization cascades down the heart and displays that t hreatening dysrhythmia. The utilization of a diagnostic information on a screen.2,3 A downward defl ection indicates 12-lead ECG always comes after the patient’s initial rhythm that the electricity is fl owing away from a positive, or moni- has been confi rmed. toring, electrode. An upward defl ection indicates that the depolarization wave is fl owing toward a positive monitoring Portable ECG Equipment electrode. If the differences in the fl ow of electricity resulted Portable ECG equipment consists of an oscilloscope and a in a zero |
net difference in direction (i.e., electricity was fl ow- printer needed to review and record ECG. The original oscil- ing both toward and away from the positive electrode (per- loscopes on an ECG machine operated similar to the fi rst pendicular) at the same time), then the resulting signal is television sets. A beam of electrons struck a phosphorescent equiphasic or fl atline. screen and produced a point of light. Slight differences in Using this technology, the movement of electricity voltages cause movement of the beam, which is displayed within the body could be observed, by the bounce of a point on the screen as fl uctuations in the point of light. The point of light, at any given moment. However, the fl ow of elec- of light could be seen to move either as an upward spike (a tricity within the heart as it travels down a conductive path- positive defl ection) or in a downward defl ection (a nega- way takes time. Therefore, the dimension of time must be tive spike). The ECG oscilloscope is also called a cardiac included if the meter is to illustrate the passage of electricity 736 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. down the conduction pathway. Oscilloscopes can add the indicates the passage of an ECG complex across the monitor. dimension of time by moving the point of light across the The volume of these counters can be adjusted, or shut off, to screen from left to right at a precise rate of speed. Speed is reduce noise pollution on scene. distance over time and is measured in fractions of a second The purpose of an ECG monitor is to alert the Paramedic in the heart. to potentially life-threatening dysrhythmias. To that end, Compared against a static grid placed over the oscil- some ECG monitors have alarms that will indicate, via vis- loscope, this horizontal left-to-right movement (manifested ible and/or audible signal, that a patient’s heart rate is above on the screen as a trace) can be measured and fl uctuations or below a certain rate. The Paramedic often has the option expressed in terms of time (seconds or milliseconds). Any of choosing the rate values (called the alarm limits) accord- vertical fl uctuations seen on the monitor can also be mea- ing to the patient circumstances. Some EMS agencies do sured. Vertical fl uctuations represent the voltage change from not permit Paramedics to alter alarm limits or to disable zero, either positive or negative. The change from zero can alarms. This fail-safe device offers another level of secu- also be measured on a grid and is expressed in terms of mil- rity to permit early detection of potentially life-threatening livolts (mV). The larger the voltage difference, the larger the dysrhythmias. fl uctuation. Finally, an additional feature on some ECG monitors Current ECG monitors not only measure the energy and is an ability to adjust the brilliance of the ECG monitor. the speed of conduction, but they also have many other fea- Depending on ambient light conditions, it may be desirable tures that are valuable to the Paramedic. to turn up the brilliance of the ECG monitor or to dampen it in order to improve the quality of the ECG. Monitor Features The standard ECG monitor typically features a sensitivity Monitor Adjustments and sweep speed control, output printer, lead selector, rate Many monitors permit the Paramedic to adjust certain vari- counter, monitor brightness control, and alarms. Many ECG ables in order to improve the ECG tracing’s usefulness. For monitors also have telemetry capabilities. Telemetry is the example, most monitors available to the Paramedic allow a ability to broadcast the ECG via telephone or radio to a dis- tant receiver, typically located at a hospital.4–6 change in speed and amplitude of a tracing. The Paramedic may want to change the speed of the rhythm passing by on the To make the ECG readable, the ECG monitor must have screen. An alteration in the speed of the tracing is an altera- both a sweep speed control and a sensitivity control. The tion in sweep speed. Standard sweep speed is 25 mm/second. sweep speed control regulates the speed of the tracing on the Increasing the sweep speed to 50 mm/second will stretch out monitor, and subsequently on the printout. The sensitivity the trace and make the trace appear slower than it actually control alters the size of the ECG tracing. Adjusting these is. However, slowing sweep speed will also allow for closer functions on the ECG monitor provides the Paramedic with examination of key features on the ECG, such as changes in some advantages in certain clinical situations. the segments or minor defl ections in the QRS. To facilitate analysis, and documentation, a printer was The Paramedic may need to also enlarge the tracing added to print out the ECG seen on the screen. The printer shown on the monitor. This is called increasing the gain. The provides a printed hard copy of the ECG tracing visible on gain increases the size of the tracing shown on the monitor the ECG monitor. In many cases manufacturers have built in screen. Occasionally key features of the ECG are too small for a 5- to 10-second delay between what is visible on the ECG clear examination without increasing the gain. By adjusting monitor and what is being printed out. This momentary delay the gain, the Paramedic can get a clearer picture. Conditions permits the Paramedic time to activate the printer if an irregu- which can cause low amplitude include a variety of medical larity in rhythm is seen on the ECG monitor and thus capture conditions (Table 33-1). the dysrythmia. In some instances one view, or lead, is better than another when trying to make an ECG interpretation. Lead selection Calibration (changing the electrical view of the heart without moving The ECG monitor is a medical device. As such, Paramedics electrodes) permits the Paramedic an opportunity to observe should regularly ensure that the ECG monitor is accurate. Any the heart from several angles at an instant. Optional leads and number of medical interventions may be performed, includ- lead selection are discussed shortly. ing defi brillation and medication administration, based in An added feature of many ECG monitors is the rate large part upon the ECG tracing. A faulty ECG monitor could counter. The rate counter is a digital readout of the number lead to an error of treatment. For this reason an ECG monitor of ECG complexes that pass in a minute, usually counting should regularly serviced by a biomedical engineer who will the tallest, or deepest, wave on the ECG. Some ECG moni- re-calibrate the ECG monitor to factory specifi cations. tors also have a fl ashing light, or other visible signal, that On a daily basis, and to assess accuracy of the ECG moni- indicates when an ECG complex has passed across a point on tor, the Paramedic compares the ECG machine’s operation the monitor. Some rate counters have an audible signal which against standard settings (i.e., industry standards). Making The Monitoring ECG 737 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Table 33-1 Conditions That May Cause ECG standardization a Low-Amplitude ECG STD 1 • Amyloidosis—deposits of proteinaceous mass in muscle fi bers • Hypothyroidism (a.k.a. myxedema) • Restrictive cardiomyopathy Endomyocardial fi brosis • Pericardial effusions Hemopericardium 1 mV = 10 mm Infectious transudate • Pericardial tamponade • Tension pneumothorax • Obesity FULL • Hypothermia 0.04 sec sure that sweep speed and gain is up to standard is called cali- bration. Most ECG monitors self-calibrate, internally setting Figure 33-2 Normal standardized standard sweep speeds and gain, when initially switched on. calibration mark. However, many ECG monitors also provide an internal user test that allows the paramedic to check calibration and operational readiness at the beginning of the shift; many Paramedic services require that the Paramedic document that calibration test The calibration mark (Figure 33-2), visible at the begin- ning of the ECG printout, is a square wave that is 10 mm high, or 1 mV, and 10 mm wide. Each box measures 0.1 mV vertically and 0.4 mm horizontally. The calibration mark is created by a calibration impulse, an electric impulse, by the ECG machine. The resulting wave should be sharply delin- eated (i.e., quick corners that make a squared wave). ECG Paper Reading an ECG on the monitor can be diffi cult at times. Therefore, a hard copy can improve the accuracy of the analy- sis. For this reason, most Paramedics print out a copy of the 0.04 second ECG, called an ECG rhythm strip. The paper used for ECG 0.1 mV recordings is imprinted on heat-sensitive paper via heated 1 mm stylus or is printed by a laser. It is lined in a manner similar to graph paper to enable a Paramedic to accurately measure and compare ECG waves. In order to determine regularity, rate, timing, and ampli- Figure 33-3 The standard ECG graph. tude of the ECG features, the Paramedic must understand the grid structure of ECG paper. The paper is lined vertically and horizontally (Figure 33-3). On the vertical axis, a line occurs amplitude, which can be roughly equated to the strength of every 1 mm and a darker line occurs every 5 mm. For the the electrical signal. horizontal axis, a line occurs every 0.04 seconds and a darker line every 0.20 seconds. The amplitude markings are correct Wire Systems assuming there is a standard gain of 10 mm/mV, and the time The wiring harness, also called the ECG cable, connects the markings are correct assuming a standard sweep speed of electrodes to the ECG monitor and is a single thick cable that 25 mm/second. separates into three, four, or fi ve thinner wires. (Some har- When assessing the rate of a rhythm or the time frame of nesses will have an additional port that will accept a six-wire a feature on the ECG, the Paramedic will use the horizontal plug to enable the acquisition of a 12-lead ECG.) markings. The horizontal axis equals time (0.20 seconds per The machine end of the harness has a pin connector that large square). When measuring the amplitude of a feature, the must be set fi rmly into its socket in order to avoid a poor con- Paramedic will use the vertical axis. The vertical axis equals nection, which will create an unreadable signal. The thinner 738 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. wires are connected to electrodes at the distal end. These, in turn, are placed on the patient. (–) (–+ ) Electrodes For a surface ECG, the electricity must pass from the heart (+) and up through the skin in order for the ECG to detect the current. The stratum corneum, the outermost layer of the skin, A Lead I does not conduct electricity well because it contains dead and dried out cells. These dead cells cause the skin to act as a resistor; resistance to the passage of electricity.7 To permit the passage of the electrical current through the skin to the (+) (–+ ) (–) ( –+ ) surface, |
the electrode must have an intermediate substance, a conductive medium which bridges the stratum corneum and connects the inside of the body with the electrode. (+) Typically an ECG electrode is used for that purpose. An (+) electrode consists of a gel-like substance that conducts elec- B Lead II C Lead III tricity well, such as silver chloride, with an adhesive on a foam or paper backing to help maintain contact (Figure 33-4). The conductive gel is designed to melt with body warmth Figure 33-5 Electrode position affects the and soak through the skin. This will enable it to overcome electrical view of the heart. skin resistance to the electrical signal and create an electrical bridge from the inside of the body to the electrode. A sticky Electrode Placement piece of foam or paper surrounds the gel. This serves to iso- late the electrode from the surrounding environment and The primary objective of monitoring the electrical activity enables the electrode to adhere closely to the skin. of a patient’s heart is to discern abnormalities of conduction Warmth is necessary for the electrode to function. or automaticity that produce potentially life-threatening dys- Without warmth the conductive gel does not melt, the electri- rhythmias. An ECG lead is a view of the heart from one par- cal pathway is ineffective, and the signal quality will be poor ticular vantage point that helps to ascertain the dysrhythmia or lost entirely. When the gel only partially melts, due to cold (Figure 33-5). For example, Lead II (a commonly used moni- skin or poor adherence of the electrode, then the quality of toring lead) views the inferior portion of the heart and would signal will also be poor (degraded) and the tracing will be help identify dysrhythmia arising from the inferior wall. Most unreadable (noisy). dysrhythmias can be ascertained using one or two leads. It is There are many reasons why an electrode will not func- important for the Paramedic to choose the lead that provides tion. If the gel on the electrode has dried, it will no longer the best chance of identifying the dysrhythmia. serve as an electrical pathway. Electrodes should be inspected For Lead II, one electrode is placed on the right wrist, regularly to ensure new and moist electrodes. one electrode on the left wrist, and one electrode on the left foot (to recreate Einthoven’s Triangle) (Figure 33-6). In many cases, it is inconvenient to place the electrodes out onto the limbs where the wires may become tangled. Therefore, the Paramedic may choose to place electrodes on the right and Street Smart Many Paramedics use the same electrodes for the monitoring ECG as for a 12-lead ECG. Key to an accurate 12-lead ECG is the re-creation of Einthoven’s Triangle. Jowett and associates suggested that placing the limb leads on the torso can lead to inaccurate interpretation of the 12-lead by producing false patterns of ischemia.9 Figure 33-4 Examples of ECG electrodes. The Monitoring ECG 739 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. devices such as pacemakers (automated internal defi brillator/ cardioverters), or medication patches. To ensure patient comfort, connect or clip the wires to the electrodes before attaching the electrodes to the skin. Pressing the snap connection to an electrode that is already on the skin is uncomfortable for the patient. Perhaps more importantly, it squeezes the gel out from under the electrode, potentially causing loss of signal. R.A. L.A. Standard Lead II Confi guration If the negative lead is on the right shoulder and the positive lead is on the left leg, then the ECG machine is monitoring Lead II. Lead II provides a view of the inferior wall of the heart.10–12 The upper portion of the conduction system resides within the inferior wall, from the SA node to the AV node. This portion of the left ventricle also receives its blood supply from the right coronary artery. R.L. Whenever there is suspicion of an acute occlusion of the L.L. (Ground right coronary artery, and therefore doubt about performance electrode) of the upper portion of the conduction system (a conduction abnormality as manifest by changes in the PR interval), then Figure 33-6 Electrode placement for limb leads. the patient should be observed in Lead II. Because Lead II provides an excellent view of the inferior wall/upper portion of the conduction system, it produces the clearest P waves. left upper arms at the deltoids. Lower electrodes are then placed on the right and left thighs. The third alternative Modifi ed Chest Lead I strategy, suggested by Takuma and associates, is to place While it may be easier to distinguish P waves in Lead II, the the electrodes in the subclavicular space (the deltopectoral placement of the electrodes may be more diffi cult in the fi eld. fossae) on the right and left and then on the right and left Also, the electrodes in Lead II may interfere with impor- lower rib cage.8 The important concept is to try to maintain tant procedures such as defi brillation. For these and other Einthoven’s Triangle. reasons, many Paramedics choose modifi ed chest Lead 1 Best results are obtained from placing the electrode over (MCL1) to monitor patients instead of/in addition to Lead II muscle and not over bony prominences. The Paramedic should (Figure 33-7). MCL1 simulates the precordial lead V1, one of also avoid placing an electrode over any jewelry, implanted the six precordial leads of a 12-lead. MCL1 lead Figure 33-7 Lead placement for MCL1. 740 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. By placing the positive monitoring electrode at the right Finally, the best ECG signal is obtained when the area sternal border at the fourth intercostal space, between the is gently abraded to remove dead skin cells and to improve fourth and fi fth ribs, and looking across the chest from the circulation (i.e., increase warmth) to the area. The use of fi ne left shoulder, the Paramedic obtains a view of the anterior grit sandpaper (commercially available for this purpose) or wall of the left ventricle. even a gauze pad to abrade the skin can markedly improve the The MCL1 lead not only permits differentiation of quality of the ECG signal. ectopic complexes (ventricular from supraventricular with aberrancy), but MCL1 keeps the defi brillation platform open for defi brillation pads or paddles. MCL1 also helps the Systematic Approach to ECG Paramedic distinguish between right and left bundle branch Rhythm Interpretation blocks. A new onset left bundle branch block as a sign of an acute coronary event will be discussed later. A rapid and accurate interpretation of a patient’s ECG rhythm Perhaps the most pressing reason to use MCL1 as a mon- is important and potentially life-saving. To attain speed and itoring lead is that it views the anterior wall. The left coro- accuracy, the Paramedic must take a disciplined approach nary artery (LCA), including the left anterior descending to ECG interpretation. Faithful adherence to a systematic coronary artery (LAD), are commonly occluded during an approach analysis of the ECG rhythm strip, a process called acute coronary event and these arteries provide blood to the ECG interpretation, promises the best results in the shortest anterior wall of the left ventricle. MCL1 provides a vantage amount of time. point from which to monitor the anterior wall and quickly There are a number of ECG interpretation schemas avail- identify lethal threatening dysrhythmias such as ventricular able. Some take a simple left to right approach to reading fi brillation. an ECG, similar to reading a book. The method originally described by Dr. Henry J. L. Marriott works well in the out- of-hospital environment as it focuses on rapid identifi cation Preparation of Skin of high-risk patients.14 Dr. Marriott’s systematic approach to Electrodes are designed to adhere to and transmit electrical ECG interpretation also can be easily integrated with the algo- signals from a warm, dry, fl at skin surface. In order to obtain rithmic approach to advanced cardiac life support advanced these conditions, the Paramedic must take several steps to by the American Heart Association. Regardless of the method prepare the skin before applying the electrode.13 of ECG interpretation chosen, the Paramedic should master First, the skin should be relatively free of hair. The that technique and resolve to use that systematic approach Paramedic can clip some hair to ensure electrode contact. with each ECG tracing. Some Paramedics use single-blade razors to clear unwanted chest hair. However, if the patient receives anticoagulants Descriptive Analysis later, then microlacerations created by the razor may bleed. Some Paramedics have a tendency to quickly label an Some Paramedics prefer to use disposable hair clippers spe- ECG rhythm because it looks like another ECG rhythm cifi cally designed for this purpose. However, handheld ban- the Paramedic has seen before. This practice relies on pat- dage scissors, the type with the blunted tips, are adequate to tern recognition. The use of pattern recognition is poor trim chest hair. practice. Errors in ECG interpretation can be made when Next, skin oils must be removed. Skin oils reduce the Paramedics fail to note the fi ne nuances that differentiate adhesion of the electrode and hinder penetration of elec- one rhythm from another (e.g., the difference between a bra- trode gel. An alcohol-soaked pad applied to the area and then dycardia with U waves versus a sinus bradycardia with a pressed against the skin in an outward-circling motion will heart block). remove dirt, oil, and other particulates which could prevent A descriptive analysis provides the building blocks to proper adhesion of the electrode. Visible perspiration also an ECG interpretation. Using the Marriott method of analy- can prevent proper adhesion of the electrode. The alcohol sis, the elements of the descriptive analysis would consist pad also helps to evaporate perspiration. The skin in the tar- of the rhythm, rate, width of the QRS complex, and atrial get area should then be dried with gauze or a towel prior to activity. placement of the electrodes in order to remove debris and Armed with a descriptive analysis, the Paramedic assem- remaining alcohol. bles the information and, using an understanding of cardiac If the patient is grossly diaphoretic, it may be helpful to anatomy (specifi cally electrophysiology), generates a rhythm apply tincture of benzoin. Tincture of benzoin is a topical interpretation. lotion that, when dried, is tacky to touch and helps electrodes On occasion, an ECG rhythm strip baffl es a Paramedic. adhere to the skin. It is important to not apply tincture of The practice of using descriptive analysis allows the benzoin directly over the electrode site as it does not con- Paramedic to accurately describe the ECG rhythm strip to duct electricity well. Properly applied, the tincture of benzoin a physician or another colleague who, in turn, may be able should leave a bull’s eye-appearing ring in which the middle to interpret the rhythm even without benefi t of seeing the is clear of the benzoin. rhythm strip. The Monitoring ECG 741 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Artifact Street Smart In some cases, it may be diffi cult to distinguish the isoelectric line because of artifact. Artifact, a disturbance in the |
isoelec- An ECG interpretation should not be made by tric line, is the result of outside interference with the signal. solely observing the ECG monitor. Before an ECG Some artifact may resemble ventricular fi brillation, possibly causing inexperienced EMS providers to react inappropri- interpretation is made, the Paramedic should print ately. More commonly, artifact makes rhythm interpretation out a hard copy of the rhythm displayed on the ECG diffi cult (if not impossible). Therefore, it is important to fi nd monitor and, using descriptive analysis, come to the source of the artifact and try to resolve it. Artifact can result from many causes including patient a conclusion about the rhythm, documenting that movement, problems with the cable, electromagnetic inter- interpretation. ference, or vehicle motion. A systematic problem-solving approach, starting at the patient and moving to the machine, often uncovers the cause of the artifact. Emergency Decision Making Patient-Induced Artifact Some medical emergencies are time-sensitive. Unfortunately, There are many easily understood reasons why the patient there may not be time to come to a comprehensive interpre- may be the source of the artifact. For example, if a patient tation about an ECG rhythm before defi nitive action must be experiences a seizure while on the cardiac monitor the ECG taken. This fact is best evidenced by the advanced cardiac strip will show artifact. In some cases, one of the fi rst warn- life support algorithms. Many of these algorithms intend ings that a Paramedic has that the patient is seizing is the that the Paramedic establish a gross analysis of the ECG sudden appearance of artifact on the monitor and the accom- rhythm strip (e.g., “wide complex tachycardia”) in order to panying rate alarms. Seizures can occur for many reasons use the algorithm. This permits quick action to resolve the (e.g., hypoxia, hypoglycemia, and the sudden hypotension dysrhythmia. A descriptive analysis, as suggested by the that results from ventricular fi brillation). Marriott method, lends itself to this type of swift decision Cardiac compressions performed during resuscitation making. can also create artifact, as can placing an electrode directly over the top of an internal electronic pacemaker. One of the most common reasons for patient-related artifact is poor Street Smart preparation of the patient’s skin prior to printing the ECG rhythm strip. Loose electrodes—undermined by sweat, dirt, An ECG monitor is a valuable tool but is limited by or hair—or dried electrode conductive gel can interfere with the Paramedic’s ability to tie the interpretation of the the signal and cause artifact. Patient movement can also cause artifact (Figure 33-8). rhythm strip to the clinical picture. The assessment of The patient should be made to be as comfortable as possible, an ECG rhythm strip provides only one piece of data in preferably lying supine or semi-reclined and with arms to the the clinical picture. Only when a Paramedic takes this side or on a fl at surface. If artifact is still observed, check for data, adds it to the history, and uses the information subtle movements such as nervous fi nger tapping or grasping the side rails. Try to discourage the patient from raising her obtained from the physical performed on the patient, head in an attempt to observe the ECG monitor. Any muscle can a diagnosis be made. tension can cause artifact. Shivering can also cause artifact. After placing the elec- trodes, the patient should be covered to prevent hypothermia and any subsequent shivering. Finally, fi ne tremulous body Determining the Isoelectric Line movements may be observed on the ECG monitor as arti- fact when the Paramedic administers defasciculating doses The first step in an ECG interpretation is to determine of paralytic drugs. the isoelectric line. The isoelectric line indicates that period of time when the myocardium, particularly the ventricular mass, has been repolarized and awaits depo- Cable-Induced Artifact larization. The isoelectric line extends from the end of ECG cables carry the signal from the body to the ECG the T wave to the start of the ventricular depolarization machine. At the start of every tour of duty, the cables should represented by the QRS complex. An isoelectric line on be visually inspected for cracks in the insulation and loose the monitor and on the rhythm strip should appear as a flat connections to the connectors at both ends. Extraneous move- line between ECG complexes. ment of the ECG harness (cable) can cause artifact. Starting 742 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 33-8 Artifact from patient movement caused the noisy baseline in this ECG tracing. at the patient, the wires should be inspected to ensure that moved away from the environment. For example, perhaps the they are securely fastened to the electrodes. patient can be moved to the rear of the ambulance. Wires that are running over the top of electrodes can cre- ate interference. Therefore, wires should be placed in such a Vehicle Motion Artifact fashion that they run parallel to one another but not on top of Little can be done to prevent vehicle motion artifact cre- one another. The Paramedic should also permit some slack in ated by rough roads. Paramedics will frequently obtain a the cable running from the patient to the ECG monitor. This “clean” (artifact-free) tracing before and after transport for slack removes the tension from the electrode wires and helps analysis and interpretation or while stopped at traffi c control prevent the electrode from being pulled off the patient. devices. Electromagnetic Interference Identify the QRS Complex The fl ow of electricity through an electric device can natu- The next step in the ECG interpretation is to identify the rally generate an electromagnetic fi eld. In most cases, elec- QRS complex. The QRS complex shows the greatest degree tronic devices are shielded to prevent this type of “radiation of variation in duration (length), polarity (direction), and leak.” If, for example, the shielding failed, then an electro- morphology (shape). The QRS complex, representing ven- magnetic fi eld might be created. ECG machines, designed to tricular depolarization, is usually the largest wave visible. detect changes in electricity, would logically be expected to The QRS complex can take on a number of combinations of pick up these fi elds and record them. Electromagnetic inter- the waves Q, R, or S. At this juncture it is not important to ference (EMI) of an ECG is seen as artifact. describe the signifi cance of these wave groupings, but rather Common sources of EMI include radios, cellular to simply identify the presence or absence of a QRS complex. telephones, televisions—in fact, any electronic or radio The purpose of identifying the QRS complex fi rst is so that device.15–17 The fi rst step in eliminating EMI is to turn off the rhythm can be described and then the rate can be calcu- electronic devices in the proximity of the patient and see if lated accurately. the artifact resolves. Another common source of EMI is over- head fl uorescent lighting. These lights, common in commer- Absence of a QRS Complex cial establishments and increasingly more common in homes, If there is no artifact and no QRS complexes are discernable, create a steady electrical signal from the 60-cycle alternating then the rhythm will appear fl atline and the heart may be in current (AC). The resulting artifact distorts the ECG tracing, asystole (no ventricular activity is detected on the surface making it diffi cult to read (Figure 33-9). ECG). The Paramedic’s fi rst reaction should be to confi rm If it is diffi cult to identify the exact source of the electri- that the patient is without pulse and has no signs of life. If the cal interference (i.e., the “noise”), then the patient should be patient is indeed unresponsive, apneic, and pulseless, then it Figure 33-9 Artifact from 60-cycle interference. The Monitoring ECG 743 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. may be necessary to confi rm asystole in a minimum of two memorization trick to help in making calculations (Table leads. It is recommended that asystole be confi rmed in more 33-2 and Figure 33-10). than one lead. The most accurate method of calculating the rate of a If there are no QRS complexes in either lead and the regular rhythm is to count the number of small boxes between monitor shows what appears to be artifact, then the Paramedic any two complexes and divide the result into 1,500. This should immediately palpate for a pulse and signs of life. method will give a very accurate result. Most Paramedics use Again, if the patient is lacking a pulse and signs of life, the a calculator when using this method. Paramedic should assume the chaotic rhythm is ventricular If the rhythm is irregular, an acceptable method is to fi brillation and proceed accordingly. It is beyond the scope count the number of QRS complexes in a six-second strip of the present discussion to talk about the treatment of life- and multiply that number by 10 to get a number per minute threatening dysrhythmias. or a rate. Many ECG printouts have “tic” marks, a line or label, every three seconds either the top or the bottom of the ECG paper. These tic marks help the Paramedic to quickly determine a six-second strip. Therefore, between three tic Street Smart marks is six seconds. The number of QRS complexes within that length of strip, times 10, equals the heart rate in beats per minute. The ECG rhythm may not be visible on the surface Since the rhythm is irregular, the choice of rhythm strip ECG of morbidly obese patients. The heart lacks the is only a snapshot in time. The rate only represents the rate at energy to get a strong enough signal to the surface that moment. However, the rate can be altered by the choice to be sensed. However, the patient may be awake of a different six-second rhythm strip. Therefore this method is the most inaccurate method of rate calculation. and alert. This fi nding adds support to the Paramedic axiom, “Treat the patient, not the monitor!” Clinical Signifi cance of Rate Generally speaking, all rates are normal, fast or slow. Heart rates between 50 and 100 are considered to be normal or nor- mocardiac and further clinical correlation is needed to ascer- Determine Rhythm tain the patient’s condition. The regularity of the rhythm is assessed by measuring from a The fast heart rate, greater than 100 beats per minute, is point on the QRS complex to the same point on the next QRS called a tachycardia and may have clinical signifi cance to complex. Typically, the tallest or deepest wave is used—the the patient’s condition as well. If the patient is exercising, it is R wave in Lead II or the S wave in MCL1. By then visually expected that the heart rate will be tachycardia. However, if inspecting the next waves in sequence and moving from left the patient is lying in bed it would not be anticipated that the to right across the horizontal axis, the Paramedic can deter- patient’s heart rate would be tachycardia. mine if events are occurring regularly, irregularly but with a There are many causes of tachycardia including con- pattern, or irregularly irregular. sumption of caffeine, cocaine, or other intoxicants that mimic Calipers make this task easy. However, care must be adrenaline (sympathomimetics). Other causes include fever, taken not to open or close the calipers inadvertently while moving from R to R. Many Paramedics use a fl at edge or piece of paper to mark the |
interval between two R to R points Table 33-2 Large Box Method of Rate and then assess subsequent R points. Some minor irregular- Calculation ity is expected in a normal rhythm. In very slow rhythms, If there is one large box between two QRS complexes, then the an alteration of one to two small boxes, representing 0.04 ventricular rate is 300. to 0.08 seconds difference, is normal and is still considered regular. Continuing the sequence: 2 large boxes ventricular rate of 150 Calculate Heart Rate 3 large boxes ventricular rate of 100 Armed with information about rhythm regularity, the 4 large boxes ventricular rate of 75 Paramedic can choose the best method for determining the 5 large boxes ventricular rate of 60 heart rate from among the several methods available. 6 large boxes ventricular rate of 50 If the rhythm is regular, then the quickest method to 7 large boxes ventricular rate of 43 calculate the rate is to count the number of large boxes 8 large boxes ventricular rate of 37 between any two QRS complexes and divide the result into 9 large boxes ventricular rate of 33 300. This method gives an accurate result. An understand- 10 large boxes ventricular rate of 30 ing of this method will allow the Paramedic to substitute a 744 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 33-10 Rate based on the number of large boxes between two QRS complexes. shock, acute coronary events, and endocrine disorders such QRS Width as hyperthyroidism. After having determined the rhythm and rate, the Paramedic In some cases, the patient may experience a sensation should examine the QRS more closely. The pressing concern of his or her heart racing, a phenomena called palpitations. is whether the QRS is wide, suggesting a ventricular origin, The presence of palpitations should alert the Paramedic to the or it is narrow, suggesting either a sinus or supraventricular possibility of tachycardia. Typically heart rates of less than origin. Ventricular rhythms are usually, but not always, dan- 150 beats per minute are well tolerated by the patient and the gerous because the origin of the rhythm is in the last pace- patient may not feel a palpitation. maker in the ventricles. While a supraventricular rhythm, A slow heart rate, called a bradycardia, may also be a complex originating above the ventricles, can be danger- clinically signifi cant but is usually not life threatening unless ous, it is generally better tolerated by the patient.18 A sinus the rate falls below 50. In that case, the patient may be light- rhythm is a supraventricular rhythm and is considered the headed secondary to hypotension. best situation. In monitoring Lead II, the QRS is normally positive. It generally consists of a small initial Q wave (negative wave Street Smart measuring less than 2 mm) followed by the positive R wave. Normal duration is from 0.04 to 0.12 second in the adult. For monitoring Lead MCL1, the complex normally begins with a It is important to note that the presence of a QRS small, narrow R wave followed by an S wave. The QRS dura- complex does not always equate with the presence tion is the same. If the QRS in any lead is greater than 0.12, of a pulse. A patient can have an electrical rhythm then it is considered to be wide and therefore possibly of a ventricular origin. without a pulse, a condition called pulseless electrical activity (PEA). This phenomenon reinforces the Ectopy Paramedic axiom of “Treat the patient, not the It is essential to determine if every complex is wide or if only monitor.” an occasional complex is wide. If there is an occasionally wide QRS, then this suggests a competing lower pacemaker The Monitoring ECG 745 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 300 150 100 75 60 50 42 Street Smart Street Smart At this point in the ECG interpretation, there Some Paramedics have a tendency to refer to a is suffi cient information in many cases to start rhythm by its ectopy. This is analogous to referring treatment of the patient. The Paramedic has to a friend by a nickname. However, it is more determined if the underlying rhythm is regular, as descriptive to refer to the rhythm by fi rst describing well as the rate and the width of the QRS complex. the underlying primary rhythm and then the ectopy Advanced cardiac life support algorithms include wide (e.g., sinus rhythm with a bigeminy of wide premature complex tachycardia, narrow complex tachycardia complexes). (both regular and irregular), and symptomatic bradycardia. is abnormal for the P to be notched or peaked. The upper limit of normal for the duration of the P wave (which refl ects atrial depolarization) is 0.12 seconds. site, called an ectopic focus. Any complex that occurs out- The normal height of the P wave is less than 3 mm, or side of the sinus is considered an ectopic complex. three small boxes, rounded and upright in Lead II. This is due An ectopic focus can compete with the sinus node for to the size and arrangement of the atrial fi bers. Any P wave dominance (the fastest cell) in terms of automaticity (creates larger than 3 mm suggests that the atrium may be enlarged the depolarization). If the ectopic focus is ventricular, and the due to an increased workload. Causes of increased atrial work ventricular pacemaker becomes dominant, the patient may include tricuspid valve disease, pulmonary hypertension, cor experience a rhythm called ventricular tachycardia. With pulmonale, or congenital heart disease. ventricular tachycardia, the rhythm is regular, the rate is fast, and every complex is wide. If only the occasional complex is wide (i.e., possibly of Street Smart ventricular origin), then the Paramedic should concentrate on determining the underlying primary rhythm. In many cases, the ectopic comple Lead II is the best single lead to view atrial activity as xes are a result of hypoxia, rate- related myocardial ischemia, or a basic electrolyte disturbance. a rule. The P wave should be upright and rounded in Correction of the ectopic rhythm is best accomplished by Lead II.19,20 correction of the underlying abnormality. In many cases, the ectopic complex appears earlier than would be expected in the course of a regular cardiac cycle. AV Relationships Increased automaticity of the ectopic focus leads to prema- Normally, the sinoatrial node (SA node) discharges, setting ture discharge, and therefore dominance, during depolariza- off a cascade of depolarizations down the conductive pathway tion. Therefore, these ectopic complexes could be described in the heart. When this occurs, the surface ECG will register a as wide premature complexes. P wave followed by a momentary pause, as the signal reaches When an ectopic complex occurs at every other complex, the atrioventricular node (AV node) and then ventricular it is called bigeminy. Bigeminy should not be confused with depolarization occurs, as represented by the QRS complex. the situation in which two ectopic complexes occur together. In a normal sinus rhythm, there should be a P wave imme- These ectopic complexes are called couplets. Ectopic com- diately preceding the QRS. If a P wave is absent, then the pace- plexes can also occur every third beat (trigeminy) or every maker may be down further in the conduction system, either at fourth complex (quadrageminy). Like bigeminy, ectopic the level of the AV node or at the level of the ventricles. complexes that occur three or four at a time are considered to If there are more P waves than there are QRS complexes, be a salvo or a run of ventricular tachycardia. then the complex is being blocked at some point along the conductive pathway. An interruption of AV conduction (an P Waves AV block) can be indicative of disease or ischemia at the Following determination of rhythm, rate, and QRS width, the level of the AV node. While AV blocks can be troubling, the next step is to identify the P wave. The normal morphology resultant bradycardia is of greater concern. and polarity of the P wave is upright (positive) and rounded in monitoring Lead II. It may be upright, fl at, or negative in Intervals monitoring MCL1. After having established rhythm, rate, QRS width, and AV While the P can be biphasic, beginning as a positive relationships, the Paramedic should proceed to examine inter- defl ection then becoming a negative wave or vice versa, it vals. Intervals are periods of time when a certain event—in 746 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. this case, a depolarization of the heart—is expected to occur. Determination of the QT interval in the fi eld is generally Prolonged or shortened intervals can be indicative of under- not necessary, except under certain specifi c circumstances lying abnormalities. (Table 33-3). It is only necessary to ascertain if the QT inter- val is abnormally long. A quick rule of thumb is that the QT PR Interval should be less than one half of the RR interval. The time for conduction down the intra-atrial pathways is rapid. In order to allow time for the blood (a viscous fl uid) Normal Sinus Rhythm to match the speed of electrical conduction, the impulse is Normal sinus rhythm (Table 33-4 and Figure 33-11) is held in the AV node. The AV delay is between 0.12 and 0.20 considered an optimal rhythm. The regular rhythm and rate seconds and is measured from the beginning of the P wave to provide for adequate fi lling of the ventricles and suffi cient the start of the QRS complex, the PR interval. ejection of blood for perfusion. If the PR interval is greater than 0.20 seconds, then the In a regular and normocardiac rhythm, where the P wave impulse is delayed. There are many causes (including isch- precedes the QRS in a timely fashion and the QRS is nar- emia) of a delayed PR interval. In some cases, the PR interval row, the Paramedic may reasonably interpret the rhythm as becomes progressively longer until the AV node no longer normal sinus rhythm. The Paramedic should learn the essen- conducts the electrical impulse. This is another indication of tial parameters of the sinus rhythm, because all other rhythms disease. that are not sinus (i.e., that do not fi t into the essential param- Conversely, if the PR interval (PRI) is shorter than 0.12 eters) are considered to be dysrhythmias. seconds, then the likelihood is that an ectopic pacemaker in the atrium has assumed dominance or that a congenital Sinus Tachycardia abnormal pathway, called an accessory pathway, has become engaged in the conduction of the impulse.21 Sinus tachycardia (Table 33-5 and Figure 33-12), is a sinus rhythm with a rate greater than 100 bpm. All other If there is no relationship between P waves and the QRS measurements of the rhythm remain the same as those for complex (AV dissociation), there may be a complete heart a sinus rhythm. If the heart rate is greater than 150 bpm, block. When a complete heart block occurs, pacemakers lower and the rhythm is sustained, then it is less likely that the |
in the heart at the level of the bundle of His, bundle branches, rhythm is a sinus tachycardia but another supraventricular or even the ventricular myocardium will take over as the pace- tachycardia. maker. These secondary pacemakers serve as a fail-safe for the heart but are generally not reliable for the long term. Sinus Bradycardia QT Interval A sinus rhythm becomes a sinus bradycardia (Table 33-6 and Figure 33-13) when the rate falls below 60 bpm, Ventricular depolarization and repolarization is represented though most patients are not symptomatic until the heart on the surface ECG tracing as the QT interval. The QT starts rate falls below 50 bpm. Any rate below 60 is considered at the fi rst defl ection of the QRS complex, regardless of the an absolute bradycardia. Alternatively, some patients can initial wave, and stops at the end of the T wave. be symptomatic with a rate above 60, even though the rate While short QT intervals do exist, some patients have does not meet the criteria for absolute bradycardia. In those congenital short QT syndromes. Paramedics are generally cases, the patient is said to be experiencing a relative bra- concerned with QT widening. QT intervals are affected by dycardia, or a rate that is too slow for the patient’s meta- sex and age. For example, men, on average, have shorter QT bolic needs. intervals (0.39 second) than women (0.41 second) at a heart rate of 70 bpm. However, prolonged QT intervals may repre- sent underlying abnormal electrolyte levels, drugs, and even Table 33-3 Etiology of Prolonged QT Interval— myocardial ischemia. Partial List QT intervals are also affected by heart rate. When 1. Antidysrhythmic drugs assessing a QT interval, the value obtained is corrected a. Vaughn-Williams Class I by using a formula. For example, Bazett’s formula for 2. Tricyclic antidepressants corrected QT interval equals the QT interval divided by the square root of the RR interval. To accommodate the 3. Phenothiazines variables such as rate, QT intervals are reported as cor- 4. Electrolyte imbalance rected (QTc). Any QTc longer than 0.40 / 0.06 seconds a. Hypokalemia in a normal heart rate should be considered prolonged. b. Hypomagnesemia A patient with a prolonged QT segment is at risk for unstable 5. Stroke ventricular tachycardia, specifi cally torsades de pointes.22,23 6. Seizures It should be noted that the QTc is of little clinical relevance 7. Cardiomyopathy in heart rates over 100 bpm. The Monitoring ECG 747 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Table 33-4 Parameters for Normal Sinus Table 33-5 Parameters for Sinus Tachycardia Rhythm (NSR) Rhythm Regular Sinus rhythm originates in the sinus node, the heart’s primary Rate Ventricular pacemaker. Conduction takes place along the conduction pathway, in a time frame conducive to adequate cardiac output. Greater than 100 bpm Rhythm Regular QRS confi guration Same complex to complex Rate Ventricular Upright in Lead II 60 to 100 bpm QRS duration Less than 0.12 seconds QRS confi guration Same complex to complex P wave Rounded and upright Lead II Upright in Lead II Atrial rate Same as ventricular QRS duration Less than 0.12 seconds AV conduction P wave to QRS = 1:1 P wave Rounded and upright Lead II PR interval 0.12 to 0.20 seconds Atrial rate Same as ventricular QT interval Less than 0.44 seconds AV conduction P wave to QRS 1:1 PR interval 0.12 to 0.20 seconds QT interval Less than 0.44 seconds Sinus Dysrhythmia Street Smart Sinus rhythm naturally slows with exhalation and then accel- Sinus dysrhythmia is a normal variant for most people. erates during inspiration. During expiration, intrathoracic pressure decreases. As a result, more blood can return to the It is extremely common in children and young adults. heart, thereby increasing preload. With an increase of blood in For this reason, some Paramedics never refer to a the heart, stretch receptors in the heart’s atrium in turn signal sinus rhythm as “normal” sinus rhythm as this implies the heart to contract slower. During inhalation, the opposite occurs. Sinus dysrhythmia (Table 33-7 and Figure 33-14) is the rhythm is regular and since many people have a most notable in children. The pacer site remains in the sinus slight variation in rhythm which is completely natural. node and conduction follows the usual pathways. II A MCL1 B Figure 33-11 Normal sinus rhythm. 748 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. II Figure 33-12 Sinus tachycardia. II Figure 33-13 Sinus bradycardia. II Figure 33-14 Sinus dysrhythmia. Table 33-6 Parameters for Sinus Bradycardia Table 33-7 Parameters for Sinus Dysrhythmia Rhythm Regular Rhythm Regularly Irregular Rate Ventricular Rate Ventricular Less than 60 bpm 60 to 100 bpm QRS confi guration Same complex to complex QRS confi guration Same complex to complex QRS duration Less than 0.12 seconds Upright in Lead II Upright in Lead II QRS duration Less than 0.12 seconds P wave Rounded and upright Lead II P wave Rounded and upright Lead II Atrial rate Same as ventricular Atrial rate Same as ventricular AV conduction P wave to QRS = 1:1 AV conduction P wave to QRS 1:1 PR interval 0.12 to 0.20 seconds PR interval 0.12 to 0.20 seconds QT interval Less than 0.44 seconds QT interval Less than 0.44 seconds The Monitoring ECG 749 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Out-of-Hospital ECG work and play activities while the Holter monitoring device records the ECG activity. At the conclusion of the desired Monitoring Equipment monitoring period (usually 48 to 72 hours), the device is During transport within a hospital and during the patient’s returned to the cardiologist who, in turn, downloads the infor- hospital stay, the cardiac patient will have electrodes connect- mation to a console or computer for analysis. ing him directly to the ECG device which is both displaying Even Holter monitoring may miss abnormal ECG activ- and storing the ECG tracings. This type of equipment, which ity that tends to occur very irregularly (as in days or weeks may be anchored above the patient’s bed or may be portable, apart). This patient may possess an event monitor, a device is called hard wire monitoring. Its limitation is that it limits that is a little larger than a credit card. When the patient senses the patient’s ability to move around. the abnormal activity, the monitor is placed on the chest for To allow a patient to begin walking in his hospital room the preset period of time. The patient can then telephone the or out in the hallway, some places use telemetry monitors. cardiologist’s offi ce and transmit the data from the card via These devices are connected to the patient by two or three telephone. wires. They collect the data and send it via radio waves to If the Paramedic needs to provide care to a patient with an antenna. The data is then transmitted by wires to the main a Holter monitor, the monitor poses no problem. While the console. The Paramedic should be aware that the radio waves Holter monitor may have hard wires or electrodes connected transmitted by cellular phones can interfere with both hard- to the patient’s chest, the electrode placement for the Holter wire and telemetry systems.24–26 Care should be taken to turn monitor is different than the placement recommended for off cell phones when transporting the patient within the hos- prehospital monitoring. Therefore, both may be used simul- pital setting. taneously without interference with the other device. Keep in mind that some cardiac treatments, such as defi - At-Home ECG Monitoring brillation and pacing, may require access to the patient’s chest. If the Holter monitor needs to be removed, simply In many cases, the problematic dysrhythmia is sporadic in remove it and the electrodes. Turn off the Holter monitor if nature. It is economically impossible to keep a patient in the the device has an ON/OFF switch. Bring the Holter monitor hospital for continuous monitoring for days or weeks in order to the hospital with the patient or give the device to a person to pick up the dysrhythmia. For this reason, a continuous type designated by the patient. The Paramedic should document of ECG monitor called Holter monitoring was invented. the disposition of the device including the name of the person Holter monitoring allows the patient to go about his routine to whom it was given. 750 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. While seemingly daunting at fi rst appearance, ECG interpretation can be learned provided the Paramedic practices ECG analysis and remembers the fundamental rules of the monitoring ECG. To improve the quality and accuracy of ECG interpretation, the Paramedic should take a disciplined and logical approach to ECG interpretation. While an ECG is important to the overall clinical picture, a stand-alone ECG is of little clinical value. It is important to correlate the patient’s clinical picture with the ECG in order to have a meaningful interpretation. Key Points: • Monitoring equipment varies according to the the signal, and a wire to conduct the signal to the specifi c monitoring need, the location of the machine. patient, and the type of event being assessed. • Wire systems vary. The important point is to place • The Paramedic must make a judgment as to the electrodes and attach the wires in such a way whether preexisting monitoring equipment must be as to mimic Einthoven’s Triangle. removed to permit appropriate patient care. • Measurements of duration, amplitude, and polarity • The speed at which the screen or paper moves is are made of each ECG feature. called sweep speed. A change may allow better examination of key features. • Apply a consistent method of assessment and treatment. First, assess the patient for the • The size of the picture on the screen or paper is presence of pulses. Next, assess the width of the called gain. QRS complex. Determine treatment timeliness. • The Paramedic must follow the agency’s policy for • In determining the name of the rhythm: documenting sweep speed and gain, which is called ■ Know the causes of dysrhythmias calibration. ■ Assess the QRS complex • ■ Assess the P waves ECG paper is standardized to allow Paramedics to ■ Do not mistake blips for P waves or miss the measure the timing of events and the intensity of P wave due to size the events. ■ Determine which P wave is related to which QRS • The horizontal axis equals time. Each light line ■ Pinpoint the primary diagnosis equals a time of 0.04 seconds; each heavy line • Normal sinus rhythm (NSR) is considered the equals a time of 0.2 seconds. optimal rhythm for most people. All other rhythms • The vertical axis equals amplitude. Each light line are compared to NSR. equals 0.1 mm or 0.1 mV. |
Each dark line equals • The presence of NSR does not eliminate the 0.5 mm or 0.5 mV. presence of patient problems. • To obtain an ECG, there must be an electrical signal, an electrode to reduce skin resistance to ThTeh eM Monointiotroirnign gE CEGCG 751 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Review Questions: 1. What steps should be taken before placing the 6. What can be done to resolve artifact? electrodes? 7. Why is it important to determine rhythm 2. What are the two standard ECG monitoring before rate? leads? 8. What are the three methods of determining 3. How does one place the ECG electrodes for heart rate? these monitoring leads? 9. What are normal and abnormal heart rates? 4. What are some causes of low-amplitude ECG? 10. What are the normal parameters of the QRS? 5. What are some common causes of artifact? Case Study Questions: Please refer to the Case Study at the beginning of the chapter and answer the question below: 1. Explain why analyzing and naming the rhythm could impact the treatment provided to Ms. Sheehan. References: 1. Ferguson JD, Brady WJ, Perron AD, Kielar ND, Benner JP, 8. Takuma K, Hori S, Sasaki J, Shinozawa Y, Yoshikawa T, Currance SB, et al. The prehospital 12-lead electrocardiogram: Handa S, et al. An alternative limb lead system for impact on management of the out-of-hospital acute coronary electrocardiographs in emergency patients. Am J Emerg syndrome patient. Am J Emerg Med. 2003;21(2):136–142. Med. 1995;13(5):514–517. 2. Hurst JW. Naming of the waves in the ECG, with a brief account 9. Jowett NI, Turner AM, Cole A, Jones PA. Modifi ed electrode of their genesis. Circulation. 1998;98(18):1937–1942. placement must be recorded when performing 12-lead 3. Wellens HJ. Bishop lecture. The electrocardiogram 80 years after electrocardiograms. Postgrad Med J. 2005;81(952):122–125. Einthoven. J Am Coll Cardiol. 1986;7(3):484–491. 10. Bayram E, Atalay C. Identifi cation of the culprit artery 4. Campbell PT, Patterson J, Cromer D, Wall K, Adams GL, involved in inferior wall acute myocardial infarction using Albano A, et al. Prehospital triage of acute myocardial electrocardiographic criteria. J Int Med Res. 2004;33(1):39–44. infarction: wireless transmission of electrocardiograms to the 11. McManus JG, Convertino VA, Cooke WH, Ludwig DA, on-call cardiologist via a handheld computer. J Electrocardiol. Holcomb JB. R-wave amplitude in Lead II of an 2005;38(4):300–309. electrocardiograph correlates with central hypovolemia in human 5. Chen EH, Hollander JE. When do patients need admission to a beings. Acad Emerg Med. 2006;13(10):1003–1010. telemetry bed? J Emerg Med. 2007;33(1):53–60. 12. Kataoka H, Kanzaki K, Mikuriya Y. Massive ST-segment 6. Mischke K, Zarse M, Perkuhn M, Knackstedt C, Markus K, elevation in precordial and inferior leads in right ventricular Koos R, et al. Telephonic transmission of 12-lead myocardial infarction. J Electrocardiol. 1988;21(2):115–120. electrocardiograms during acute myocardial infarction. J Telemed 13. Learning D. EKG Tech Video. Utica, New York: Delmar Telecare. 2005;11(4):185–190. Thomson Learning; 1998. 7. Faes TJ, van der Meij HA, de Munck JC, Heethaar RM. The 14. Upshaw CB, Jr., Silverman ME, Henry JL. Marriott: Lucid electric resistivity of human tissues (100 Hz-10 MHz): a meta- teacher of electrocardiography. Clin Cardiol. 2007; analysis of review studies. Physiol Meas. 1999;20(4):R1–10. 30(4):207–208. 752 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 15. Schlimp CJ, Breiteneder M, Seifert J, Lederer W. Interference of patients with mitral stenosis: the value of the P-wave area. Acta 16.7-Hz electromagnetic fi elds on measured electrocardiogram. Cardiol. 2003;58(2):139–141. Bioelectromagnetics. 2007;28(5):402–405. 21. MacKenzie R. Short PR interval. J Insur Med. 2005;37(2): 16. Kolb C, Zrenner B, Schmitt C. Incidence of electromagnetic 145–152. interference in implantable cardioverter defi brillators. Pacing 22. Shantsila E, Watson T, Lip GY. Drug-induced QT-interval Clin Electrophysiol. 2001;24(4 Pt 1):465–468. prolongation and proarrhythmic risk in the treatment of atrial 17. Fleischhackl R, Singer F, Nitsche W, Gamperl G, Roessler B, arrhythmias. Europace. 2007;9(4):37–44. Arrich J, et al. Infl uence of electromagnetic fi elds on function 23. Roden DM. Clinical practice. Long-QT syndrome. N Engl J of automated external defi brillators. Acad Emerg Med. Med. 2008;358(2):169–176. 2006;13(1):1–6. 24. Brodlie M, Robertson D, Wyllie J. Interference of 18. Mulroy JF, Thayer JJ, King JE. How do I manage stable narrow- electrocardiographic recordings by a mobile telephone. Cardiol complex SVT? Nursing. 2005;35(10):14. Young. 2007;17(3):338–339. 19. Gorenek B, Birdane A, Kudaiberdieva G, Goktekin O, 25. Tri JL, Severson RP, Firl AR, Hayes DL, Abenstein JP. Cellular Cavusoglu Y, Unalir A, et al. P wave amplitude and duration may telephone interference with medical equipment. Mayo Clin Proc. predict immediate recurrence of atrial fi brillation after internal 2005;80(10):1286–1290. cardioversion. Ann Noninvasive Electrocardiol. 2003;8(3): 26. Tri JL, Hayes DL, Smith TT, Severson RP. Cellular phone 215–218. interference with external cardiopulmonary monitoring devices. 20. Zeng C, Wei T, Zhao R, Wang C, Chen L, Wang L. Mayo Clin Proc. 2001;76(1):11–15. Electrocardiographic diagnosis of left atrial enlargement in ThTeh eM Monointiotroirnign gE CEGCG 753 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. KEY CONCEPTS: Upon completion of this chapter, it is expected that the reader will understand these following concepts: • Paramedic use of 12-lead ECG as the fi rst step in a critical care pathway for patients with acute coronary syndrome • Accurate acquisition of the 12-lead ECG • Analysis of the 12-lead ECG to make a patient prognosis, determine treatment, and plan for an appropriate destination Case Study: The Paramedics were called to the home of Jennie Swinter. Mrs. Swinter is an 82-year-old widow, living alone on a small farm that she still farms for vegetables. She called EMS because she became exhausted and out of breath after walking to the bathroom. The inexperienced Paramedic commented that at her age, Mrs. Swinter should be tired and out of breath. The more experienced Paramedic suggested that many acute processes could account for Mrs. Swinter’s complaints. The Paramedics obtained an ECG right after placing Mrs. Swinter on oxygen. It showed ST elevation and hyperacute T waves in Leads II, III, and aVF. Mrs. Swinter complained of feeling very lightheaded and afraid. Repeat vital signs were obtained. Rather than the 118/66 found earlier, she had a pressure of 80/48. She also had jugular venous distention while semi-sitting and clear lung sounds. 754 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Diagnostic ECG—The 12-Lead 755 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. OVERVIEW Death from acute myocardial infarction remains a leading reason for mortality in the United States despite advances in medicine. It has been estimated that 50% of patients with acute coronary syndrome (which, if left untreated, leads to AMI) are transported by EMS and the majority of cardiac arrests occur in the prehospital setting. It is therefore important that Paramedics be able to identify and aggressively treat these patients. Chief Concern ascertain the ventricular wall involved, and predict the coronary artery that is affected. Not only is this information valuable There are a number of causes of chest pain. Of particular con- downstream, to the emergency physicians and cardiologists cern for the Paramedic is chest pain of a cardiac etiology. who will eventually treat the patient, but it is important for the Patients with cardiac-related chest pain are at high risk for Paramedic. By being able to estimate the location and extent acute myocardial infarction and sudden cardiac death. of injury, the Paramedic can predict, with relative confi dence, The identifi cation of the patient with potential for acute the clinical course that the patient will take. This prognostic myocardial infarction is predicated on a clinical history which ability permits the Paramedic to prepare for predictable com- is suggestive of acute coronary syndrome and electrocardio- plications related to the acute coronary event. graphic fi ndings. The latter, electrocardiographic fi ndings, are not always present in patients who are at the beginning of the event (i.e., early in the evolution of the acute myocar- Atypical Presentations of ACS dial infarction). The maxim “Treat the patient, not the moni- While it is obvious that patients with substernal chest pain tor” holds true for these patients. Treatment for suspected (SSCP) should have a 12-lead ECG, other occasions when a acute myocardial infarction—specifi cally morphine, oxygen, 12-lead ECG may be necessary are sometimes less obvious. nitrates, and aspirin—should not be withheld because of a For example, middle-aged females often do not present with lack of electrocardiographic fi ndings. It has been estimated chest pain. These patients tend to present with atypical pre- that upward of 50% of patients who will develop an acute sentations for acute coronary syndrome.5,6 myocardial infarction had no confi rmatory electrocardio- These atypical presentations can include sharp rather graphic (ECG) fi ndings upon the initial ECG.1–4 than crushing chest pain, shortness of breath, unexplained weakness, and sudden diaphoresis. Unfortunately, some of these symptoms can be mistaken for menopausal signs, lead- Street Smart ing to delayed treatment. The belief that a patient with an acute coronary event must have concomitant substernal chest pain is a misconception. One study suggested that serial 12-lead ECGs Another group of patients who have an atypical presen- identifi ed acute myocardial infarctions in 75% of tation are the elderly. This group of patients tends to have a patients upon whom the initial 12-lead ECG exhibited higher frequency of acute myocardial infarction, even when nonspecifi c ECG changes. The importance of an identifi ed early in the evolution, and complications such as heart and renal failure. early baseline 12-lead ECG was supported by that For these reasons the Paramedic should have a low study. Therefore, it is advisable for all Paramedics threshold for 12-lead ECG acquisitions. The best support for to obtain an initial baseline 12-lead ECG as soon as this argument is found in the frequency that 12-lead ECG is obtained in the emergency department. possible. Thereafter, serial 12-lead ECGs should be performed every 15 to 30 minutes for the fi rst 2 hours of patient contact. Rhythm Strip The primary mission of all Paramedics has always been to prevent sudden cardiac death from dysrhythmia. This has However, that is not to dismiss the importance of obtain- been the essence of Paramedic care since the advent of ing a 12-lead ECG as soon as possible on a patient with sus- Dr. Pantridge’s “mobile coronary care units” in Belfast, pected acute coronary syndrome. A 12-lead ECG can also help Ireland, over half a century ago. However, with the advent the Paramedic estimate the location of the coronary occlusion, of fi brinolytics and invasive cardiology, the original mission |
756 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. has been expanded to include rapid acquisition and interpre- heart. They observed a triphasic pattern to the electricity’s tation of 12-lead ECGs. fl ow. The 12-lead ECG stands at the center of the decision Continuing the work of Bayliss and Starling, Willem pathway when managing patients with ischemic chest pain. Einthoven, who had also witnessed Waller demonstrate an Delays in obtaining the 12-lead ECG must be eliminated ECG in 1889, used a silver string galvanometer to reproduce whenever possible. The most effective means of obtain- the triphasic waves that Bayliss and Starling had observed. ing a 12-lead ECG at the earliest point in time is to have a Willem Einthoven named the defl ections of these waves P, Q, Paramedic obtain one.7 R, S, and T, a convention that lasts to this day. The importance of obtaining a rapid and accurate 12-lead Continuing his work with the “electrokardiogram” ECG is underscored by the American Heart Association’s (EKG) in 1905, Einthoven transmitted his fi rst EKG over (AHA) statements. The AHA states that upon recognition 1.5 kilometers to another lab using a telephone cable. This was of acute coronary syndrome and a suspected acute coronary the fi rst recorded experience with telemetry.10 Einthoven also event, a 12-lead ECG should be obtained as soon as pos- went on to standardize the electrocardiogram by referencing sible but no later than ten (10) minutes upon arrival at the the body and using the designators Leads I, II, and III. These hospital.8,9 This rapid 12-lead ECG acquisition and interpre- fi rst leads formed an equilateral triangle which is now referred tation will facilitate the patient’s transfer to cardiac centers to as “Einthoven’s Triangle.” From this platform, Einthoven for interventional cardiology. This time frame has been dem- was able to distinguish normal “EKG” from abnormal, noting onstrated to decrease both morbidity and mortality. premature ventricular contractions, heart blocks, atrial fl utter, The effi ciency of this process can be substantially and other dysrhythmia. For this and other work, Einthoven was improved with 12-lead ECGs being obtained by Paramedics awarded the Nobel Prize in medicine in 1924 for “inventing the and the diversion of ambulances to cardiac centers. The electrocardiogram.” He is commonly referred to as the “father American College of Emergency Physicians (ACEP) supports of electrocardiology.” this process in their position paper entitled “Out-of-Hospital 12-Lead ECG.” Standard Limb Leads While ACEP acknowledges that 12-lead ECG acquisition Einthoven’s limb leads used two electrodes, one negative and will prolong scene times, many Paramedics have become very one positive, and measured the electrical potential between adept at obtaining 12-lead ECGs in minimal time. Studies these electrodes as it fl owed from negative to positive. Because have shown that Paramedics can obtain 1 2-lead ECGs at the the limb leads required two leads which measured the current point of care in the fi eld in approximately 5 minutes. difference between the leads’ electrodes, they were—and still The advent of Paramedic 12-lead ECGs has greatly are—referred to as bipolar leads. Einthoven’s original bipo- affected physicians’ opinions of Paramedics regarding the lar limb leads provided electrical information relating to the treatmet of acute coronary syndromes. Paramedics are viewed heart’s electrical activity along the frontal plane of the body as a part of the continuum of care that starts in the fi eld and (Figure 34-1). ends in the interventional cardiologist suite. It is recognized Perhaps the most useful of these bipolar leads was Lead II that aggressive Paramedic care can substantially impact car- in that its orientation, from right shoulder to the left foot, was diac patient morbidity and mortality. more or less in alignment with the heart’s electrical conduc- tion system. For this reason, Lead II provides the best view of Origins of the Electrocardiogram error of conduction. It is often used to monitor patients for an The electrocardiogram has a long history that may have started irregular heart rhythm, a disturbance in conduction along the with Italian physicist Carlo Matteucci. Matteucci, interested heart’s electrical pathway, called a dysrhythmia. in the works of the noted physicist Luigi Galvani, continued Unfortunately, because of its orientation along the frontal Galvani’s work on bioelectricity and started to investigate the plane, Lead II only permits a view of the heart’s inferior wall. role of electricity in the human body. Matteucci observed that However, the bulk of the ventricular mass is in the anterior wall.11 with every heartbeat there was a passage of electrical current in the body. What Matteucci did not realize when he made Even with the use of three limb leads, the ECG only that observation was that he was actually witnessing the birth viewed the frontal plane and the inferior and lateral wall of of electrocardiography. the heart (Figure 34-2). However, the majority of the ventric- Following Matteucci’s early lead, noted British physi- ular mass lies along the transverse plane in the anterior wall. ologist Augustus Waller, of St. Mary’s Medical School in Thus, even with these additional leads, the electrical activity London, created the fi rst tracing of the heart’s electrical of the anterior wall was still not being captured by the ECG. activity using his lab assistant Thomas Goswell as a patient in 1887. Subsequently, British physiologists William Bayliss Precordial Leads and Edward Starling from the University College of London, In an effort to obtain a more comprehensive view of the heart, following Waller’s direction, attached a terminal to the right researchers sought to create new leads. In 1931, researchers hand of a patient and to the skin overlying the apex of the Wilson, MacLeod, and Barker devised a method for recording Diagonostic ECG—The 12-Lead 757 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. R L RA LA – I + – – R L CT F II III F + + i RL LL Figure 34-1 Standard limb leads. Figure 34-3 Wilson’s central terminal (i.e., the virtual negative electrode) and the creation of the unipolar lead. aVL electrode is now available to become an “exploring” lead aVR which can be placed anywhere on the thorax to view any angle of the heart. The use of a single positive electrode, using Wilson’s central terminal, created the unipolar lead Lateral (Figure 34-3). I Using the central terminal concept, Wilson placed elec- CX RCA LAD trodes in a semicircle around the precordium, that portion of skin that overlies the heart. Wilson’s unipolar precordial chest leads encircled the anterior ventricular wall from the septal wall on the right to the lateral wall on the left. This permitted a complete view of the anterior myocardium. These leads were originally called the V leads (V for voltage). In 1938, the American Heart Association Inferior standardized the precordial leads and called them V1, V2, V3, V4, V5, and V6. Adding these precordial (chest) leads III aVF II to the standard limb leads gave nine views of the heart along both the frontal plane and the transverse plane. Figure 34-2 Frontal plane’s relationship to the heart. Augmented Leads— A More Complete Picture the electrical activity of the heart along any of its surfaces. While six precordial chest leads gave physicians a better view They continued to use the three limb leads. However, through of the anterior wall, the three bipolar limb leads did not give the use of electrical resistors, they were able to move the neg- physicians the same view of the inferior wall. Einthoven’s ative electrode to the center of the body, proximal to the right Triangle (the origin of the standard limb leads) is an equilat- atria and the SA node, to form a central point called Wilson’s eral triangle and has, by defi nition, angles of 60 degrees. Use central terminal (CT). of these angles left wide gaps with the potential for much of Because the negative electrode is a “virtual” electrode, the heart’s electrical activity to be unrecorded by these stan- not an actual electrode, in the center of the body, the positive dard limb leads. 758 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. r o Ante i r RA LA + RA LA RA LA LL + Lead a VR + LL LL Lead a VF Lead a VL Figure 34-4 Augmented lead placement and the relationship of augmented limb leads to the standard limb leads. Using Wilson’s central terminal theory, Goldberger simple ECG rhythm monitor, a narrower frequency range recorded the activity between each of the limb leads’ posi- between 0.5 Hz and 30 to 50 Hz removes distortions which tive electrodes and the central terminal, adding three addi- interfere with the rhythm’s correct analysis. However, it does tional limb leads. Unfortunately, when the signals were so at the cost of accuracy when measuring segments of the recorded, they were too small to be properly examined and ECG complex. In the simple ECG rhythm monitor, an ST seg- required a boosting of the signal in order to identify any ment may appear far above (elevated) or below (depressed) the characteristics. In 1942, Goldberger devised a method to baseline, indicating potential ischemia or acute injury/infarct. boost, or augment, the signal (hence the title “augmented” Paramedics are generally directed to take patients with an ST leads) (Figure 34-4). segment above baseline to an interventional cardiology cen- Combining the lead type and the positive electrode loca- ter as opposed to the local hospital.12–15 A false positive in this tion gave rise to the names of Goldberger’s augmented leads regard is not only an inconvenience to the patient and to the (i.e., augmented voltage right or aVR, then augmented voltage patient’s family, but misuses critical cardiac services needed left or aVL, and augmented voltage foot now called aVF). for more acutely ill patients. To obtain a proper diagnostic 12-lead ECG that correctly Acquisition of the 12-Lead ECG shows all segments, the American Heart Association recom- mends that a frequency range of 0.05 Hz to 150 Hz be used. The importance of acquiring a high-quality 12-lead ECG, However, switching from monitoring mode to diagnostic as explained earlier, cannot be overstated. Clinical decisions mode raises the problems of artifact which were previously regarding the patient’s treatment and transportation are based, eradicated. Therefore, the Paramedic must take other mea- in part, on the 12-lead ECG. Therefore, it is imperative that sures to reduce artifact. the Paramedic know how to obtain a clear and concise 12-lead ECG. 12-Lead ECG Artifact Diagnostic 12-Lead ECG The common sources of ECG artifact can be broadly classi- fi ed as physiologic and nonphysiologic. Physiologic artifact versus Rhythm Monitoring includes muscle artifact and skin artifact. The fi rst, muscle Tracings of early ECGs were often plagued with artifact and artifact, is the result of muscle movement or muscle tension. distortions that made reading the ECG diffi cult. These early Muscle tension is the result of agonist and antagonist muscles ECG machines were intended to monitor the rhythm only. To competing to maintain a limb in one position. Any time a solve these problems, electrical engineers resorted to adjust- muscle contracts, it produces an electrical current which will ing the frequency range, that area of the electric signal that be detected |
as an electromyographic signal (EMG) by the is being recorded. They also used electronic fi lters such as ECG. An EMG is seen as narrow rapid spikes on the ECG common mode rejection. monitor.16 In order to capture subtle changes in amplitude and dura- To prevent EMG on the ECG, the patient should be posi- tion which are necessary for the interpretation of a diagnostic tioned comfortably, in an effortless position, with arms and 12-lead, the 12-lead ECG monitors require a wider frequency legs supported by the stretcher. In some cases, it may be more range than simple three-lead ECG rhythm monitors. In the prudent for the Paramedic to perform the ECG on the patient’s Diagonostic ECG—The 12-Lead 759 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. bed or couch rather than the stretcher because the patient’s Patient Preparation arms hang off the stretcher. Folding of the arms across the chest only creates muscle tension and resultant EMG. To prevent EMG interference, the Paramedic should fi rst The other source of physiologic artifact is skin move- place the patient in a comfortable position. Preferably, the ment. Whenever the skin is stretched under an electrode, it patient should be supine with arms at the sides and the entire will create an epidermal signal. For example, when a patient body supported. If the patient is not relaxed, because of a inhales and exhales, the movement of the skin will create painful condition such as arthritis, then the Paramedic might baseline shifts (wandering baseline) as the electrodes move consider using analgesia or sedatives. along with the chest wall. To prevent epidermal signal inter- The Paramedic should then prepare the skin before apply- ference, it is important to properly place the electrodes on the ing the electrodes. If the patient’s chest hair interferes with the patient’s chest away from the thoracic cage. Paramedic’s attempts to closely adhere the electrodes to the An example of a nonphysiologic source of ECG artifact skin, then the chest hair needs to be removed. While it might is electromagnetic interference (EMI). Whenever alternat- be expeditious to use a straight razor to remove the hair, shav- ing current (AC) electricity passes through a wire, it produces ing the chest can create microlacerations that can bleed if the an electromagnetic fi eld. Therefore, whenever a 12-lead ECG patient is given fi brinolytics later. Also, the hair follicles can monitor is in the vicinity of a wire carrying AC electricity, become infected (folliculitis). The patient’s chest hair should the monitor will pick up the electromagnetic fi eld as 60-cycle be carefully trimmed using either a commercially available interference. An example of common sources of 60-cycle clipper or a pair of blunt tipped bandage scissors. EMI are fl orescent lights, particularly those with a malfunc- tioning ballast, and poorly shielded ambulance convertors. Visually, 60-cycle EMI will present on the 12-lead ECG as a Street Smart fuzzy baseline. Static electricity can also produce artifact on the ECG. The patient may build up an electrical charge (static electric- If the patient is grossly diaphoretic, some Paramedics ity). When the patient, as the charged body, is in proximity of have used antiperspirants to dry the area. These an uncharged body, such as the ECG monitor, then electricity antiperspirants often contain aluminum oxide as an will pass between the two and be recorded on the ECG. This active agent. Aluminum oxide interferes with the occurs frequently in dry climates. One of the more common sources of artifact is electrode electrical signal and will reduce the quality of the failure. Since the outer layer of skin is electrically “dead,” an 12-lead ECG. electrical signal cannot be transmitted across the skin with- out a conductive medium to act as a bridge between the inner body and the electrode. The typical ECG electrode uses sil- While wiping the contact surface with a gauze pad will ver chloride as the conductive medium. When a metal, such reduce the pickup of 60 Hz EMI and motion artifact, it will as silver chloride, is placed next to an electrolyte solution only reduce the skin’s resistance by 1,000 to 5,000 ohms. (i.e., the interstitial fl uid), then an electromagnetic force is It is important to not only remove the dead cells of the created and an electromagnetic “signal” is sent to the ECG stratum corneum but to also scratch the lower stratum monitor. granulosum.17 Scratching the stratum granulosum improves the ECG signal by allowing the electrode gel to permeate the skin and contact the electrolyte solution (i.e., interstitial fl uid). Street Smart Typically, either fi ne weight sandpaper (220 to 3,400 grit) or a commercially available gritty ECG preparation gel is used. Most 12-lead ECG cables are covered, or shielded, Five to ten strokes of either a gel-soaked gauze pad or sand- to prevent the monitor from picking up extraneous paper is suffi cient. The skin should be slightly reddened but not abraded. 60-cycle EMI. The presence of 60-cycle EMI on the The area immediately surrounding the electrode contact monitor is a sign of either a defective cable or a should be cleansed with an alcohol-soaked preparation pad. broken lead. The alcohol helps to remove surface fats which can under- mine the electrode’s adhesive and prevent close skin contact with the electrode’s gel. If the skin is not properly prepared, then the skin can cre- It is important that the gel on the electrode be moist. Most ate an impedance to this signal of approximately 100,000 to electrodes come prepackaged and have an expiration date. 200,000 ohms. Simple site preparation can reduce the skin’s The Paramedic should fi rst confi rm that the electrodes are impedance to less than 10,000 ohms in 90% of patients and not expired before proceeding. Next, the Paramedic should thereby markedly improve the quality of the ECG signal. remove the electrode from the package and remove the plastic 760 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The electrode should be placed on the properly prepared skin Street Smart overlying muscle, not bone. The resulting leads—Lead I, Lead II, and Lead III—are therefore a function of the polarity ascribed to them by the ECG monitor. Often these electrode Electrode gels depend on the body’s warmth to wires are labeled for ease of application. liquefy the gel so that it can penetrate the skin. If the While technically correct, the placement of electrodes patient’s skin is cold, then the gel will not melt and on the ankles and wrists of the patient is often mechanically the ECG signal will be poor. Waiting until the patient inconvenient. Problems with resting tremors and clothing pre- vent the Paramedic from obtaining an accurate 12-lead ECG. is warmed, or applying hot packs over the electrodes, This distortion can be minimized if the electrodes are moved can improve the quality of the ECG. more centrally. In 1966, Mason and Likar suggested mov- ing the electrodes to the shoulders and the hip. To properly place the limb electrodes in the Mason–Likar modifi cation, protective cover over the gel. With one fi nger, the Paramedic the right arm electrode is moved to the right infraclavicular should gently compress the gel. Moist electrode gel should fossa, approximately 2 cm below the clavicle. The left arm have a little spring when gently compressed. Dried electrode electrode is similarly placed in the left infraclavicular fossa, gel will be stiff and unyielding. Dried electrodes should be and the left leg electrode is moved next to the left iliac crest in discarded immediately as they are of no practical use. the iliac fossa. This placement of the limb leads maintains the After confi rming that the gel on the electrode is still moist, integrity of Einthoven’s Triangle without the inconvenience the lead wire should be attached to the electrode. The gel under of distal limb lead electrodes. the electrode is formed into a pod so that the gel stays concen- Because the ECG machine electrically converts the bipo- trated in an area when the electrode is then placed on the skin. lar limb leads into unipolar augmented leads using the same If the electrode is placed on the skin fi rst and then the lead wire leads and electrodes, it is unnecessary to add additional elec- is attached, the pressure from attaching the lead wire can crush trodes for the augmented leads. the pod, disperse the gel, and diminish the signal quality. Street Smart Street Smart To ensure consistency in application of the 12-lead If moisture or blood is expected to cover the electrode, ECG data, the Paramedic should document if the the application of bio-occlusive dressing over the 12-lead ECG was obtained using the Mason–Likar electrode can prevent the moisture from undermining modifi cation. The documentation may simply state the electrode and interrupting the ECG signal. that all electrodes were placed on the torso. Electrode Placement Precordial Leads Wilson’s precordial leads measure the ECG potentials across Accurate electrode placement is important. In some cases, the anterior wall of the left ventricle. Precordial leads are to the prehospital 12-lead ECG may not display ischemic be placed according to specifi c landmarks. Variation in the changes. However, when serial ECGs obtained later are com- placement of precordial electrodes can sometimes produce pared against the initial 12-lead ECG, the differences become diagnostically signifi cant changes in the 12-lead ECG. apparent. These comparisons are only valid if the electrodes The fi rst electrodes, V1 and V2, are placed within the 4th have been placed in the same position. intercostal space at the right and left sternal border, respec- The American Heart Association emphasized proper lead tively. Mistakenly, Paramedics may palpate the space just placement in 1938 when it fi rst standardized the placement below the clavicle, assume it is the 1st intercostal space, and of precordial leads. It continues to establish the standard for start counting down three more spaces. This placement is electrode placement in order to obtain a clinically relevant incorrect and will cause V1 and V2 to be placed too high. 12-lead ECG.18 The Paramedic should fi rst identify the suprasternal notch above the sternum and palpate inferiorly until a ridge is felt. Standard Limb Leads The ridge on the bone is the connection of the manubrium Limb leads are traditionally placed where Einthoven placed to the body of the sternum (the angle of Louis). Moving lat- them—on the end of the extremities. One electrode should be erally to the right, the Paramedic should palpate the second placed on the ventral surface of the right and the left wrist and intercostal space along the sternal border and then palpate the another placed on the ankle proximal to the medial malleolus. spaces downward until the 4th intercostal space is palpated. Diagonostic ECG—The 12-Lead 761 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 34-5 Precordial electrode placement. The fi rst precordial electrode, V1, is placed on the right The Paramedic should document if it is necessary to per- s ternal border and V2 is placed across from V1 at the same form the 12-lead ECG on a patient in a semirecumbent posi- level on the left sternal border. tion, such as in a wheelchair |
or recliner. The patient’s change From the V2 position, the Paramedic should palpate the in position from Fowler’s position, at a 45-degree angle, causes 5th intercostal space and move laterally to the midclavicular the heart to swing anterior and closer to the chest wall. line to place the V4, the third electrode. The fourth electrode placed is V3, which is placed midpoint along an imaginary Dextrocardia line that runs between V2 and V4. Continuing to palpate along the 5th intercostal space, the Some patients have a congenital condition in which the body’s Paramedic should place V5 at the left anterior axillary line, organs are mirror opposite of normal. Situs inversus, which in line with the iliac crest, and V6 at the 5th intercostal space is a complete reversal of all thoracoabdominal organs, occurs along the left midaxillary line (Figure 34-5 and Table 34-1). in less than 1 in 10,000 patients but has been a documented If the patient has large breasts, male or female, place V4 medical phenomenon since 1643. If the heart and lungs are under the breast and V3 over the breast. The V4 electrode opposite and the abdominal organs are in their usual position, should be placed fl at against the chest and not partially on the this is referred to as dextrocardia.19 breast and the chest. This position would cause the electrode When the Paramedic initially places the patient on the to fold over on itself and will not sense the electrical activ- monitor to determine a rhythm, it will be noted that Lead I ity. If the patient is small or thin, then place the electrodes is inverted. An inversion in Lead I is suggestive of dextrocar- between the ribs, avoiding the bony prominences, if possible. dia. A standard 12-lead ECG will support the diagnosis. The patient with dextrocardia will have a P wave axis greater than Table 34-1 Lead Names with Correct Electrode 90 degrees and a poor R wave progression, both discussed Placement shortly.20 If dextrocardia is suspected, or the patient confi rms LA Left arm over muscle or fl esh dextrocardia, then the Paramedic should proceed by placing RA Right arm over muscle or fl esh the electrodes on the right side of the thorax. The Paramedic LL Left leg over muscle or fl esh should make a note on the 12-lead ECG printout that dextro- RL Right leg over muscle or fl esh cardia is suspected and right-sided chest leads were placed. V1 4th ICS RSB, 4th right intercostal space at the sternal border V2 4th ICS LSB, 4th left intercostal space at the sternal border 12-Lead ECG Tracing V3 Between V2 and V4 V4 5th ICS MCL, 5th left intercostal space at the midclavicular line Before reading a 12-lead ECG the Paramedic must under- stand the standard layout of the printout. Like a rhythm, a V5 5th ICS LAAL, 5th left intercostal space at the anterior axillary line 12-lead ECG is never read off the monitor screen but instead V6 5th ICS LMAL, 5th left intercostal space at the midaxillary line is printed out for careful analysis. 762 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 34-6 Normal 12-lead ECG. A 12-lead ECG is printed in a standard four-column For ease of conceptualization, the left ventricle is said format. The 12-lead ECG machine reads three leads simul- to have four walls. It is actually a cone-like shape with taneously for 2.5 to 3 seconds until all 12 leads are obtained artifi cially contrived sides. The lower portion of the left ven- and then prints out the 12-lead ECG. tricle, next to the epigastrium, is called the inferior wall. The Beginning on the far left column, the printout contains the portion of the left ventricle that is shared with the right ventri- standard limb leads I, II, and III. The 12-lead ECG machine then cle (the septum) is called the septal wall. That foremost por- uses the limb leads and, with the creation of Wilson’s central tion of the left ventricle, where the bulk of the myocardium terminal, creates the augmented leads, aVR, aVL, and aVF. exists, is called the anterior wall. The last wall, the lateral wall, Moving from the limb leads to the precordial leads, the is actually an extension of the left ventricle’s anterior wall. 12-lead ECG machine reads and records the precordial leads, starting with V1, V2, and V3, then reads and records V4, V5, Contiguous Leads and V6 (Figure 34-6). In some instances, the 12-lead ECG machine will simul- An ECG lead gives the Paramedic a view of a particular taneously record both the 12-lead ECG and the monitor lead portion of the left ventricle. The 12-lead ECG allows the and a single monitoring strip may be printed across the bottom. Paramedic to have several views of the heart in an effort to Although most machines will default to Lead II for the moni- try and capture evidence of myocardial injury. When two or toring strip, the Paramedic may choose to record a different more leads look at the same wall of the left ventricle, they are lead depending upon the patient’s condition. said to be contiguous leads. ECG leads are related to each other by the position of the positive electrode which, in turn, affords a specifi c view of Street Smart a particular portion of the ventricle. In the standard 12-lead ECG, the limb leads II, III, and the augmented lead, aVF, the positive electrode is located on the lower extremity and looks Some older 12-lead ECG machines can only print a up toward the bottom of the heart. The bottom of the heart is single lead at a time. These machines, called single- a portion of the left ventricle called the inferior wall. Thus, channel machines, print the 12-lead ECG in the same these leads (II and aVG) are called inferior leads and can be said to be contiguous. sequence but in one very long ECG strip. Leads I, aVL, V5, and V6 have the positive electrode located on or beneath the left arm. These leads look at the heart’s lateral wall and are called lateral leads. Similarly, Electrocardiographic Assessment leads V1 through V4 have the positive electrode on the front of Left Ventricular Function of the chest. These leads look at the front portion or anterior wall of the left ventricle. The front of the chest is a large The left ventricle is essential for cardiac output to the body area. Thus, these leads are broken into subcategories. V1 (in general) and to the brain (in particular). All other portions and V2 have the positive electrode over the interventricular of the heart (the atriums and the right ventricle) could be con- septum and are also referred to as septal leads. V3 and V4 sidered auxiliary to the left ventricle. In fact, loss of any one continue to be known as true anterior leads. of these auxiliary portions of the heart is survivable, whereas In some cases, the evidence of myocardial damage loss of the left ventricle is usually fatal. For this reason, the spreads across two walls of the left ventricle. In those cases, 12-lead ECG focuses on the left ventricle. both walls are used in the description. For example, injury Diagonostic ECG—The 12-Lead 763 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Table 34-2 Contiguous Leads artery. The right coronary artery (RCA) runs the length of the heart and has a minor branch, called the marginal branch, • Pure changes towards its terminus. Conversely, the left coronary artery II, III, aVF Inferior (LCA) divides almost immediately at its mainstem into the V1, V2 Septal left anterior descending coronary artery (LAD) and the cir- V3, V4, V5 Anterior cumfl ex (Cx). I, aVL, V5, V6 Lateral The right coronary artery (RCA) provides blood to the infe- • Mixed changes rior wall of the left ventricle and to the AV node in the majority of patients. Thus, ECG changes in the inferior leads of II, III, V1, V2, V3, V4 Anteroseptal and/or aVF would suggest that the RCA may be involved. I, II, III, aVL, aVF, V5, V6 Inferolateral The left main coronary artery serves the entire anterior I, aVL, V3, V4, V5, V6 Anterolateral wall including the septum. Occlusions of the left main stem, II, III, aVF, V1, V2 Inferoseptal referred to as “widow makers” (thus emphasizing the impor- • Global changes tance of the LCA), can cause global anterior wall damage. V1, V2, V3, V4, V5, V6 Global anterior ECG changes in the anterior leads of V1 to V4 and the lateral I, II, III, aVL, aVF, aVR, leads of I, aVL, V5, and V6 suggest that the LCA is affected. V1, V2, V3, V4, V5, V6 Global The LCA almost immediately bifurcates, giving rise to the left anterior descending (LAD) coronary artery and the cir- cumfl ex coronary artery (Cx). The LAD artery serves the cen- to both the anterior wall and the septal wall, as evidenced tral portion of the anterior wall of the left ventricle. Therefore, by ECG changes in the contiguous leads V1, V2, V3, and anterior wall ECG changes would be expected (V3 and V4). V4, would be referred to as anteroseptal. Similarly, myo- Lesser branches off the LAD, called the septal perfora- cardial damage to both the inferior and the lateral wall, as tors (SP), provide the septum with blood, including the bundle evidenced by ECG changes in Leads I, II, III, aVL, aVF, V5, branches. Atherosclerotic involvement of the SP will injure and V6 would be called inferolateral. If there are changes the septum and may cause ECG changes in leads V1 and V2 suggestive of damage to the entire myocardium (i.e., ECG and possible bundle branch blocks. changes in all leads), then the term “global” is used. ECG The LAD then continues to run along the anterior inter- changes in only two contiguous leads are necessary to make ventricular (AIV) groove which separates the right and left a presumption of myocardial injury (Table 34-2). ventricles toward the apex of the heart. Along its path another minor branch of the LAD, which cuts diagonally away from the AIV and toward the anterolateral wall and the apex of the Street Smart heart, is the diagonal (Dx). Distal occlusions of the Dx can give rise to ECG changes in leads I, aVL, V5, and V6 as well as V4 and V5. When a Paramedic sees global changes across all The circumfl ex coronary artery (Cx) was the second artery of the 12-leads, consideration should fi rst be given at the bifurcation of the left coronary artery. The Cx follows the to extra-cardiac causes (i.e., those conditions, atrioventricular groove to the lateral wall of the left ventricle. In most cases (approximately 85% of patients), the Cx stops at such as hypoxia, that could lead to damage to the the left lateral wall. In 15% of patients, the Cx continues and entire heart).21–23 The likelihood that all of the provides perfusion to the AV node. Normally blood for the AV coronary arteries could have a catastrophic event node comes from the right coronary artery. In those cases, the patient is said to be “left dominant,” indicating an alternative simultaneously is extremely unlikely. blood supply to the AV node as opposed to the normal blood supply. The diffi culty for the patient who is left dominant arises when an |
occlusion of the left coronary artery occurs and almost Relationship to Coronary Arteries the total of the left ventricle’s myocardium is hypoperfused The main coronary arteries perfuse specifi c areas of the heart (Figure 34-7 and Table 34-3). and, in particular, the left ventricle. By evaluating the 12-lead ECG for evidence of myocardial injury in the contiguous leads, the Paramedic can infer that ECG changes in those Interpretation contiguous leads raises a suspicion of involvement of specifi c The primary value of a Paramedic-obtained 12-lead ECG coronary arteries. in the fi eld is the identifi cation of myocardial injury and The coronary arteries originate at the sinus of Valsalva the patient’s transportation to the defi nitive care center. and proximal to the aortic valve, with which they have a sym- However, the value in a 12-lead ECG is not only in the iden- biotic relationship. There are two coronary arteries which are tifi cation of myocardial injury but also in the Paramedic’s simply called the right coronary artery and the left coronary ability to make a prognosis based on that information. By 764 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Left coronary artery Left circumflex branch Right coronary artery Muscular branch Left anterior decending branch Marginal branch Figure 34-7 Coronary artery anatomy. Table 34-3 Relationship of Leads to Walls to Coronary Arteries • II, III, aVF Inferior Right coronary artery (RCA) * • V1, V2 Anteroseptal Left anterior descending (LAD)/(SP) * • V3, V4 Anterior Left anterior descending (LAD) • V3, V4, V5, V6 Anterolateral Diagonal (Dx) • I , aVL, V5, V6 Lateral Circumfl ex (Cx) • V1, V2, V3, V4, V5, V6 Global anterior Left mainstem (LCA) R L Septal activation from left to right having information about the location of the myocardial injury, the Paramedic can prepare for complications associ- Figure 34-8 Septal depolarization. ated with that injury. 12-Lead ECG Identifi cation A Q wave is not always visible in every patient, nor is it seen in every lead (Figure 34-8). The presence of a small Q wave, of Myocardial Injury called a physiologic Q wave, is normal.24 Following the depolarization of the septum, ventricular The era of the ECG identifi cation of acute myocardial infarc- depolarization occurs. Normally, ventricular depolarization tion may have started with Harold Pardee when he published proceeds from the endocardium outward to the epicardium the fi rst ECG of an acute myocardial infarction, describing (Figure 34-9). The specifi c wave pattern (i.e., rS, Rs, etc.) is a the T wave as “tall” and “starts from a point well up in the function of the electrode’s placement. For example, since the descent of the R wave.” From that point, physicians have energy is going away from V1, the QRS defl ection should be had a keen interest in using the 12-lead ECG to identify the negative. The energy is going toward V6 and the QRS defl ec- patient with acute coronary syndrome who is at risk for an tion in V6 should be primarily positive. acute myocardial infarction. Normally the segment between the QRS and the T wave, Normal Depolarization called the ST segment, is isoelectric as the Purkinje fi bers start to repolarize (Figure 34-10). and Repolarization Ventricular repolarization is represented by the T wave. Normal ventricular depolarization begins with the onset In a reverse process, normal repolarization begins at the epi- of the QRS complex. The fi rst negative defl ection, called a cardial surface and progresses through the ventricular walls Q wave, represents the depolarization of the septum. to the endocardium. The process of repolarization involves Diagonostic ECG—The 12-Lead 765 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. * * * * * * R L R L R L Activation of anteroseptal region of the Activation of major portion of ventricular Late activation of posterobasal ventricular myocardium myocardium from portion of the left ventricle, endocardial to epicardial surfaces the pulmonary conus, and the uppermost portion of the interventricular septum Figure 34-9 Ventricular depolarization. Ventricular Ventricles Ischemia repolarization repolarized Injury 450 ms 600 ms Infarct Electric force due to infarct + – + – + – – + + – – –– + – + R + + R T T P P Q Q Figure 34-11 The ischemic penumbra. Figure 34-10 Ventricular repolarization. cell necrosis and myocardial infarction called penumbra resuming a negative interior of the cell compared to the out- (Figure 34-11). The cellular changes that occur during pen- side. The combination of the interior of the cell becoming umbra can be witnessed by the Paramedic as changes in the more negative while moving away from the positive electrode ECG. These ischemic patterns are the result of abnormal results in a positive defl ection on the screen. The T wave rep- repolarization. resenting ventricular repolarization is positive or upright in There are three successive stages before myocardial all leads except aVR. cell death: ischemia, injury, and infarction. These stages are evolutionary and affect tissues incrementally, spread- Ischemic Patterns ing out from a central point in a bull’s eye fashion. They can be described as the three “I’s” of acute coronary syn- A healthy myocardial cell requires oxygen, glucose, and a drome (ACS). balance of electrolytes in order to function (i.e., to depolar- ize, then repolarize). Abnormal depolarization/repolarization Ischemia occurs whenever the myocardial cells lack these essential conditions. The most common cause of myocardial dysfunc- The fi rst change is myocardial ischemia. During the isch- tion is acute occlusion of the coronary arteries. emic phase, myocardial cells are deprived of oxygen and As a result of this occlusion, and subsequent hypoxia, hypoxia ensues. During this phase, the myocardial cells the myocardial cells go through a predictable pathway to convert to anaerobic metabolism to conserve energy. This 766 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. J Point V1 V4 To decide if an ST segment is depressed or elevated, the Paramedic starts by identifying the J point. The J point is the start of the ST segment and is found at the juncture of V2 V5 the QRS and the ST segment, the point where the angle from the QRS changes. To fi nd the J point, the Paramedic starts at the beginning of the P wave and draws a straight line across V3 V6 to where it crosses the T wave. If any portion of the ST seg- ment is below that line, then there is ST-segment depression. If any portion of the ST segment is above this line, there is an Figure 34-12 Hyperacute T waves. ST-segment elevation. If the Paramedic is unable to fi nd the beginning of the P wave, then the line is drawn from the bot- tom of the calibration wave straight across. decreased cellular activity slows myocardial repolariza- tion. As coronary perfusion occurs from the surface (or epi- ST-Segment Elevation cardium) inwardly, the deeper myocardial tissues become As the injury continues and becomes full thickness (transmu- ischemic fi rst. This limited ischemic involvement is called ral), the ST segment starts to rise (ST-segment elevation). subendocardial ischemia. This slowing of repolarization Myocardial injury, as manifested by ST-segment elevation does not alter the direction of repolarization; therefore, the in the ECG leads overlying the area, generally occurs after ECG will appear normal, but it does lengthen the time for 20 to 40 minutes of ischemia.25 Some examples of ST- repolarization. Accordingly, the fi rst manifestation of myo- segment elevations in the anterior leads include some cardial ischemia can be a lengthening QT interval. “tombstone” elevations in V2, V3, and V4 (Figure 34-13). As the cell’s sodium–potassium pump starts to falter, due to insuffi cient ATP, potassium leaks from the cell. The Patterns of Ischemia and Penumbra leaking potassium causes an increase in the amplitude of the At this point, the Paramedic may see a complex picture of T waves, called a hyperacute T wave, in the leads facing T wave inversions, ST-segment depressions, as well as ST the damage (Figure 34-12). elevations. These markings represent the process of ischemia Transmural ischemia occurs as the ischemia and are manifestations of penumbra. The key is to focus on reaches the point where it affects the entire thickness of those leads that indicate the greatest degree of damage. The the myocardium, from the endocardium to the epicardium. other ECG changes should radiate away from the location of Then, the deeper myocardial cells begin to malfunction. the primary event. Normally, when repolarization occurs, the polarity changes as potassium is pumped back into the cell. This reverses the cur- Infarction rent. Repolarization results in an upright T wave on the ECG. However, when the ischemic endocardial cells deeper in Without oxygen, the myocardial cells eventually die (myo- the myocardium fail to repolarize, the result is a loss of the cardial infarction), and the area begins necrosis, a physi- change in direction of polarity which normally occurs dur- ologic process in which dead cells are removed and new ing repolarization. This failure to change in direction causes cell growth may occur. The ECG hallmark of this change a negative defl ection in the T wave. Without repolarization is the development of pathologic Q waves. Pathologic and the subsequent negative polarity of the myocardium, the Q waves indicate electrical silence (i.e., no depolarization) normally upright T waves become inverted in the ECG leads that overlay the ischemic area. In some cases, inverted T waves will be one of the fi rst electrocardiographic changes that the Paramedic will observe. Street Smart Injury It is estimated that in some 50% of initial ECGs taken The persistent hypoxia causes the myocardial cells to change on patient’s with cardiac related chest pain, the from ischemia to injury. The faltering sodium–potassium pump of the injured myocardial cells can no longer maintain Paramedic may not see ST-segment elevations with polarization and the cell becomes electrically inert. At fi rst the initial 12-lead ECG because the event has not the injured endocardial cells tend to draw the ST segment evolved to that level. Nevertheless, it is important to downward (ST-segment depression). An ST segment, by defi nition, is a >1 mm depression below the J point from iso- obtain a baseline ECG for later analysis, particularly electric baseline. To decide if the ST segment is depressed, for QT intervals and T wave changes. the Paramedic must fi rst ascertain the J point. Diagonostic ECG—The 12-Lead 767 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. A B C D E F Figure 34-13 ST-segment elevation due to acute MI tracings. A and B show oblique straightening; C and D show a concave upward appearance; E and F show a more horizontal or fl attened ST appearance. in that portion of the ventricular wall. Because that portion Pathologic Q |
Wave of the ventricular wall is electrically silent, the depolariza- QRS tion in the opposite wall, going away from the electrodes in complex that lead, is the only signal present. It is recorded as a nega- tive defl ection on the ECG. Width Q waves can also represent the depolarization of of QRS: the intraventricular septum. As the septum depolarizes 1 Box from left to right, any leads that are looking from the left 0.04 sec. (i.e., the lateral leads I, V5, and V6) will show a negative defl ection. These physiologic or septal Q waves are normal x (Figure 34-14). While some Q waves are normal (physiologic), the Q waves associated with infarction (pathologic Q waves) are deep (greater than 25% of the R wave) and wide (typi- cally 0.04 seconds). These characteristics, and the presence Q wave >1/3x of Q waves in contiguous leads, suggests pathology and infarction.26 The presence of a Q wave in a 12-lead ECG is confi rma- tion that the patient has had a transmural myocardial infarc- A significant Q wave should be: 1. One-third height of QRS complex tion. Q waves can remain for years, alerting the Paramedic 2. 0.04 second (one small box wide) in duration to the presence of an acute myocardial infarction (AMI) in the past. In up to 30% of 12-lead ECGs with Q waves, Figure 34-14 Q waves. 768 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Street Smart A Normal An isolated pathologic Q wave in Lead III may be a Ventricular G wall normal fi nding and is not indicative of an inferior wall AMI unless it is accompanied by other ECG changes in the contiguous leads II and aVF. B Ischemic area T Wave S-T the Q waves resolve, especially in the inferior wall, within C Ischemic zone one year.27 "Injury" Electrocardiographic Diagnosis Q of Acute Myocardial Infarction D Ischemic zone Zone of "injury" Infarction To make an electrocardiographic diagnosis of acute myo- cardial infarction, the Paramedic looks for hyperacute T waves, T wave inversions, ST-segment depressions, and ST-segment elevations as well as Q waves in all leads. E Ischemic zone When a pattern of ischemia is noted (ECG changes in con- Infarction tiguous leads), then the Paramedic may have a high index of suspicion that the artery which perfuses the correspond- ing wall is occluded.28 The presence of Q waves in the face of concomitant ST F Infarct (healed) elevation speaks to the evolution of the infarction and may Scar indicate that this MI has been in progress for several hours (Figure 34-15). However, the presence of ST elevations indi- cates that there may be myocardium that can be salvaged with Figure 34-15 Wave changes during evolution thrombolytic therapy or interventional cardiology. of myocardial damage. Reciprocal Changes Supporting evidence of an acute myocardial infarction in Table 34-4 Reciprocal Changes progress are reciprocal changes. Reciprocal changes are ST-segment depressions seen on the 12-lead ECG in leads Reciprocal Reciprocal Wall Artery Lead Wall Leads that face the wall opposite of those with ST-segment eleva- tions. Reciprocal changes are more commonly seen in infe- Inferior RCA II, II, aVF Lateral I, aVL rior wall AMI (approximately 70%) versus anterior wall AMI Anterior LAD V3, V4 Inferior II, III, aVF (about 30%).29,30 The presence of reciprocal changes is an Lateral Cx I, aVL, V5, V6 Inferior II, III, aVF excellent marker of acute myocardial infarction in progress and has a positive predictive value of 90%. The ST-segment depression of reciprocal changes is thought to be due to “mirror refl ections” of the electrical signal from the affected wall. The ST-segment depression seen in a reciprocal change is more downsloping than those Street Smart caused early in an AMI and is typically seen when the AMI is large. ST depressions seen in reciprocal changes can be As an example of the predictive value of reciprocal helpful in distinguishing infarction from the normal changes, ST depression in leads V1, V2, V3, and V4 (all ante- variants in African American males who have ST rior leads) suggests an acute myocardial infarction in evolu- tion in the posterior wall and an occlusion of the circumfl ex elevations. artery (Cx) (Table 34-4). Diagonostic ECG—The 12-Lead 769 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. R Wave Progression may also observe that the T wave is opposite in defl ection to the QRS in all precordial leads, as well as a notching in the In a normal 12-lead ECG, there is a series of changes in the anterolateral leads. primary defl ection of the QRS from negative in V1 to posi- The characteristic appearance of a notched QRS in V6 tive in V6, called an R wave progression, in the precordial (i.e., RsR’) is the result of the electrical impulse crossing the leads. Starting with the deep S wave in V1, the defl ection right bundle branch, depolarizing the right ventricle, then in the precordial leads gradually changes direction, with a crossing the interventricular septum to depolarize the left transition at approximately V3 or V4, until V6, where there ventricle. is a tall R wave. A common cause of an LBBB is occlusion of either the Whenever there is an electrical disturbance in the ante- left anterior descending (LAD) coronary artery or one of the rior wall, secondary to ischemia, then the R wave progression septal perforators which branch from the LAD. These coro- is disturbed (specifi cally when there is a loss of R waves in nary arteries perfuse the septum and the bundle branches that the anterior precordial leads). The loss of an R wave progres- lie within. sion, sometimes called a reverse R wave progression, is sug- Because of the delayed repolarization, the ST segment of gestive of an anterior wall AMI. the septal leads will be elevated and the 12-lead ECG will have If the transition occurs early (i.e., before V3), it may be the appearance of an anterior wall AMI (AWMI). However, indicative of a posterior wall AMI. The Paramedic may then there are a number of benign conditions, including advanced want to consider obtaining leads V7, V8, and V9 (discussed age and hypertension, that can also cause an LBBB.31 later). If the transient occurs later, after V4, it can be sug- In some cases, because of advanced atherosclerotic dis- gestive of an anterior wall AMI. However, a late transition ease, the patient may experience a rate-related bundle branch can also occur if the patient has a thick chest or has respira- block. These blocks occur because the bundle branches are tory disease, particularly if there are small R waves in the incapable of repolarizing, secondary to decreased perfusion, right precordial leads, or may be a normal variant in some at faster rates. Because of slower conduction, there is reduced women. strength of contraction and the patient may experience heart failure. Street Smart Street Smart Some Paramedics may use the term “poor R wave progression.” The American Heart Association prefers Whenever an LBBB occurs, the patient is at risk of the term “reverse R wave progression” instead. It heart failure. Therefore, the administration of any should be noted that improper lead placement can Vaughn-Williams Class 1 drugs (i.e., lidocaine or cause a reverse R wave progression. procainamide) can slow conduction even further, leading to worsened heart failure and even to drug- induced complete heart block. The isolated appearance of a reverse R wave progression (RRWP) should not be taken to mean that the patient is hav- ing an anterior wall AMI. There are other causes of RRWP Typically, the altered electrical pathway associated with which include a pre-existing left bundle branch block, dex- LBBB makes the ECG diagnosis of AMI complicated. Therefore, trocardia, and Wolff–Parkinson–White (WPW) syndrome. if a Paramedic observes an LBBB on initial 12-lead ECG, no Nevertheless, the presence of a reverse R wave progression, further interpretation is possible because a diagnosis of AMI by coupled with a good history for ACS and other 12-lead ECG ECG cannot be made with confi dence. However, the presence of changes in the anterior leads, is helpful in diagnosing an ante- a new onset LBBB during the course of patient care is an ECG rior wall AMI. fi nding highly suggestive of an AMI. The Paramedic should report the appearance of a new New Onset Left Bundle Branch Block onset LBBB and, coupled with a patient history suggestive A left bundle branch block (LBBB) (Figure 34-16) is a par- of ACS, have a high index of suspicion that the patient is tial heart block (when the impulse fails to be conducted) having an AMI.32–34 Patients with a new onset LBBB have which involves one or both the left fascicles of the left bun- a worse prognosis for their AMI compared to those without dle. As a result, the ventricular wall of the affected side must the conduction delay. Because of the prolonged conduction, be depolarized by a wave front from the opposite side. This and the resultant decreased inotropy, a patient with an LBBB delay in depolarization prolongs the QRS to greater than may experience as much as a 25% loss of cardiac output. 0.14 seconds for a left bundle branch and a small narrow Paramedics should treat new onset LBBB more aggressively, R wave (less than 0.04 seconds) in all leads. The Paramedic with a keen eye on the development of heart failure. 770 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. I aVR V1 V4 II aVL V2 V5 Block of left main bundle branch Right or III aVF V3 V6 bundle block of left anterior branch and posterior fascicles Wide QRS complex prolonged (≥ 0.12 second). with ST depressions and inverted T waves, particularly in leads I, aVL, V5 and V6 Electrical vector directed toward left ventricle as is normal, but delayed and prolonged Figure 34-16 Left bundle branch block. infarction (MI) or ischemia, heart failure, pulmonary embo- Street Smart lism, or valvular disease. An LBBB during the course of an AMI can progress Nondiagnostic ECG to a complete heart block. As a result of this In some cases, the patient may have a benign 12-lead ECG. The absence of patterns of ischemia on a 12-lead complete heart block (CHB), the escape rhythm ECG does not preclude the diagnosis of an AMI. When the will be idioventricular. Typically, patients with an 12-lead ECG is nondiagnostic, the Paramedic should main- idioventricular rhythm require a pacemaker. tain a high index of suspicion based on the patient’s clinical presentation and, more specifi cally, the history of present illness. Right Bundle Branch Block In some cases, the diagnosis of AMI on 12-lead ECG is missed because of the low amplitude of the QRS. When the A right bundle branch block (RBBB) is a type of heart block amplitude of the QRS is less than 5 mm in the standard limb in which the impulse fails to be conducted down the right leads (i.e., low amplitude QRS), an assessment of ST-segment bundle of the bundle of His. In a RBBB, the impulse travels change is nearly impossible. Causes of low voltage, resulting rapidly to depolarize the interventricular septum and |
down the in a low amplitude QRS, include pericardial effusions leading left bundle branch to activate the left ventricle. Since the right to constructive pericarditis, pleural effusions, and obesity.35–37 bundle branch is blocked, the impulse must cross the inter- ventricular septum to activate the right ventricle. Because it takes more time to depolarize the entire ventricle, the QRS is Electrical Alternans greater than 0.12 seconds in width. When every other ECG complex has alternating amplitude The ECG diagnosis of RBBB is also supported by a (i.e., the one QRS complex is smaller when compared to small terminal R wave in V1 and a slurring of the S wave in the next), then the patient may have electrical alternans. the lateral leads (i.e., Lead I and V6). The T wave in V1 will Electrical alternans is more frequently seen in the precordial also be in the opposite defl ection of the QRS. leads and is a sign of pericardial effusion. A RBBB is one of the most common defects in ventricular The alternating amplitude of the QRS is thought to be the conduction (Figure 34-17). RBBB occurs often, and without result of the heart swinging, in a pendulum fashion, from apparent cause, in normal hearts. Treatment is directed at the the wave created in the pericardium as the heart beats within cause of the conduction defect, which can include myocardial the accumulation of fl uid. Diagonostic ECG—The 12-Lead 771 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. I aVR V1 R' V4 R II aVL V2 V5 Sinoatrial (SA) node Atrioventricular Left anterior fascicle (AV) node Common III aVF V3 V6 bundle of His (AV) Bundle Right and left bundle Block branches Purkinje fibers Total QRS complex prolonged (≥0.12 second). Terminal broad S wave in lead I. RSR' complex in lead V1 Late abnormal Left posterior electrical vector fascicle bypasses block Figure 34-17 Right bundle branch block. Alternative Etiologies for ECG Abnormalities Street Smart The Paramedic should keep an open mind when reading a 12-lead ECG for alternative causes of prolonged QT intervals, One of the fi rst ECG changes associated with T wave abnormalities, and ST-segment elevations. Although hypothermia is a prolonged QT interval. The diffi culty these aberrant changes do not typically mimic the pattern in obtaining a 12-lead ECG, because of the cold skin of ischemia, a quick glance could mislead a Paramedic into thinking that there is a pattern of ischemia. Careful atten- and resultant poor penetration of the electrode gel, tion to the ECG for patterns of ischemia and a disciplined makes this assessment problematic. approach to interpretation will yield the best results. Prolonged QT Intervals The length of the QT interval is inversely related to the One of the fi rst ECG changes which can occur as a result patient’s heart rate. Therefore, when calculating a patient’s QT of anterior wall myocardial ischemia (AWMI) can be a pro- interval, it must be corrected with the heart rate. Typically, longed QT interval. However, there are a host of other etiolo- Paramedics and physicians use Bazett’s formula to obtain gies for prolonged QT intervals.38,39 The majority of causes the correct QT interval. Under emergency conditions, the of acquired prolonged QT intervals involve electrolyte QTc (corrected QT) can be derived from information on the abnormalities (e.g., hypokalemia) and medications. Vaughn- 12-lead ECG. Alternatively, the Paramedic can take the heart Williams Class I and III drugs are the leading offenders and rate and, for every ten (10) beats above 70, subtract 0.02 sec- have been repeatedly implicated as the cause of prolonged onds from 0.40 seconds, and for every ten (10) beats below QT intervals. Other potential offenders include psychotropic 70 add 0.02 seconds. medications (particularly tricyclic antidepressants and phe- nothiazines), antibiotics (such as erythromycin), and toxins T Wave Abnormalities (such as organophosphates).40 Generally, the T wave in a normal ECG is in the same defl ec- In some cases, the cause of the prolonged QT interval is tion as the preceding QRS in the limb leads. The normal congenital. These patients may have presented in their youth T wave is slightly asymmetrical, with the upstroke of the with unexplained syncopal episodes. For this reason, any leading edge of the T wave being gentle compared to the patient, regardless of age, who has an unexplained syncope downstroke. Any deviation from those conditions would should be a candidate for a 12-lead ECG. be abnormal. 772 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. T wave abnormalities can include T wave inversion, fl at- Table 34-6 Causes of ST-Segment Depression tened or low-amplitude T waves, and peaked or hyperacute T • Hypokalemia waves. There are numerous causes for the T wave abnormalities • Hypothermia that can be suggestive of a number of disorders (Table 34-5). With the exception of hyperkalemia, the isolated presence of • Hypertrophy–Ventricular a T wave abnormality is not diagnostic of any condition and requires further investigation. Medications, for example, can cause alterations in the Hyperacute T Waves ST segment. A classic cause of ST-segment depression is digitalis. Digitalis alters ventricular depolarization, resulting Hyperacute T waves are defi ned as T waves greater than 5 mm in a “ladle” appearance of the ST segment (Figure 34-18). in the limb leads and greater than 10 mm in the precordial Other causes of ST-segment depression include suba- leads. While a peaked T wave in contiguous leads is sugges- rachnoid hemorrhage and hypokalemia. Hypokalemia (serum tive of ischemia, hyperacute T waves in all leads is highly sug- potassium less than 2.8) will produce ST-segment depression in gestive of hyperkalemia.41,42 Hyperkalemia can be the result 80% of patients, along with fl attened T waves (Figure 34-19). of renal failure or crush injury, or seen in cases of diabetic Similarly, ST-segment elevation can be a normal vari- ketoacidosis (DKA). Conversely, fl attened T waves are sugges- ant, with some patients demonstrating a 1 to 2 mm ST seg- tive of hypokalemia, a defi cit in serum potassium that can be ment rise, particularly if the ST segment has an upward the result of potassium-wasting diuretics (e.g., furosemide). concavity and/or a notch at the J point (Table 34-7). This fi nding is particularly common among African Americans ST-Segment Abnormalities and leaves the ST segment with a fi shhook appearance. While an ST-segment depression is suggestive of ischemia when seen in select contiguous leads, a global ST-segment depression, affecting all of the precordial leads, suggests the Street Smart etiology is likely extra-cardiac (Table 34-6). Table 34-5 Potential Causes of T Wave Current pacemakers are so effi cient that they do not Abnormalities leave a “foot print” (a pacer spike) on the rhythm • CNS disorders strip. The only evidence of a pacemaker may be the Cerebrovascular accident (CVA) slow and wide QRS as well as a slight ST-segment Subarachnoid hemorrhage elevation noted in the precordial leads. • Cardiac disease Mitral valve prolapse Myocarditis Special Case of Pericarditis Pericarditis Pericarditis is an infl ammation of the pericardial sac. As the Ventricular hypertrophy pericardium surrounds the entire heart and is closely adherent Conduction disorders to the heart’s surface, infl ammation of the pericardium will • Bundle branch block cause diffuse and widespread ST-segment elevation in practi- • Ventricular preexcitation cally all leads of a 12-lead ECG.43 • Post ventricular tachycardia When the ST-segment elevations appear unrelated to the • Electrolyte disorders pattern of ischemia seen with any specifi c coronary arteries, there should be a suspicion of pericarditis. Further assessment, Hyperventilation including auscultation for a pericardial rub and an assessment • Pulmonary conditions of the chest pain while lying and seated, are in order. Pulmonary embolism Pneumothorax • Gastrointestinal conditions Table 34-7 Etiologies of Normal ST-Segment Elevation Acute pancreatitis Acute cholecystitis • Therapeutic digoxin • Pharmacology • Pre-excitation syndromes Digitalis WPW Antidysrhythmic agents LGL Alcohol • Early repolarization syndromes (Congenital) Cocaine Brugada syndrome Diagonostic ECG—The 12-Lead 773 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 34-18 Digitalis effect on the ST segment. Figure 34-19 Hypokalemia. Nonspecifi c ST Changes In some instances, the ST segment changes do not fi t a pat- Vasospastic Angina tern of ischemia, nor are they contributory toward another One of the causes of transient patterns of myocardial is diagnosis. In some cases, the ST changes are transitory but chemia is vasospasm. This vasospasm may be the result of not evolutionary. In those cases, the Paramedic merely notes many etiologies, including hyperventilation. These patients that the 12-lead ECG has nonspecifi c ST changes. may present with symptoms consistent with acute coro- There are a number of causes of nonspecifi c ST changes nary syndrome. 12-lead ECGs taken during this time will including improper lead contacts, electrolyte abnormalities, d emonstrate ST-segment elevations that seemingly dis- drug-induced changes, and hyperventilation. Even a drink of appear spontaneously. This condition is called variant or cold water can cause nonspecifi c ST changes. Prinzmetal’s angina. 774 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Approach to 12-Lead ECG Diagnostic Quality Interpretation The last information in the left lower corner of the 12-lead ECG is related to frequency response (Figure 34-22). When There are several published approaches to the analysis and the ECG is used as a monitor for dysrhythmia, the machine interpretation of the 12-lead ECG and each of these meth- reduces the frequency response (i.e., the sample from the sig- ods has one common characteristic. Success in accurate nal) to 0.5 Hz and 20 to 50 Hz. This helps eliminate some of 12-lead interpretations requires a disciplined approach to the the artifact but also diminishes the quality of the ECG. analysis as well as the avoidance of any presumptions. Most The 12-lead ECG must have a frequency response of Paramedics read a 12-lead ECG from left to right, starting 0.05 (not 0.5) Hz to 150 Hz. By “opening” the range, minor at the left corner. The left corner provides information about changes in the ECG are observable. In this way, the 12-lead calibration, speed, and diagnostic quality. ECG can be diagnostic. Unfortunately, the artifact and noise eliminated by the narrow sample supports the importance of Calibration proper skin preparation and proper electrode placement. The 12-lead ECG machine is a scientifi c instrument. As such, it needs to be calibrated to ensure its accuracy. Unlike the 12-Lead ECG Analysis past, when Paramedics had to physically calibrate the ECG Having confi rmed that the 12-lead is accurate (calibrated) machine, current machines are self-calibrating. To demon- and that the 12-lead ECG is diagnostic, the Paramedic can strate this internal calibration, the ECG machine marks the then proceed to analysis. There are several systems of analy- calibration as a squared off calibration mark at the beginning sis. |
The P, Q, R, S, T method helps to ensure that no change of the recording (Figure 34-20). Standard gain is 1 mV to or abnormality is left undetected. Regardless of the method- 10 mm (10 small boxes) of amplitude. ology of analysis, the Paramedic should always maintain a Speed detailed approach to analysis and never rush to judgment over what appears to be obvious signs of ECG changes. The deci- The paper speed (Figure 34-21) is critical for the analysis of sion to label a 12-lead ECG as indicative of acute coronary the 12-lead ECG. The correct paper speed should be 25 mm/ syndrome must be coupled with the patient’s clinical picture second. In some instances, the Paramedic may have slowed and the whole picture taken into consideration. the paper speed to better analyze slope characteristics. (The The start of every 12-lead ECG analysis is to confi rm delta wave of WPW is sometimes diffi cult to discern when the that the patient is not experiencing a dysrhythmia. The fi rst paper speed is 25 mm/second.) However, a slower, or faster, mission of a Paramedic and emergency physician remains the paper speed will impact on the measurement of intervals (i.e., treatment of dysrhythmia. This point is emphasized by the PRI, QRS, and QT), leading to errors in interpretation. placement of a rhythm strip on the bottom of some 12-lead Calibration mark Figure 34-20 Calibration marking on the 12-lead ECG. Diagonostic ECG—The 12-Lead 775 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Paper speed Figure 34-21 The paper speed is indicated on the 12-lead ECG. Frequency response Figure 34-22 The frequency response is indicated on the 12-lead ECG. ECGs. Once the Paramedic has confi rmed that the patient that are indicative of either an old myocardial infarction or a rhythm is normal (i.e., there is a P wave associated with a new myocardial infarction that is late in its evolution. The lat- QRS) and sinus in origin, then the Paramedic can proceed to ter fi nding, Q waves in a late evolving MI, have some impli- the rest of the analysis. cations for further complications. Some Paramedics analyze the 12-lead ECG by pro- Following a search for Q waves, the Paramedic should ceeding in a left-to-right and top-to-bottom fashion. Other take a moment and look at the R wave progression. A reverse R Paramedics, with a trained eye, look for Q waves in the leads wave progression (RRWP) is suggestive of anterior ischemia. that are associated with specifi c coronary arteries (e.g., Leads A RRWP can be likened to an early warning system, alert- II, III, and aVF) overlying the right coronary artery located ing the Paramedic to the possibility of sudden cardiac death in the inferior wall. Paramedics look for pathologic Q waves before other ECG changes, such as ST-segment elevation, 776 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. occur. Anterior wall MI (AWMI) can rapidly progress to Paramedic Prognosis either heart failure or sudden cardiac death. If the AV node is suffering from a lack of oxygenated blood, it Next, the Paramedic should look for ST-segment eleva- will malfunction. As noted in previous chapters, the AV node tions and ST-segment depressions, which are indicative is responsible for delaying the impulse and allowing the atria of reciprocal changes. The importance of delaying to fi nd to contract and push blood into the ventricles. The node is ST-segment elevations, suggestive of an ST elevation myo- also the electrical connection between the atria and the ventri- cardial infarction (STEMI), is to reinforce the importance cles. The artery that serves the AV node is the right coronary of a disciplined approach and to prevent the Paramedic from artery. If ischemic or injury patterns in the ECG leads which leaping to conclusions. look at the area served by the RCA occur, the Paramedic can Finally, the Paramedic would turn to analysis of the T anticipate conduction abnormalities in the monitoring strip. waves. While T waves are supportive of an argument for ACS, The conduction abnormalities may lead to a decrease in coro- isolated T wave abnormalities may have no signifi cance at all. nary output suffi cient to decrease preload and drop the blood Therefore, T wave changes should only be considered in the pressure. Concurrently, blood may back up into the venous context of other ECG changes and the patient’s history. system, leading to distention in the neck veins. Also associ- ated with RCA occlusions are bradycardias. 12-Lead ECG Interpretation With LAD occlusions, the conduction is affected at the Like the approach to a 12-lead ECG analysis, the approach bundle of His, making for more serious conduction abnor- to the 12-lead ECG interpretation must likewise be dis- malities and unreliable escape mechanisms. The anterior wall ciplined. First, the Paramedic should assemble the list of is the largest portion of the left ventricle and is responsible abnormalities (i.e., presence and location of Q waves, R for ejecting blood into the high pressure system. Damage to wave progression, ST changes, and T wave abnormalities). the anterior wall may lead to the inability to eject the blood Refl ecting on these changes, the Paramedic should assess delivered to it and the backup of blood to the lungs. Anterior for lead groupings. Lead groupings are ECG changes in wall damage caused by occlusion of the LAD may lead to contiguous leads that are suggestive of involvement of a pump failure. Treatment options for anterior wall damage specifi c ventricular wall. include anticipation of cardiogenic shock, gross irritability of Armed with this information, the Paramedic can attempt the muscle cells leading to ventricular fi brillation, and reduc- to identify the culprit artery that is involved. Understanding tion of heart rate and workload, leading to a reduction in myo- coronary artery involvement can help the Paramedic pre- cardial oxygen demand. dict the progression of the acute coronary event and prepare for these predictable events. For example, the right coro- Further 12-Lead ECG Interpretation nary artery (RCA) supplies the AV node in the vast majority As the heart’s muscle depolarizes, the energy moves down the of patients.44 ECG changes suggestive of an inferior wall electrical pathway from the sinoatrial node (SA node) to the myocardial infarction (IWMI) implicate the right coronary atrioventricular node (AV node) as a wave front. The electri- artery (RCA) and vis-á-vis the AV node ischemia. This AV cal wave front then moves across the septum in a left-to-right node ischemia can manifest as type I heart block. The fi rst fashion, then to the bundle branches, and fi nally the wave indication of a type I heart block is a prolonged PR interval front radiates outward across the ventricular mass. Each of (PRI). Therefore, a Paramedic confronted with a possible these electrical events can be recorded, over time, on an ECG. IWMI would monitor the PRI in an IWMI for a possible The graphic representation of these events is the traditional heart block. PQRS complexes seen on an ECG. Finally, the Paramedic should consider the 12-lead ECG There is another way to look at the electrical event. as a whole. ECG changes in adjoining walls may be sugges- Instead of looking at depolarization in fragments of P, Q, R, tive of the extent and the evolution of the AMI. For example, and S, the Paramedic could look at the sum of these events. ST changes and T wave abnormalities across all of the pre- The sum of these electrical events would be the common cordial leads, from V1 to V6, are suggestive of an extensive direction of the electrical wave front called the mean electri- AMI. Such a pattern of ischemia could be suggestive of a cal vector (Figure 34-23). left main coronary artery occlusion.45 The implications of To explain vectorography in another way, these electrical left main coronary artery occlusion include acute pulmonary events could be likened to a battle front during a war. While edema (backward failure), cardiogenic shock (forward fail- an army may send out many patrols, some going in different ure), and sudden cardiac death (cardiac arrest). directions, the main objective of the army is to move the front A combination of Q waves, ST changes, and T wave forward. This common direction would be the army’s vec- abnormalities across one or more ventricular walls may be tor. Similarly, while there may be minor defl ections on the suggestive of an AMI later in its evolution. While every ECG, the major direction of the energy during depolarization STEMI has the potential for reversal, the prognosis in a late is toward the apex of the heart. This common direction, or evolution AMI is poorer and the morbidity higher. vector, of the energy of depolarization is called the heart’s Diagonostic ECG—The 12-Lead 777 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. – – – aVL aVR Left + –30° + Right superior + 0° I – Normal – – Right +30° + + + Mean +120° +60° Electrical Vector +90° III II Figure 34-23 Electrical vector. aVF Figure 34-25 Axis determination using the Hexaxial Reference System hexaxial reference system. –90° –120° –60° the depth of the S wave. An equiphasic wave would be nei- ther going toward the vector nor away from it, but would be AVR(+) –150° –30° AVL(+) perpendicular to it. Using that lead, the Paramedic would plot it on the hexaxial reference system (Figure 34-25). The lead represented on the perpendicular spoke would be the heart’s +180° 0° I(+) mean electrical axis in degrees. For example, if the equipha- sic QRS was Lead I, then the perpendicular axis would be 90 degrees. +150° +30° This method of axis determination, while very accurate, is cumbersome in the fi eld. An acceptable alternative is the +120° +60° Grant method. With the Grant method, the Paramedic would II(+) +90° II(+) AVF(+) refer to Lead I and Lead II only (Figure 34-26). If both leads are upright, then there is a normal axis deviation. If Lead I Figure 34-24 Hexaxial reference system. is upright but Lead II is primarily downward in defl ection, electrical axis. Any aberration from a normal electrical axis –90° could be indicative of disease (which is explained in more detail shortly). To help conceptualize the heart’s normal axis, and to help Extreme right Left axis determine if there is any axis deviation, an artifi cial construct axis deviation deviation called the hexaxial reference system was created. To create I I the hexaxial system, the limb leads were drawn around the heart and Lead I, the lead that is horizontal and on the right side, was assigned zero degrees and the left side 180 degrees. II II As the limb leads are part of Einthoven’s Triangle (an equilat- ±180° 0° Right axis eral triangle), then Lead II would be at 60 degrees and negative deviation Normal 120 degrees and Lead III would be at 120 degrees and nega- tive. The three axes are then all drawn into the middle of the I I heart and the three augmented leads overlaid with aVF at 90 degrees, aVL at negative 30 degrees, and aVR at 30 degrees II II and negative 150 degrees. |
The resulting construct shows the heart divided into equal 30-degree segments (Figure 34-24). The traditional method of calculating the mean electri- +90° cal axis was to fi nd the most equiphasic lead of the frontal leads (I, II, III, aVR, aVL, and aVF). An equiphasic lead is Figure 34-26 Determination of axis using an QRS complex with an R wave that is equal in height to Lead I and Lead II. 778 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. then a left axis deviation is assumed. Alternatively, if Lead Differentiating VT from SVT I is primarily downward but the QRS in Lead II is upright, with Aberrant Conduction then it can be assumed it is a right axis deviation. If the QRS Paramedics (and other practitioners) often have diffi culty for both Lead I and Lead II is negatively defl ected, then the determining whether a fast rhythm with a wide QRS complex axis is called an extreme left axis deviation; nicknamed is ventricular tachycardia or supraventricular tachycardia with “no man’s land” because it represents extreme abnormal aberrant conduction. Some patients can tolerate a sustained depolarization. monomorphic ventricular tachycardia for a prolonged period of time, despite opinion that patients cannot tolerate ventricu- lar tachycardia (VT). Because the patient is tolerating what Street Smart appears to be a wide complex tachycardia of unknown etiol- ogy, the assumption is it must be supraventricular tachycardia Many 12-lead ECGs provide a reading of the axis, (SVT) with aberrant conduction. Some patients do develop a rate-related bundle branch block. listed as P-R-T axes. The Paramedic need only read The determination is important as treatments for SVT, the R axis and compare it to the hexaxial reference to such as calcium channel blockers, can lead to rapid patient determine the axis. deterioration if the rhythm is actually VT. Instead of trialing a medication to “see if it works,” at the risk of patient discom- fort and wasted time, a 12-lead ECG can provide the neces- sary information. Ventricular tachycardia occurs most often in patients Street Smart with acute cardiac ischemia or those with a cardiac history. The Paramedic should fi rst obtain a quick patient history, To reduce confusion, some Paramedics use their paying attention to antiarrythmic medications that indicate a thumbs to represent the QRS defl ection—Lead I on the previous history of cardiac dysrhythmia or medications that right hand and Lead II on the left hand. If Lead I is may predispose the patient to arrhythmias (proarrhythmic medications). upright (i.e., the right thumb is up and the left thumb Alternatively, supraventricular tachycardias often occur is down), then there is a left axis deviation. If both in otherwise healthy individuals. Some of these patients Lead I and Lead II are negative, then both thumbs may have a history of SVT or a diagnosis of WPW or LGL syndromes. are down. Next, the Paramedic should obtain a 12-lead ECG, pay- ing particular attention to axis deviation and R wave progres- sion. The fi rst step is to determine if the rhythm is regular. Axis Deviation Ventricular tachycardia is usually very regular. SVT with aberrancy is also usually regular unless the underlying cause Axis deviation is any time the heart’s axis is not normal. is an atrial fi brillation with a rapid ventricular response. If the Determining axis deviation is another means of observing rhythm is atrial fi brillation, then the ventricular response will many pathological conditions. Coupled with other physical be irregularly irregular. While regularity will not help differ- fi ndings, axis determination can help the Paramedic establish a entiate an interpretation of either VT or SVT, an irregularly diagnosis. For example, a right axis deviation which is abnor- irregular rhythm is suggestive of atrial fi brillation.48 mal can often suggest pulmonary pathologies such as pulmo- nary embolism and chronic obstructive pulmonary disease.46 Next, the Paramedic should examine the QRS morphol- ogy in V1. In ventricular tachycardia, the V1 lead will be an R A slight left axis deviation, from 0 to (-) 30 degrees, may wave, where typically there is no R wave. Looking across the be physiologic and seen in obese patients or women who are in chest leads, the Paramedic may also observe an S wave where their third trimester of pregnancy. A larger left axis deviation, typically there is no S wave. from (-) 30 to (-) 90 degrees, is often associated with left ven- In fact, if all of the QRS complexes in the chest Leads tricular hypertrophy, secondary to heart failure, inferior wall MI, or (in some cases) Wolff Parkinson White syndrome.47 V1 through V6 are in the same direction (a phenomena called concordance), the ECG interpretation favors VT. The direc- Of greater concern to the Paramedic is an extreme left tion of the QRS (the polarity) can be either positive or nega- axis deviation (>180 degrees) into “no man’s land.” While tive but should be in the same direction. conditions such as congenital transposition of the great ves- Next, the Paramedic should look at Lead I and Lead sels and dextrocardia can produce this, extreme left axis II. If both leads are negative, or the R vector on the 12-lead deviation in the normal heart is suggestive of ventricular ECG reads between (-) 90 degrees and (-) 180 degrees (i.e., tachycardia. During ventricular tachycardia, the electrical extreme left axis deviation), then the interpretation of VT is source is in the ventricle and the wave front runs backward supported. through the conduction system. Diagonostic ECG—The 12-Lead 779 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Table 34-8 Comparison of VT vs. SVT Paramedic does not usually have access to lab results, the with Aberrancy patient’s history may suggest the potential for electrolyte dis- turbances. For example, patients in end-stage renal disease Supraventricular may experience elevation of potassium levels while those Ventricular Tachycardia Tachycardia patients receiving diuretics may have a decreased level of • History of ischemia • Healthy individual potassium unless they receive potassium supplementation. • Proarrythmic medications • History of SVT A normal potassium level, between 3.5 mEq/L and • Regular or irregular rhythm • Regular or irregular rhythm 4.5 mEq/L, is important for optimum cardiac cell function. If • Dissociated P wave activity • P waves before each QRS the patient is hypokalemic (i.e., serum potassium less than 3.5 • Concordance in the chest leads • R wave progression mEq/L), then the patient may be prone to decreased inotropy. • In V1 ( MCL1), R wave, Rr’, QR, RS • In V1 (MCL1), rSR’ This can lead to generalized weakness or malaise, and/or dys- rhythmias such as atrial fl utter and bradycardia. • In V6 (MCL6), rS, QS, QR • In V6 (MCL6), qRs Causes of hypokalemia are numerous and include vom- • QRS duration of 0.16 sec or more • QRS duration > 0.12 but iting, aggressive gastric suctioning, diarrhea (secondary to < 0.16 sec infectious diseases), or abuse of potassium-wasting diuret- • Initial notching or slurring of QRS • Absent or ending slurring ics such as furosemide. With hypokalemia, the 12-lead ECG of QRS may show T wave fl attening, ST-segment depression, and/or • Axis of –90 to –180 degrees • Axis of –90 to 180 U wave development.49,50 Hypokalemia is often associated with low magnesium Finally, the Paramedic should observe the 12-lead ECG levels or hypomagnesemia (Figure 34-27). Hypomagnesemia for the presence of P waves. Atrial depolarization still occurs may predispose the patient to a form of polymorphic ven- in VT, independent of the ectopic ventricular pacemaker. tricular tachycardia called torsades de pointes.51 Because of the independent atrial and ventricular activity Albuterol is a bronchodilator but also drives potas- (i.e., atrial–ventricular dissociation), P waves will randomly sium into the cells. Aggressive use of albuterol (i.e., stacked appear throughout the 12-lead ECG. P waves that appear reg- treatments) may cause changes in cellular uptake of potas- ularly in front of a QRS suggest a supraventricular ectopic sium, putting the patient at risk for low potassium levels and pacemaker (Table 34-8). dysrhythmias. Perhaps more problematic for the Paramedic may be Miscellaneous Effects on the ECG hyperkalemia. A serum potassium level above 4.5 mEq/L is Electrolyte abnormalities, particularly potassium, can cause considered hyperkalemia. One of the most common causes changes in the appearance of the 12-lead ECG. While the of hyperkalemia is kidney failure. Patients who are on kidney 2.8 2.5 2.0 1.7 Hypokalemia 6.5 7.0 8.0 9.0 Hyperkalemia Figure 34-27 ECG changes associated with hypokalemia and hyperkalemia. 780 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. dialysis are at obvious risk of hyperkalemia prior to dialy- An acute rise in intracranial pressure secondary to sub- sis. Other at-risk patients include patients with diabetes who arachnoid hemorrhage, intracerebral bleed, or an epidural are experiencing diabetic ketoacidosis, patients with severe bleed may lead to wide and deeply inverted T waves in the burns, patients with crush injury, and those patients with chest leads.53–55 The Paramedic’s attention is likely focused acute tubular necrosis secondary to shock. on other more urgent matters during one of these events. The common ECG alterations seen in hyperkalemia However, 12-lead ECG evidence, if obtained, may be useful are changes in the T wave. At potassium levels greater than at the emergency department. 4.5 mEq/L but less than 6.5 mEq/L, the T wave appears tall and Hypothermia affects all cellular functions and can also peaked and is best seen in inferior leads (Lead II and Lead III). cause changes in the ECG. When a patient is hypothermic, all As the potassium level continues to climb toward 8 Eq/L, the of the interval durations (i.e., PR, QRS, and QT) lengthen and QRS starts to widen and a left axis deviation may be appreci- positive defl ections at the J point, or point where the ventricu- ated. Finally, as the potassium level climbs above 8 mEq/L, the lar complex ends and the ST segment begins, become notice- P waves all but disappear and the QRS starts to fl atten into a able. These defl ections are in the same direction (polarity) as sine wave confi guration. It is at this time the patient’s cardiac the QRS and are termed Osborn waves (sometimes called the output has dropped precipitously and the patient is at risk for camel-hump sign). The Osborn wave is seen in all leads, but ventricular fi brillation or asystole. is more prominent in the inferior limb leads. The size of the Arrhythmias caused by hyperkalemia are very diffi cult to Osborn waves correlates directly with the degree of hypo- treat with defi brillation or the usual emergency drugs without thermia. Osborn waves are often diffi cult to discern because lowering the serum potassium level. Calcium chloride, calcium of artifact from muscle tremors (Figure 34-28), but are seen gluconate, or sodium bicarbonate, all competitive electrolytes, in 80% of patients with hypothermia (below 33°C/91.4°F).56 may be used to lower potassium levels. Alternatively, serial Finally, pericarditis, an infl ammation between the treatments with Albuterol may help to treat mild to moderate pericardium and the epicardium, can cause chest pain hyperkalemia. In severe cases, it may be necessary to adminis- and 12-lead ECG abnormalities. Initially, the |
Paramedic ter 50% dextrose with short-acting insulin.52 The insulin helps may be led to believe that the chest pain is secondary to drive both glucose and potassium into the cells. to acute coronary syndrome. However, nitrates are not use- ful in treating the pain of pericarditis, so it is important for the Paramedic to seek historical clues to the diagnosis of pericarditis (i.e., fevers, etc.) as well as ECG evidence. Street Smart The infl ammation that occurs between the sac surround- ing the heart and the epicardium leads to swelling which Calcium is needed for regular cell function. Loss of puts some pressure on the myocardium. The myocardium calcium (serum calcium levels less than 8.5 mg/dL) cannot repolarize as it normally does due to the swelling, so there are T wave changes. The T will become pointed or hypocalcemia is rare. Typical causes of calcium and tall (similar to a hyperacute T wave found in an MI). disturbances are chronic diseases. The effect of However, the changes tend to occur in all leads rather than calcium is seen on the QT interval. Hypocalcemia within contiguous leads only, leading the Paramedic to sus- pect other causes for the chest pain, such as pericarditis. causes a widened QT interval whereas an elevated serum calcium causes a short QT interval. To Evaluation remember that calcium is related to QT, the One of the advantages of the 12-lead ECG is its ability to Paramedic need only remember that QT interval is predict the clinical progression of the patient’s disease if corrected for heart rate and recorded on the 12-lead left unchecked. For example, in the case of a patient with an anterior wall myocardial infarction (AWMI), the patient may ECG as such (i.e., QTc). The little c could represent eventually develop cardiogenic shock secondary to lost myo- calcium, to remind the Paramedic of other causes of cardial function. In this case, the patient had an IWMI that prolonged/shortened QT intervals. could, predictably, either extend to the mitral valve (causing J wave Extra-Cardiac Causes of ECG Changes Potentially devastating extra-cardiac pathologies, such as I intracranial hemorrhage, hypothermia, and pericarditis, can also cause changes on the 12-lead ECG. While not pathogno- monic for these pathologies, they are another sign to be added Figure 34-28 Osborn wave secondary to to the symptom complex for diagnosis. hypothermia. Diagonostic ECG—The 12-Lead 781 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Figure 34-29 Lead placement for a 15-lead ECG, which is helpful in assessing the right ventricle. mitral valve regurgitation) or extend into the right ventricle. It 15-Lead ECG is estimated that 50% of IWMI extend into the right ventricle, with a resultant loss of preload. An additional diagnostic test available to the Paramedic if the Paramedic suspects right ventricular involvement is the 15-lead ECG.57 The electrode placement for a 15-lead ECG will place positive electrodes onto the right side of the chest Street Smart and view the right ventricle. Locations for these electrodes are the 5th right intercostal The right ventricle essentially primes the pump (the space at the midclavicular line, 5th right intercostal space ante- rior axillary line, and 5th right intercostal space at midaxillary. left ventricle). Loss of right ventricular function, The corresponding V4 to V6 wires from the left chest elec- secondary to myocardial injury, can lead to profound trodes are switched over to the right electrodes and the ECG is hypotension. For this reason, some Paramedics rerecorded (Figure 34-29). The repeated ECG is marked right perform a 15-lead ECG to identify right ventricular chest leads or V4R, V5R, and V6R. involvement before administering vasodilators such as nitroglycerin. 782 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. The diagnostic 12-lead electrocardiogram is a useful tool in the Paramedic’s assessment tool box with the potential to improve patient outcome by early detection of cardiac abnormalities. This is especially true in situations where the patient presents with an acute ST elevation myocardial infarction, where the patient can be triaged to the appropriate hospital, or in cases of dynamic changes in the ECG that change with treatment, uncovering underlying cardiovascular disease. Key Points: • Death from AMI remains a national health problem. • Understanding an acute myocardial infarction • requires an understanding of penumbra. Aggressive prehospital treatment including obtaining and interpreting a 12-lead ECG can • Additional ECG evidence, such as new onset left favorably impact patient mortality and morbidity. bundle branch block (LBBB) and reverse R wave • progression (RRWP), are important in supporting Paramedics must have a higher index of suspicion the diagnosis of myocardial infarction. with patient populations that may present with atypical cardiac symptoms. • Some 12-lead ECGs do not show acute changes. • The Paramedic should focus on treating the patient A regular ECG uses standard limb leads, augmented based on history. limb leads, and precordial leads. • • There are numerous extra-cardiac causes to ECG The regular ECG allows for inferior, anterior, abnormalities. and lateral views of the left ventricle, as well as combinations. • 12-lead ECG interpretation takes a disciplined • approach that gathers all the pertinent information Accurate 12-lead ECG requires proper patient to prevent premature interpretation. preparation including standardized electrode placement. • Based on the 12-lead ECG interpretation and the • patient history, the Paramedic can make a fi eld A 12-lead ECG is printed in a standard diagnosis. confi guration. • • Additional information is also available from the Viewing a specifi c combination of leads, called 12-lead ECG that can lend insight into other health contiguous leads, allows correlation to specifi c conditions. ventricular walls. • • The 12-lead ECG can help differentiate ventricular Based upon coronary artery anatomy, ECG changes tachycardia (VT) from supraventricular tachycardia. in contiguous leads permit Paramedics to estimate damage in specifi c arteries. • The addition of three right-sided leads can help • identify right ventricular AMI. Estimation of damage in specifi c arteries permits prognosis and planning. • Early detection of MI, via 12-lead ECG, and rapid transportation to an interventional cardiac care center can lead to better patient outcomes. Diagonostic ECG—The 12-Lead 783 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Review Questions: 1. Why is Paramedic use of 12-lead ECG the fi rst 5. Where are leads placed for a right-sided ECG? step in a critical pathway for patients with acute 6. What are some atypical presentations of acute coronary syndrome? coronary syndrome that might require the 2. What are the key elements necessary for an Paramedic to obtain a 12-lead ECG? accurate acquisition of a 12-lead ECG? 7. List the ECG changes that occur as an acute 3. List the ECG abnormalities associated with an myocardial infarction evolves. inferior wall MI, anterior wall MI, and lateral 8. What is penumbra? wall MI. 9. What is the signifi cance of a new onset left 4. Which leads are affected on an ECG of a bundle branch block? patient experiencing an inferolateral MI? An 10. List potential causes of T wave abnormalities. anterolateral MI? Case Study Questions: Please refer to the Case Study at the beginning of the 2. How can an early ECG assist the Paramedic in chapter and answer the questions below: determining appropriate patient destination? 1. What is the benefi t of a baseline ECG? References: 1. Pope JH, Selker HP. Diagnosis of acute cardiac ischemia. Emerg and thrombolysis by prehospital care providers. Can J Cardiol. 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Lilly L. Pathophysiology of Heart Disease: A Collaborative with emphasis on electrocardiographic manifestations. Timely Project of Medical Students and Faculty. Philadelphia: Top Med Cardiovasc Dis. 2007;11(8):E22. Lippincott Williams & Wilkins; 1997. 46. Baydur A. Pulmonary physiology in interstitial lung disease: 27. O’Brien TX, Ross J, Jr. Non-Q-wave myocardial infarction: recent developments in diagnostic and prognostic implications. incidence, pathophysiology, and clinical course compared with Curr Opin Pulm Med. 1996;2(5):370–375. Q-wave infarction. Clin Cardiol. 1989;12(7 Suppl 3):III3–III9. 47. Klein RC, Vera Z, et al. Electrocardiographic diagnosis of left 28. Eskola MJ, Nikus KC, et al. Value of the 12-lead ventricular hypertrophy in the presence of left bundle branch electrocardiogram to defi ne the level of obstruction in acute block. Am Heart J. 1984;108(3 Pt 1):502–506. anterior wall myocardial infarction: correlation to coronary 48. Rawles JM, Rowland E. Is the pulse in atrial fi brillation angiography and clinical outcome in the DANAMI-2 trial. Int J irregularly irregular? Br Heart J. 1986;56(1):4–11. Cardiol. 2008;131(3):378–383. 49. Martin ML, Hamilton R, et al. Potassium. Emerg Med Clin 29. Parle GP, Kulkarni PM, et al. Importance of reciprocal leads North Am. 1986;4(1):131–144. in acute myocardial infarction. J Assoc Physicians India. 50. VanderArk CR, Ballantyne F, 3rd, et al. Electrolytes and the 2004;52:376–379. electrocardiogram. Cardiovasc Clin. 1973;5(3):269–294. DDiaigaognostic ECG—The 12-Lead 785 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 51. Janeira LF. Torsades de pointes and long QT syndromes. Am 55. Stober T, Kunze K. Electrocardiographic alterations in Fam Physician. 1995;52(5):1447–1453. subarachnoid haemorrhage. Correlation between spasm of the 52. Weisberg LS. Management of severe hyperkalemia. Crit Care arteries of the left side on the brain and T inversion and QT Med. 2008;36(12):3246–3251. prolongation. J Neurol. 1982;227(2):99–113. 53. Salvati M, Cosentino F, et al. Electrocardiographic changes 56. Ortak J, Bonnemeier H. Cool waves: resolution of Osborn waves in subarachnoid hemorrhage secondary to cerebral aneurysm. after prolonged hypothermia. Resuscitation. 2007;75(1):5–6. Report of 70 cases. Ital J Neurol Sci. 1992;13(5):409–413. 57. Somers MP, Brady WJ, et al. Additional electrocardiographic 54. Mayer SA, LiMandri G, et al. Electrocardiographic markers of leads in the ED chest pain patient: right ventricular and posterior abnormal left ventricular wall motion in acute subarachnoid leads. Am J Emerg Med. 2003;21(7):563–573. hemorrhage. J Neurosurg. 1995;83(5):889–896. 786 Foundations of Paramedic Care Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. A&O Alert and oriented ATP Adenosine triphosphate ABC Airway, breathing, circulation ATSDR Agency for Toxic Substances and Disease ABF American Burn Foundation Registry ABG Arterial blood gas ATV Automatic transport ventilator AC Alternating current AV Atrioventricular node AC Antecubital avdp Avoir de pois ACE Angiotensin-converting enzyme AVPU Alert, voice, pain, unresponsive ACEP American College of Emergency Physicians AWMI Anterior wall acute myocardial infarction ACLS Advanced cardiac life support BAAM Beck airway airfl ow monitor ACS Acute coronary syndrome BARNACLE Benefi ts, alternatives, risks, nature, ACTH Adrenocorticotropic hormone answers, consents, lacks treatment, explanations ADA Americans with Disabilities Act BIAD Blind insertion airway devices ADEA Age Discrimination in Employment Act BiPAP Bilevel positive airway pressure ADH Antidiuretic hormone BLS Basic life support ADL Activities of daily living BOLO Be on the lookout ADP Adenosine diphosphate BP Blood pressure AED Automated external defi brillator BPG Blood pressure gas AEIOU-TIPS Alcohol, epilepsy, insulin, overdose, BPH Benign prostate hypertrophy uremia, trauma, infection, psychiatric, stroke BPM Beats per minute AEMT Advanced emergency medical technician BSA Body surface area AHA American Heart Association BSI Body substance isolation AHF Antihemophiliac factor BTE Behind the ear AICD Automated implantable cardioverter defi brillators BURP Backward, upward, rightward pressure AIDS Acquired immune defi ciency syndrome BVM Bag-valve mask AIA Aspirin-induced asthma CAAHEP Commission on the Accreditation of Allied AIR Allergies, intended effect, reasonable risks Health Education Programs AIV Anterior interventricular CAAS Commission on the Accreditation of Ambulance ALJ Administrative law judge Services ALS Advanced life support CABG Coronary artery bypass graft AM Amplitude modulation CAD Computer-assisted dispatch AMA Against medical advice CAD Coronary artery disease AMA American Medical Association CAMP Cyclic adenosine monophosphate AMI Acute myocardial infarction CAST Cardiac arrhythmia suppression trial AMPLE Allergies, medications, past medical history, CBC Complete blood count last meal, events CBF Cerebral blood fl ow ANI Automatic number identifi cation CC Chief concern ANSI American National Standards Institute cc Cubic centimeter APA American Psychiatric Association CCU Coronary care unit APAP Acetaminophen CDC Centers for Disease Control and Prevention APCO Association of Public Safety Communications CFR Code of Federal Regulations Offi cials CHART Chief complaint, history, assessment, Rx APHA American Public Health Association [prescription], treatment ARC American Red Cross CHARTIE Chief complaint, history, assessment, Rx ARDS Adult respiratory distress syndrome [prescription], treatment, intervention, evaluation ARF Acute renal failure CHB Complete heart block ASA Acetylsalicylic acid CHEATED Chief concern/complaint, history, ASTM American Society of Testing and Materials examination, assessment, treatment, evaluation, AT&T American Telegraph and Telephone disposition ATLS Advanced trauma life support CHF Congestive heart failure Acronyms 787 Copyright 2010 Cengage Learning. 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CINAHL Cumulative Index to Nursing and Allied Health ECF-A Eosinophil chemotactic factor of anaphylaxis CIRT Critical incident response team ECF Extracellular fl uid CISD Critical incident stress debriefi ng ECG Electrocardiogram CMS Centers for Medicaid and Medicare Services ED Emergency department CNS Central nervous system EDD Esophageal detection devices CoAEMSP Committee on Accreditation of Educational EDD Expected date of delivery Programs for the EMS Professions EDRF Endothelial-derived relaxing factor COE Council of Experts EDV End diastolic volume COHgb Carboxyhemoglobin EGTA Esophageal gastric tube airway COMSPEC Communications specialists EHF Extremely high frequency COMT Catechol-O-methyltransferase EJV External jugular vein COP Colloidal osmotic pressure ELF Extremely low frequency COPD Chronic obstructive pulmonary disease EMD Emergency medical dispatch CO2 Carbon dioxide EMG Electromyographic signal CPAP Continuous positive airway pressure EMI Electromagnetic interference CPP Cerebral perfusion pressure EMLA Eutectic mixture of local anesthetics CPR Cardiopulmonary resuscitation EMR Emergency medical responder CPS Cycles per second EMS Emergency Medical Services CQI Continuous quality improvement EMSC EMS for children CRF Corticotrophin-releasing factor EMT Emergency medical technician CSF Cerebrospinal fl uid ENA Emergency Nurses Association CT Central terminal ENS Emergency notifi cation system CTZ Chemoreceptor trigger zone EOA Esophageal obturator airway CVA Cerebrovascular accident EOM Extraocular movements CVAD Central venous access devices EOMI EOM intact CVP Central venous pressure EPIC Eliminate preventable injuries of children Cx Circumfl ex EPS Extrapyramidal symptoms DARE Data, action, response, evaluation ER Emergency room DC Direct current ERIC Educational Resources Information Center DEA Drug Enforcement Administration ERV Emergency response vehicle DEEDS Data Elements for Emergency Departments ET Endotracheal DG Dorsogluteal ETA Estimated time of arrival DHHS Department of Health and Human Services ETC Esophageal tracheal Combitube DIC Disseminated intravascular coagulation EtCO2 End-tidal carbon dioxide levels DKA Diabetic ketoacidosis EtOH Ethanol DNAR Do-not-attempt-resuscitation ETT Endotracheal tube DNR Do-not-resuscitate EVO Emergency vehicle operator DO Designated offi cer FAX Facsimile DO Doctor of Osteopathic Medicine FCC Federal Communications Commission DOPE Displacement, obstruction, pneumothorax, FDA Food and Drug Administration equipment FDNY Fire Department of New York DOT Department of Transportation FEMA Federal Emergency Management Agency DP Dorsalis pedis FF Firefi ghters DPAHC Durable power of attorney for health care FFP Fresh frozen plasma DPI Dry powder inhalers FHS Fetal hydantoin syndrome DRG Diagnosis-related group FLSA Fair Labor Standards Act DSD Dry sterile dressing FM Frequency modulation DSMB Data and Safety Monitoring Board FMLA Family and Medical Leave Act DSM-IV Diagnostic and Statistical Manual, fourth FUO Fever of unknown origin edition GABA Gamma aminobutyric acid DTR Deep tendon refl ex GCS Glasgow Coma Scale Dx Diagonal GERD Gastroesophageal refl ux disease EAS Emergency alert system GTT Drops 788 Acronyms Copyright 2010 Cengage Learning. 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HACE High-altitude cerebral edema LEO Law enforcement offi cer H&H Hematocrit and hemoglobin LEO Low Earth orbit HAPE High-altitude pulmonary edema LES Lower esophageal sphincter HAPI-SOCS History, activity, pain, infection, smoker, LF Low frequency orthopnea, cough, sputum LGL Lown-Ganong-Levine Hb Hemoglobin LMA Laryngeal mask airway HBV Hepatitis B LMP Last menstrual period HCFA Health Care Finance Administration LMR Land mobile radio HCV Hepatitis C LMWH Low-molecular weight HDL High-density lipoproteins LOS Line of sight HELP Head elevated laryngoscopic position LOX Liquid oxygen HF High frequency LPM Liters per minute HFNC High-fl ow nasal cannula LQTS Prolonged QT syndrome HIPAA Health Insurance Portability and Accountability LR Lactated Ringer’s Act LSD Lysergic acid diethylamide HIV Human immunodefi ciency virus MAC Membrane attack complex HMO Health maintenance organization MAO Monoamine oxidase HOH Hard of hearing MAP Mean arterial pressure HPI History of present illness MCI Multiple casualty incident HPV Human papillomavirus MCL1 Modifi ed chest Lead 1 HSV Herpes simplex virus MDI Metered dose inhaler HTLV Human T-lymphotropic virus MDT Mobile data terminals IAFC International Association of Fire Chiefs MER Medication error reporting IAFF International Association of Firefi ghters MeSH Medical subject headings I&D Incision and drainage MetHgb Methemoglobin ICD-10 International Classifi cation of Diseases, 10th MF Medium frequency Revision MFI Medication-facilitated intubation ICF Intracellular fl uid MHS Marine Hospital Service ICP Intracranial pressure MI Myocardial infarction ID Internal diameter MMR Measles, mumps, rubella ILMA Intubating LMA MMWR Morbidity and Mortality Weekly Report ILO International Labor Organization MODS Multiple organ dysfunction syndrome IM Intramuscular MOI Mechanism of injury IN SAD CAGES Interest, sleep disorder, appetite, MRT Modulated receptor theory depression, concentration, activity, guilt, energy, MSU Mobile subscriber units suicidal ideation MVC Motor vehicle collision IND Investigational new drug NAD No |
apparent distress IO Intraosseous NAEMSE National Association of EMS Educators IOM Institute of Medicine NAEMSP National Association of Emergency Medical IRB Institutional Review Board Services Physicians ITE In the ear NAEMT National Association of Emergency Medical IU International unit Technicians IV Intravenous NAP Narrative, assessment, plan of treatment IVAD Implanted vascular access device NASEMSO National Association of State EMS Offi cials IWMI Inferior wall myocardial infarction NEMSES National EMS Education Standards JV Jugular vein NEMSIS National EMS Information System JVP Jugular venous pressure NEMSSOP National EMS Scope of Practice KVO Keep vein open NF National formulary LAD Left anterior descending coronary artery NG Nasogastric LBBB Left bundle branch block NHANES National Health and Nutrition LCA Left coronary artery Examination Survey LDL Low-density lipoproteins NHR Natural hormone replacements LEMON Look, evaluate, Mallampati, obstruction, NHTSA National Highway Traffi c Safety neck mobility Administration Acronyms 789 Copyright 2010 Cengage Learning. 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NIDDM Non-insulin dependent diabetes mellitus PMI Point of maximal intensity NIH National Institute of Health PO “Per os” or by mouth NKDA No known drug allergies POLST Physician’s order of life-sustaining treatment NMBA Neuromuscular blocking agent POMR Problem-oriented medical recordkeeping NO Nitric oxide POS Point of service NP Nasopharyngeal PPE Personal protective equipment NPH Neutral protamine Hagedorn PPO Preferred provider organization NPO Nothing by mouth PRBC Packed red blood cells NRB Nonrebreather PRI PR interval NREMT National Registry of Emergency Medical PSAP Public safety access point Technicians PSDA Patient Self-Determination Act NRFM Nonrebreather face mask PSI Pounds per square inch NRHA National Rural Health Association PT Prothrombin times NS Normal saline PTL Pharyngeal-tracheal lumen NSAID Nonsteroidal anti-infl ammatory drugs PTSD Post-traumatic stress disorder NSC National Standard Curriculum PTT Partial prothrombin time NSR Normal sinus rhythm PVC Polyvinyl chloride NSTEMI Non-ST-segment elevation myocardial PVC Premature ventricular contractions infarction PVR Peripheral vascular resistance OG Orogastric PVS Persistent vegetative state OJT On the job QA Quality assurance OPA Oropharyngeal Airway QI Quality improvement OPQRST AS/PN Onset, provocation, quality, QRS Quick response system radiation, severity, timing, associated symptoms, RAS Reticular activating system pertinent negatives RBBB Right bundle branch block OSHA Occupational Safety and Health Administration RCA Right coronary artery OTC Over the counter RCT Randomized clinical trial PaCO2 Arterial pressure of carbon dioxide REM Rapid eye movement PAD Public access defi brillation RF Radio frequency P&S Physicians and surgeons RFR Radio frequency radiation PCA Patient-controlled analgesia RIC Rapid infusion catheter PCP Primary care provider RMA Refusal of medical assistance PCR Patient care report RMP Resting membrane potential PCS Personal cellular service ROSC Return of spontaneous circulation PCVC Percutaneous central venous catheters RR Respiratory rate PDA Personal digital assistant RRWP Reverse R wave progression PDCA Plan-do-check-act RSI Rapid sequence intubation PDR Physician’s Desk Reference SA Sinoatrial PE Physical examination SAFE-R Stimulation reduction, acknowledgement, PE Pulmonary embolism facilitate, explain, restore PEA Pulseless electrical activity SAMPLED Signs, allergies, medications, past medical PEARLS Partnership, empathy, apology, respect, history, last of something, events, directives legitimization, support SARS Severe acute respiratory syndrome PEEP Positive end expiratory pressure SCD Sudden cardiac death pH Potential hydrogen SCT Specialty care transport PHI Personal (or protected) health information SHF Super high frequency PHS Public health service SI Le Systeme Internationale d’unites PICC Peripherally inserted central catheter SIR Special incident report PIER Public information, education, relations SIRS Systemic infl ammatory response syndrome PIM Potentially infectious materials SLF Super low frequency PIO Public information offi cer SLUDGEM Salivation, lacrimation (tearing of the PL Private line eyes), urination, defecation, gastrointestinal pain, PM Preventative maintenance emesis, miosis PMH Past medical history SMS Slow muscle stimulating 790 Acronyms Copyright 2010 Cengage Learning. 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SOAP Subjective, objective, assessment, plan TRALI Transfusion-related acute lung injury SP Septal perforators TROPO Tropospheric SRS-A Slow acting substances of anaphylaxis TTJV Transtracheal jet ventilation SSCP Substernal chest pain TV Tidal volume SSM System status management UCLA University of California at Los Angeles SSRI Selective serotonin re-uptake inhibitors UHF Ultra high frequency STD Sexually transmitted disease ULF Ultra low frequency STEMI ST-segment elevation myocardial infarction USP United States Pharmacopeia SVN Small volume nebulizer UVC Umbilical venous access SVT Supraventricular tachycardia VHF Very high frequency SWAT Special weapons and tactics VL Vastus lateralis TACO Transfusion-associated circulatory overload VLDL Very-low density lipoproteins TBI Traumatic brain injury VLF Very low frequency TBW Total body weight VT Ventricular tachycardia TCA Tricyclic antidepressants WEMT Wilderness EMT TEMS Tactical EMS WFPHA World Federation of Public TKO To keep open Health Associations TNT Trinitrin WHO World Health Organization TOT Turned over to WO Wide open TPA Tissue plasminogen activator WPW Wolff-Parkinson-White syndrome Acronyms 791 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Abandonment Situation in which a Paramedic walks opposite direction to that used for normal diffusion, away from or discontinues care for a patient without which requires an expenditure of energy. turning over care to another provider who has the Activities of daily living (ADL) The everyday events same or higher level of training. people perform in the course of their life, such as Abnormal automaticity Spontaneous impulses eating, dressing, driving, performing personal hygiene, generated in cardiac muscle that may interfere with and generally caring for themselves. the SA node’s contraction-regulating impulses. Act-utilitarianism An approach to ethical decision Abrasions An irritated area on the skin caused by making in which the Paramedic weighs the outcomes wearing or rubbing away by friction. or consequences of performing the act against not Abscess A localized collection of pus surrounded by performing the act and then makes a decision that infl amed tissue. maximizes the intrinsic good. Absolute bradycardia A sinus rhythm with a rate Acute coronary syndrome (ACS) A complex below 60 bpm. of symptoms associated with the continuum of Abstract An abbreviated summary that hits a research cardiovascular disease, emphasizing its morbidity (and study’s highlights. more importantly, its mutability) and not simply its Accessory muscles Muscles recruited to assist with mortality. body functions when the normal muscles used for Acute hemolytic reaction A serious bodily that task are inadequate. For example, in respiratory response to a transfusion that most often occurs distress, accessory muscles may be used to help as a result of an A-B-O blood type incompatibility, expand the rib cage, allowing the patient to inhale. which leads to agglutination and hemolysis of the Accessory pathway A congenital abnormal cardiac transfused blood. electrical pathway that may be indicated by a short Acute myocardial infarction (AMI) Death of cardiac PR interval. muscle tissue. Acetylcholine The chief neurotransmitter released Acute renal failure (ARF) The net effect of prolonged into the synapse from the nerve’s presynaptic hypoperfusion, leading to a reduction in the kidneys’ membrane during neurotransmission. ability to function. Acetylcholinesterase A chemical that breaks down Acute respiratory distress syndrome (ARDS) A acetylcholine. serious reaction to various injuries that involve the Acid A substance with a pH value less than 7; a lungs. molecule that has a proton that is not orbited by a Acute respiratory failure Dysfunction within the paired electron. lungs that impairs respiration. Acid load Excessive amounts of acid in the tissues to Acute traumatic stress An unexpected and sudden the point that tissues are acidotic. stressful event which is unlike the stress of day-to-day Acidemia Condition in which the amount of hydrogen EMS and understandably requires a different approach atoms in an arterial blood gas sample is below 7.35. to relieve. Acidosis Excessive acid in a body system that can Adenosine triphosphate (ATP) The chemical energy have a profound effect upon the body’s uptake, source in a cell used to power the rest of the cell’s distribution, and the effectiveness of medications functions. administered. Administrative law judge (ALJ) One who decides Acknowledging Responding to a patient’s answer cases involving violations of a department’s to a question with a positive reply, either verbal or regulations. nonverbal, that encourages further dialogue. Adrenergic transmission The transmission of Actionable Determination if a claim can be the a nervous system signal using adrenaline as the basis for a lawsuit. To be actionable , a claim must neurotransmitter. generally have the four elements of a tort. Advanced directives Written declarations of Action potential A stimulus that raises the resting patient intent during specifi c circumstances, which membrane potential above a specifi c threshold. are designed to provide guidance when a patient is Active transport The movement of a chemical threatened with living in a persistent vegetative state substance through a gradient of concentration in the or being affl icted with a terminal illness. 792 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Advanced emergency medical technician (AEMT) Alkalemia Condition in which the amount of hydrogen An EMS professional trained to administer a limited atoms in an arterial blood gas sample is above 7.45. number of drugs and perform skills that have been Alkaloids Nitrogenous chemicals which are alkaline in shown to positively impact patient survival. nature and often chemically combined with acids to Advanced life support (ALS) Additional skills create water-soluble salts, such as morphine sulfate or and equipment offered by Paramedics over and atropine sulfate. above basic life support, such as intubation and Allergic reactions A bodily response that occurs when ventilation. exposed to a certain substance, ranging from sneezing Adverse drug reaction An unwanted or harmful and rashes to severe complications. biological response to a drug that creates a Alpha-adrenergic blockers Competitive blockers subsequent negative impact upon the patient’s health. occupying the adrenergic receptor and preventing the Aerobic metabolism The step in the metabolism catecholamine drug from attaching to the adrenergic process in which the cell uses oxygen to create ATP receptor. Alpha-adrenergic blockers can be divided as from glucose. either long-acting and short-acting or competitive and Affi davit A sworn written statement which attests to noncompetitive. facts that pertain to a legal case. Alpha1 adrenergic receptors Sympathetic Affi nity An attraction to or liking of something. neuroreceptors primarily involved with excitation. Against medical advice (AMA) Situation in which They are located in the peripheral vascular beds, on patients refuse medical care in opposition to all logic the arteriole side, and control the sphincters (round when confronted with a clear and immediate danger muscles) of the bladder, intestine, and the iris of the to their health. pupil. Ageism A stereotypical view of the elderly as frail or Alpha2 adrenergic receptors Sympathetic feeble. neuroreceptors found in the gastrointestinal tract Age of majority The legal age a person must be in where they decrease bowel motility, via relaxation of order to consent to a medical procedure; 18 years of the smooth muscles within the intestinal walls. age in most states. Alternative hypothesis A result in a research study Agglutination Clumping together of red blood cells. indicating the treatment is a plausible explanation for Agonist A drug or other chemical that can combine a change. with a receptor on a cell to produce a physiologic Alternative medicine Techniques other than reaction typical of a naturally occurring substance. traditional |
western medicine people may attempt Airlock A technique in which the Paramedic injects for a more natural treatment, such as use of mega- a small bubble of air into the injection, essentially vitamins, therapeutic massages, chiropractic sealing off the drug below from leaking out to the medicine, and acupuncture. subcutaneous tissues above. Alveoli A large collection of small sacs in the lung that Akinetic State of being without motion. provides a larger surface area for gas exchange than if Alarm A signal on an ECG machine that indicates, via the lung were made up of a single large sac; singular visible and/or audible signal, that a patient’s heart is alveolus. rate is above or below a certain rate. Ambulatory Able to walk. Alarm stage The fi rst stage of the general adaptation Americans with Disabilities Act (ADA) A law that syndrome, during which the body responds to the prohibits discrimination based on disability in hiring, stressor via the central nervous system. promoting, training, and retiring. Alert report A notifi cation sent to the receiving AMPLE A mnemonic used to determine a patient’s medical facility about an incoming patient arrival. The past medical history, consisting of questions about information in the alert report is brief and concise: allergies, medications, past medical problems, last age, sex, chief complaint, mental status, vital signs, oral intake, and events preceding the incident. treatments in progress, and an estimated time of Amplitude modulation (AM) When modulating an arrival (ETA). audio signal, changing the wave’s height. Algorithm A logic tree in fl owchart format that simply Anaerobic metabolism The phase of glucose states: if this, then do that; if not this, then do metabolism that does not utilize oxygen, in which the this other thing. Algorithms can be useful during an cell changes glucose into pyruvate acid, which is in emergency when time is of the essence. turn converted into lactic acid. Algor mortis The body’s natural cooling. As the body’s Analgesia A condition where the patient does not feel metabolic processes cease, so does the production pain, yet remains conscious. More importantly, the of heat. patient retains his or her protective refl exes. Glossary 793 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Analgesics Medications that relieve pain by inhibiting Artifact A disturbance in the isoelectric line of the synthesis or release of prostaglandins or an ECG as a result of outside interference with the stimulating opiate receptors (opiate agonists). signal. Anaphylactic response An exaggerated immune Arytenoid One of three separate cartilaginous response that can lead to severe airway compromise structures in the aryepiglottic folds that are attached and/or cardiovascular collapse secondary to relative to each other and other structures by ligaments as hypovolemia. well as the intrinsic and extrinsic muscles of the Anaphylatoxins Substances that increase the larynx. degranulation of mast cells and attract other white Ascites Accumulation of fl uid in the peritoneal cavity. blood cells (leukocytes) to the site. Assault An intentional tort involving a threat of Anasarca Total body edema. violence, either physical or verbal. Anemia Condition in which the blood is lacking red Asthma A chronic lung disorder marked by recurrent blood cells, hemoglobin, or volume. airway obstruction and labored breathing. Anemic hypoxia A low hematocrit, or other red blood Ataxia A disequilibrium in one’s walk that resembles cell abnormality, that can lead to oxygen deprivation a drunkard’s stagger. at the cellular level. Atherosclerosis The underlying pathology of Anesthesia A lack of sensation, painful or otherwise. coronary artery disease, which starts as a streak of Anesthetic drugs primarily induce anesthesia by fat (cholesterol) on the walls of an artery. The fat interfering with or blocking nerve conduction. infi ltrates into the wall of the artery and forms Angulated Describes an extremity where the bone a fatty lesion. is obviously fractured and displaced at an abnormal Atrial diastole State during the cardiac cycle in which angle. the atria are at rest. Anorexia nervosa A psychiatric illness involving Atrial kick The active contribution of blood to the problems with self-image characterized by self- ventricle by the atria during the cardiac cycle. starvation and bulimia. Atrial systole State in which the atria contract during Antagonist A drug or other chemical that interferes the cardiac cycle. with the physiological action of another substance, Atrioventricular (AV) node A small mass of especially by combining with and blocking its nerve specialized cardiac muscle fi bers, located in the receptor. wall of the right atrium of the heart, that receives Antecubital fossa (AC) A triangular cavity of the heartbeat impulses from the sinoatrial node and elbow joint that contains a tendon of the biceps, the directs them to the walls of the ventricles. median nerve, and the brachial artery. Atropine A parasympathetic blocker that decreases Anticholinergics Drugs that block acetylcholine from vagal response. binding to either muscarinic or nicotinic receptors and Augmented leads A modifi ed unipolar limb type stop parasympathetic activity. made from combining the lead type and the positive Antigens Foreign proteins found in bacteria. electrode location (i.e., augmented voltage right or Antimetabolites Drugs that prevent enzymes from aVR, augmented voltage left or aVL, and augmented stimulating a cell’s metabolism. voltage foot now called aVF). Antitussive A cough suppressant. Auscultation An assessment performed by listening, Anoxia Hypoxia of such severity that permanent typically using a stethoscope. damage results. Autoimmune response An immune response Anxiolytics CNS depressants that reduce apprehension, triggered by some infections that causes damage to fear, and anxiety. the host. Aortic stenosis A condition in which the leafl ets of Automatic answers Short, single-word responses the aortic valve become scarred over time and the such as “yes” or “no” given in reply to closed-ended pathway through the valve narrows. questions. Apical pulse The pulse rate at the chest. Automaticity A cell’s ability to generate its own action Apologize An admission of fault or error accompanied potential. by a request for acceptance of that admission. Automatic transport ventilators (ATV) Mechanical Apoptosis A normal physiological process in which old devices that deliver a specifi ed volume of or damaged cells are destroyed so new ones can take respiratory gas. their place. Autonomic nervous system The body system Appeal A request for an appellate court to change the that maintains the involuntary, yet essential, life- decision issued by a trial level court. preserving functions such as digestion. 794 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. AV block An interruption of AV conduction that can be Beta1 adrenergic receptors Sympathetic indicative of disease or ischemia at the level of the neuroreceptors that cause the muscle of the heart, AV node. the myocardium, to beat harder and stimulate the AVPU A technique used to report the patient’s general heart to beat faster. Beta1 adrenergic receptors level of consciousness. A stands for alert, V stands for are also found in the kidneys where they cause the responsive to voice, P stands for responsive to pain, secretion of renin. and U stands for unresponsive. Beta2 adrenergic receptors Sympathetic Axis The major direction, or vector, of the energy of neuroreceptors that act upon the smooth muscles depolarization in the heart. found in the bronchial walls, the level of the terminal Axis deviation Any situation in which the heart’s axis bronchioles, and cause bronchodilation. is not normal. Beta-blockers Medicines that block the sympathetic Bachmann’s Bundle A special pathway the SA node nervous system action at the Beta receptors. uses to communicate with the left atrium. Beta-selective Drugs that preferentially targets either Bacterial contamination Infection of blood products Beta1 or Beta2 receptors. often due to contamination during the blood Bevel An angled surface of a needle point designed to collection process, which can lead to septic patients quickly pierce the skin with a minimum of pain. following transfusions. Bigeminy Condition in which an ectopic complex Balanced anesthesia Process of using a combination occurs at every other complex. of anesthetic agents—some inhaled and some injected Bilateral Relating to both the left and right sides. intravenously—to minimize the side effects that occur Bioavailability The difference between the amount of with using only one particular anesthetic agent. a drug administered and the amount that is bound and Barotrauma Physical damage to tissues, or an injury unavailable for use. For example, imagine an aspirin caused by an imbalance between pressures in the pill with 325 mg of active ingredient is swallowed, and environment and those within the body. then after various factors come into play, only 150 mg Barrel The shaft of a syringe. is free and unbound in the blood plasma. Thus, less Base Atoms that lack a proton and therefore want than 50% of the medication is bioavailable. to accept protons from an acid in order to become Bioethics A form of applied ethics—that is, ethics electrically balanced; a substance with a pH value applied to the medical situation—which creates a set greater than 7. of guiding principles for the medical practitioner. Baseline vital signs An initial set of vital signs taken Biological death Death associated with irreversibility, from the patient against which all subsequent vital meaning that any efforts to prolong life would be signs are compared to check for changes. futile. Basic life support (BLS) The early assistance given Biotransformation A detoxifi cation process in the to patients in the fi eld, such as CPR, oxygen, and body that simply transforms a drug—by oxidation, suction. hydrolysis, or reduction—into a water-soluble Battery An intentional tort involving unwanted compound which can be excreted in the urine. touching. Bipolar leads Use of two electrodes—one negative Behavioral emergency Abnormal or bizarre behavior and one positive—to measure the electrical potential that may include violence or threats of violence. between the leads’ electrodes. Benefi cence A belief that the physician’s actions are Blastocyst A hollow, fl uid-fi lled ball formed by the acts of mercy and charity, a good act performed for zygote. The cells inside of the blastocyst will form the people at a time of need. human, whereas the cells on the outside will form a Benign Something that will not harm or threaten protective covering that eventually develops into the health. placenta. Benzodiazepines Medicines that help relieve Blebs A small blister created when injecting nervousness, tension, and other symptoms by medication, which is about the size of a mosquito slowing the central nervous system. These drugs bite; a change in the cell wall membrane. are short acting, share the characteristics of the Blind insertion airway device (BIAD) An airway other benzodiazepines, and have been studied in the management tool that is placed blindly and provides prehospital environment as a sole agent to facilitate an airway that is superior to face-mask ventilation, intubation. yet is not as protective as an endotracheal tube. Best practices Those actions which have led to the Blocking behaviors Self-protective behaviors that most desirable outcomes in the past. inhibit free dialogue with the Paramedic. Many Glossary 795 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. of these blocking behaviors are manifestations of Bronchodilation Widening of the airway’s lumen. psychological defense mechanisms. Bronchospasm Temporary narrowing of the smaller Blood bank Location where donated blood and air passages of the bronchi due to violent, involuntary blood products are evaluated and stored for future contraction of the smooth muscle of |
the bronchi that transfusions. sometimes accompanies a respiratory infection. Blood-brain barrier Tight slit junctions in the Bronchus Either of the two primary divisions of the capillaries of the brain which prevent toxins and trachea that lead into the right or left lung; plural is chemicals, including drugs, from easily passing into bronchi. the brain. Buffered Actions taken to render an atom neutral (not Blood chemistry A study of the blood’s chemical to have an electrical charge). composition, such as its level of electrolytes. Bulimia Eating disorder characterized by binge-eating Blood pressure A measure of the pressure within the and then purging via laxatives or vomiting. blood vessels that make up the circulatory system. Bundle of His A wide, thick group of cardiac muscle The pressure will vary depending upon the type of fi bers that conducts an electrical impulse to the vessel and the phase of heart contraction. interventricular septum. Blood-typing Classifying blood as A, B, AB, or O based BURP technique A method to improve laryngoscopic on antibodies. view through backward, upward, and rightward Body armor A form of personal protective equipment pressure. used to protect the Paramedic from thrown objects or Butterfl y IV catheters A throwback to the days projectiles like bullets. of steel needles, in which short steel needles are Body habitus One’s physique or body build. embedded into a plastic anchor device that has wings, Body language The transmission of a message by like a butterfl y. nonverbal visual cues. Experts suggest that 70% of any Calibration Process used to assess the accuracy of the spoken message is conveyed by body language. ECG monitor, in which the Paramedic compares the Body substance isolation Protection worn to keep a ECG machine’s operation against standard settings. patient’s body fl uids from coming in contact with the Capacity The mental ability to understand what one is Paramedic, such as latex gloves. being told. Bolus A concentrated volume of fl uid infused rapidly Capillary refi ll A measure of the patient’s ability to over several seconds or minutes. perfuse the extremities with oxygenated blood. Borrowed servant doctrine Situation in which the Capnography The process of tracking the carbon Paramedic in charge of an emergency is responsible dioxide in a patient’s exhaled breath, which enables for the actions of those Paramedics working in a Paramedics to objectively evaluate a patient’s subordinate role. ventilatory status. Bounce A radio wave phenomenon that occurs Capnometry The determination of the end-tidal whenever a short wave strikes a refl ective surface and partial pressure of carbon dioxide. is redirected in another direction. Capsule Medicinal powder placed within a gelatin Bradycardia A heart rate that is under 60 beats per casing that generally makes it easy to swallow and minute for an adult or below the lower limit of normal keeps it from easily dissolving in the water-based for a child. saliva of the mouth. Bradykinesia Extremely slow movement. Cardiac action potential The electrochemical Brain dead A state in which an electroencephalogram activity of the heart’s individual cells. shows zero brain activity, indicating brain death. Cardiac cycle A single contraction (one heartbeat), Breach of duty Situation in which a Paramedic fails during which blood fl ows through all four chambers to perform patient care in conformance with the of the heart. This contraction includes an entire standard of care. sequence of events from atrial fi lling through Breakthrough seizure An unexpected epileptic ventricular fi lling and ejection. seizure in a person who has had good seizure control, Cardiac monitor A device that shows the electrical which occurs when the drug level in the plasma drops and pressure waveforms of the cardiovascular system; below the therapeutic level. the ECG oscilloscope. Bronchial sounds Lung sounds auscultated over Cardiac output The volume of blood pumped out of the larger airways that are louder and sound like air the left ventricle with each contraction. rushing through a hollow tube. Cardiac skeleton A fi brous matrix to which the Bronchoconstriction Narrowing of the airway’s lumen. muscles, valves, and rings of the myocardium 796 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. are attached and that separates the atria from Channel crowding Situation in which several agencies the ventricles. share the same radio frequencies. Cardiogenic shock Problems with the heart that lead Chart audit A system of quality review performed to its failure to pump. retrospectively in which the Paramedics reviews the Cardioselective Beta-selective drugs that only affect chart against care standards. the heart. CHEATED A mnemonic for an EMS-specifi c, user- Carina Level of the 5th thoracic vertebrae; an friendly documentation method highlighting chief anatomical part, ridge, or process. concern/complaint, history, examination, assessment, Carotid bruit A whooshing sound heard in a carotid treatment, evaluation, and disposition. artery that has plaque buildup on the artery walls. Chemical hiatus Situation in which the drug level in Carotid pulse A measure of the beats produced by the body drops below the therapeutic level before the blood fl ow taken in the anterior neck. infusion has assumed dominance. If left untreated, a Carrier squelch A type of squelch control that potentially life-threatening return ventricular ectopy eliminates background static during pauses in a radio could occur. transmission, essentially muting the radio between Chemical name A description of a drug according to its transmissions and thereby improving the message’s elemental chemical makeup and molecular structure. overall quality. Chemotactic factors Chemical messengers released Case law Law established by previous judicial by mast cells that attract specifi c leukocytes (white decisions. blood cells) to the injury site. Case report An example of a descriptive study Chemotherapy Use of drugs to combat infections and Paramedics use to report interesting or unique cases, diseases, most notably cancer. which allow other Paramedics to gain insight into a Chest leads Leads in which the exploring electrode is problem. placed on the chest and the other is connected to one Case-control study An observational study method in or more limbs. which the Paramedic compares cases—those patients Chevron Method for securing a catheter hub that with the disease—to controls—those patients without involves slipping the inverted tape, sticky side up, the disease—and then examines the procedures under the hub until it adheres to the hub, then performed on both to see if there was an association crossing it over the hub. between outcomes. Chief concern or complaint (CC) The main reason Catecholamines A classifi cation of very potent for which the patient is seeking medical care. adrenergic agonists that cause a direct response from Cholinergic transmission The transmission of a the adrenergic receptor. nervous system signal using acetylcholine as the Cell An area that a mobile radio transmission tower neurotransmitter at the motor endplate. services for cell phone calls. Chordae tendinae Strong cords of connective tissue Cell-mediated immunity Immunity that results from that connect the mitral valve to the papillary muscle the activity of T lymphocytes of the heart’s left ventricle. Cellular telephones Low-powered wireless Choreography The ability to organize a team’s efforts transmitters (radios) that work within close proximity in order to deliver appropriate interventions in a to a radio tower. timely manner. Cellulitis A skin infection. Chromosomes A double helix of DNA that carries Cell wall membrane A porous semipermeable dual genetic information. layer lipid–protein matrix that makes up the outside of Chronotropy To make the heart beat faster. a cell. Circumfl ex (Cx) A minor branch of the left coronary Celsius scale A method of measuring temperature artery that bends around to the left side of the heart and based on a system of 10 in which water freezes at 0°C provides blood to the lateral wall of the left ventricle. and water boils at 100°C. Civil law The legal system designed to handle cases Central nervous system depressants Drugs that not of a criminal nature, often involving business produce a state of reduced central nervous system transactions, such as contracts, torts, estates, trusts, activity. wills, real estate matters, commercial matters, and Central venous pressure (CVP) A measurement used grievances against the government. to assess a patient’s hemodynamic status. Clarifi cation Communication technique in which a Cerebellum The portion of the brain responsible for Paramedic asks the patient to restate the message in coordination of muscles and balance. other words. Glossary 797 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Climacteric An age-related decrease in sex hormone Cognitive restructuring Action taken to reframe the production that occurs in both men and women. brain’s interpretation of a stimulus so that it is non- Clinical death The absence of vital signs. Clinical threatening. death is characterized by unresponsiveness to loud Cohort study An observational study method that verbal and painful stimuli, absence of breathing, and examines patients who have been exposed to a an absence of a central pulse. treatment and compares them to a group that was Clinical decision making The process of systematic not exposed to the same treatment. The patients are analysis and critical thinking the Paramedic uses to followed to determine outcomes. make clinical decisions that will be incorporated into Cold maceration Process of letting medicinal herbs a patient’s treatment plan. steep in cold water. Clinical trial Experimental medical research process Colloid Blood substitutes that contain proteins and in which subjects are assigned at random to either are capable of both pulling fl uids from within the the treatment group or to the non-treatment interstitial space into the circulation (to help augment group (i.e., those receiving standard care [control the circulating volume) and remaining within the group]). bloodstream for a prolonged period of time (to help Clock method Procedure used to determine the maintain the circulating volume). infusion rate in which the Paramedic mentally Colorimetric device Encapsulated pieces of litmus visualizes a clock with a sweep hand pointing out paper over which an exhaled breath fl ows. When the drug infusion rate. When the sweep hand is at carbon dioxide is in the presence of water, it forms the 15 second point, it represents 1 milligram of carbonic acid; the pH sensitive litmus paper in the drug at 15 drops per minute or 15 milliliters an hour. colorimetric device detects this acid and changes color. When the sweep hand is at the 30 second position, Combining forms Creating a word by placing two it represents 2 milligrams of the drug infusing at or more roots together, separated by a vowel, to 30 drops per minute, and so forth. explain a complex process. For example, the term Clonic Repetitive muscle contractions during a “cardiomyopathy”, meaning disease of the muscle of convulsion. the heart, is made up of “cardia-” (meaning heart), Closed-ended questions Questions that generally “my” (meaning muscle), and “patho” (meaning start with words like “do,” “is,” or “are” and require disease), with the letter “O” separating the roots the answer to be a short, direct reply—usually just “cardia”, “my”, and “patho.” “yes” or “no.” Closed-ended questions are used when Command presence The ability to present oneself as specifi c information is needed quickly. the person of authority. Clot tubes A red top blood sample tube that contains Commercial ambulance services For-profi t no additives or preservatives to prevent blood EMS services that provide interfacility medical clotting. transportation as well as emergency medical services Coagulation The thickening process through which the to patients. Many of these commercial ambulance blood makes clots. services originated from the funeral homes that Coagulation cascade The process the body uses to previously provided the service. manufacture fi brin and fi brinogen. Communications Act of 1934 A resolution which Coagulation factors Proteins which act to attract states that the President of the United |
States has platelets to each other to build platelet plugs. control over all government radios and that the Additionally, coagulation factors are key to the Federal Communications Commission (FCC) has control production of fi brin and fi brinogen, two materials over the civilian use of radios. that serve to solidify and stabilize the platelet plug, Communications specialists (COMSPEC) Enhanced making it impermeable to liquid. 9-1-1 staff that dispatch emergency responders to Coagulative necrosis Condition in which muscle people who are unable to speak or who have lapsed cells die, such as in myocardial infarction, the into unconsciousness. skeleton of the cell remains, and the tissue remains Community-based EMS Volunteer (nonprofi t) EMS firm. squads that operate independently of local fi re Coded (or tone) squelch Sometimes called private departments or hospitals. line, a type of squelch control that permits the radio Competency assurance The necessity of the to receive only the intended signal by eliminating Paramedic not only to maintain minimal skills and an reception of nearby broadcast messages and only adequate knowledge base, but to continue to remain accepting signals with the correct code. current with updates to EMS. 798 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Complementary medicine See Alternative medicine. Continuous quality improvement (CQI) An ongoing Complete blood count (CBC) The quantity of each process of review and re-engineering, in order trying type of blood cell in a given sample of blood, often to refi ne a process and improve its delivery. including the amount of hemoglobin, the hematocrit, Contractility The cardiac muscle fi bers’ ability to and the proportions of various white cells. shorten or contract. Complete heart block Obstruction of electrical Contributory negligence A legal assertion that an signals through the AV node or at the bundle of His, action, although not directly causing an injury or in which case pacemakers lower in the heart at the problem, nonetheless made it worse. level of the bundle of His, bundle branches, or even Cormack-Lehane grading system A quantitative the ventricular myocardium will take over as the measure system that grades the view of the glottic pacemaker. opening by how much is occluded by the tongue— Comprehensive Drug Abuse Prevention and Grade I is a clear view of the entire glottic opening Control Act of 1970 (Controlled Substance whereas IV is visualization of the tongue or soft palate Act) A law that expanded the Drug Enforcement only. Proper patient position and external laryngeal Administration’s authority to include schedules of manipulation can improve the view by one to two grades. potentially dangerous and addictive drugs that had Coronary artery disease (CAD) The series of events special restrictions. that leads up to and includes myocardial infarction. Concealment Any object that blocks the pursuer’s Coronary circulation A special set of arteries and vision of the Paramedic, although it does not offer veins that supplies blood to the muscles of the heart. physical protection. Cortisol A glucocorticoid hormone that stimulates the Concentration gradient The difference in production of glucogen from amino acids and fatty concentration between two solutions in different acids contained in lipids. areas (i.e., on two sides of a membrane). When a Cost–benefi t ratio A classic economic analysis that concentration gradient exists, the higher concentration asks the question of whether it is advantageous will diffuse across the membrane to the lower- (i.e., cost-effective) to take a particular action or concentration solution until a balance is reached. make a change in a procedure. Concept formation The inductive logic process Costal margin The lower edge of the chest (thorax) of forming ideas about what is causing a patient’s formed by the bottom edge of the rib cage. condition based on the patient’s history and the Costovertebral angle Area located over the lower Paramedic’s knowledge base. ribs just medial to the posterior axillary line. Conduction system Specialized cardiac cells designed Countermeasures Steps that could be effective in to carry on the heart’s electrical rhythm. reducing injury. Conductivity The ability of an electrical stimulus to be Couplets Situation in which two ectopic complexes transmitted from cell to cell. occur together. Congestive heart failure (CHF) The heart’s inability Cover Any object that cannot be penetrated by a to pump strongly enough to completely meet the projectile, from bullets to frying pans. Examples of body’s needs for oxygen and nutrients. cover include telephone poles and even fi re hydrants. Conjunctiva The mucous membrane that lines the Crenate Dehydration and collapse of a cell. inner surface of the eyelids. Crepitus Crackling or popping sounds under the skin or Conscious sedation The fi rst stage of anesthesia near joints. where the patient does not feel pain but is awake Cricoid pressure Also called the Sellick’s maneuver, enough to maintain protective airway refl exes. a procedure that involves identifying the cricoid Constitutional examination An evaluation that ring and gently applying approximately 10 pounds of assesses the patient’s general appearance. pressure in a posterior direction throughout airway Constitutional signs/symptoms General nonspecifi c management; from the onset of ventilation until fi ndings, such as fevers, unexplained weight loss, night completion of intubation. sweats, chills, headaches, nausea, and vomiting, that Criminal law Laws dealing with violations of a person’s are often common to all sick patients. duties to the community and for which the written law Contiguous leads Situation in which two or more requires the person to provide satisfaction. leads look at the same wall of the left ventricle. Critical incident response team (CIRT) Individuals Continuous infusion A volume of fl uid evenly called in during an acute stress situation to meet administered over the course of a period of time with the affected personnel, typically front-line (i.e., an hour). responders. Glossary 799 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Critical incident stress debriefi ng (CISD) An Decode To interpret and understand a message. intervention to defuse stressors in an acute stress Decubitus ulcers Also known as pressure ulcers, tender situation, such as a line-of-duty death, serious injury or infl amed patches that develop when skin covering a of a coworker while on-the-job, and post-event weight-bearing part of the body is squeezed between suicide of a fellow responder. bone and another body part, or a bed, chair, splint, or Cross-match Comparing a donor’s blood to a patient’s other hard object, creating pressure or friction. blood to determine compatibility of antibodies and Deep tendon refl exes (DTRs) Involuntary muscle type. contraction in the muscle associated with a tendon. Cross-sectional survey A snapshot of a certain Defasciculating dose A small dose of a non- aspect of a population at a given moment in time that depolarizing paralytic which, when administered the researcher is interested in, obtained by means of before administering a certain drug, prevents the observation. fasciculations associated with that drug. Crowning Part of the childbirth process in which the Defensive medicine The practice of a Paramedic infant’s head begins the passage into the birth canal, performing a wide variety of random tests to limit indicating delivery will occur within several minutes. liability or criticism from the medical director, rather Cryoprecipitate The protein portion of plasma made than performing just those tests that benefi t the up of concentrated clotting factors. patient. Crystalloids Electrolyte-containing fl uids Paramedics Defusing An immediate intervention intended to use during trauma resuscitation that, when avert acute stress reactions among the emergency dehydrated, create crystals. responders. Cultural competence A Paramedic’s ability to Degranulate The process of breaking down or losing function effectively within the diverse populations granules. that she serves. Delirium A sudden change in mental function, usually Culture The culmination of life experiences in a associated with reversible metabolic derangements locality or region that affects the way a person thinks (e.g., hypoxia, or the toxic effects of medications). and behaves. Deltoid An intramuscular injection site in the muscle Cyanosis A bluish hue that develops when the patient that overlays the shoulder and extends downward develops a decreased oxygen level in the blood. toward the elbow, forming an inverted triangle in the Cytopathic Manifestations of disease at the cellular level. process. Cytoplasm A fl uid mixture inside a cell, primarily Demobilization An opportunity to mitigate the effects made up of water and organelles, which has a specifi c of the acute stressors and to decrease the incidence cellular function(s). of acute traumatic stress reactions. Dangerous instruments Any object that could be Denature To break down a protein’s complex folded used, under the right circumstances, to produce structure. serious injury or even death, such as a broken bottle Deontology Duty-based ethics in which the decision or box cutter. as to whether an action is right or wrong is based on Data and Safety Monitoring Board (DSMB) A principles and not upon the consequences. group of individuals who are not directly involved in Depolarization A cascade of ionic changes at a cell a research study but who can nonetheless make an wall that occurs as electrolytes transfer across the cell objective decision about the research based on the in an attempt to balance (neutralize) the charge. merits of the data. Depolarizing neuromuscular blocker One of the Data dredging Sometimes called data mining, it two major classes of neuromuscular blockers; binds to means conducting research by searching through a the acetylcholine receptor and causes the muscle to database without a predefi ned scientifi c question in depolarize or contract. mind (i.e., without a predefi ned hypothesis). Deposition Out-of-court testimony made under oath and Dead airtime A period in which no radio transmissions recorded by an authorized offi cer for later use in court. are made on a particular channel. Descriptive analysis Based on the Marriott method of Deadly weapons Objects that are, by design, analysis, a way to gather information for a thorough intended to infl ict death or disability (e.g., a gun or ECG interpretation consisting of review of the rhythm, a knife). rate, width of the QRS complex, and atrial activity. Decoction Process of bringing water to a boil then Descriptive study Documentation that simply states steeping medicinal herbs in the water (like one would that a condition or situation exists without trying to steep a teabag), then drinking the resulting solution. offer an explanation. 800 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Detailed physical examination A more thorough Distracting injury Situation in which a pain (often evaluation given to low-priority patients with whom dull visceral pain) is overshadowed by another more the Paramedic has more time. intense pain from another injury; for example, a Developmental milestones The skills and abilities fractured femur taking attention away from chest a child achieves at certain ages in his or her life, pain. measured against the norms of other children. Distress A negative response to stimuli that overcomes Dextrocardia Condition in which the heart and lungs the body’s innate defenses and serves as the body’s in a body are opposite their normal position while the maladaptive reaction to stress. abdominal organs are in their usual position. Distributive shock The third category of the Diagnosis Identifi cation of a disease or disorder based Hinshaw–Cox shock classifi cation, which is descriptive on available symptoms and testing. of the problem of poor blood distribution. Distributive Diagnosis-related groups (DRG) Groups of patient shock includes |
shock caused by the widespread populations with the same or similar diagnosis, who vasodilatation seen with severe infections and during may benefi t from similar treatments. anaphylactic reactions, to name a few causes. Diaphoretic To be profusely sweaty. Diuretics Medications that cause the increased loss of Diaphragm A large, thin, dome-shaped muscle that fl uid and salts from the body. divides the abdomen from the thorax. Divine command ethics Extrinsic ethics based Diastolic blood pressure The minimum blood upon a higher authority, such as the Bible’s Ten pressure measured during diastole when the heart Commandments or Buddha’s Four Noble Truths and relaxes and fi lls. Eight Paths to Righteousness, in which that higher Digital intubation An endotracheal intubation authority has predetermined what qualities a virtuous technique that uses the Paramedic’s hand to identify person would have and calls upon the person to laryngeal structures and to guide tube placement. display those virtues through correct action. Diminished autonomy Standard that states any Dominance A condition of superiority, as in when person who is mentally incapable of making an the actions of one bodily function are faster than or informed decision (e.g., by virtue of age or infi rmity) overpower the actions of another. cannot willingly consent to participate in research. Do-Not-Resuscitate (DNR) order Sometimes called Diphasic A wave that begins as a positive defl ection a Do-Not-Attempt-Resuscitation (DNAR) order, a then becomes a negative wave or vice versa; having directive from the patient that artifi cial means of life two phases. support should not be used, generally in cases when a Diplomacy To calmly and thoughtfully resolve issues condition is terminal and artifi cial life support will just without angering the parties in the dispute. delay the inevitable. Direct questioning An interviewing technique DOPE A mnemonic Paramedics use to help remember in which a Paramedic asks simple, unambiguous the causes of problem intubations. The D in dope questions of the affected party about the situation at stands for displaced endotracheal tube; the O stands hand. for obstructions of the endotracheal tube, such Disclosure An open dialogue between patient and as a mucous plug; the P suggests the possibility of provider in which the provider tells the patient about a pneumothorax; and the last letter, E, indicates the procedure, including its attendant risks, and equipment failure. recommends the procedure. Dormant A state of biological rest a disease may stay Disease An abnormal change in the function of cells, in until favorable conditions exist for it to reanimate. tissues, or organs. An example of each is cancer in Dorsalis pedis (DP) pulse A measure of the beat cells, emphysema in tissues, and acute myocardial created by blood fl ow measured over the dorsum of infarction in organs. the foot. Disorder A physiological deviation from a normal Dorsifl ex The ability to raise toes above the horizontal homeostasis. toward the tibia. Disseminated intravascular coagulation (DIC) Dorsogluteal (DG) The most common intramuscular A condition in which, after initial blood clotting injection site, located in the gluteus medius. factors are partially consumed by massive coagulation Dose The amount of drug needed to produce the throughout the body, the remaining clotting factors desired effect. are insuffi cient to protect the body. Double-blinded randomized clinical trial (RCT) Distention An abnormal expansion, such as in a vein or A prospective scientifi c study that controls known the abdomen. and unknown variables, leaving only one variable to Glossary 801 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. be manipulated. Subjects are then chosen at random information about trends and rates of disease within to be included in either the experimental treatment a population, often cited as X number of cases of Y group or in the control group. disease per 1,000 or per 100,000 of Z population. Double-blind study A research study in which both Ectopic To occur in an abnormal or atypical position. the researcher and the participants are unaware of Ectopic beats Aberrant cardiac beats resulting from which group the subject is in. abnormal automaticity. Downregulation A decrease in the number of cell Ectopic focus Any complex that occurs outside of the receptors in a cell due to changes in hormone levels. sinus of the heart’s cavity. Dress-up philosophy Technique in which Paramedics ED50 The dose of a drug that effectively creates the add barrier devices for protection as the situation therapeutic effect in a majority of patients. warrants. Edema A dramatic fl uid buildup in the body’s tissues. Drug Any material which, when injected, ingested, Edentulous A state of having no teeth. inhaled, or absorbed into the body, is used for Effi cacy The power to produce an effect; the ability of the diagnosis, treatment, or cure of a disease or a drug to realize its full intended therapeutic effect. condition. Ejection fraction The percentage of blood pushed and Drug decline The idea that while a drug moves squeezed out of the heart, typically 60% to 75% of the through the body various forces and organs are end diastolic volume. weakening it, reducing its effectiveness. Elastic gum bougie A device made entirely of wound Drug reservoir A type of drug depot in the body, gum rubber, with a hard, smooth, and round plastic created when drugs bind to certain substances, that tip, that resembles a very long stylet. The device is stores the drug until it is needed. The effect of a drug directed through the vocal cords and into the trachea reservoir is to prolong the drug’s action within the body. to serve as a guide for an endotracheal tube. Dry powder inhalers (DPI) Respiratory device that Electrical alternans Situation in which every other uses a solid drug pulverized into micro-fi ne particles ECG complex has alternating amplitude (i.e., the one for inhalation. QRS complex is smaller when compared to the next). Duplex A radio that uses two frequencies—one to Electrical storm Multiple recurrent episodes of transmit and one to receive—so that an operator can ventricular fi brillation. talk and listen at the same time, permitting more Electrocardiogram A device used to monitor cardiac rapid communications. rhythm. Duration The length of a QRS complex wave. Electromagnetic interference (EMI) Disruptions of Duty to act An element of a tort that implies a an ECG signal caused by the fl ow of electricity through Paramedic must act whenever called upon to perform an electric device, such as a radio, cellular telephone, patient care (i.e., the Paramedic is “on duty”). or television, which creates an electromagnetic fi eld. Dyskinesia Lack of ability to control body movements. Electromyographic signal (EMG) An electrical Dysplasia Situation in which there are too many current recorded by the ECG any time a muscle new, or immature, cells being produced that are not contracts, appearing as narrow rapid spikes on the functional. ECG monitor. Dysrhythmias An abnormality of the electrical activity Electroporation The effect of electrical current in the heart. passing through the tissue. Ecchymosis Blood from ruptured vessels moving into Elixir A sweetened tincture used for medicinal purposes. other tissues; bruising. Emancipated minors A special class of youths who ECG interpretation A systematic approach used to are below the age of majority but are permitted to rapidly and accurately analyze an ECG rhythm strip. give informed consent, provided they are capable of ECG rhythm strip A printed hard copy from an understanding the consequences of their decisions and ECG machine of at least one lead that shows the that they are not impaired by alcohol or drugs. These ECG complexes over a long period of time allowing include married persons, single parents, the military, Paramedics to analyze the rhythm. and youth living on their own. Echo technique Communication method in which the Embryo An unborn child at any stage of development physician gives an order and the Paramedic, in order between conception and birth. to ensure it’s been interpreted correctly, repeats the Emergency doctrine Policy invoked when family order back to the physician exactly as received. members or guardians are not present that states Ecological study Sometimes called a correlational if a parent was present the parent would want the study, this type of research design serves to provide child treated and transported to the hospital. The 802 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. emergency doctrine is usually invoked only in cases of Emulsions Finely pulverized particles placed into oils, life- or limb-threatening emergencies. such as cod liver oil. Emergency exception A situation in which a care Endocardium A single-layer thick sheet of epithelial provider performs a procedure without fully explaining cells that act as a lining in the heart; the heart’s it to the patient because the delay created by a lengthy innermost layer. explanation might compromise the patient’s health. Endocrine shock A fi fth classifi cation of shock, Emergency medical dispatch (EMD) A dispatch which recognizes the importance of hormones in algorithm in which the communications specialist maintaining homeostasis. The classic endocrine shock interrogates the caller, gives prearrival instructions, is hypoglycemic shock. and uses preset criteria to make a response Endogenous Originating within the body. determination before dispatching the appropriate EMS Endorphins Neuromodulators that reduce the responder units. sensation of pain and affect emotions by attaching to Emergency medical responder (EMR) An EMS opiate receptors on the neuron, which in turn inhibit provider who is expected to render life-saving care neural activity. with minimal equipment; for example, a police offi cer Endotoxins Poisons produced by bacteria during an or fi re fi ghter providing rapid response. infection that stimulate chemical mediators to affect Emergency Medical Services (EMS) The fi eld the hypothalamus. of medicine that involves transporting the sick or Endotracheal tube The basic tool of endotracheal wounded to medical care and providing treatment to intubation which provides a conduit for oxygenation patients prior to their arrival at the hospital. and ventilation between the patient’s lungs and the Emergency Medical Technician-Ambulance A ventilator (person or machine). national standard curriculum established in 1969 for End-tidal carbon dioxide (ETCO2) A standard the training of ambulance drivers/attendants in new method of measurement and monitoring carbon skills and life-saving techniques. dioxide levels used for both confi rming endotracheal Emergency Medical Technician (EMT)–Basic Part tube placement and monitoring patient status, of a team that responds to the emergency scene, ventilation, and continuing tube placement. typically aboard an ambulance, and is trained to Enhanced excitability The ability to respond to a provide initial care on scene as well as medical care much weaker stimulus. to the patient while in transit to the hospital. Enteral Administration of drugs through the Emergency vehicle operator (EVO) Any individual gastrointestinal tract, either through pills taken orally who operates a vehicle en route to a response call. or through suppositories. Emergent An assessment classifi cation in which the Enteric coating A protective coating on a tablet that patient’s condition unexpectedly developed and is in permits the tablet to travel, unaltered, through the need of immediate medical attention. stomach and into the intestine for absorption. Empathy An emotional understanding of the patient’s Environmental risk Modifi able risk factors that are a feelings; to be able to understand what it is like to function of one’s lifestyle or occupational choice, such walk in the other person’s shoes. as farmers developing respiratory issues from their Empiric therapy Treatment based on initial exposure to dust. observations obtained during the primary assessment. Epicardium The heart’s outermost part; a part of the EMS Act of 1973 Federal legislation that delineated pericardium that is closely adherent to the heart. the 15 aspects of an EMS system that needed Epidemiology The study of the |
causes, distribution, improvement including education (both public as well and control of disease in populations. as provider), improved communications (including Epiglottis A “U” shaped structure in the upper airway public access), and system evaluation, but offered attached to the anterior pharynx between the base little money to help make those improvements. of the tongue and the larynx that protects the lower EMS Agenda for the Future Overall framework which airway from foreign body aspiration. suggests that EMS will be more intimately intertwined Epilepsy A neurological disorder characterized by with public health, as well as public safety, over time recurrent seizures that occur without known cause. and continue to evolve along with health care. Epistaxis Nosebleed. EMS Education Agenda for the Future The plans Equianalgesic Drug characteristic in which a dose that emerged from the 1996 meeting of over 30 EMS of a new medication formulation has the same organizations held with the intent of implementing the ability to produce analgesia as 10 milligrams educational portions of the EMS Agenda for the Future. of morphine. Glossary 803 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Equiphasic A fl atline pattern on an ECG machine that Event report Documentation following a mass casualty occurs if the differences in the fl ow of electricity incident that details the situation and conditions that result in a zero net difference in direction. occurred which led to the incident. Triage tags are Equity A concept of fairness or evenhandedness. To be attached to this report. accepted, any change must appear to be equitable to Evidence-based practice A research approach all parties concerned. based on observed experimental results, in hopes Erythema Abnormal redness of the skin caused by of making the results more reliable and valid than capillary congestion. peer reviews. Erythrocytes Red blood cells that transport oxygen Exacerbation Periodic episodes in which a chronic and carbon dioxide through the blood. disease returns, or fl ares up. Escape mechanism A form of backup pacemaker Excitability The ability to respond to a stimulus. in the heart that will continue to prompt Excited delirium A physical state a restrained contractions (at a slower rate) if the SA node stops patient may reach if agitated and combative in which sending impulses. he becomes tachycardic, hypertensive, and has Esophageal intubation detection devices (EDD) hyperpyrexia. Devices used to confi rm endotracheal tube placement. Exercise A series of physical activities, both aerobic Two major styles of these devices exist: self-infl ating (e.g., walking or jogging) and strength training, which bulbs and syringe style aspirators. is considered optimal to perform for maintaining Esophageal-tracheal Combitube (ETC) A rescue health. device placed into the esophagus that allows tracheal Exhaustion The fi nal, recovery stage of the general placement. The double-lumen design allows for adaptation syndrome, which occurs when the body’s endotracheal as well as esophageal intubation. response is insuffi cient to meet the challenge of the Ethical relativism When a majority of Paramedics stressor. agree to a specifi c conduct or course of action, Exogenous Originating outside of the body. determining that it does more good than harm, which Exotoxins Proteins produced by bacteria that are suggests the act is ethical. released into the interstitial fl uid. They are then Ethics From the Greek “ethos” meaning character, a absorbed, because they are highly soluble, into system of guiding principles that govern a person’s surrounding cells. conduct. Expanded scope of practice Assigning additional Ethics committee A group that can help individuals, duties and responsibilities to Paramedics beyond the including Paramedics, deal with common ethical scope of practice to provide health care where scarce concerns. healthcare resources exist. Ethnocentrism A view that one’s own cultural Exposure Situation in which blood or bodily fl uids from practices and customs are superior. a patient are spilled, splashed, or dripped onto or Etiology The origin of a disease. injected into a Paramedic. Etomidate A sedative that functions primarily as a Exposure report A special incident report completed hypnotic, although it also is an excellent amnestic. after an exposure that details the circumstances that Eustress A positive, manageable form of stress from resulted in the Paramedic being exposed, in hopes daily activities. that a future exposure will not occur in the same Eutectic mixture of local anesthetics (EMLA) manner. A cream that helps to reduce the pain of needle Expressed consent During an emergency situation, insertion, consisting of lidocaine 2.5% and an assumption that if a patient does not object to prilocaine 2.5%. receiving care, consent for the procedure has been Evaluation and Management Documentation given. Guidelines Standardized histories that permit External laryngeal manipulation A technique the Paramedic to identify diseases, disorders, and used to improve visualization of the glottic syndromes, vis-á-vis, through symptom pattern opening in which the Paramedic performs direct recognition, and document the medical necessity of laryngoscopy with his left hand while manipulating the therapeutic services provided to the patient. the larynx with his right hand. Once he has Event monitor A credit-card sized device patients an improved view of the glottic opening, the may use to record abnormal ECG activity that occurs Paramedic has an assistant take over the external very irregularly (as in days or weeks apart). When the laryngeal manipulation, holding the larynx patient senses the abnormal activity, the monitor is absolutely still. placed on the chest for a preset period of time. Extracellular water The water that is outside of cells. 804 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Extrinsic trigger A stimulus prompting an airway Fetal alcohol syndrome Umbrella term covering a spasm that originates outside the body, such as variety of birth defects caused by a mother drinking pollen, dust, and mold. during pregnancy. Exudate A collection of white blood cells and fl uids; Fetal hydantoin syndrome (FHS) Birth defects whitish discharge. such as cleft lip, cleft palate, and congenital heart Facilitation Interviewing technique in which the anomalies seen in children born to mothers taking Paramedic nods his head in acknowledgement and says hydantoins during pregnancy. “Go on,” as well as tries to make eye contact, which Fibrin An elastic, insoluble, whitish protein produced may encourage the patient to continue talking about a by the action of thrombin on fi brinogen and forming subject. an interlacing fi brous network in the coagulation of Facsimile machine A device that, using digital blood. technology, can transmit a high-quality copy of Fibrinogen A protein in the blood plasma that is documentation from one location to another. essential for the coagulation of blood and is converted Fading Progressive weakening of a radio wave as it to fi brin by the action of thrombin in the presence of encounters more and more obstacles. ionized calcium. Fahrenheit scale A standard used to measure Fick principle The process of getting oxygen to the temperature based on freezing and boiling cells, which can be summed up in fi ve key concepts: temperatures of a water and salt solution. In this oxygenation, ventilation, respiration, circulation, and scale, water freezes at 32°F, water boils at 212°F, cellular respiration. and a person’s body temperature is 98.6°F. Fidelity The physician’s obligation, and therefore the Failure to thrive Situation in which a child does not Paramedic’s obligation, to keep any promises made to grow as expected, perhaps due to psychosocial or the patient. nutritional imbalances. Field A place to enter data on a chart or form. Fallout Situation that occurs in the airway whenever Field diagnosis See Paramedical diagnosis large particles carried in the air current settle out as Fight or fl ight The body’s instinctive response to a airfl ow velocity is lost. potential life threat, either to resist it or avoid it. This False imprisonment A restriction of movement or primitive stress response may have been critical to the a confi nement that abridges the patient’s right to survival of primeval man, but can be unhealthy today. freedom, such as by the use of restraints. Fire-based EMS Using the fi re service, with their FarMedic© An EMS course specifi cally directed to the combination of trained personnel, life-saving rural or farm emergency. equipment, emergency vehicles, and strategically Fasciculations Transient fi ne muscle contractions, located stations, as the platform for delivery of EMS; seen after administration of a depolarizing the predominant means of delivering EMS in the neuromuscular blocker. United States. Febrile non-hemolytic reaction An elevation of the First-due report A brief synopsis of the scene size-up patient’s temperature of 1°C from baseline within two obtained by the fi rst arriving responder. hours of the start of a transfusion which begins shortly First pass metabolism A chemical degradation of after the initiation of the transfusion or a new unit. a drug by the liver that markedly reduces the drug’s It is often secondary to minor antibodies present in bioavailability. the recipient’s blood that cause a mild reaction when Fixed-post staffi ng The method of resource allocation exposed to the donor’s blood. in which EMS is stationed in centrally located Federal Communications Commission (FCC) standing facilities, from which ambulances respond to The agency with rule-making and enforcement emergencies. responsibility for civilian radio frequencies. Fixed-wing aircraft A traditional airplane, rather than Feedback The mechanism by which the Paramedic can a helicopter, used by fl ight Paramedics to transport ensure the message sent was the message received patients. and decoded; that is, the message heard was the Flail segment Condition that develops when two message sent. or more adjacent ribs are fractured in two or more Fee for service A “pay as you go” approach to health places, which produces an unstable area of the chest care, with a certain amount of medical care provided that impedes normal respiration. gratis to the poor or uninsured. Flashback A return of blood that may be observed in Femoral pulse A count of the beats created by blood the tubing when an IV solution bag is lowered below the fl ow in the femoral artery that is measured at the level of the patient’s heart, which indicates that the IV patient’s groin. access remains patent. Glossary 805 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Flight Paramedic The most highly trained level of to determine which patients require immediate EMS provider; this individual transports critically ill transport. patients from emergency scenes or other facilities to Generation A span of time used to differentiate defi nitive care. advancements (e.g., the next generation of drugs). Fluori-methane A topical refrigerant, sometimes Generic name A simple name given to a drug, often called vapocoolant spray, that numbs the skin at the listed by the manufacturer in the United States injection site in as little as 15 seconds. Pharmacopeia (USP). Flush the line A procedure in which the Paramedic Genetic make-up Those physical characteristics that runs fl uid through an intravenous administration set make up a person, including appearance, disposition, to remove any air bubbles in order to prevent an air and so on. embolism. Genotype An individual’s genetic make-up. Focused/vectored physical examination (PE) Gestalt A decision-making process in which the A more detailed evaluation following the primary Paramedic comes to a conclusion not through a assessment in which the Paramedic looks for summation of symptoms but rather from patterns observations that the physician will most likely observed in |
similar situations in past practice and request. experience. Also referred to as the Paramedic’s “gut Followership A willingness to follow a leader’s feel.” direction and to support the mission, putting aside Glottis The space between the vocal cords. personal ambitions. Glucagon An enzyme that breaks down glycogen into Food, Drug, and Cosmetic Act Law that prohibits individual glucose molecules. the sale of new drugs before they go through safety Glycogen A dual molecule in the liver and muscles that testing. stores any glucose which is not needed immediately by Foreseeable harm Risks that can reasonably be the body. expected as a result of a medical procedure. Glycolysis An aerobic process during which the body Frequency modulation (FM) When modulating an uses eight different enzymes to divide glucose and audio signal, changing the wave’s speed. create a chemical called pyruvate. Fresh frozen plasma Blood component formed by Glyconeogenesis The production of glucogen from removing the red blood cells and platelets from whole amino acids and fatty acids contained in lipids. blood. The remaining liquid component of the blood Glycoside Any of a group of organic compounds, is still rich in several of the clotting factors needed as occurring abundantly in plants, that yield a sugar and part of the coagulation system. one or more nonsugar substances on hydrolysis. Functional job description Tasks described in a job Good Samaritan statutes Laws that protect well- description that are needed to perform the functions meaning people who, although they have no duty to of the job, excluding rare or marginal job functions. provide care to an injured person, do so nonetheless. Functional syncytium A group of myocardial cells Governmental immunity Also called sovereign that act as a unit. immunity, a practice in which the government is Gain Enlargement in the size of the tracing shown on exempt from liability for torts committed by its the ECG monitor screen. employees except to the extent that it has consented Gait The way a patient walks. by statute to be sued. Gallop The combination of the normal and extra heart Gross negligence Intent to willfully, or with reckless sounds that occur with changes in ventricular fi lling. disregard for a patient, cause harm to a patient. This produces a galloping rhythm, similar to hearing a Ground wave High-frequency (HF) radio transmissions horse gallop. that are capable of being transmitted over the land. Garbage can diagnosis An imprecise and Guidelines General rules that provide the Paramedic overgeneralized fi eld diagnosis the Paramedic might with direction while also permitting use of her make that lends little direction to patient care. knowledge and experience to shape clinical decisions. Gene A sequence of nucleotides in DNA on a Whenever guidelines are in use, the Paramedic must chromosome that determines an individual’s physical be willing to discuss and defend the clinical decisions. characteristics. Gum Sometimes called resin, a complex sugar in plants, General adaptation syndrome The body’s a polysaccharide, that when moistened becomes a predictable pattern of response to stressors. gelatinous material. General impression A Paramedic’s overall evaluation Haddon matrix An easily understood concept map of of the patient, in which she assesses the patient’s injury causation and prevention. Using a model similar mental status, airway, breathing, and circulation, to the one used for disease, Haddon plotted the 806 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. factors that cause injury across a horizontal X-axis and Hematocrit The volume of red blood cells in the blood the stages of an injury process along the Y-axis. The expressed as a percentage. result was an injury prevention matrix. Hematoma A mass of clotted blood that forms in a Half-life (t½) The point when the decline of the swelling as a result of a broken blood vessel. amount of a drug in the bloodstream due to Hematopoiesis The manufacturing process the body metabolism reaches 50%. uses to create the three main solid components Hands-off The process in which one mobile radio tower of blood: red blood cells, white blood cells, and switches the transmission to another tower so that platelets. there is no interruption in transmission. Hemicorporectomy Amputation at the waist. Hanger Hook-like device an IV bag is hung from. Hemocytoblast The generic stem cell from which all Hanging the bag Process of suspending an intravenous other blood cells (red, white, and platelets) develop. solution for delivery to the patient. Hemoglobin The molecule in red blood cells that Hard-wire Use of physical transmission lines for accepts oxygen in the lungs and carries it to the communication rather than radio waves, i.e., wireless. body’s tissues to allow cellular respiration. Hard wire monitoring Devices that feature electrodes Hemolysis The disintegration of red blood cells, running from the device to the patient, causing resulting in a release of hemoglobin. limited mobility for the patient. Hemostasis The stoppage of blood fl ow through a Harrison Act A law established in 1914 that made it blood vessel or body part. illegal to obtain “narcotics” (e.g., morphine) without Hemothorax Collection of blood in the pleural cavity a prescription. which can cause lung collapse. Head elevated laryngoscopic position (HELP) Heparin sulfate An anticoagulant released from A patient position that places the head in extension the endothelium of the walls of the arteries that along the atlanto-occipital joints, bringing the temporarily prevents blood clot formation in the pharyngeal, laryngeal, and oral axes into alignment narrowed coronary arteries. using an elevation pillow. It can also be used in Heparin well An intermittent infusion device fi lled patients who are unable to lay fl at (i.e., CHF with heparin to prevent clot formation in the device. patients or morbidly obese patients) or to help clear Hepatectomy The surgical removal of a portion of the secretions. liver. Healthcare proxy This person has a responsibility to Hepatojugular refl ux An elevation of venous pressure review the medical record, consult with healthcare visible in the jugular veins when fi rm pressure with providers, and give consent to either initiate or to the fl at hand over the liver. refuse care for the patient. Hermeneutics The Paramedic’s ability to put Health Insurance Portability and Accountability himself in the patient’s situation, with all of the Act (HIPAA) Federal legislation that has placed accompanying physical and cultural infl uences, in conditions upon all healthcare providers that protect order to understand the patient better. patient privacy during claims processing, data Hernia Openings in the muscle and tissue layers that analysis, utilization review, quality assurance, and allow the an organ to protrude through the opening practice management. into another cavity. Health maintenance organization (HMO) A Hertz A unit of frequency measured in cycles per managed care system that provides payments to second. healthcare providers at a negotiated annual per capita Hexaxial reference system An artifi cial construct rate. These rates are based on practice history of the created to help conceptualize the heart’s normal axis insured patients and helps to prevent fl uctuations in and to help determine if there is any axis deviation. payments, thus making expenses, costs, and budgets High-fl ow nasal cannula (HFNC) An advance in more predictable. nasal cannula technology in which, by humidifying and Heart failure Situation in which an impaired heart warming the oxygen and using membrane technology, cannot meet the body’s demands for perfusion. up to 40 LPM is comfortably delivered to the patient Heave To cause to swell or rise. When referring to through a nasal cannula. the heart, a heave indicates the heart is beating so High priority patients Patients with the most forcibly that the chest wall is felt to move by the serious, yet treatable, conditions. They are generally Paramedic assessing the patient. transported to the hospital immediately, with further Heel stick Puncturing an infant’s heel with a lancet assessment being performed en route. then drawing the blood off with a capillary tube to History of present illness (HPI) A chronological acquire a sample. description of the development of the patient’s Glossary 807 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. present illness, including symptoms the patient is Hyoid The only bone in the body that does not directly currently displaying, which may help the Paramedic articulate with another bone. Instead, it serves as a make a diagnosis. This can be determined by asking common point of attachment for a number of muscles when, where, why, and how type questions about the and ligaments that function in swallowing and airway problem. maintenance. History taking Medical questioning to determine the Hyperacute T wave An increase in the amplitude of disorder, syndrome, or condition affecting the patient T waves in the leads facing cellular damage. that resulted in the call for assistance. Hypercapnia Condition in which the partial pressure of Histoxic hypoxia The inability of the cells to accept or carbon dioxide dissolved in an arterial blood gas sample use oxygen, such as in cyanide poisoning. is greater than 45; increased carbon dioxide levels. Holter monitoring A continuous type of ECG monitor Hypercarbia Condition in which the amount of that records the ECG activity while the patient goes bicarbonate ions in an arterial blood gas sample is about his routine work and play activities, which is greater than 30. often used on patients with sporadic dysrhythmia Hyperlipidemia An abnormally high level of problems. triglycerides and cholesterol which, when Homeostasis The processes a body undertakes to try uncontrolled, can lead to atherosclerosis. to maintain a constant state of balance or equilibrium. Hyperoxia Condition in which partial pressure of Horizontal equity Injury prevention strategy in oxygen dissolved in the arterial blood gas sample is which standards are broadly applied to all individuals greater than 100. equally, such as the level of a legal blood alcohol Hyperplasia An abnormal increase in the number of content. cells due to frequent cell division/reproduction which Horizontal leadership A leadership style that causes the tissue or organ to increase in size. “fl attens the pyramid” so Paramedic leaders work Hyperpnea Deep breathing. toward linking, or networking, with the members of a Hyperrefl exive Refl exes that are signifi cantly more public safety team. Horizontal leadership emphasizes brisk than normal. an “out and back” line of communication instead of Hyperresonant Percussion notes that sound similar to an “up and down” line of communication and can be striking a drum, indicating an increased amount of air visualized more like a wagon wheel. in the chest. Hormones The chemical messengers that stimulate the Hypertension A systolic blood pressure that is above body’s organs and help to maintain the body’s internal the upper limit of normal. environment. Hyperthermia A condition that occurs if too much Hospice A concept of care focused on providing for the heat builds up in the body’s core; a body temperature physical, emotional, and spiritual needs of a terminal above 38°C (100.4°F). patient. Hypertonic Fluid that has less water and more salt Hospital-based EMS An EMS system design where a (electrolytes) than the solution on the other side of hospital provides EMS services in the form of a fl ycar a semipermeable membrane. Hypertonic fl uid on the or ambulance. other side of a semipermeable membrane will pull Hotline A telephone number dedicated to providing the fl uids into itself. caller with immediate assistance. Hypertrophy An increase in either the weight or Huber needle A beveled needle intended to pierce a functional capacity of a tissue or organ beyond what stopper without coring it, thereby preventing leakage is normal. of the contents within the catheter from leaking out Hyperventilation A deeper than normal respiration of the stopper when the needle is withdrawn. that may be caused |
by respiratory distress, a Human dignity The right of every person to be treated metabolic condition, or drug overdose. respectfully, regardless of his or her station in life. Hypnotic state A sleep-like condition often induced by Human rights Rights based on a commonly desired a large dose of CNS depressants. human condition (i.e., freedom from want, freedom Hypocapnea Condition in which the partial pressure from pain, and freedom from suffering). Human rights of carbon dioxide dissolved in an arterial blood gas involve universally accepted standards of justice. sample is less than 35. Humoral immunity The component of the immune Hypocarbia Condition in which the amount of system involving antibodies that circulate as soluble bicarbonate ions in an arterial blood gas sample is less protein in blood plasma. than 22. Hydrostatic pressure Pressure created by the force Hypoglycemia Condition in which blood sugar (or behind the volume of water in the body. blood glucose) concentrations fall below a level 808 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. necessary to properly support the body’s need for in a subcutaneous pocket under the skin’s surface. energy and stability. Implanting the entire device affords the IVAD the skin’s Hypokalemia The development of low sodium protection, which decreases the rate of infection, as potassium in the blood serum. well as protects the port from physical trauma. Hyporefl exive Refl exes that are signifi cantly less brisk Implied consent An assumption that an unconscious than normal. patient in danger would consent to a life saving Hyporesonant Percussion note that is dull in character procedure if awake and capable of consenting. and often indicates fl uid in the lung. Incidence The number of new cases of a disease per Hypotension A systolic blood pressure below the lower standardized group per time. An example would be 1 limit of normal. case per 100,000 per year of x disease. Hypothermia A condition that occurs if there is too Incision and drainage (I&D) A minor surgical little heat in the body’s core; a body temperature less procedure used to release pus or pressure from a site than 35°C (95°F). such as an abscess. Hypotonic Fluid that has more water and less salt Indirect statement A question that asks for an (electrolytes) than the solution on the other side of explanation that is not constrained by the question. a semipermeable membrane. In an effort to balance An example of an indirect statement would be, concentrations, the water from the hypotonic solution “Please tell me about your pain.” will cross the membrane until the two solutions are In extremis An appearance of grave illness or mortal balanced. injury. Hypoventilation Shallow respirations that can be Infarction A large area of necrosis in a tissue or organ. caused by drug overdose, head injury, or another Infl ammation A protective reaction of tissue to condition. irritation, injury, or infection, characterized by Hypovolemic A state of decreased circulating blood localized pain, redness, swelling, and sometimes loss volume. of function. Hypovolemic shock The fi rst category of the Initial assessment See Primary assessment. Hinshaw—Cox shock classifi cation, which includes Initial impression A global patient assessment made shock that arises from trauma (hemorrhagic shock) but on initial contact with a patient based on a myriad of also includes other etiologies where there is a loss of factors such as patient presentation, environmental circulating blood volume. factors, gross observation, and resources on-scene. Hypoxemia A decreased oxygen level in the blood. Injury Something that damages or harms. Hypoxia Condition in which partial pressure of oxygen Injury prevention See Prevention; Injury prevention dissolved in an arterial blood gas sample is less than strategies. 70; low oxygen concentration that causes cells to Injury prevention strategies Techniques used to go redirect their metabolic processes to anaerobic about implementing Haddon’s countermeasures, which respiration in an effort to sustain the cell. include engineering safety into products or processes, Hypoxic hypoxia Lack of oxygen, due to an oxygen educating people about the dangers, increasing or poor environment, which can lead to hypoxia. improving enforcement of laws and regulations which Iatrogenic Adverse effects or complication that results promote safety, and providing economic incentives for from a medical intervention. people to use safer products or processes. Idiosyncratic reaction Situation in which a drug Inotropy To make the heart beat harder. produces an unpredictable reaction that is not allergic Insensible loss The volume of fl uid that is lost from in nature or due to overdose and resultant toxicity, the body in the form of perspiration off the skin but often due to the patient’s genetic make-up. (1.1 liters/daily) and the vapor in the breath. Immune complex Situation in which an antibody Insight An understanding of the patient’s current has attached to an antigen and stimulates the or chronic medical condition, as well as the complement system. consequences of inappropriate treatment; the ability Immunocompetent Capable of providing immunity. to make reasonable decisions. Immunoglobulins A type of protein globulin. Five Inspection A physical examination technique that types of immunoglobulins have been identifi ed: involves looking closely at the patient. IgA, IgD, IgE, IgG (gamma globulin), and IgM. Each Inspiratory capacity The total of the tidal volume immunoglobulin fi ts into the surface of an antigen in a plus the inspiratory reserve volume, which is a key and lock fashion, linking them together. measure of the maximum air that can be inspired. Implanted vascular access device (IVAD) A Institutional Review Board (IRB) An independent central venous catheter that has the port buried ethics committee consisting of experts from the fi elds Glossary 809 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. of theology, sociology, psychology, and medicine, the police power to provide consent is not generally which is responsible for reviewing all aspects of a invoked for minor emergencies or elective procedures. proposed research project in terms of the potential Ions An atom that has a positive or negative charge due psychosocial impact and to ensure that all human to a gained or lost electron. subject research is ethical. Ischemia A defi cient supply of blood going to a body Integrity A personal commitment to a code of moral or part due to an obstruction of the infl ow of arterial ethical behavior which serves as a foundation for the blood. patient–provider relationship. Ischemic hypoxia Problems of circulation that can Intended biological effect The modifi cation a drug lead to oxygen deprivation at the cellular level. is designed to have on the function of a tissue or an Ischemic patterns Changes in an ECG as the result of organ, such as reduce fever, eliminate pain, and so abnormal repolarization. on. Isoelectric line A line on the ECG that extends from Interference Extraneous electromagnetic energy heard the end of the T wave to the start of the ventricular on the radio as crackles and dead spots. depolarization represented by the QRS complex. Internal locus of control The idea that one has the This line indicates the period of time when the ability to remain in control of a given situation. myocardium, particularly the ventricular mass, has International unit (IU) A standardized measurement been repolarized and awaits depolarization. An that reveals the quantity of a biologically active isoelectric line on the monitor and on the rhythm strip substance, such as a hormone or vitamin, required to should appear as a fl at line between ECG complexes. produce a specifi c response. Isometric Exercise using free weights. Interpretation An interviewing technique in which Isotonic In terms of exercise, resistance exercises. In the Paramedic tries to determine the meaning of terms of fl uid management, a balanced solution (equal a message based on what is said and the speaker’s water and salt on both sides of a membrane). nonverbal cues. IV bags Soft plastic solution containers that collapse Interstitial fl uid The fl uid between cells. as the solution is withdrawn, eliminating the need for Interval A segment and an ECG wave together. venting. These create a closed system that helps to Intimate space In the theory of proxemics, an area decrease the risk of outside contamination. about the size of a beach blanket where patients IV push Procedure in which a Paramedic a medication feel most vulnerable. Entry into that space is only by attaching a syringe fi lled with the medication to an permitted to those people whom the patient trusts. infusion device and rapidly injects the medication. Intracellular water The water that is within cells. Jaundice A yellowish hue of the skin, which can Intradermal Injections that place a small quantity indicate liver failure or obstruction of the bile duct. of medicine just under the epidermis and in close Joule heat Heat caused by the buildup of thermal proximity of the subcutaneous tissue. energy as a result of electricity overcoming resistance Intramuscular injection Injection deposited between from the tissues. the layers of muscle, which is a common method of J point The start of the ST segment found at the medication administration. juncture of the QRS and the ST segment, the point Intraosseous (IO) An injection into the bone marrow. where the angle from the QRS changes. Intravascular fl uid A type of extracellular water Jugular venous pressure The force at which blood found in the blood, which is primarily made of plasma fl ows throughout the venous system, which can help and constitutes about 4% of the total body weight diagnose issues in the lung and heart. (3 or 4 L). Junctional tissues A long strip of tissue below the Intrinsic rate The rate at which the pacemaker cells AV node connecting the atria and the ventricles that of the heart depolarize. is capable of independently initiating a stimulus Intrinsic trigger A stimulus prompting an airway if the SA nodal impulse should fail to depolarize spasm that originates within the body, such as through one fi rst. stress or exercise. Jurisdiction The court having authority to decide a Inverted T waves A negative T wave that’s normally legal case, typically based on location. positive and upright, which may indicate coronary Justice The application of the concept of fairness, ischemia. which implies impartiality in the administration of Involuntary consent Situation during a life or limb rewards. In terms of research, the belief that one emergency in which an offi cer can provide consent group of people should not bear all the risks of for a person in custody (e.g., a prisoner). Involuntary research when the benefi ts of said research would consent is usually reserved for true emergencies; benefi t all persons in the larger society. 810 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. J-wire A special tightly wound spring wire with an negative electrode is on the right arm. The positive open hook at the end to prevent it from puncturing electrode is on the left arm. soft tissues, which is inserted into the hub of a needle Lead II An electrode point that notes the change during the Seldinger technique. between the right arm and left leg and provides a Kaizen Japanese concept of continual self- view of the inferior wall of the heart. The positive improvement that emphasizes process and system electrode is located on the left leg. thinking. Lead |
III An electrode point that measures change Keep the vein open (KVO) A slow infusion of fl uid between the left arm and left leg. The positive designed to be just enough to keep the veins from electrode is on the left leg. occluding. Leading question A question that may direct Kefauver-Harris Act A 1962 amendment to the the patient toward an answer that might not Federal Food, Drug and Cosmetic Act that required necessarily have been given if asked in another all drugs to undergo an extensive review that not only manner; for example, asking “Was the pain ensured the public’s safety, but also reassured the crushing?” rather than “Tell me what the pain in public that a drug would do what it claimed to do. your chest was like.” Ketamine A dissociative anesthetic that provides Left anterior descending coronary artery (LAD) excellent amnesia, analgesia, and anesthesia during A coronary artery branch that provides blood to the procedures and intubation. Most notably, however, it anterior wall of the left ventricle. has minimal respiratory depression even at very high Left bundle branch A division of the bundle of His doses. that lies within the septum and serves as a further Kinematics The branch of dynamics that studies passageway for electrical impulses into the left motion apart from mass and force considerations. ventricle. Kinesics The study of nonverbal behavior in Legitimate interest A determination of which interpreting communications. individuals need access to a patient’s confi dential Knowledge base The Paramedic’s previous medical information, and the extent of the experiences, anecdotal information, and formal information they are entitled to view. medical education. Legitimization The process in which a Paramedic Korotkoff sounds Sounds heard during the infl ation listens and seeks to understand the patient and and defl ation of the cuff that are caused by the the patient’s concern, regardless of how seemingly change in the nature of blood fl ow through the artery. insignifi cant the problem. This process supports the Labor Uterus contractions which signify the start of the patient and demonstrates caring. childbirth process. LEMON law A rapid mnemonic used to predict a Lacerations A torn or ragged wound. diffi cult airway when evaluating a patient. The Landline A hard-wired telephone. elements of the LEMON law are to: Laryngeal mask airway A blindly inserted airway ■ L—Look externally for anything that will hinder device designed to be used in situations where ventilation or intubation face-mask ventilation was inappropriate but the ■ E—Evaluate the 3-3-2 rule to assess the airway invasiveness of endotracheal intubation was not anatomy necessary. ■ M—Mallampati classifi cation Laryngoscope The primary, compact, and self- ■ O—Obstruction, either new or chronic, should be contained device healthcare providers use to visualize evaluated the larynx. ■ N—Neck mobility should be determined if not Larynx Also known as the “voice box,” the upper group contraindicated (contraindicated in suspected of structures of the lower airway that contains the C-spine injury) vocal cords. Les ambulance volantes Light two-wheeled LD50 Shorthand for lethal dose 50%, the drug dosage carriages used by the French military in the early where 50% of the test animals given that dose died. 1800s that carried an attendant as well as a driver, Lead Any of the conductors connected to the often viewed as the precursor to the modern electrocardiograph, each comprising two or more ambulance. electrodes that are attached at specifi c body sites Leukocytes White blood cells, which help the body and used to examine electrical activity by monitoring fi ght off disease. changes in the electrical potential between them. Leukotrienes Slow acting substances of anaphylaxis Lead I An electrode point that measures the voltage that produce chemical effects similar to histamine and change between the right arm and the left arm. The help to prolong the infl ammation. Glossary 811 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Libel Situation in which a falsehood damaging to a Lymphedema The swelling of tissues on a limb due to person’s reputation is written or printed and then lymphatic obstruction. disseminated to the public. Lymphocytes Almost colorless cells found in the Lidocaine A common local anesthetic and blood, lymph, and lymphoid tissues, constituting antiarrhythmic drug. approximately 25 percent of white blood cells and Life-long learning The commitment made by all including B cells, which function in humoral immunity, Paramedics when they attain their fi rst certifi cation to and T cells, which function in cellular immunity. remain current with the state of the profession. Lysosomes Tiny sacs in a cell that contain enzymes Lighted stylettes Malleable stylettes with a bright which can break down proteins. light source at the distal end and a power source Macintosh blade A curved laryngoscope blade with at the proximal end. When placed in the trachea, a common sizes from 1 to 4 with a large fl ange and fl at bright, well-circumscribed light is seen in the midline surfaces to control the tongue. of the trachea. Macro-drop Administration set with a short, straight Line of sight (LOS) The path that radio transmissions line that has few obstructions, such as fi lters or take over land, which ideally are free of obstructions medication portals. It is used when volume replacement that will impede the radio waves. is needed (e.g., during a trauma resuscitation). Line-out To place a single diagonal line across any Macroglossia A state of having an abnormally large open areas of a document in order to prevent the tongue. addition of new content to a PCR by others after the Magmas Powdered drugs with particles so large that Paramedic has completed the PCR. they are visible when they are mixed, or suspended, in Lipid-soluble A substance that is able to be dissolved water. in lipids (fat). Malfeasance Wrongdoing or misconduct; for example, Lipophilic Characteristic of being attracted to lipids. if the Paramedic performed an inappropriate Liquid oxygen (LOX) Concentrated oxygen in liquid procedure (e.g., gave a fl uid bolus to a hypertensive form. head-injured patient). Liquifactive necrosis Process in which cells that are Malignant Cancerous; something that will cause harm largely lipid in content, such as the neurons of the or damage health. brain, simply liquefy upon death and leave a pool in Malignant hyperthermia A skeletal muscle their place. disease that leads to a life-threatening reaction to Literature Published reports of research. succinylcholine and some other inhaled anesthetics. Livor mortis A condition caused by relaxation of the Malpractice Failure to exercise an appropriate degree vascular bed and a pooling of blood in dependent of professional skill during a service, resulting in portions of the body. injury, loss, and damage. Loco parentis Legal doctrine that states if a child Managed health care A fi nancial system where a has been left in the custody and care of another large corporation or the government obtains health adult (e.g., a schoolteacher) then that adult has the insurance for its workers via private sources, who then authority to provide consent for medical care. gather groups of healthcare providers and obtains Lotions Topical medications mixed in water. a reduced rate in exchange for a guaranteed client Lower esophageal sphincter (LES) A functional base. The managed healthcare insurance plan then portion of the esophagus where its walls contract mandates that patients seek treatment from this inwardly, forming a physical barrier to the refl ux of preferred medical group, in essence managing the stomach contents up the esophagus. care that the patient will receive by providing medical Low priority patients Patients with relatively minor care for the lowest price. conditions who can typically be treated in a more Mandatory reporting A situation in which one is focused manner on-scene. required by law to report a crime, such as child Lozenges Medicines intended to dissolve in abuse, sexual assaults, gunshot wounds, certain the mouth. communicable diseases, and animal bites. Luer lock A needle adaptor that attaches to the Mason–Likar modifi cation Adjustment in the syringe hub by use of a twist connection, where the placement of electrodes to help Paramedics obtain adaptor on the syringe is grooved and will mate with a a more accurate 12-lead ECG, which involves moving fl ange on the needle hub. the electrodes to the shoulders and the hip rather Lymphangitis Infl ammation of the lymphatic channels than the ankle and wrist. in the skin that occurs when there is spread of an Masses A large, fi rm area of considerable size in infection from a site distal to the channel. the body. 812 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Master problem list In a POMR recordkeeping system, complex created by the complement system which a list of the medical conditions for which a patient attaches itself to the cell’s walls and forms a tube had been, or currently was, receiving treatment. from the outside to the inside. The tube allows water Mean arterial pressure (MAP) The average blood to enter the cell, the cell to swell, and the cell to pressure in the arterial system over time, typically lysis. about 60 to 80 mmHg. Memory cells Clone cells that have a memory of the Mechanism of action The way a drug specifi cally make-up of the original cell. works upon a cell. Meniscus A concave-curved shape liquid assumes due Mechanism of injury (MOI) A description of the forces to tensions within a syringe. applied to a patient with the potential to cause injury, Menopause An age-related cessation of a woman’s such as a motor vehicle collision (MVC) or a fall. menses for an entire year, generally indicating the Medical command An immediate and direct physician end of the woman’s reproductive abilities. involvement in patient care. The physician’s authority Mentors Experienced master Paramedics who take on can be exercised either on-scene or over-the-air at graduate Paramedics as their protégés to teach them the time of an emergency. paramedicine. Medical ethics The way Paramedics behave in regard Meta-analysis A technique used when it is diffi cult to patients. to obtain a large population of study subjects, or the Medical intelligence The healthcare provider’s event being studied is relatively rare. The results process of learning from experience and past medical of several similar small studies are combined and practice and then coming to a decision. a statistical hypothesis test is applied, taking into Medical lines Sometimes called lifelines, a means of account differences in subjects and methods used adding medications directly into the circulation. before a conclusion is made. Medical oversight When a physician is involved in the Metabolic acids Acids formed during anaerobic quality assurance/quality improvement process and metabolism and amino acids formed by the provides direction, either in the form of protocols or breakdown/oxidation of proteins. education, to Paramedics. Metabolism Biochemical reactions that need to occur Medical Priority Dispatching™ A classifi cation for life processes to go on. system designed to ensure the right response gets to Metabolite A chemical produced by degradation of a the right person at the right time. medication into subcomponents that may be active or Medical record Documentation about the patient’s inactive. condition that will be used in the future by other Metaplasia Replacement of one adult cell type with physicians and allied healthcare professionals for another type of adult cell. patient care. As a part of the medical record, the Metered dose inhaler (MDI) Portable and simple- patient care report often provides vital information to to-operate respiratory device that delivers a specifi c physicians about the origin of a condition or disease. amount of aerosolized medication to the lungs. Medical restraint Any device used to immobilize a Micro-drop Administration set with |
fi ne control of patient for both the patient’s and the care provider’s the infusion stream, used when careful titration of safety; may include straps, jackets, and so on. medicated fl uid is desired (e.g., when a medical Medical self-help Instructions provided to patients by patient needs a slow infusion of a drug). 9-1-1 on self-rescue actions they can take during the Micrognathia A state of having a small jaw. time before responders arrive. Milieu An environment where an action can occur. Medical utility An assumption that those with the best Military emergency medicine The largest and oldest medical prognosis should be treated with the medical EMS service, consisting of those who provide emergency provider’s limited resources. medical care to members of the armed forces. Medication-facilitated intubation The use of Miller blade A straight laryngoscope blade with adjunctive medications during intubations, either common sizes from 00 to 4 with a small and curved to provide sedation or cause muscular paralysis to fl ange designed to open a conduit to the larynx on protect patients and improve their quality of care. the right side of the mouth and hold the tongue in the Medulla oblongata The part of the brain responsible midline to the left side of the mouth. for controlling involuntary vital functions; the Minimum data sets Certain fi elds with requested brainstem. information that must be completed on a PCR or other Membrane attack complex (MAC) In cases where form. the body does not recognize the bacteria and cannot Minute ventilation A measure of the total volume mount an effective antigen—antibody defense, a of gas that passes through the lungs in a minute. It Glossary 813 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. equals the respiratory rate (RR) times the volume per receptors and indirectly open ion channels that cause breath (Tidal Volume, or TV). depolarization. Muscarinic receptors, by defi nition, Misfeasance To perform a legal action in an illegal are more sensitive to muscarine, a naturally occurring manner; for example, if the Paramedic performs the chemical found in mushrooms, than to nicotine. correct procedure but does so incorrectly. Mutation A change in the DNA sequence of one gene. Mitochondria The largest organelle in the cell, found Myocardial infarction The death of myocardial cells. outside a cell’s nucleus, which produces energy. Myocardial ischemia A condition that occurs prior Mitosis The process of cell division. to myocardial cell death in which the heart tissue Mobile data terminal Laptop or handheld computers is slowly or suddenly deprived of oxygen and other inside a vehicle a Paramedic can use to create a nutrients. downloadable document for transmission over a Myocardium A muscular layer that actually performs telephone line, via modem, over the Internet, or by the heart’s work by contracting forcefully and using wireless technologies. ejecting blood from within the heart’s chambers. Mobile subscriber units (MSU) The various varieties Myoglobulinuria A condition in which the protein of cellular phones for use within a cellular radio products of muscle breakdown clog the kidneys. system. The three main varieties are the portable Narcotic The hallucinogenic effects of opiates, thought cellular telephone, the transportable cellular to be the result of stimulation of the sigma receptors telephone, and the mobile telephone. located in the limbic system. Modifi ed chest Lead 1 (MCL1) An alternative Narcotics A class of drugs known for their ability to ECG lead Paramedics may use to monitor patients induce a profound state of sedation. instead of/in addition to Lead II. MCL1 simulates the Nares The openings to the nose; nostrils. precordial lead V1, one of the six precordial leads of a Nasogastric tube A single-lumen tube passed through 12-lead. the nose into the stomach to evacuate air from the Morality A personal code of conduct. stomach. Moral obligations Certain mores that go beyond the Nasotracheal intubation The process of aiding basic human rights which every patient enjoys; for respiration by placing an endotracheal tube through example, an off-duty Paramedic’s moral obligation the patient’s nostril and into the trachea. may be to provide care when coming in contact with National Association of EMTs (NAEMT) A an injured person. professional organization, founded in 1975, whose Morbidity The incidence of disease. mission is to represent the views and opinions of all Morphology The shape of a QRS complex wave. prehospital care providers. Mortality The state of death. National Centers for Injury Prevention and Motion A request sent to a judge for some action Control A federal agency tasked with injury (i.e., dismiss the case, order a party to do something, surveillance. postponement, cease and desist orders, etc.). A motion National EMS Core Content Created under the can be verbal, but is most often a written request that leadership of the National Association of EMS contains pertinent points for the judge to consider. Physicians (NAEMSP) a curriculum that defi nes the Mucolytics Drugs that thin mucous secretions and entire universe of disorders, diseases, syndromes, and physically break down the viscosity of mucus by skills that an EMS provider might encounter and for breaking apart the mucoprotein structure. which he would be expected to provide emergency Multiple organ dysfunction syndrome (MODS) A care. failure of two or more organ systems. National EMS Education Program Accreditation A Multiplex Radios that permit the transmission of audio designation that assures students their EMS education signals as well as data. will meet national standards and assures the public Municipal EMS service A government-fi nanced that graduates of those educational programs will be and administered EMS system that may exist as an competent providers. independent entity or cross-trained with the police or National EMS Education Standards Created under fi re department. the leadership of the National Association of EMS Murphy’s sign Right upper quadrant tenderness that Educators (NAEMSE), the basis for EMS instruction that worsens when the patient takes a deep breath while provides direction for EMS educators regarding both the quadrant is palpated. A Murphy’s sign indicates the core content and the scope of practice. gallbladder infl ammation National EMS Scope of Practice (NEMSSOP) Muscarinic receptors Parasympathetic Created under the leadership of the National neuroreceptors that are slower than nicotinic Association of State EMS Offi cials (NASEMSO), an 814 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. organizational plan that clearly defi nes four levels of Neurotransmitter A chemical messenger that EMS providers and identifi es the knowledge and skills transmits a nervous signal across the synapse. required for each level. Nicotinic receptors Chemical receptors from National Formulary (NF) A drug reference manual the parasympathetic nervous system found in the that lists medications which are approved for central and peripheral nervous system as well as prescription. It contains specifi c chemical information the neuromuscular junction with skeletal muscles. that is more helpful to the pharmacist and Cholinergic stimulation of nicotinic receptors is quick manufacturer than the physician. in onset and short in duration, causing a sodium infl ux National Registry of Emergency Medical and local depolarization. Technicians (NREMT) An organization that Nitric oxide (NO) A colorless, poisonous gas involved provides a process of practical testing and written in oxygen transport to the tissues, the transmission of examinations for the certifi cation of Paramedics, nerve impulses, and other physiological activities. providing proof that the individual being licensed is NKDA Acronym that stands for “no known drug minimally competent to provide a specifi ed level of allergies.” care. The majority of states currently accept National No apparent distress (NAD) An appearance of not Registry certifi cation for state licensure. having diffi culty. National Standard Curriculum (NSC) A seminal Nociceptors Pain receptors in the body that respond document that defi nes the scope of practice for many to chemical, mechanical, or thermal stimulus. EMS providers distributed by the National Highway Noisy Characteristic of an ECG signal that is of poor Traffi c Safety Administration (NHTSA). quality and produces an unreadable tracing. Nature of illness The history of the present patient’s Non-depolarizing neuromuscular blockers One illness, often reported by the patient himself or the of the two major classes of neuromuscular blockers; patient’s family. competes with acetylcholine for the receptor but does Necrosis A physiological process in which living cells not cause the receptor to fi re. die, often due to disease, injury, or some other Nonfeasance A failure to perform the correct or pathological state. required procedure, which would be an error of Needle cricothyroidotomy A type of surgical airway omission; for example, if a Paramedic were to arrive performed by piercing the cricothyroid membrane on-scene of a cardiac arrest and the defi brillator with a large bore needle and catheter, allowing rapid failed because of a dead battery, which the Paramedic access to an otherwise obstructed airway. should have checked during routine maintenance. Negative pressure ventilation A mechanical Nonjudgmental Providing services based upon human ventilation technique in which a negative pressure need, with respect for human dignity, unrestricted environment is created around the patient’s chest, by consideration of nationality, race, creed, color or thus sucking air into the lungs. An iron lung is an status. example. Non-malfeasance A concept suggesting that no act of Negligence A failure to exercise the degree of care harm will be done during a medical treatment. that a prudent person would exercise. Nonrebreather face masks (NRB) Oxygen masks with Negligence per se Situation in which a Paramedic an oxygen reservoir that can deliver up to 80% FiO2; commits a criminal act, and the patient is injured as a they do not deliver 100% FiO2 because there will always result of that criminal act. The assumption is that the be some room air mixing through the open side port. Paramedic’s negligence fl ows from the criminal act. Nonspecifi c ST changes Situation in which the ST Neostigmine An acetylcholinesterase inhibitor that segment changes do not fi t a pattern of ischemia, can be used to reverse the effects of the competitive nor are they contributory toward another diagnosis. (non-depolarizing) NMBAs. Causes of nonspecifi c ST changes include improper Neuroleptics Major tranquilizers that prevent nausea. lead contacts, electrolyte abnormalities, drug-induced Neuromodulator Substances that inhibit the changes, hyperventilation, and even a drink of cold transmission of painful sensations to the brain and water. spinal cord by adjusting, or modulating, the rate of a Norepinephrine The chief neurotransmitter used in neuron’s discharge. the sympathetic nervous system. Neuromuscular blocking agents (NMBAs) Normal saline (NS) A solution of 0.9% sodium chloride Medications that block transmission of nerve impulses in sterile water (0.9% NaCl) that contains the same to skeletal muscle at the neuromuscular junction. amount of salt as does blood. NSS has become an Neuroreceptor A chemical receptor that receives EMS standard solution in many systems because it is messages from the neurotransmitters. compatible with all medications as well as blood. Glossary 815 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Normal sinus rhythm An optimal rhythm to provide the fi rst strip of tape, which will absorb any tension adequate fi lling of the ventricles and suffi cient on the tubing and potentially prevent the IV catheter ejection of blood for perfusion. from being displaced. Normocardiac A heart rate between 50 and 100, Oncotic Caused by swelling (e.g., oncotic pressure). which is considered to be normal. |
On-line medical control Medical command technique Nosocomial A hospital-acquired infection. in which physicians can give medical direction and Notary public A public offi cer recognized by the exercise medical command via the base radio. court who can verify the Paramedic’s writings to Open-ended questions Questions that allow the authenticate them as evidence. patient to express himself without restriction, with Null hypothesis When considering the results of a answers that can be used as a springboard to other research study, the supposition that the treatment questions. Open-ended questions usually begin with did not create changes (i.e., any changes are purely words like “how,” “what,” or “could” and ask for an random and coincidental). The purpose of the study is explanation. to determine if the null hypothesis is true or false. Operational competence A Paramedic knowing Nutritional fl ow The daily process of excretion and how the various team members interact, knowing an reabsorption of approximately half the nutrient- organization’s policies and procedures, and possessing laden fl uids in the body that is essential to the body’s situational awareness. sustenance. Opsonization A process in which the plasma proteins Nystagmus A fi ne tremble of the eye when holding mark resistant bacterium by attaching fragments of a lateral gaze; unequal movement or oscillating eye themselves to the bacterial cell wall, thus enhancing movements that are usually involuntary. the impact of the leukocytes. Obesity A growing health crisis when an individual’s Optic Pertaining to the eyes. body mass index is 30 or greater; a common layperson Orientation A person’s awareness of himself in terms defi nition of morbid obesity is 100 pounds over ideal of place and time. weight. Orogastric tube A single-lumen tube passed through Observational study In contrast to the descriptive the mouth into the stomach to evacuate air from the study, a study that asks a question and poses a simple stomach. explanation or hypothesis. To have a scientifi cally Orotracheal intubation The most common technique valid result from an observational study, one must used to intubate patients, in which a laryngoscope is control extraneous confounding variables that could used to visualize the larynx and the vocal cords, and account for the desired change. an endotracheal tube is observed to pass through the Obstructive shock The fi nal category of the Hinshaw– vocal cords. Cox shock classifi cation, which deals with the physical Orphan drugs Drug therapies for rare or uncommon impairment of forward blood fl ow despite an effective diseases, which generally are unprofi table for pump, an adequate blood volume, and a normal manufacturers to produce because the drugs are so vasculature. Examples of obstructive shock include rarely used. massive pulmonary clots, embolism, and a collapsed Orthostatic hypotension An abnormal decrease lung (pneumothorax), which proceeds to crush the in blood pressure that occurs when someone heart as well. stands up. Ockham’s razor A theory that simply states that if Orthostatic vital signs Vital signs that change with all things are equal, the simplest solution tends to be position. For example, when an individual changes the best one. In other words, common things occur position from lying down to standing, the blood commonly. pressure normally has a tendency to drop due to Oils Substances that have been extracted from plants gravity. for centuries for their use as food additives as well as Oscilloscope An electronic instrument that medications. produces an instantaneous trace on the screen of Ointments Topical medications placed in either a cathode-ray tube corresponding to oscillations of lanolin, an oil from sheep’s wool, or petroleum jelly. voltage and current, used in some cases to measure Oliguria An decreased output of urine, below 20 mL electrocardiograms. per hour. Osteoporosis A loss of calcium from the bones Omega loop Creation of a stress loop when securing an secondary to a decrease in hormones. intravenous administration set tubing to the patient. Otic Pertaining to the ear. Initially, a strip of tape is laid across the adaptor and Otitis media A middle ear infection marked by pain, against the skin. Then a loop of tubing is taped across fever, or hearing loss. 816 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Outcomes evaluation A matter of comparing the Paramedic fi eld diagnosis See Paramedical level of injury or illness before and after an injury diagnosis. prevention program. Paramedical diagnosis A broad and comprehensive Over-the-counter (OTC) Nonprescription medications identifi cation of a syndrome, a group of signs and that can be purchased by the public without a symptoms that suggest a disease, or a primary prescription so patients can self-treat minor illnesses. disorder of homeostasis, such as hypoxia, in a patient Ovum A female gamete; the egg in a female fertilized upon assessment by the Paramedic. by a sperm cell to create an embryo. Paramedicine A special subset of medicine that Oxygenation The ability to move oxygen from the air Paramedics provide in the out-of-hospital setting. in the lungs into the blood. Parasympathetic nervous system The portion of p value The probability of random chance causing the the autonomic nervous system responsible for the changes in a clinical trial, rather than the treatment. body’s involuntary vegetative functions including An acceptable p value is arbitrarily assigned by the digestion, heart rate, and the like, largely controlled researcher prior to the start of the study and is by the vagus nerve. These functions are summarized symbolized as . as “feed and breed.” Packed red blood cells (PRBC) Blood component Parasympathomimetic A chemical agent that mimics formed by removing nearly all of the plasma from the action of acetylcholine. a unit of blood and adding a small volume of Parenteral A method of drug administration that preservative to the unit. bypasses the gastrointestinal system, such as Pain threshold The amount of stimulus required to injection, which is preferred during an emergency elicit a pain response in a person. because of the rapidity of onset of the medication’s Palliative care Measures used to increase comfort and action as well as predictability of the drug levels. reduce pain, such as medication. Past medical history (PMH) Signifi cant historical Palpation Evaluation that involves the provider placing information necessary to determine the nature and his hands or fi ngers on the patient’s body in an effort potential severity of the patient’s illness or injury. to detect any abnormalities. All patients should be questioned about issues like Palpitations The sensation of one’s heart having an chronic illnesses, medications taken, allergies, and irregular and/or rapid heartbeat. use of tobacco, alcohol, or other drugs. Pandemics Outbreaks of diseases that spread Pathogen An organism that causes an infectious throughout a country or a region, which may reach disease. disaster proportions if not prevented or controlled in Pathogenesis The sequence of events—at the an appropriate fashion. molecular and cellular level—that leads to organ Papillary muscle Muscles that stabilize, open, dysfunction. and close the valve leafl ets with each myocardial Pathologic Physical changes as a result of disease. contraction. Pathophysiology The study of the causes of suffering Paradigm blindness The attitude that “we have in the normal human condition. always done it this way.” Paradigms can sometimes Patient advocate An individual who fi ghts for the become barriers to innovation and improvement. rights and wishes of the patient in terms of health Paradoxical respiration A disruption in normal care. Whenever a Paramedic acts to help a patient respiration in which, during inhalation, the fl ail obtain needed health care, he is acting in the segment is drawn inward by the negative pressure advocacy role. in the chest rather than expanding outward with the Patient autonomy The patient’s ability to control rest of the chest wall. During exhalation, the opposite her person and her personal destiny through decision occurs due to the increased pressure in the thorax making. Followed to its logical conclusion, patient during exhalation. autonomy implies that patients could decide to do Paraglossal approach An intubation technique nothing about a fatal illness, a decision that might that involves inserting the entire length of the lead to their own demise. laryngoscope blade blindly into the esophagus and Patient care report (PCR) Documentation completed then slowly withdrawing the blade under direct by the Paramedic indicating the care provided to a visualization. particular patient. Paramedic The highest level of EMS provider, Patient concordance The process of shared decision whose skill level and education includes advanced making between the healthcare provider and patient. assessment and diagnosis of syndromes and disorders Pattern recognition A tendency to quickly label an ECG and the treatment thereof. rhythm because it looks like another ECG rhythm seen Glossary 817 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. previously, which is poor practice because it negates the patient compartment at will, all the while nuances that differentiate one wave from another. transmitting and receiving critical patient information. PCR audits A careful review of the patient care report Personal space In the theory of proxemics, the documentation for specifi c data that allows healthcare area where a patient would engage in a one-on-one managers, EMS administrators, and EMS physicians to conversation. This personal space, about one and one- ensure that acceptable patient care is provided to all half feet to four feet, is the distance within which most patients equally. Paramedics initially interview patients for a history. Peak expiratory fl ow The maximum velocity of gas Pertinent negatives Those symptoms which, if movement during exhalation. present in a patient, could indicate a more serious Peak-load staffi ng EMS practice in which, during underlying problem. predictable hours of high demand, additional pH scale A measure of the differing degrees of acidity ambulances are placed in-service at strategic or alkalinity in a substance. The range of pH is from locations. 0 to 14, with 7 being neutral. Values lower than 7 PEARLS A mnemonic (partnership, empathy, apology, are acids, values higher than 7 are bases, and pure respect, legitimization, and support) that includes the distilled water is neutral (pH is an abbreviation for qualities needed to provide for a strong Paramedic– potential hydrogen). patient relationship. Phagocytosis A process in which neutrophils destroy Peer reviewed An article or research study that was bacteria by engulfi ng them. critically appraised by experts in the fi eld for validity. Pharmacodynamics The study of how drugs come to Penumbra A predictable pathway of cell changes create their therapeutic effect. leading to cell necrosis and myocardial infarction. Pharmacogenomics A combination of pharmaceutical Percussion The act of lightly but sharply tapping the research with the study of the human genome. body surface to determine the characteristics of the Pharmacokinetics The study of how drug absorption, underlying tissue. distribution, detoxifi cation, and elimination affect a Percussion note The sounds that result from the drug’s therapeutic value. act of percussion. Air-fi lled structures will produce Pharmacological effect A new or different effect a hollow, tympanic percussion note similar to that a drug generates in the body other than what was of a drum. Fluid-fi lled structures will produce a dull expected. percussion note. Solid structures will provide a loud, Pharmacology The study of drugs. well-defi ned percussion note. Pharynx The area of the airway composed of the Percutaneous central venous catheters (PCVC) spaces behind the nose (the nasopharynx) and the oral A central venous access device inserted into the cavity (the oropharynx). deep veins via the subclavian vein (in the chest), the Phenotype The visible outward expression of the internal jugular vein (in the neck), and the femoral chromosome, which is the result of the genetic vein (in the groin). infl uences of both parents. Percutaneous cricothyrotomy A surgical technique Phlebotomy |
The act of drawing or removing blood used to gain entry to the trachea through placement from the circulatory system in order to obtain a of a needle, then guidewire, then a small bore sample for analysis and diagnosis. tracheostomy tube in a rapid fashion with less Physical examination Also called an exam, an bleeding than a traditional surgical cricothyrotomy. assessment of the patient from head to toe in an Pericarditis An infl ammation of the pericardial sac effort to detect signs associated with a disease or that surrounds the heart. condition. Pericardium The membranous sac fi lled with serous Physician extenders Allied health professionals who fl uid that encloses the heart as well as the roots of the work under the license granted to the physician. aorta and other large blood vessels. Physician’s Desk Reference (PDR) A reputable Peripherally inserted central catheter (PICC) A source of information about prescription and over-the- very long central venous access catheter placed within counter medications; a compendium of manufacturer a vein in the antecubital fossa that is threaded into drug-prescribing information which is usually found the vena cava while under fl uoroscopy. in a package insert required by law to accompany all Peritoneum The inner lining of the abdomen. medications. Persistent vegetative state (PVS) A permanent Physician’s Order of Life-Sustaining Treatment state of unconsciousness. (POLST) A more detailed description than a DNR Personal digital assistants (PDA) Personal palm order of the patient’s wishes, placed in the form of a computers Paramedics can use as they move about physician’s order. These forms are generated through 818 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. a discussion between patients and their physician emergency services while still in the fi eld and to that addresses specifi c situations including utilizing transmit critical information to the emergency artifi cial hydration, nutrition, intubation, antibiotics, department. and other medical therapies. Point of service (POS) A managed care system with Physiologic A physical loss of cells as a result of the qualities of both an HMO and a PPO. The patient is normal changes of aging or simple disuse; a natural allowed to choose a healthcare provider from among development of cells. a list of preferred care providers (PCP) but may elect Physiology The study of the body’s functions, in its to see another “out of system” provider, without a normal human condition, which focuses on the physical, referral, at a substantially higher copayment and/or mechanical, and biochemical processes that go on deductible, similar to a fee-for-service arrangement. inside the body every day (i.e., how the body works). Polarity The direction of a QRS complex wave. PIER A model public education system developed by Portable radios Radio devices that can be carried the National Highway Traffi c Safety Administration from place to place. (NHSTA) which stands for public information, Positional asphyxia Situation in which a patient education, and relations. in excited delirium develops hypoxia and goes into Piggyback infusion The process of administering cardiac arrest when restrained prone, particularly if a medication infusion by attaching the secondary hobble restrained. intravenous line containing the medication to a Positive pressure ventilation A mechanical primary intravenous line to eliminate the need for a ventilation technique in which the pressure in the second intravenous line. patient’s airway is increased, thus forcing air into the Pitting edema The amount of indentation produced lungs. Intubation or a bag-valve mask are examples. when the edematous limb is pressed over the tibia by Postmortem Specifi c changes within the body that are the examiner’s fi nger. associated with death. Placebos Inactive drugs used in research trials that Post-traumatic stress disorder (PSTD) According appear similar to the actual drug in order to create to the Diagnostic and Statistical Manual, the blinding for the participants. development of “characteristic symptoms following Placenta The vascular organ that connects the unborn exposure to an extreme traumatic stress involving child to the mother’s uterus, providing safety and direct personal experience of an event that involves nutrition during its development. actual or threatened death or serious injury, or other Plain English transmissions The use of everyday threat to one’s physical integrity; or witnessing an speech to transmit information rather than using event that involves death, injury or a threat to the codes or jargon. physical integrity of another person.” Plantarfl exion The ability to push the toes downward Potable infusions Process of boiling water over the and away from the tibia. top of medicinal herbs and immediately drawing off Plaque Fatty lesion formed in the artery as a result of the solution. atherosclerosis. Potent Chemically or medically effective; strong. Plasma cells Cells that generate antibodies. Potentially infectious materials (PIM) Any Platelet See Thrombocytes. substance with the ability to transmit bacteria to Platelet plug A concentrated mass of platelets that another material. serve as a short-term fi x to a plaque rupture. Potentiation Situation in which one drug increases the Pleura The delicate serous membrane that lines each effectiveness of another drug. half of the thorax and is folded back over the surface Power The ability to attribute the changes in a of the lung on the same side. research study to the treatment rather than chance. Pleural effusion Excess fl uid that builds up in the Predictable injury pattern Characteristic injuries fl uid-fi lled space that surrounds the lungs, which can associated with a particular mechanism of injury. cause diffi culty breathing. Preferred provider organization (PPO) A managed Pneumothorax Condition in which air or another gas is care system that serves as a modifi ed fee-for- present in the pleural cavity as a result of disease or service schedule, permitting patients to choose their injury. healthcare provider from among a roster of approved Point The end of a needle, often cut obliquely in such a physicians. fashion that a sharp leading edge is created. Prefi x An affi x placed at the beginning of a root word Point of care Testing done in the fi eld by the to modify that root word; for example, adding the Paramedic, such as capillary blood draws, which prefi x “un-” to the root word “do” makes “undo,” the enhance the Paramedic’s ability to provide immediate opposite of do. Glossary 819 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Pre-induction agents CNS depressants administered Process server A person hired by an attorney to as a premedication before the introduction of deliver a summons and complaint to the defendant in anesthesia to decrease the incidence of fear or panic a case. (anxiolysis) or combativeness (sedation) in the patient. Prodrugs A precursor of a drug that is converted Preload The volume of venous blood entering the heart into its active form in the body by normal metabolic during diastole. processes. For example, heroin is a prodrug that, when Prescription drugs Drugs that cannot be dispensed by acted upon by the liver, metabolizes into morphine. a pharmacist without the written or verbal order of a Product liability The responsibility a manufacturer has physician or a mid-level healthcare provider, such as a to ensure a drug (or other product) is not defective physician’s assistant. (unfi t for its suggested use or results in harm to the Pressured speech Condition characterized by a consumer). patient speaking so fast it appears she has an urgency Professional development Steps a Paramedic may or pressure to speak quickly. take to continue advancement of his or her EMS skills, Preventative maintenance (PM) A program that which may include attendance at state and national forestalls the incidence of failure, thereby decreasing EMS conferences or regional workshops, consultation the incidence of injury and potential litigation. with medical directors for guidance and education on Prevention The steps taken to avoid illness or injury. new technologies, and review of EMS trade journals. Primary assessment The Paramedic’s initial Prognosis The expected outcome from a disease, evaluation performed to fi nd and manage any life- determined by a culmination of modifi able risk threatening injuries or conditions the patient might factors, nonmodifi able risk factors, and the have by assessing for (and correcting, if possible) any availability of treatments. threats to airway, breathing, and circulation. Progress notes In a POMR recordkeeping system, new Primary infusion A continuous intravenous set entries in the medical record. to which other medications may be added as Pronator drift An indicator of upper motor neuron supplements. weakness that is tested for by asking the seated Primary rhythm The main heartbeat. patient to hold her arms out with the palms facing the Prime wave The fi rst wave in a QRS complex in a ceiling and then close her eyes. The test is positive if situation where a wave repeats itself. The prime wave one arm drifts away from the starting position. is represented by a capital letter and the second Prospective research The most scientifi cally valid wave is represented by a lowercase letter. For research, in which an attempt is made to account for example, a proper notation of a QRS might read RSr. all predictable or known confounding variables, to Primum non nocere The duty to “fi rst, do no harm.” control those variables, and then add a treatment. If PR interval The distance from the beginning of the P change occurs, then it may be reasonable to conclude wave to the start of the QRS complex. that the treatment may have caused that change. Privacy offi cer An offi cer at a healthcare agency Prostaglandin A chemical mediator released from responsible for providing patient record security the mast cell that creates the sensation of pain, and recording security awareness training of all although its primary function is to increase vascular employees, as well as implementing a privacy permeability and smooth muscle contraction later in protection plan within the agency. the infl ammatory response. Private line (PL) See Coded (or tone) squelch. Protected health information (PHI) Facts from a Problem-oriented medical recordkeeping (POMR) patient’s medical record that are not to be dispersed Recordkeeping system in which a master problem list to the public without authorization. records the medical conditions for which that patient Protective custody Situation in which a law had been, or currently was, receiving treatment. enforcement offi cer assumes temporary custody of Indexed as such, new entries in the medical record a child in order for the child to receive medical care would be placed into the patient’s fi le under the after the parent refuses to give consent. problem listed. All healthcare professionals, from Protocols A written set of mandatory instructions physicians to nurses to dieticians, would place their for the Paramedic to use in specifi c situations in entries into the patient’s record. This system provides the absence of the physician. Protocols, almost by some order to the records needed by hospitals, defi nition, assume that one patient’s situation is the medical specialties, and allied healthcare providers— same or similar to another patient’s condition in the all of whom need the same information. same situation. Process evaluation A measurement of the means Proxemics A theory based on the concept that four used to carry out a program and how successful it was. spaces surround a person—intimate space, personal 820 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require |
it. space, social space, and public space—which provide medicines. The law further stipulates that if a varying levels of comfort when people move within medicine contains any of the 11 “dangerous” drugs, them. then the drug(s) have to be listed on the label. Proximate cause The immediate or direct reason why Purkinje fi bers Cardiac muscle fi bers that connect something occurred. In legal terms, the action that directly with the ventricular myocardium, allowing the created an injury or reason for a claim. ventricles to contract nearly simultaneously with the Prudent layperson standard An approach to defi ning atrioventricular node, creating a functional syncytium. an emergency that simply estimates if another citizen, Pursed lip breathing A sign of increased work of not a physician, who was in the same or similar breathing, in which the patient puckers his or her circumstance would think it appropriate to call EMS. lips while exhaling, providing some resistance to Public Health Model A framework showing the exhalation that provides pressure to keep the alveoli connections between host, agent, and environment in open. preventing injury. Putrefaction A process of decomposition within Public Health Service A federal program which the body characterized by greenish discoloration, makes up a key portion of the Department of Health secondary to hemolysis of blood, and slippage of and Human Services. With 5,700 commissioned health the skin from the skeleton, due to breakdown of services offi cers and 51,000 civilian employees, all subcutaneous fat. led by the Surgeon General, the current United States Pyelonephritis An infection of the upper urinary tract Public Health Service provides support to county and and kidney. state Public Health Departments as well as health care Pyrexia A fever that makes the body’s environment to medically underserved areas. hostile to bacteria. Public information offi cer (PIO) An EMS agency Pyrogen Chemical mediator that produces fever. employee whose responsibility is to interface with the Pyrogenic reaction A devastating systemic news media and provide public information. complication of intravenous therapy that occurs Public safety access point (PSAP) A centralized when a contaminated fl uid, or fl uid run through a communications center which runs 24 hours a day, contaminated administration set, is infused and leads seven days a week, and contains the entire 9-1-1 to nearly immediate sepsis. operation; a place where a service callback or QRS complexes A combination of two or more ECG additional emergency information would be available. waves, which combine in predictable ways to describe Public space In the theory of proxemics, the area one other cardiac events and are the basis for ECG would occupy with a stranger without fear but with an interpretation. ability to fl ee if danger should arise. Quadrageminy Situation in which ectopic beats occur Public trust An understanding between the patient every fourth beat. and the Paramedic that the patient will be treated Quality assurance (QA) Verifying a program’s with dignity and respect in the same manner a compliance with established standards. physician would treat the patient. Quarantine The practice of isolating diseased Pulse oximetry A noninvasive measurement of the individuals from the larger community. percentage of hemoglobin in arterial blood that is Quickening Fetal movements during the second bound to oxygen molecules. trimester that serve as the fi rst signs of life. Pulse pressure The difference between the systolic Q waves Pathologic waves on an ECG that indicate and diastolic blood pressures. The pulse pressure can electrical silence (i.e., no depolarization) in a certain provide the Paramedic with an indication about the portion of the ventricular wall. blood volume status or compensation for illness in a Radial pulse A measure of the beats created by blood given patient. fl ow taken at the wrist over the radial artery. Pulseless electrical activity (PEA) A situation in Radio head A small remote radio control panel placed which the patient displays electrical activity in the in the driver’s and/or patient compartment of an heart but no signs of contraction; an electrical rhythm emergency vehicle. The actual transmitter is usually without a pulse. placed in a different location in the vehicle. Punitive damages Money paid to reimburse an Range A certain set of acceptable physical parameters individual for more than just the actual damages the body uses to try maintaining a normal equilibrium. suffered that prompted a court case; a monetary fi ne Rate counter A digital readout on some ECG monitors designed to “punish” the loser of the case. that measures the number of ECG complexes that pass Pure Food and Drug Act of 1906 A law that in a minute, usually counting the tallest, or deepest, prohibits the use of false or misleading claims about wave on the ECG. Glossary 821 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Reasonable accommodations Actions taken by an Relative bradycardia A sinus rhythm with a rate that employer to make a workplace more accessible for a is too slow for the patient’s metabolic needs. person with special needs, such as adding ramps or Release of information A written authorization elevators. allowing documents to be given to an attorney. Rebound tenderness Tenderness that becomes worse Reliable Giving the same result on multiple trials. when the pressure is suddenly released during palpation Remission Situation in which the body’s defenses, or that may indicate irritation of the peritoneum. medical treatment, may force the disease into a non- Recanalization The process of re-opening an artery to active state. Remission does not mean the patient has restore blood fl ow. been cured, but rather means the disease has been Reception The process of interpreting a sent message, stopped. which may be infl uenced by both physical and cultural Remodeling To change the shape of something, such factors. as the interior chamber of a ventricle. Receptor The portion of a cell that attracts a certain Repeaters Radios that pick up, amplify, and then molecule. retransmit a radio transmission, which can extend the Reciprocal changes ST-segment depressions seen on range of a VHF almost indefi nitely. the 12-lead ECG in leads that face the wall opposite of Repolarization The restoration of a polarized state those with ST-segment elevations. across a membrane, as in a muscle fi ber following Recovery For cells, a return to a former functional contraction or the recovery of the myocardial cell. capacity. For a person, a return to health. Rescue devices Airway management tools used when Reentry phenomenon The reexcitation of a region intubation is not successful, such as a blind insertion of the heart by a single electrical impulse, which may airway device. cause ectopic beats, tachyarrhythmia, or an abnormal Residual Physical or chemical changes that remain in conduction mechanism. a patient after an encounter with a disease, such as Refereed A review process in which an editor will scars or hemiplegia. typically distribute an article to a panel of expert Resistance The second stage of the general Paramedics, who offer input and edit the article. adaptation syndrome, during which the body attempts The article is returned to the author, who revises the to reestablish homeostasis, utilizing the endocrine article based on the edits. and/or the immune system. Reference librarian A librarian trained in research Respect High regard based upon a nonjudgmental techniques who can help researchers develop a search attitude toward the patient. strategy to identify which resources, such as articles, Respiratory acid Acid in the body formed when excess will be most helpful in a study. carbon dioxide reacts with water to form carbonic Referred pain Pain from one source transmitted to acid (H2CO3) before conversion into bicarbonate, other parts of the body, via common nerve pathways. which is the intermediary step in carbon dioxide Refl ected path When using the radio wave transport. phenomenon of bounce, using enough refl ective Resting membrane potential A difference in the surfaces so that the redirected radio transmission will electrical potential between the outside of the cell roughly result in the intended direction of travel. and the inside of the cell while in a resting state. Refl ection An interviewing technique in which the Reticular activating system (RAS) A complex Paramedic repeats the patient’s words, which may network of interconnected refl exes in the brainstem encourage additional responses. Refl ection is helpful that maintains wakefulness. because it typically doesn’t interrupt the patient’s Retrospective research Research technique in which train of thought. a Paramedic looks at past practice, typically from Refractory Unable to respond to a new stimulus. patient care reports, to determine how to resolve a Refusal of medical assistance (RMA) A situation in current issue or question. which a patient can consent to a medical procedure, Re-uptake The reabsorption of a neurotransmitter and yet still refuses care. by a neuron following impulse transmission across a Regulations Rules established by a government synapse. department to regulate the conduct of citizens. Reverse R wave progression The loss of an R wave Regurgitation A backfl ow of blood into the atria. progression, which is suggestive of an anterior wall AMI. Rehabilitation Steps such as taking a rest break, Reverse use- (rate) dependent Drugs that prolong eating some food, drinking fl uids, and using lavatories the repolarization of normal myocardial tissues, as that help EMS responders handle stress more electrographically demonstrated by a prolonged QT effectively while at the scene of a prolonged incident. interval. 822 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Rhabdomyolysis A breakdown of skeletal muscle R wave progression A series of changes in the releasing cell contents including myoglobin. primary defl ection of the QRS from negative in V1 to Rib retractions Situation in which the work of positive in V6 in a normal 12-lead ECG. breathing increases and more effort is needed to SAFE-R A crisis intervention model consisting of fi ve generate the negative pressure in the thorax required steps: stimulation reduction, acknowledgement, for inspiration. When this happens, the skin between facilitation, explanation, and return or restoration. the ribs is pulled inward because of this negative Safety offi cer In a large emergency situation, an pressure in the chest. individual assigned to maintain scene safety for the Right Something to which a person is entitled based on responders. society’s sense of fair play. Saline locks Process of fi lling the intermittent infusion Right bundle branch A division of the bundle of His device with saline to seal, or lock, the device and that lies deep within the myocardium and serves as a prevent thrombus formation. further passageway for electrical impulses to the right Salvo see Run of ventricular tachycardia. ventricle. Satellite phones Satellites that radio waves are sent Right chest leads ECG recording technique in which to, in which they literally bounce off the satellite and the V4 to V6 wires from the left chest electrodes are return back to Earth, bypassing obstructions such as switched over to the same relative position on the mountains. surface of the right chest and the ECG is rerecorded as Scanners Multiband radio receivers that monitor V4R, V5R, and V6R. several radio frequencies, including those used by Right coronary artery (RCA) Cardiac artery that cellular telephones. provides blood to the right atrium and ventricle and Scene safety Steps taken to ensure the Paramedic’s the inferior portion or wall of the left ventricle. well-being when responding to an emergency Rigor mortis A stiffening of the muscles, which often situation, such as rerouting traffi c, assessing for occurs after death. threats, securing unstable areas, and the like. Risk The likelihood that a situation could lead to harm. Schizokinesis A physiological theory that suggests Risk factors Traits or practices that tend to make past |
painful experiences, unconsciously recalled by a person more or less vulnerable to a disease as trigger words, can elicit an autonomic nervous system compared to another person. response. In some cases, this response could be Risk management A plan that emphasizes safety and harmful to the patient. whose goal is to reduce Paramedic injury in an effort Scientifi c method The acquisition of knowledge to promote a culture of safety in an organization. through objective observation and considered reasoning. Risk manager An individual in an organization who Sclerosis An infl ammation, thickening, or hardening of identifi es known hazards and then tries to mitigate a body part. those hazards. Scope of practice The duties and responsibilities that Root A word, often supplemented with prefi xes or fall under a particular Paramedic’s experience and suffi xes, that relates to the main idea and often skill level. describes the organ involved or the key symptom. Scored Adding a depression across the middle of a Rovsing’s sign Pain in the right lower quadrant that tablet that makes dividing the tablet in half easier. occurs when the left lower quadrant is palpated, Script An idea in the Paramedic’s mind about a set of which is often associated with appendicitis. symptoms that has an associated symptom complex Rub A low-pitched, soft scratching sound that occurs at and an associated fi eld diagnosis and treatment plan. any time during the cardiac cycle. Sedative Medications used to decrease a patient’s Rules out A deductive process in which the Paramedic level of consciousness, lessen irritability, decrease eliminates all explanations for the patient’s condition excitability, or cause muscular relaxation. that don’t match the symptoms, thereby leaving the Segment The space between ECG waves. correct diagnosis. Seldinger technique A catheter-over-the-wire Runaway infusions An out-of-control drip infusion technique used to cannulate the femoral vein. that results in the patient being overmedicated. Self-awareness Possessing a conscious understanding Running the line out The process of clearing of one’s life infl uences and prejudices. intravenous administration tubing of any air and Semantics The meanings of words. running fl uid freely from the end. Senescence A breakdown in the body’s ability to Run of ventricular tachycardia Nonsustained bursts monitor for organ system failure and to repair those of ectopic ventricular beats that occur three or four at organs, which is inherent in the concept of being a time. elderly. Glossary 823 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Senile dementia Altered mental status caused by patient is asked to bring her right knee to the chest irreversible damage to the brain that typically is as far as practical. This position provides optimal manifest over a long period of time (e.g., a series of access to the anus while minimally compromising the brain attacks, such as strokes). patient’s dignity. Sensitivity A measure of how often a medical fi eld test Simulcast The ability to interact with several gives a correct positive result. departments of an organization at once. Sepsis A toxic condition resulting from the spread of Single-blind study A research study in which the bacteria or its toxic products from a focus of infection. subjects do not know which group they are in, Septal hematoma A form of nasal trauma that results although the researcher does. in a bruise or bleeding. Sinoatrial node (SA) The initial portion of the Septic shock Condition in which the patient develops conduction system, located just beneath the a potentially serious drop in blood pressure from a epicardium on the posterior wall of the right atrium systemic infection in the blood. near to the end of the vena cava and at the junction Serial vital signs All vital signs taken after the of the sinus of Valsalva and the atria. baseline vital signs that are useful to illustrate trends Sinus bradycardia A sinus rhythm with a rate below in vital sign changes. 60 bpm, although most patients are not symptomatic Serotonin A neurotransmitter found primarily in the until the heart rate falls below 50 bpm. gastrointestinal tract that causes arterial and venous Sinus dysrhythmia An irregular heart rhythm constriction. characterized by alternating increases and decreases Serve In legal terms, to cause to be delivered, as in a in the heart rate. summons or other document. Sinus of Valsalva An area adjacent to the aortic valve Settlement A sum of money paid to the plaintiff in that creates a space between the aortic wall and each order to conclude a case without going through a trial. semilunar wall. Shams Ineffective devices used in research trials that Sinus tachycardia A sinus rhythm with a rate greater appear similar to the actual device in order to create than 100 bpm. blinding for the participants. Situs inversus A condition characterized by complete Shared decision making Collaborative medical reversal of all thoracoabdominal organs, such that practice in which the patient is seen as being they are positioned the mirror opposite of normal. interdependent with, rather than dependent on, Skip A radio wave transmission technique to overcome the Paramedic. In a shared decision-making model, the problem of obstacles to line of sight, in which the the patient is consulted about clinical decisions, high-frequency radio antenna is directed toward empowering her with current information about her the sky. The radio signal then rises until it strikes the state of health. ionosphere, a layer of atmosphere where the sun’s Shared practice The knowledge that both physicians ultraviolet rays ionize the gasses, and the signal is and Paramedics are responsible for the patient’s care. refl ected back to Earth. Shock–liver A form of liver failure. Sky wave A radio wave transmitted into the Shunting A displacement of blood volume to the core atmosphere for a return to Earth rather than being circulation. transmitted across land. Side effects Unintended reactions one may have to a Slander Situation in which defamatory lies about a medication in addition to its therapeutic effect, such person are told to others. as drowsiness or nausea. Slip-tip A syringe adaptor that simply slides inside the Sign Indication that appears during a physical needle hub. examination that suggests the cause of a disease or Small volume nebulizer (SVN) An alternative injury. platform for the delivery of inhaled medications in Sign-out An authentication measure in which the which the medication is suspended in a stream of air Paramedic writes the time, date, and initial after which is then smashed against a round surface in the the last entry. The sign-out indicates that the PCR SVN, creating micro-fi ne particles that are ideal for was written and completed by the person listed “in- inhalation. charge” at the time and date listed. SOAP notes One of the earliest standardized Simplex A radio system that only allows communication documentation formats, which contains subjective in one direction at a time, such as a walkie-talkie; the (S) information obtained from the patient or the simplest radio system. patient’s family, objective (O) information obtained Sim’s position A modifi ed left lateral position used during physical examination, an assessment (A) of the when administering medication rectally in which the patient’s problem, and a plan (P) for action. 824 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Social norm A rule of conduct that regulates the Star of life The symbol of EMS as represented by six interaction between people but is not specifi c to one points: detection, reporting, response, on-scene care, individual. care in transit, and transfer to defi nitive care. Social space In the theory of proxemics, an area of Starling’s law A cardiac theory that states the heart’s relative safety where strangers can enter, with certain stroke volume increases in response to an increase in expectations of conduct. A dining room in a restaurant the volume of blood fi lling the heart (the end diastolic is an example of the use of social space. volume). The increased volume of blood stretches the Somatic pain Acute sharp, burning pain that often ventricular wall, causing cardiac muscle to contract arises from the skin, ligaments, muscle, fascia, bones, more forcefully. or joints. Unlike visceral pain, somatic pain can be Static Radio interference caused by unshielded localized to a specifi c area. electrical devices emitting 60 cycle interference, Spacer A device attached to a metered dose inhaler lightning in the atmosphere, bursts of radio waves that allows a more controlled inhalation of smaller, from sunspot activity, and even the spark plugs in an ideal-sized drug particles suspended in the vapor automobile. within the chamber than are possible with the Status asthmaticus Persistent bronchospasm that is metered dose inhaler alone. resistant to routine treatments. Special incident reports (SIR) Documentation Status epilepticus A condition of unremitting completed by the Paramedic that is not directly convulsions interspersed with brief instances of coma. related to patient care but is instead used for Statute A law enacted by legislation rather than administrative purposes or as a part of a court previous case decisions. proceeding. Statute of limitations The time allowed from the Specialty Care Transport (SCT) A growing occurrence of an incident during which a lawsuit can subspecialty in EMS, in which Paramedics perform be fi led. The statute of limitations simply states that critical care interfacility transportation by a plaintiff (usually the patient) cannot commence a transporting sick and injured patients from outlying lawsuit after a certain amount of time has passed. clinics and critical access hospitals to tertiary care Sternal notch An anatomical position near the base of centers. the neck. Specifi city A measure of how often a patient with a Sternal retractions Situation in which the work of negative medical fi eld test truly does not have the breathing increases and more effort is needed to condition the test is designed to detect. generate the negative pressure in the thorax required Spike Sometimes called a bayonet, a very sharp point for inspiration. When this happens, the skin at the on an administration set which is used to pierce the top of the sternum is pulled inward because of this fl uid container. negative pressure in the chest. Spirits Liquid medications brewed from various materials Stethoscope A medical instrument used to listen that have a volatile oil that evaporates at room inside the body, consisting of hollow fl exible tubes temperature and leaves a distinctive odor in the air. connected to ear pieces that join to a piece placed Spontaneous abortion Situation that occurs in about against the area to be evaluated. 30% of pregnancies in which the zygote fails to implant Stewardship To uphold the noble traditions of and the pregnancy prematurely ends; often referred medicine while caring for patients. to as a miscarriage. Stigma A negative connotation attached to Squelch control A static-reduction technique in participation in a program, such as labeling and public radio transmissions that reduces the amount of signal embarrassment. received between transmissions, narrowing the Stochastic effects Long-term complications from reception of radio waves and eliminating background ionizing radiation exposure. interference. Stock solution A standard concentration of a solution Standard leads The 12 leads used in a standard that may be diluted to weaken its potency for certain electrocardiogram, comprising the standard bipolar patients. limb leads I—III, the augmented unipolar limb leads, Strain Signs of fatigue often seen when the body is and the standard precordial leads. repeatedly overstimulated, perhaps by constant Standard of care Care and treatment that another bombardment by stress-inducing stimuli. Paramedic with the same or similar training would Stress The body’s reaction to stimuli; a disruption in have rendered in the same or a similar situation. homeostasis. Standing orders Preauthorized medical orders often |
Stress management A process of coping with chronic given to Paramedics by physicians. stress in an effort to recover from its effects. Glossary 825 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Stress reduction Actions an individual takes to paraphrases the patient’s words to ensure that the eliminate the source of stress. message sent was correctly received. Stressors Stimuli that cause stress. Modern stressors Summary dismissal A request by the defendant’s include psychosocial pressures from family, coworker attorney to end a court action based upon the facts in complaints, and supervisors’ demands, as well as such the case, stating that the facts of the case are clear things as unrealistic expectations and noise pollution. and without dispute. Strike-out A method of error correction on the patient Summary judgment Determination by a judge to care report in which the Paramedic crosses through dismiss or decide a case solely on the preliminary the mistake with a single line, leaving the content evidence without conducting a trial. below the strike-out legible. Next to the strike-out, Support Assistance that promotes another’s interests. the Paramedic should place the date and initial the Suppositories Medication within a wax carrier that strike-out to indicate authorship. melts at body temperature and is typically given ST-segment depression A reduction of the ST internally for a local effect; often administered in the segment, which is a >1 mm depression below the vagina, urethra, or rectum. J point from isoelectric baseline. Supraventricular rhythm A cardiac rhythm ST-segment elevation A rise in the ST segment, originating above the ventricles, indicated by which is a >1 mm depression below the J point from a narrow QRS. isoelectric baseline. Surfactant A fl uid that decreases the alveoli’s surface Stylet A commonly used adjunct to oral intubation that tension and prevents the alveoli from collapsing during provides rigidity to the endotracheal tube. expiration. Subcutaneous emphysema The presence of air Surgical anesthesia A near-coma state of sedation between the layers of the skin that indicates a leak in in which the patient loses protective refl exes in the respiratory system. a head-to-toe (cephalocaudal) direction. Subcutaneous injection Injection in the layer of skin Surgical cricothyroidotomy A surgical procedure to directly below the dermis and epidermis, which is gain entry to the trachea through the anterior neck by the slowest and least dependable means of obtaining making an incision through the cricothyroid menbrane. therapeutic drug levels in the bloodstream. Suspension Medications that will not dissolve in a Subendocardial ischemia Condition that occurs solvent and thus remain as fi nely pulverized particles during myocardial ischemia in which the deep fl oating in a liquid. myocardial tissues becomes ischemic fi rst, since Sweep speed The speed of the rhythm passing by coronary perfusion occurs from the surface (or on the ECG monitor screen. Standard sweep speed epicardium) inwardly. is 25 mm/second, although the Paramedic may alter Subpoena A legal command or direction issued by the this speed to get a closer look at certain features of court to appear at a certain place, such as the offi ce an ECG. of the plaintiff’s attorney or the courthouse, at a Sympathetic nervous system The portion of the particular time. autonomic nervous system responsible for those Substituted judgment Situation in which a surrogate emergency responses that are at “stand-by,” ready decision maker has the responsibility to know the to provide the person with the ability to fl ee (fl ight) patient’s preferences and must place the patients’ or fi ght. wishes before the surrogate’s wishes. Sympathomimetics Drugs that mimic the effects of Succinylcholine A depolarizing neuromuscular the sympathetic neurotransmitter norepinephrine. blocker composed of two acetylcholine molecules Symptom Something that indicates the presence of a hooked back to back. It offers a rapid onset of physical disorder. action (30 to 60 seconds) and rapid termination of Symptom complex A list of abnormal conditions effect (3 to 12 minutes) with return of suffi cient found by the Paramedic during the history of the ventilation to sustain life in 8 to 10 minutes. present illness and the physical examination. Succinylcholine produces muscle fasiculations at Symptom pattern A series of conditions associated onset of action. with a known disease. The Paramedic compares the Suffi x An affi x placed at the end of the root word to symptom complex against the symptom pattern arrive modify that root word; for example, adding the suffi x at a diagnosis. “-less” to the root word “help” makes “helpless,” Synapse The point at which an impulse passes from meaning something different than “help.” one neuron to another. Summarization Communication technique in which Syncope A transient loss of consciousness that the Paramedic takes the patient’s own words, then spontaneously resolves. 826 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Syndrome A collection of symptoms that characterize Teachable moment The time when the patient has a a condition or state. heightened awareness of a problem and is receptive to Synergism The interaction between drugs which can information. occasionally lead to unexpected or extra effects. Telemetry The process of transmitting measurements Syntax The rules of grammar. and recordings to another location, where they are Syrups Medicines mixed with sugar and water. interpreted; a monitoring device connected to a System architecture The arrangement of radio patient by two or three wires that collects data and components. Currently, two radio architectures sends it via radio waves to an antenna. exist in EMS: traditional land mobile radio (LMR) Teleological A model of ethics that simply states the architecture and cellular system architecture. end justifi es the means. This approach implies that, Systemic Pertaining to more than one internal organ even though some harm may occur, in the end if the system. outcome is good then the behavior is ethical. Systemic infl ammatory response syndrome 10-codes A system from the 1920s in which police (SIRS) Localized infection leading to systemic departments that only had one radio frequency used infection leading to sepsis, then on to septic shock and abbreviated messages designed to minimize airtime. multiple organ dysfunction syndrome. Plain speech is preferred over 10-codes to avoid Systemic pathology Illnesses and ailments of humans confusion and improve interoperability. related to specifi c organs. Tenderness A soft or yielding texture; physically Systems review A head-to-toe approach to history weak. gathering in which the healthcare provider starts Tentative fi eld diagnosis A determination of what’s at the head, questioning about issues/concerns causing the patient’s problems performed upon initial that may be present at the nervous system level evaluation. (stroke, seizures), and moving downward to cover the Teratogen Toxic substance or agent such as an illegal cardiovascular system, respiratory system, abdomen, drug or an infection such as rubella (measles) or genitourinary system, extremities, and behavioral toxoplasmosis that could lead to fetal malformation. disorders. Teratogenic effect Exposure to ionizing radiation System status management (SSM) A dynamic that can cause birth defects and cancer in subsequent alternative to fi xed-post staffi ng in which ambulances generations as a result of changes in the structure of are “on the road” and moving to new locations to DNA. improve response times. Tertiary care Highly specialized care provided in areas Systole Ventricular contraction. such as trauma centers and cardiac centers. Systolic blood pressure The maximum blood Therapeutic effect See Intended biological effect. pressure measured during systole when the heart Therapeutic index The ratio of the difference contracts. between a drug’s median effective dose (the ED50) Tablet A dry medicinal powder that is compressed into and the median lethal dose (the LD50). a pill shape. Therapeutic level (t) The point when the drug Tachycardia A heart rate that is over 100 beats per levels attain the targeted value, as manifested by minute for an adult or above the upper limit of normal observation of the therapeutic effect. for a child. Therapeutic touch Intentional touching that mimics Tachypnea Rapid breathing. earlier comfort experiences (such as a mother stroking Tactical EMS (TEMS) EMS providers working with an infant’s cheek) and telegraphs reassurance, police SWAT teams trained on how to provide care understanding, and caring to the patient as a means to to the wounded while in hostile surroundings as well heal. as maintain the health of the SWAT team members Third spacing A process that occurs when colloidal during prolonged operations. osmotic pressure is low, in which fl uid leaks from the Tactile fremitus Vibrations palpated on the chest wall intravascular space and into the interstitial space. that occur with speech. 3-3-2 rule A simple method for rapidly evaluating a Tamponade Compression performed to control patient’s anatomy, in which a Paramedic should be bleeding. able to place three fi ngers between the tip of the chin Tardive dyskinesia A neurological disorder and the hyoid bone, place three fi ngers between the characterized by involuntary movements of the upper and lower teeth at the maximal mouth opening, extremities often caused by long-term use of certain and place two fi ngers between the thyroid notch and drugs (antipsychotic or neuroleptic). the fl oor of the mouth. Glossary 827 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Thrill Vibration of the chest associated with heart Transfusion-associated circulatory overload contraction. (TACO) Situation that occurs when the patient Thrombin A protease in blood that facilitates blood receives more volume of blood products than can be clotting by converting fi brinogen to fi brin. handled by the circulatory system. Thrombocytes Platelets; blood cells that aid in Transfusion-related acute lung injury (TRALI) clotting. A new acute lung injury that occurs within six Thrombophlebitis An infl ammation of a vein that may hours of a transfusion and is directly related to the develop at an IV insertion site. transfusion. Thrombus A mature clot made of platelets cross-linked Translaryngeal illumination Using a lighted stylet with fi brin and other blood cells in a fi rm meshwork; a during endotracheal intubation to take advantage of blood clot. the larynx’s proximity to the anterior surface of the Thyroid gland A highly vascular, “H” shaped structure neck. that lies along the sides of the larynx and upper Translocations Gross breaks in some chromosomes trachea. with subsequent rejoinings at new locations. Tidal volume The volume of a normal breath, Transmission The process of conveying a approximately 5 to 7 cc/kg of ideal body weight. message, which can be either a true and accurate Tincture Medicinal substance that is dissolved in representation of the sender’s thoughts or may alcohol. be conveyed in such a way that the meaning is Tincture of benzoin Medication often applied to skin misconstrued by the receiver. before applying tape or another adhesive bandage, Transmural ischemia The stage of myocardial used to both prevent allergic reactions on the skin ischemia when the ischemia affects the entire from the bandage and to help the tape or bandage thickness of the myocardium, from the endocardium adhere longer. to the epicardium. To keep open (TKO) The minimal infusion rate Transtracheal jet ventilation (TTJV) Ventilation needed to keep veins from becoming occluded by a of the lungs using special high-pressure devices clot. through a large bore catheter placed through the Tolerance Resistance to a drug over time, which cricothyroid membrane, which is a commonly taught prompts the patient to take larger doses of the drug and performed |
emergent oxygenation technique. to acquire the same effect. Trauma Mechanical injury due to abrupt and sudden Tonic A series of whole body contractions that often physical forces acting upon the body, such as friction, precede a seizure. blunt force, or penetrating force. Tonicity A solution’s ability to exert an osmotic Trauma line Intravenous access inserted into the pressure upon the membrane. vascular space so that intravascular volume can be Topical Medications meant to be applied to the skin. replaced quickly. Tort A civil or private wrongful act, other than a breach Treatment pathway The continuum of patient care of contract, resulting in some type of injury or harm which starts with the primary assessment and is (not necessarily physical injury). continued in the emergency department, critical care Total body clearance The sum of all drug excretion units, rehabilitation fl oors, and homecare services. from the kidneys, skin, lungs, and liver. Triage tag A form of documentation tag used in mass Toxicology The study of poisonous substances. casualty incidents to quickly prioritize patients based Toxin Any substance capable of causing cell injury and on how quickly they need assistance (i.e., immediate death, including poisons. treatment vs minor injury). Trace A horizontal left-to-right movement on an ECG Trigeminy Situation in which ectopic complexes occur monitor. every third complex. Trachea A conduit for respiratory gasses to pass to and Tripod position A position patients may assume from the lungs. when in respiratory distress to help with breathing, Tracheobronchial suctioning Direct suctioning of in which they place their hands on their knees or the secretions in the bronchial tree. legs and lean forward in a sitting position, creating a Trade name Drug name manufacturers give a tripod. This position allows the overworked accessory patented drug to distinguish it from other similar muscles to work better, although most patients begin drugs. to tire when they are in such severe respiratory Transdermal Pertaining to topical medication distress. absorption, in which medicines are applied to the skin Troches Lozenges that dissolve and are absorbed in the and absorbed into the body. mouth through the oral mucosa. 828 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Trunking A technique whereby, using computers, assessment and evaluation is needed before treatment multiple users can communicate over fewer is initiated. frequencies, with the computer selecting the Use- (rate) dependent Drugs which act upon the frequency to be used based on availability. ionic channels during the open/active state and Turgor A distended state of tension in living cells. preferentially will be attracted to rapidly depolarizing Turned over to A process of transferring a patient to ectopic pacemakers. another care provider with equal or greater skill. Uvula A fl eshy lobe that typically hangs in the midline Tympanic membrane Sometimes called the eardrum, of the pharynx. a thin membrane that separates the external ear from Vagus nerve The major parasympathetic nerve which the middle ear. originates in the medulla, exits the skull at the base Type and crossed Donor blood that is successfully of the brain, travels down the neck (proximal to the matched to recipient blood. larynx), branches into the heart and lungs, innervates Type and cross-matched See Type and crossed the stomach, passes through the digestive tract, and Type I error A common error made in an experiment in ends in the anus. which the researcher rejects the null hypothesis and Valecula The space formed between the anterior- accepts the alternative hypothesis when in fact it is superior surface of the epiglottis and the posterior not supported. base of the tongue. Type II error A common error made in an experiment Valid Logically correct and accurate. in which the researcher incorrectly fails to reject Value judgment A Paramedic’s decision as to which the null hypothesis; a failure to observe the change course of action is the correct course of action in created by the treatment when one did occur. terms of right or wrong. Umbilical cord A connection between the mother’s Vapocoolant spray See Fluori-methane. placenta and unborn child (at the navel) used to Vasopressor A chemical that causes vasoconstriction, transfer nutrition, respiratory gasses, and wastes in particularly on the arterioles. the months prior to the child’s birth. Vastus lateralis (VL) An intramuscular injection site Unilateral Relating to only one side. on the anterior thigh. The Paramedic mentally divides Unipolar lead The use of a single positive electrode, the vastus lateralis muscle into three equal portions. using Wilson’s central terminal, to record differences Choosing the middle section of the VL, the Paramedic in electrical potential. prepares the intended injection site with an alcohol- United States Pharmacopeia (USP) A drug reference soaked pad. created by an independent nongovernmental science- Vector The sum of electrical events which makes up based public health organization called the United the common direction of the electrical wave front. States Pharmacopeia. The United States Pharmacopeia Vecuronium A non-depolarizing neuromuscular is made up of over 1,000 scientists, practitioners, and blocking agent commonly used by Paramedics in the representatives from various colleges of medicine and prehospital setting. pharmacy who set the standards for medication Venous cannulation The process of threading a manufacturing in the United States. catheter into a vein. Universal donor Name given to Type O blood, since it Ventilation A measure of how well a patient is moving can be given to any of the A-B-O blood types without air in and out of the lungs during inhalation and adverse reactions. Type O blood does not have surface exhalation. proteins that incite the immune response, which ends Ventricular diastole Condition after a contraction in hemolysis. when the ventricles of the heart are in a relaxed state. Universal law A situation that demands action by any Ventricular rhythms A heartbeat originating from person in that situation, as a matter of duty. the ventricle, indicated by a wide QRS. This is Universal recipients Name given to individuals with usually, but not always, dangerous because the Type AB blood, since they can receive blood from any origin of the beat is in the last pacemaker in the donor. This is because people with Type AB blood do ventricles. not have antibodies against A or B proteins present in Ventricular systole Condition in which, with the the plasma. pressure elevated in the ventricles, the ventricular Upregulation An increase in the number of cell muscle fi bers contract forcefully and generate receptors in a body cell due to changes in chemical suffi cient pressure to force open the aortic and levels. pulmonary valves to eject blood out of the heart. Urgent An assessment classifi cation in which the Ventricular tachycardia A rhythm experienced when patient’s condition is not emergent, suggesting further the ectopic focus is ventricular and the ventricular Glossary 829 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. pacemaker becomes dominant. With ventricular Vital signs Objectively measured characteristics of tachycardia, the rhythm is regular, the rate is fast, basic body functions, such as temperature, pulse, and every beat is wide. respirations, and blood pressure. Vital signs provide Ventrogluteal (VG) An intramuscular injection site the Paramedic with an indication as to how well the located on the lateral thigh proximal to the hip. patient’s body is functioning or compensating for an Venturi masks Special masks with a restricted intake injury or illness. that permits an exact percentage of oxygen. These Volume overload A potentially devastating can be used to deliver oxygen, although their use in complication of intravenous infusions that occurs the prehospital environment is generally limited to when a positional IV access is inadvertently adjusted specialty care services. and the infusion fl ow is unrestricted. Veracity An adherence to truthfulness. When a Paramedic V/Q mismatch A mismatch between the amount of practices being truthful with all of her patients, then the lungs that are fi lled (alveolar ventilation) and the that Paramedic can be said to have veracity. capillary circulation (pulmonary perfusion). Verbal consent A spoken request for permission Walked on Suppression of a radio signal. to perform a procedure, accompanied by a simple Wellness A state of physiologic equilibrium free of explanation, which can improve patient compliance disease. More than an absence of illness, it is an and decrease the risk of misunderstanding. active process of becoming aware of, and making Vertical equity Injury prevention programs where the choices toward, a more successful existence. people most affected receive the major emphasis. For Wide open (WO) A rapid infusion of intravenous example, if statistics demonstrate a higher number fl uid. of accidental shootings among children in low-income Wilderness EMT (WEMT) An EMS provider in rural households, then public health programs could be and woodland areas with special training that fosters justifi ably organized to emphasize prevention within critical thinking as well as creativity when working in that population. an environment where supplies may be limited and Vesicular sounds Lung sounds auscultated over the patient transport to defi nitive care prolonged. peripheral, smaller airways that sound like leaves Witness A person who can confi rm testimony or rustling in the wind. evidence presented in a case, or authenticate Vicarious liability Based on the legal principle information provided. respondeat superior (“let the master answer”), the Working diagnosis A presumptive conclusion the basis that a person is accountable for the actions of Paramedic makes based on the available signs and others. symptoms. Virtue ethics A somewhat middle ground approach to World Health Organization (WHO) The most ethics that does not depend on consequence-driven prominent and infl uential international public health decisions or duty-driven decision making, but upon agency. virtues. The virtue ethics approach suggests that a Z-track An injection technique in which the Paramedic “right-thinking” person will make the best decision for holds the drug-fi lled syringe in the dominant hand, the patient based upon a predetermined set of virtues. bevel up, and pulls gentle traction on the injection Visceral pain Poorly localized pain that arises from site with the nondominant hand as a means to prevent the internal organs and is usually described as leakage. pressure-like, dull, or aching. Zygote A fertilized ovum. 830 Glossary Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 9-1-1, 28 acetaminophen, 180–181, 690, adrenocorticotropic hormone 693–694 (ACTH), 166 A acetylcholine, 164, 479, 639 adulthood, developmental stage, abandonment, patient, 86 acetylcholinesterase, 479 144–149 abbreviations, medical terminology, acetylsalicylic acid, 498 adult respiratory distress syndrome 205–207 acid-base balance, 192–193, 495–500 (ARDS), 191 abbreviations, prescription acid load, 158, 192, 495, 497 Advanced Cardiac Life Support notations, 618 acidosis, 494, 497–499 (ACLS), 180 ABC system, shock assessment, acinus, 360 advanced directives, 78, 96–97, 149 192–193 acknowledging, patient responses, advanced emergency medical abdomen 236–237 technician (AEMT), 26 abdominal pain, assessment of, ACLS (Advanced Cardiac Life advanced life support (ALS), 279–281, 282 Support), 180 documentation, 345–346 chest pain, assessment of, 277 action potential, 655–656 adverse drug reactions, 630–631 distention, 258, 280, 410 active listening skills, 231 advice, offering, 237 fever, assessment of, 295–296 active transport, drug advocacy, patient, 11 palpation of, 259–260, 261 metabolism, 625 Advocates for EMS, 6 patient history, surgical, 344 activities of daily living (ADL), 99, AEIOU-TIPS, 248 physical exam, 258 147 aerobic metabolism, 159–160 pregnancy, assessment of, act-utilitarianism, 73 affi davit, 88, 347 296–297 acute coronary syndrome (ACS), African Americans, 61, 177 quadrants and nines, 281 |
191, 652–654, 756 after action reports, 44 trauma, assessment of, 299 acute heart failure, 672 against medical advice (AMA), 94, 95 abdominal aorta, 281 acute hemolytic reaction, 607 Age Discrimination in Employment abdominal muscles, 365 acute myocardial infarction, 180, Act (ADEA), 99 aberrant conduction, ECG, 193, 647–652, 660–661, ageism, 147 779–780. See also ECG 769–774. See also cardiovascular Agency for Toxic Substances and (electrocardiogram) system Disease Registry (ATSDR), 19, 111 abnormal automaticity, acute renal failure (ARF), 181, 190. age of majority, 90 cardiac cells, 725 See also kidneys agglutination, 604–605 ABO blood groupings, 605 acute respiratory failure, 191. aging, 177, 287–289, 293, 295–296. abortion, spontaneous, 133 See also respiration See also elderly abrasions, 258, 289, 292–293, 298 acute traumatic stress, 43–44 agonal respiratory pattern, 264 abscess, 188, 293 Addison’s disease, 700 agonist, 630, 639–640 absolute bradycardia, 747 adenosine, 564, 663–664 AIDS, 50, 184 absorption, drugs, 624 adenosine triphosphate (ATP), air embolism, intravenous abuse 158, 159 infusions, 576 drug, 621–622 administration sets, IV fl uids, airlock, injections, 541 patient history, 249 558–561, 586 air trapping respiratory pattern, 264 reporting, 30–31, 89 administrative law judge (ALJ), 84 airway. See also intubation academia, 508 adolescence, 142–144 anaphylactic shock, 185 accessory muscles, respiration, adrenal glands, 166, 700–701 anatomy of, 354–363 265–266, 276–277, 361–363 adrenaline, 166, 191 assisted ventilation, 412–413 accessory pathway, 747 adrenal medulla, 701 automatic transport ventilators access to healthcare, 112–113 adrenergic agents, 641–643 (ATV), 401–402 “Accidental Death and Disability” adrenergic nerves, 639 barrier devices and pocket (Farrington), 121 adrenergic transmission, 164 masks, 400–401 accreditation, 27 adrenocortical insuffi ciency basic management algorithm, ACE inhibitors, 666 (Addison’s disease), 700 396–398 Index 831 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. airway. See also intubation cont. airway management, overview, American National Standards continuous positive airway 380–382 Institute (ANSI), 46 pressure, 413–417 blood gas interpretation, 508 American Public Health Association, face-mask ventilation, 405–409 ECG rhythms, 742 111, 112 intubation, algorithms, 382–388 intubation, 382–388, 426, American Red Cross (ARC), 6, 21 management, equipment for, 453–454 American sign language, 235 398–403 non-intubating airway American Society of Testing and management, overview, management, 384–386 Materials (ASTM), 46 380–382 overview, 31 Americans with Disabilities Act medication-facilitated scene size-up and primary (ADA), 98–99 intubation, 476–485 assessment, 215 amino acid neurotransmitters, 165 non-intubating algorithm, triage, 273 amiodarone, 662, 702 384–386 algor mortis, 194 amnesia, 282 obstructions, managing, 386, 412 alkalemia, 508 AMPLE, past medical history, 343 opening, 403–404 alkaloids, 616 ampoules, 536–537 oxygen-powered ventilation alkalosis, 494, 499–500 amyloidosis, 738 devices, 401 allergic reactions, blood amyotrophic lateral sclerosis (ALS), patient assessment, 218 transfusions, 606–607 167, 168 patient assessment, ventilated allergies anaerobic bacteria, 193 patient, 409–410 anaphylactic shock, anaerobic metabolism, 159 percutaneous devices, 449–450 medications for, 642, analgesia, 686, 689–694 prehospital management 702–703 anaphylactic shock, 180, 185, 190, algorithm, 382 disinfectants, 568 631, 642, 702–703 rapid sequence intubation, drugs, 248, 631 anaphylatoxins, 188 9 P’s, 483–485 past medical history, 343 anasarca, 191 rupture, 277 allied healthcare providers, 5 anatomy suction, 402–403, 411–412 alpha-adrenergic blockers, 644 airway, 354–363 surgical airway, 448–450 alpha adrenergic receptors, 166, 641 airway, pediatric, 368–370 ventilatory care, continuing, ALS (advanced life support), bony thorax, 361–363 409–412 documentation, 345–346 heart, 720–721 akinetic cardiac muscle, 193 alternative hypothesis, 61 long bones, 576–577 alarm, stress and, 163 alternative medicine, 238 anemia, 268, 269, 706 alarms, ECG, 737 alveoli anemic hypoxia, 179, 180 albumin, 162, 188, 190, 496 alveolar fi lling, 179 anesthesia, 541, 686–688 albuterol, 532–533, 780 alveolar volume, 363 anger, patient, 237, 249 alcohol anatomy and physiology, angina, 653–654, 659, 756, 774 altered mental status, 360–361 angiotensin, 166, 193 assessment of, 287–289 carbon dioxide transport, angiotensin-converting enzyme as disinfectant, 567 494–495 (ACE) inhibitors, 666 ECG readings, 773 oxygen transport, 492–494 angulated extremities, 285–286 fetal malformations, 133 respiratory alkalosis, 499–500 animal bites, 89 fl uid loss, 555 Alzheimer’s disease, 147–148, 168 animals, drug sources, 616 patient history, 248, 249 Amber alert, 28 ankles, edema, 274 scene inspection, 258 ambulance anorexia nervosa, 143, 554 syncope, assessment of, 283 development of, 20 antacids, 703 withdrawal, 685 system confi gurations, 28–29 antagonist, 630, 639–640, 691–692 alcoholism, 42 vehicle safety, 46 antecubital fossa (AC), 566 aldosterone, 193, 666 American Academy on Physician and anterior hypothalamus, 162 alertness, level of, 217, 279 Patient, 7 anterior pituitary gland, 166 alert report, 331 American College of Emergency anterior wall MI (AWMI), 777 algorithms, care Physicians (ACEP), 6, 9, 22, 31, 92 antiadrenal medications, 701 airway management, American Medical Association (AMA), antibiotics, 710, 772 non-intubating, 396–398 6, 342 antibodies, 188 832 Index Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. anticholinergics, 532–533, mean arterial pressure (MAP), physical exam and, 259 640–641, 704 192, 193 ventilated patients, 409–410 anticoagulants, 649–650, 705 plaque, 647–648 authority, delegation of, 44 anticonvulsant medication, 694–697 pulmonary artery, 367–368 autism, 138 antidepressant medication, right coronary artery autogenic training, 43 707–708, 772 (RCA), 724 autohypnosis, 43 antidiarrheal medications, 704–705 artifacts, ECG, 742–743 autoimmune response, 185–189 antidiuretic hormone (vasopressin), aryepiglottic folds, 356–357 automated implantable cardioverter 166, 664, 667–668, 702 arytenoid cartilage, 357 defi brillators (AICD), 655 antidysrhythmic drugs, 654–656, ascites fl uid, 279 automatic answers, patients, 236 747, 773 ascorbic acid, 184 automaticity, cardiac cells, 725 classifi cation of, 656–663 aspiration, 357, 404–405, 427 automatic number identifi cation antiemetics, 704 aspirin, 498, 650, 690, 692–693 (ANI), 28 antifungals, 711 assault, 85 automatic transport ventilator, 384, antigens, 158, 185 assessment, patient. See also 401–402, 408–409, 447 antihelmintics, 711 physical examination autonomic nervous system, 42, antihemophilic drugs, 705–706 airway, 218 164–166, 638–639 antihistamines, 703 breathing, 218–221 autonomy, patient, 62, 75, 89–92, antihyperlipidemic drugs, 649 circulation, 221–222 96–97, 315, 346 antimetabolites, 630 current health status, 247 AVPU, mental status assessment, antimicrobials, 710 documentation, 344–345 217–218 antineoplastic medication, 711 general impression, 216 AV relationships, ECG, 746 antioxidants, 180 intubation preparation, axillary vein, 564 antiprotozoal, 711 437–439 axis deviation, ECG, 779 antipsychotic medications, 539–540, mental status, 217–218 706–708 overview, 214, 216 B antiseptics, 710 priority decision making, Babinski refl ex, 136–137 antitussives, 689 222–223 Bachmann’s Bundle, 722 antivirals, 710 asthma, 178, 414, 532–533, back injuries, prevention of, 41, 46 anxiety, 42, 707 645–647, 780 backward, upward, and rightward anxiolytics, 685 ataxia, 695, 702 pressure (BURP), 439–440 aortic stenosis, 275 atherosclerosis, 284, 647–652 bacterial infections, 184–185, 607, apartment complexes, calls to, 49 ATP (adenosine triphosphate), 709–711. See also sepsis/septic apical pulse, 262, 263 158, 159 shock apnea, 264 atrial diastole, 721 bacteriostatic solutions, 710 apneustic center, 366 atrial fi brillation, 287 bag-mask ventilation, 399–400, apneustic respiratory pattern, 264 atrial kick, 721 406–407 apoptosis, 168 atrial systole, 721 bag-valve-mask ventilation, 365, apothecary system, 518 atrioventricular node (AV), 722 384, 428, 447, 450, 533–534 appeal, legal, 85 atrophy, cellular, 167 Baker, Sara Josephine, 111 appearance, professional, 12 atropine, 165, 483, 531, 665 balance, assessment of, 284 appendicitis, 281 atropine sulfate, 640–641 balanced anesthesia, 687 ARDS (adult respiratory distress audits, chart, 9 Bandura, Albert, 133 syndrome), 191 auscultation barbiturates, 685, 695, 707 arterial blood gases, 507–510 abdomen, 295 BARNACLE, obtaining consent, 90 arterial puncture, 574 abdominal pain, assessment barotrauma, 183, 427 arteries of, 281 barrel, syringe, 534 blood gases, 507–510 blood pressure, 266 barrier devices, 50–51, 400–401 brachial artery, 266, 566 bowels, 279 Barton, Clara, 21 carotid arteries, 284, 359–360 heart, 274, 284 baseline vital signs, 222. See also coronary, 723–724 intubation confi rmation, vital signs coronary arteries, 191, 647–652, 431–432, 442 basic life support (BLS), 723–724, 764, 770–771, 777 lungs, 276, 278, 295 documentation, 345–346 Index 833 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. basilic vein, 564, 566 blocking behaviors, patient, 237 blood products, 603–604 basophils, 602 blood. See also acid-base balance; history of, 600 battery, 85 bleeding; blood pressure; blood procedure and documentation, Baumrind, Diana, 138–139 transfusions 608–609 behavioral health, 110, 344 blood products, 603–604 reactions, 606–608 behavior emergencies, 92–94 carbon dioxide transport, transfusion sets, 561 behaviorism, 133 494–495 BLS (basic life support), Belmont Report, 62 clotting, 191 documentation, 345–346 benefi cence, 76 complement system, 188 B lymphocytes, 189 benign prostatic hyperplasia, components of, 601–603 body armor, 48 167, 644 coronary circulation, 723–724 body fl uids, safety and, 49–52, benign tumors, 167 cultures, 579 535–536 benzodiazepines, 477–478, 685–686, distributive shock, 190 body habitus, 345 695, 707 fl ow, interruption of, 179 body language, 231, 233, 234, 245 benzoin, 567 fl uid balance, 162 body mass index (BMI), 40–41 benztropine, 697 gases, 183, 497–500, 507–510 body substance isolation, 50–51, be on the lookout (BOLO) alerts, 28 groups and compatibility, 215, 216 best practices, 25, 63 604–606 body temperature beta adrenergic blockers, 644, 645, hematocrit, 179 aspirin and, 693 659, 660–661 infection control, 49–52 homeostasis, 158 beta adrenergic receptors, 166, oxygen transport, 492–494 oxygen/hemoglobin binding, 494 191, 641 oxyhemoglobin curve, 163 physical exam, 268 bevel, needle, 535 phlebotomy, 577–582 regulation of, 162–163 bicarbonate, 495 platelets, 711 respiratory acidosis, 498 biceps tendon, 283, 284 respiration, metabolic process, respiratory alkalosis, 499 bigeminy, 746 366–368 thermometers, 524 bile, 649 samples, intravenous access, 569 body weight, 345, 521–524 Bill of Patient Rights, 74, 75 shunting, 162, 166, 191 bolus, 522, 626 binge-eating, 143 typing, 578 bonding, infants, 138 bioavailability, medication, 628 volume, stress and, 166 bones bioethics, 72–76 bloodborne pathogens, 49–52 bony thorax anatomy, biofeedback, 43 blood-brain barrier, 627, 684 361–363 biological death, 194 blood glucose, 158, 698–700 extremity pain, assessment biostatistics, 109 blood pressure of, 289 biotransformation, drugs, 628–629 alpha-adrenergic blockers, 644 intraosseous access, 576–577, Biot’s respiratory pattern, 264 beta adrenergic blockers, 581–582, 589–590 bites, animal, 89 644, 659 late adulthood, 147 blades, laryngoscope, 429–430 calcium channel blockers, 663 thoracic structures, 364–365 blastocyst, 133 high blood pressure, borrowed servant doctrine, 87 blebs, 193, 538 assessment of, 290–292 botanical remedies, 619 bleeding. See also blood mean arterial pressure (MAP), botulism, 185 abdominal pain, assessment 192, 193 bowel obstructions, 295, 555 of, 279 medications, 659 bowels, patient history, 344 carotid arteries, 359–360 physical exam, 266–268 bowel sounds, 279 disorders, 539, 705–706 pre-eclampsia/eclampsia, 709 2,3-BPG, 494 hemorrhagic shock, 192 pregnancy, assessment of, brachial artery, 266, 566 jugular veins, 359–360 296–297 brachial pulse, 262 patient assessment, 222 risk factors for, 177 bradycardia, 192, 262, 745, 747 postpartum hemorrhage, 709 vasodilator therapy, 669–670 bradykinesia, 696 subarachnoid, 773 blood transfusions bradykinin, 188–189 vasoconstriction, 166 blood components, 601–603 bradypnea, 264 blind insertion airway devices blood groups and compatibility, brain (BIADs), 388 604–606 lesions, 292 834 Index Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. medications for central butterfl y IV catheters, 563 cardiogenic shock, 166, 180, 190 nervous system, 684–688 butterfl y needles, 581 cardiomyopathy, 747 shock and, 192 cardiovascular system. See also ECG survival of, 9 C (electrocardiogram) brain death, 194 caffeine, 622 abdominal pain, assessment brainstem, 684 calcium, 193, 781 of, 281 breach of duty, 86 calcium channel blockers, 662–663 acute coronary syndrome, breakthrough seizure, 694–697 calibration, ECG, 737–738 652–654 breast cancer, 177 cancer, 143, 167, 177, 711 acute heart failure, 672 breathing. See also airway cannabinoids, 704 acute myocardial infarction, airway, pediatric, 368–370 cannulation, catheter-over-needle, 180, 193, 647–652, 660–661, altered mental status, 587–588 769–774 assessment of, 287–288 cannulation, external jugular adrenergic |
agents, 641–643 body temperature, 162 vein, 569 altered mental status, patient assessment, 218–221 capacity to understand, 90, 289. assessment of, 287 physical exam, 263–266 See also mental status anaphylactic shock, 185 physiology of, 363–368 capillary blood draw, 538–539 beta adrenergic blockers, 644, positional asphyxia, 93–94 capillary diffusion, drugs, 627 645, 659, 660–661 shortness of breath, capillary membranes, 161, 186 chief concern, exam, 274–276 277–279, 280 capillary refi ll, 276 cholinergic agents, 640, 665 trauma, assessment of, capnography, 388, 432–433, 443, coronary artery disease, 298–299 503–507 medications for, 647–652 work of breathing, 265–266 capsules, medications, 517. dysrhythmia, 654–656 bronchi, anatomy of, 360 See also medications electrical storm, 661 bronchial sounds, 276 carbamazepine, 695 emergency medications, bronchoconstriction, 645 carbonated beverages, capnography overview, 647 bronchodilation, 166, 532–533, and, 505 extremity pain, assessment of, 645, 780 carbon dioxide. See also airway 289–290 bronchoscopes, 446 acid-base disorders, 497–500 heart failure, 661, 665–674 bronchospasm, 295, 532–533, 646 altered mental status, high blood pressure, brown fat, 135, 136 assessment of, 288 assessment of, 290–292 Brugada syndrome, 134, 773 blood levels, 365–366 late adulthood, 147 bruises capnography, 270–271, 503–507 myocardial injury, ECG abdominal pain, assessment end-tidal carbon dioxide, 271, identifi cation of, 765–769 of, 279 431–433, 442–443 patient history, 344 altered mental status, metabolic alkalosis, 499–500 pregnancy, assessment of, assessment of, 288–289 metabolism, 366–368 296–297 extremity pain, assessment shortness of breath, shortness of breath, of, 289 assessment of, 279 assessment of, 279 HEENT, assessment of, 292–293 carbonic acid, 192, 193, 495 syncope, assessment of, physical exam, 258 carbonic anhydrase inhibitors, 668 284–285 trauma, assessment of, 219, carbon monoxide poisoning, vasopressors, 642, 664, 298, 299 502, 507 667–668 bruits, carotid, 284 carboxyhemoglobin, 507 carina, 360 buccal drug administration, 527 cardiac action potential, 724–725. carotid arteries, 284, 359–360 buffering systems, body, 495–496 See also pregnancy carotid bruits, 284 bulimia, 143 cardiac arrest, 30, 506–507 carotid pulse, 260–263 bulking agents, 705 Cardiac Arrhythmia Suppression Trial cartilage bundle branch blocks, ECG, (CAST), 655 thorax anatomy, 361–363 770–771, 773 cardiac cycle, 721–726 trachea, 360 bundle of His, 722–723 cardiac glycosides, 670–672 case-control study, 60–61 burn injuries, 182, 556 cardiac output, 266 case law, 84 BURP technique, 439–440 cardiac skeleton, 720 case reports, 60 Index 835 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. casualties, multiple, 347 chest questions for, 250 catecholamines, 191, 192, 642, pain, 274–277, 756 school-aged, 141–142 672–674 palpation of, 276–277 shootings, incidence of, 122 catheter, IV, 570–571 trauma, assessment of, statute of limitations, 89 catheter-over-the-needle devices, 298–299 chlamydia, 143 563, 587–588 wounds, 219 cholecystitis, 773 cell-mediated immunity, 189 chevron method, 570–571 cholesterol, medications for, 649 cellular physiology, 158–160, Cheyne-Stokes respiratory cholinergic agents, 640, 646 179–183 pattern, 264 cholinergic blocking agents, 665 cellular respiration, 179–180 chief concern cholinergic nerve, 639 cellular telephones, 28, 123, abdominal pain, assessment of, cholinergic receptors, 640 327–328 279–281, 282 cholinergic transmission, 164 cellulitis, 289, 296 altered mental status, chordae tendineae, 721 cell wall membranes, 158 assessment of, 287–289, 290 Christmas disease, 706 Celsius scale, 524 chest pain, 274–277, 756 chromosomes, 133–134 Center for Medicare and Medicaid documentation, 342 chronic obstructive pulmonary Services (CMMS), 339, 342 extremity pain, assessment of, disease (COPD), 414, 499 Centers for Disease Control and 289–290, 291 chronotropy, 166 Prevention (CDCP), 19, 60, 111, fever, assessment of, 293, circulation. See also blood 179, 341 295–296, 297 coronary circulation, 723–724 central nervous system, 163, 638, focused exam matrix, 272–273 Fick principle, 179–180 684–688 general exam, 273–274 hypoxia and, 180 central venous access, 582–585 HEENT, assessment of, 292–293 patient assessment, 221–222 central venous pressure, 582 high blood pressure, shunting, 162, 166, 191 cephalic vein, 564–565 assessment of, 290–292 circumfl ex (Cx), 723–724 cerebellum, 284, 684 patient history, 246 citric acid cycle, 159 cerebral cortex, 684 pregnancy, assessment of, civil law, 85 cerebral hemorrhage, 287 296–297, 298 civil lawsuits, process of, 87–89 cerebral hypoxia, 163 shortness of breath, 248, Civil Rights Act, Title VII, 99 cerebral perfusion, 192 277–279, 280 clarifi cation, patient responses, cerebral perfusion pressure (CPP), syncope, 282–287, 288 236–237, 245 192, 193 trauma, assessment of, climacteric, 146 cerebrovascular accident, 167, 773 297–300 clinical death, 194 cerebrum, 684 child abuse, 30–31, 89 clinical decision making, 312–316 certifi cation, 27 childbirth, 133, 134, 296–297, 347, clinical trials, research, 59–60 certifi cation examinations, 6 708–709 clinician, Paramedic role, 8 cervical cancer, 143 children clock method, 523 cervical collars, 443, 453 adolescence, 142–144 clonic contractions, 694–697 cervical immobilization, 387 airway anatomy and closed-ended questions, 236 cervical spine physiology, 368–370 closed form documentation, 341 injuries, modifi ed jaw airway management, 415 Clostridium tetanus, 185 thrust, 404 blood pressure, 268 clot-busters, 650–652 intubation and, 438–439 blood samples, 569 clot tubes, 578 trauma, assessment of, 298 consent, 62, 90, 92 coagulation cascade, 602–603, chart audit, 9 convulsions, 530 648–649 CHEATED format, documentation, dosing, medication, 522 coagulation system, 188, 191 342–346 emancipated minors, 92 coagulative necrosis, 193 chemical hiatus, 626–627 injections, 542–543 cocaine, 531, 641, 661, 773 chemical names, drugs, 617 intraosseous access, 581–582 codeine, 689–690 chemicals, cell injury and, 179–181 intubation, 428, 430, 453–454 cognitive development chemicals, drug sources, 616 phlebotomy, 578–582 adolescents, 143 chemotactic factors, 186 preschool age, 139–141 early adulthood, 145 chemotherapy, 629, 711 pulse rates, 262 infants, 138 836 Index Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. late adulthood, 147–148 compassionate touch, 233 convulsions, 163, 530, 694–697. middle adulthood, 146 compensatory damages, 87 See also seizure middle childhood, 141 complaint, legal, 87 coordination, assessment of, preschool children, 140 complementary medicine, 238 282–283, 284, 285 theories of, 132–133 complement system, 188 CO-oximetry, 507 cognitive restructuring, 43 complete blood count (CBC), 603 COP (colloidal osmotic cohort study, 61 complete heart block, 747 pressure), 162 cold injuries, 181 computer-assisted dispatch (CAD), 28 COPD (chronic obstructive colloidal fl uids, 556 computer-assisted radios, 327 pulmonary disease), 414, 499 colloidal osmotic pressure (COP), concealment, defi ned, 49 Cormack-Lehane grading system, 162, 191, 669 concentration, medication, 520 440–441 colonic hemorrhage, 190 concentration gradients, 625 corneal abrasion, 293, 294 colorimetric capnometry, 432–433, concept formation, 312 corniculate cartilage, 357 443, 503–507 conception, 133, 134 coronary arteries. See also colorimic end-tidal carbon dioxide concern-based physical exam, cardiovascular system measurement, 387 272–273. See also chief concern coronary artery disease, medications color prefi xes, medical concrete operational stage, for, 647–652 terminology, 203 development, 141 ECG, 12-lead, 764 coma, 136, 384 conditioning, operant, 133 left anterior descending combined form documentation, 341 conduct disorders, 42 coronary artery (LAD), Combitube, 434–435, 447, 454 conduction system, heart, 722–723 723–724, 770–771, 777 command and control, 44 conductivity, cardiac cells, 725 right coronary artery command presence, 12 confi dence, 12 (RCA), 724 commercial ambulance services, 29 confi dentiality, 30, 75, 97–98, 340 shock and, 191 Commission on Accreditation of confrontation, patient coronary care, prehospital, 22–23 Allied Health Education Programs interviews, 245 coronary circulation, 723–724 (CAAHEP), 6, 27 congestive heart failure, 555, 654 coronary ischemia, 191 Commission on the Accreditation of conjunctiva, 268, 269 coronavirus, 176 Ambulance Services (CAAS), 7 conjunctival erythema, 293 corticosteroids, 646 Committee on Accreditation of consciousness, 282–287, 288, corticotrophin-releasing factor Educational Programs for EMS 499–500 (CRF), 166 Professions (CoAEMSP), 27 conscious sedation, 686 cortisol, 166, 700 common household system, consent, 62, 89–92, 346 cost-benefi t analysis, injury dosing, 518 constitutional examination, 344–345 prevention, 123 communicable diseases, 89 constitutional signs, 314 costovertebral angle (CVA) communication. See also constitutional symptoms, 343 tenderness, 279, 281 documentation; patient care contiguous leads, ECG, 763 costs, fi nance systems, 31–32 report (PCR) continuing medical education, 9–10 cough suppressants, 689 EMS systems, 28 continuous infusion, 522–523 couplets, 746 family and friends, 251 continuous positive airway pressure court systems, 85. See also legal hearing impaired, 234–235 (CPAP), 413–417 considerations improving, 232–238 continuous quality improvement cover, defi ned, 49 interpersonal, 8 (CQI), 9 CPAP (continuous positive airway overview, 230–231 contraceptives, 701 pressure), 413–417 prescription notations, 618 contractility, cardiac cells, 725 CPP (cerebral perfusion pressure), public safety communications, contractions, childbirth, 296 192, 193 328–332 contributory negligence, 87 CPR (cardiopulmonary radio technology, 322–327 control devices, IV fl uids, 559 resuscitation), 21–22, 78, 86, 97 teamwork and, 322 Controlled Substance Act crack cocaine, 531 treatment and transportation, (1970), 621 crackles (rales), 191 331–332 conus elasticus, 357 cranial nerve exam, 282–283, 292, community-based EMS, 29 conversions, medication units, 293, 298 compassion, 8 519–520 crenate, 556 Index 837 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. crepitus, abdominal, 260 decision making. See clinical diagnosis, by Paramedic, 8, 342–343, cricoid pressure, 404–405, 439, 484 decision making 345–346. See also chief concern; cricoid ring, 358, 369 decision to treat, 9 clinical decision making cricothyroid ligament, 357, 369 decompensated shock, 192 diagnosis related groups (DRGs), cricothyroidotomy, 436–437, 448–449 decubitus ulcers, 288–289, 296 342–343 cricothyrotomy, 461 deep tendon refl exes, 282–283, 297 diagnostic suffi xes, medical criminal law, 84–85. See also legal deep vein thrombus, 180 terminology, 203 considerations defasciculating dose, 482 diaphoretic skin, 268 crisis process, 43 defi brillation, 23, 655 diaphragm, 362 critical-incident response team defusing, 44–45 diaphragmatic breathing, 43, 362 (CIRT), 44 dehydration, 293, 296, 555–556 diarrhea, 295–296, 554–555, 704–705 critical incident stress debriefi ng delegation of authority, 44 diastole, heart auscultation, 274 (CISD), 44 delirium, 147–148, 163 diastolic blood pressure, 266–268 Crohn’s disease, 185 Delmar’s Drug Reference, 619–620 diastolic heart failure, 665–674 cromolyn, 646 deltoid muscle injections, 540 diazepam, 517, 530, 539, 685–686, 709 cross-matching, blood, 578 dementia, 147–148, 289 DIC (disseminated intravascular cross-sectional surveys, 60 demobilization, 44 coagulation), 191 crowning, childbirth, 296, 298 deontological model of ethics, 73 differential diagnosis, 314 Cruzan, Nancy, 96 Department of Health and Human Diffi cult Airway Algorithm, 381–382 cryoprecipitate, 604 Services, 19, 111 diffusion, 160–161 crystalloid fl uids, 556 Department of Transportation digital intubation, 427, 445–446, cultural considerations, 72, 218, (DOT), 22 458. See also intubation 231, 232, 245, 250 depolarizing neuromuscular digitalis, 663, 670–672, 773, 774 Cumulative Index to Nursing and blockers, 479–481, 641 Digoxin, 539 Allied Health (CINAHL), 59 deposition, 88, 347 dilution, medication, 520 cuneiform cartilage, 357 depot medications, 539 diminished autonomy, 62. Curandero, 238 depressants, central nervous system, See also consent curare, 165, 640–641 684–686 diphtheria, 49–50 current health status, 247 depression, 42, 143, 148, 248, 250 diplomacy, 8 Cushing’s syndrome, 701 dermatomes, 283 directional terms, medical cyanide poisoning, 180, 181, descriptive analysis, ECG, 741 terminology, 208 498, 670 descriptive studies, 60 disasters, planning and response, cyanosis, 276, 277–278, 288–289 destination decisions, 94, 96 108, 110, 113 cystic fi brosis, 177, 184 development, personal disclosure, limited, 98 cytochrome oxidase, 181 adolescence, 142–144 disclosure, risks and cytochrome P-450 system, conception to childbirth, recommendations, 89–90 628–629, 695 133, 134 disease cytoplasm, cells, 158 early adulthood, 144–145 cell injury, pathological, 193 infants, 135–139 death from, 193–194 D late adulthood, 147–149 defi ned, 176 damages, tort action, 87 middle adulthood, 146–147 etiology of, 176–178 dangerous instruments, 49 middle childhood, 141–142 genetic disorders, 184 Data and Safety Monitoring Board newly born, 135 iatrogenic disease, 178 (DSMB), 62 preschool children, 139–141 immune reactions, 185–189 data dredging (mining), 59 theories of, 132–133 infections, 184–185 Data Elements for Emergency developmental milestones, 138. See metabolic disorders, 184 Departments (DEEDS), 341 also development, personal morbidity and mortality, 179 deadly night shade, 640 dexamethasone, 700–701 necrosis and, 193 deadly weapons, 49 dextrocardia, 762 physical causes, cell injury, death, 77–78, 148, 193–194, 238 dextrose 5% in water (D5W), 161 181–183 “Death in a Ditch” (Farrington), 121 diabetes mellitus, 167, 185, 344, as a process, 178–179 death rate, 179 555, 565–566, 698–700 |
shock syndrome, 190–193 debriefi ngs, 44 diabetic ketoacidosis, 498 systemic defense, 185–189 838 Index Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. disease outbreaks, 108 dorsogluteal (DG) injections, 540–541 extremity pain, assessment disinfectants, 567–568, 710 dosing, medication, 518–520 of, 289 dislocations, joint, 289 DOT National Standard Curriculum, 6 HEENT, assessment of, 292–293 disorder, defi ned, 312 double-blinded randomized clinical physical exam, 258 disorders of homeostasis, 8–9 trial (RCT), 59, 60 trauma, assessment of, 219, disposition, documentation, 346 Down syndrome, 184 298, 299 disseminated intravascular drainage, 188 ECG (electrocardiogram) coagulation (DIC), 191 dress-up philosophy, 50–51 acute coronary syndrome, distal tubule diuretics, 669 DRGs (diagnosis related groups), atypical presentation, 756 distention, abdominal, 258, 280, 410 342–343 acute myocardial infarction, distracting injury, 689 drip chamber, 558 diagnosis of, 769–774 distress, 41–45, 145, 163 drip rate, IV fl uids, 571–572 anatomy, 720–721 distribution, medications, 628 driving safety, 47 artifacts, 759–760 distributive shock, 190 drug decline, 626 at-home monitoring, 750 diuresis, 166, 667–668 drug intoxication cardiac cycle, 721–726 diuretic agents, 668 airway management, 383 electrodes, 739–741, divine command ethics, 74 altered mental status, 761–762, 763 diving accidents, 183 assessment of, 287–289 importance of, 756–757 divorce, impact of, 142, 145 drug classifi cations, 620–622 12-lead, acquisition of, DNAR (Do-Not-Attempt- medical restraints, 92–94 759–760 Resuscitation), 149 narcotic antagonists, 692 12-lead, interpretation, 775–782 dobutamine, 642, 673–674 overdose, 531 12-lead, origins of, 757–759 documentation patient communication, 238 12-lead tracing, 762 CHEATED format, 342–346 patient history, 248, 249 15-lead ECG, 782 confi dentiality, 340 respiratory acidosis, 498 left ventricular function hazardous materials scene inspection, 258 assessment, 763–765 operations, 346–347 syncope, assessment of, 283 myocardial injury, legal proceedings, 347 drug orders, 521–522 identifi cation of, 765–769 multiple casualties, 347 drug reservoirs, 627 normal sinus rhythm, 747–749 patient care report, 339–342 drug-resistance, 178 out-of-hospital monitoring, 750 physical exam, 273 drugs. See medication portable equipment, 736–739 pregnancy and childbirth, 347 dry gangrene, 193 principles of, 726–729 purpose of, 338–339 dry powder inhalers (DPI), 532–533 rhythm interpretation, 741–747 refusal of medical dry sterile dressing, 571 echo technique, 331 assistance, 346 durable power of attorney for health eclampsia, 709 special incident reports care (DPAHC), 97 ecological study, 60 (SIR), 347 duty, breach of, 86 economic damages, 87 transfusions, 608–609 duty to act, 85–86 economic incentives, injury types of, 340–341 D5W (dextrose in sterile water), 161 prevention, 123 dogs, 49 dying, communication about, 238 economic research, 62–63 domestic violence, 30–31, 49 dyskinesia, 696 ectopic beats, heart, 725 do no harm, 9 dysplasia, 167 ectopic focus, 746 Do-Not-Attempt-Resuscitation dysrhythmia, 654–656 ectopic pacemaker, 656 (DNAR), 149 ectopy, 745–746 Do-Not-Resuscitate (DNR) order, E edema, 161, 162, 191 78, 97 eardrums, 183 extremity pain, assessment dopamine, 165, 193, 642, 673, ears, 292–293, 295, 526 of, 289 696, 708 eating disorders, 143 high blood pressure, DOPE, intubation problems, 443, 454 ecchymosis assessment of, 291 dormant disease, 178 abdominal pain, assessment infi ltration, 575 dorsal arch, 565 of, 279 lymphedema, 567 dorsalis pedis (DP) pulse, altered mental status, myxedema, 702 260–263, 262 assessment of, 288–289 peripheral, 274 Index 839 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. education electronic documentation, 340–341. EMS Agenda for the Future, 25–27 communication and, 232 See also documentation EMS Education Agenda for the injury prevention, 123, 124–125 electrophysiology, heart, 724–725 Future, 26 patient care reports and, 338 electroporation, 182 EMS for Children (EMSC), 6 Educational Resources Information Eliminate Preventable Injuries of EMT-A National Standard Curriculum Center (ERIC), 59 Children (EPIC), 124–125 (NSC), 6 education standards, 27 elixirs, defi ned, 516. See also emulsions, defi ned, 516. education systems, 6–7 medications See also medications continuing medical education, emancipated minors, 92 encouraging behaviors, 236–237 9–10 embolism, intravenous infusions, 576 endocardium, 720 EMS Education Agenda for the embolism, pulmonary, 773 endocrine shock, 190 Future, 26 embryo, 133 endocrine system, 158, 163, 166, effective dose (ED50), drugs, 622 emergencies, defi nition of, 339 190, 344, 697 effi cacy, drugs, 630 Emergency Alert System (EAS), 28 end-of-life decisions, 77–78 ego, 132 emergency departments, 112–113 endomyocardial fi brosis, 738 Einthoven, Willem, 726 emergency doctrine, 92 endorphins, 165, 166, 689 Einthoven’s triangle, 758–759 emergency medical dispatch endotoxins, 163, 185, 187, 188 ejection fraction, 722 (EMD), 330 endotracheal tubes. See also EKG emergency medical responder intubation ventilated patients, 410 (EMR), 26 airway anatomy, 357 elastic gum bougie, 435–436, 445, Emergency Medical Service (EMS) capnography, 503, 505 459–460 evolution of, 18–25 oral intubation, 439–443 elasticity, skin, 296 future agenda, 25–27 overview, 427–428 elbow, 566 injury prevention and, 121–124 passing, 441–442 elder abuse, 30–31 mission of, 27–32 troubleshooting, 271 elderly “Emergency Medical Services at end-tidal carbon dioxide (EtCO2), altered mental status, the Crossroads” (Institute of 271, 431–433, 442–443 assessment of, 287–289 Medicine), 112 engineering, injury prevention developmental stage of, emergency medical technician and, 123 147–149 (EMT), Basic, 26 enhanced 911, 28 fever, assessment of, 293, Emergency Notifi cation System enhanced excitability, cardiac 295–296 (ENS), 28 cells, 725 injections, 542–543 Emergency Nurses Association (ENA), 6 enteral administration, drugs, intravenous access, 566 emergency response vehicle 527–530, 624–625 venipuncture, 568 (ERV), 46 enteric coating, 517 electrical alternans, 771 emergency vehicle operator environmental health, 109–110 electrical burns, 182 (EVO), 47 environmental risks factors for electrical storm, 661 emergent conditions, decisions disease, 177 electrocardiogram (ECG). See ECG about, 313 eosinophil chemotactic factor of (electrocardiogram) Emerging Infectious Disease anaphylaxis (ECF-A), 186 electrocardiography Journal, 111 eosinophils, 186–187, 602 anatomy, 720–721 emesis, 404–405 ephedrine, 642 cardiac cycle, 721–726 emetics, 704 epicardium, 720 principles of, 726–729 emotionally disturbed patients, 92–94 EPIC (Eliminate Preventable Injuries electrodes, ECG, 739–741, 761–762 emotional stressors, 42 of Children), 124–125 electrolytes, 161, 556, 747, 773, empathy, 7, 231, 236–237, 245 epidemics, 110 780–781 emphysema, 277, 299, 413, epidemiology, 109, 179 electromagnetic energy 532–533, 555 epigastric pain, 281 exposure, 182 empiric therapy, 316 epiglottis, 356, 369, 403 electromagnetic interference (EMI), employment law, 98–99 epilepsy, 694–697 743, 760 EMS. See Emergency Medical epinephrine electromyographic signal (EMG), Service (EMS) drugs that mimic, 166 759–760 EMS Act (1973), 23 intranasal administration, 531 840 Index Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. norepinephrine, 642 external jugular vein (EJV), 565, fee for service, 32 shock and, 191, 193, 673, 703 569. See also jugular vein feet, 274, 285–286 stress and, 42, 166 external laryngeal manipulation, 441 femoral line, 591–592 epistaxis, 293, 526, 531 extracellular water, 160 femoral pulse, 260–263 equianlagesic, 690 extraocular movements (EOM), 283 femoral vein, 584 equiphasic ECG, 736 extrapyramidal system, 707 fentanyl, 479, 531 equipment bags, 48 extremities ferritin intoxication, 706 equity, defi ned, 123 extremity pain, assessment of, fetal alcohol syndrome, 133 ergot compounds, 644 289–290, 291 fetal malformation, 133 Erikson, Erik, 132–133, 145, 147, 148 patient history, 344 fetus, 627, 695, 708–709 error of omission, 86 syncope, assessment of, 285–287 fever errors, in documentation, 340 trauma, assessment of, 299 altered mental status, errors, in research, 61 exudate, 186 assessment of, 287–289 errors, medication, 519 eye protection, 51, 215, 216 aspirin and, 693 errors, response to, 7 eyes assessment of, 293, 295–296, 297 erythema, 289 HEENT, assessment of, fl uid loss and, 554 erythrocytes (red blood cells), 162, 292–293, 294 infl ammation and, 187 179, 601, 602, 603–604. medication for, 526 respiratory acidosis, 498 See also blood nystagmus, 695 respiratory alkalosis, 499 4-E’s, injury prevention, 123 syncope, assessment of, 283 fi beroptic assisted intubation, 427, escape mechanism, heart rate, 725 trauma, assessment of, 298 446. See also intubation esophageal detector, 387, 431–432 vision loss, 146 fi brin, 603, 649, 650–652 esophageal-gastric tube airway fi brinogen, 603, 649, 650–652 (EGTA), 388, 434–435 F fi brinolytics, 650–652 esophageal obturator airway face mask, nonrebreather Fick principle, 179–180 (EOA), 388 (NRFM), 398 fi delity, 76 esophageal-tracheal Combitube face-mask ventilation, 388, 405–409 fi eld diagnosis, 8, 192–193, 346 (ETC), 434–435, 447 facilitation, patient interviews, 245 fi ght or fl ight, 42, 164 estrogen, 701 facsimile machines, 328 fi lters, in-line, 559–560 ethical relativism, 73 Fahrenheit scale, 524 fi nger stick, 538–539 ethics, 61–62, 72, 76–78 failure to thrive, 139 fi nger sweep, 412 ethnocentrism, 232 Fair Labor Standards Act (FLSA), 99 fi re-based EMS, 28–29 etomidate, 478 fallout, 532 fi rst-due report, 330–331 eustress, 41, 163 false cords, 357, 358 fi rst pass metabolism, 517 eutectic mixture of local anesthetics false imprisonment, 85 fi xed-post staffi ng, 30 (EMLA), 541 false negatives, 61 fi xed-wing aircraft, 30 evaluation, documentation, 346 false positives, 61 fl ail segment, 299, 300 evaluation, prevention programs, 125 family and friends, communication fl ashback, IV fl ow, 574 Evaluation and Management with, 251 fl ash bulb, 559 Documentation Guidelines, 342 Family and Medical Leave Act fl atline, 736 event monitor, 750 (FMLA), 99 fl ight Paramedic, 30 event report, 347 FarMedic, 30 fl ow rate, IV fl uids, 571–572 evidence-based practice, 25, 58–60 farm emergencies, 30 fl ow-restricted oxygen-powered Ewald tube, 528 farmer’s lung, 177 ventilation devices, 408 exacerbation, disease, 178 Farrington, Deke, 121 fl uid, airway, 218 excitability, cardiac cells, 725 fasciculations, 641 fl uid balance, 158, 160–162, 554–555 excited delirium, 93–94 fat, brown, 135, 136 fl uid dynamics, gastric tubes, 528 exhaustion, stress and, 163 fear, patients, 237 fl uid dynamics, pulmonary exotoxins, 185 febrile non-hemolytic reaction, 607 treatments, 532 experimental studies, 61 Federal Communication Commission fl uid loss, sources of, 554–555 explanation of outcomes, 346 (FCC), 28 fl uid overload, 277, 291 exposure report, 347 Federal Emergency Management fl umazenil, 686 expressed consent, 91 Agency (FEMA), 7 fl uori-methane, 541 Index 841 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. fl ush the line, 576 gallbladder, 281, 498 gluten sensitivity, 185 focused physical exam gallop, heart rhythm, 275, 297 glycine, 165 abdominal pain, 279–281, 282 gamma aminobutyric acid glycogen, 159–160 altered mental status, (GABA), 165 glycolysis, 159, 166 assessment of, 287–289, 290 gamma rays, 182 glyconeogenesis, 166 chest pain, 274–277 gangrenous necrosis, 193 glycoprotein IIB-IIIA receptor documentation, 345 gas exchange, 191 blockers, 652 extremity pain, assessment of, gas gangrene, 193 glycosides, 616, 670–672 289–290, 291 gastric distention, 258, 280, 410 goiter, 702 fever, assessment of, 293, gastric tubes, 451, 528 Good Samaritan Act, 86 295–296, 297 gastroesophageal refl ux disease governmental immunity, 88–89 HEENT, assessment of, 292–293 (GERD), 703 gowns, 51, 215, 216 high blood pressure, gastrointestinal tract Grant method, ECG, 778 assessment of, 290–292 abdominal pain, assessment Grave’s disease, 702 matrix, 272–273 of, 279, 281 gross negligence, 85 pregnancy, assessment of, alpha adrenergic receptors, 166 growth hormone, 166 296–297, 298 chest pain, assessment of, 277 guidelines, 315 shortness of breath, 277–279, 280 disorders, medications for, Guillain-Barré, 167 syncope, 282–287, 288 703–705 gums, drug sources, 616 trauma, assessment of, fever, assessment of, 295–296 gunshot wounds, 89 297–300 infection defense, 186 gut impression, patient folk medicine, 238 opiates and, 689 assessment, 216 followership, Paramedic role in, 12 shock and, 190, 191 gynecological examination, 296. fontanel, 138 GCS (Glasgow Coma Scale), 193 See also childbirth Food, Drug, and Cosmetic Act gender identity, 142 H (1937), 622 general adaptation syndrome, Haddon, William Jr., 121–122 Food and Drug Administration (FDA), 42, 163 Haddon matrix, 121–122 19, 111 generic names, |
drugs, 617 half-life, drugs, 626 foreign body, airway, 218 genetic disorders, 184 Hall, Edward T., 232 foreign body, eyes, 293, 294 genetic engineering, drug sources, hallucinations, 289. See also foreseeable harm, 90 616–617 alcohol; drug intoxication; forsifl ex, feet, 285–286 genetics, human development and, psychiatric emergencies fosphenytoin, 695 133–134 haloperidol, 539–540 fracture Geneva Treaty, 21 hand gestures, 233 extremity pain, assessment genital herpes simplex virus type 2 hand washing, 178 of, 289 (HSV-2), 143 HAPI-SOCS, 248 intravenous access, 567 genital human papilloma virus hard of hearing patients, 234–235 patient history, 344 (HPV), 143 hard wire monitoring, 750 ribs, 277 genital warts, 143 Harrison Act (1914), 621 sternum, 277 genitourinary system, 344 hazardous materials operations, free radicals, 180 genotype, 133–134 346–347 fresh frozen plasma, 604 GERD (gastroesophageal refl ux hazards, countermeasures to, 122 Freud, Sigmund, 132 disease), 703 hazards, scene, 214 functional job description, 99 Gesell, Arnold, 138 head, 282, 292–293, 298 functional syncytium, 721 Glasgow Coma Scale (GCS), 193 head elevated laryngoscopic position funding, EMS, 23, 31–32 glottis, 357, 369 (HELP), 439 fungi, infections from, 184–185 gloves, 50–51, 215, 216 head-tilt, chin-lift, 218, 403, 439 furosemide, 668 glucagon, 160, 166, 531 healer, Paramedic role, 8 G glucocorticoid hormone, 166 healthcare proxy, 78, 97 GABA (gamma aminobutyric glucocorticoid medications, health insurance, 32 acid), 165 700–701 health maintenance organizations gag refl ex, 359, 399 gluconeogenesis, 160 (HMOs), 32 gait, assessment of, 287 glucose, 9, 158, 159–160, 698–700 Health Professions Commission, 5 842 Index Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. health services, integration of, helminths, infections from, history, patient, 223, 244–251, 30–31 184–185, 186 342–344, 555 hearing, 146, 283 HELP (head elevated laryngoscopic history of emergency medical hearing aids, 235 position), 439 service, 18–25 hearing impaired patients, 234–235, Helsinki Declaration (1964), 77 history of pharmacology, 614–615 250–251 hematocrit, 179, 578, 603 history of present illness, 246, heart. See also ECG hematoma, 293. See also bruises 342–344 (electrocardiogram); heart failure hematopoiesis, 601 histoxic hypoxia, 180 acute coronary syndrome, hemicorporectomy, 194 HIV/AIDS, 50, 184 652–654 hemocytoblast, 601 Hoff’s law, 163 acute heart failure, 672 hemodynamic instability, 190 Holter monitoring, 750 acute myocardial infarction, hemoglobin Homeland Security Advisory 660–661, 769–774 acid-base balance, 496 System, 28 adrenergic agents, 642 blood components, 602, 603 homeostasis, 158, 190–193 anatomy of, 720–721 co-oximetry, 507 homeostasis, disorders of, 8–9 auscultation of, 274 hypoxia and, 179 homicidal patients, 92–94, 289 beta adrenergic blockers, 645, oxygen binding, 367–368, horizontal equity, defi ned, 123–124 659, 660–661 492–494 horizontal leadership, 11 beta adrenergic receptors, 166 pulse oximetry, 269–270, hormone replacement therapy, cholinergic agents and, 500–503 146, 534 640, 665 hemolysis, 604–605 hormones, 158, 163, 166, 190, coronary artery disease, hemopericardium, 738 344, 697 medications for, 647–652 hemophilia, 539, 706 hospice, 149 dysrhythmia, 654–656 hemorrhage. See bleeding hospital-aquired infection, 178 electrical storm, 661 hemorrhagic shock, 192 hospital-based EMS, 29, 112–113 electrocardiographic hemostasis, 602 hospitals, 94 principles, 726–729 hemothorax, 276 hostile working environment, 99 emergency medications, Henry Street Settlement, 111 hostility, patient, 237, 249 overview, 647 heparin, 650, 705 house calls, scene hazards, 47–48 heart rate, 164, 744–745 heparin sulfate, 647–648 HPV (genital human papilloma myocardial injury, ECG heparin well, 570 virus), 143 identifi cation of, 765–769 hepatectomy, 167 Huber bevel, 535 shock and, 191 hepatitis, 50 Huber needles, 585 syncope, assessment of, 284 hepatojugular refl ux, 277, 281 human dignity, respect for, 75 vasopressin, 642, 664, 667–668 herbal remedies, 619 human rights, defi ned, 74 vasopressors, 642 heredity, disease risk factors, 177 human subjects, research, 61–62, 77 heartburn, 703–704 Hering-Breuer refl ex, 364 humerus bone, 566 heart disease, 274–277, 290–292 hermeneutics, 231 humoral immunity, 189 heart failure hernia, 279, 281 Huntington’s disease, 134 chest pain, assessment of, 277 heroin, 531. See also illicit drug use hydantoins, 695 fl uid loss, 555 herpes virus, 143 hydrogen peroxide, 180, 193 hypoxia, 180 hexaxial reference system, 778 hydrostatic pressure, 161 medications for, 661 high-fl ow nasal cannula hyoepiglottic ligament, 356 pregnancy, assessment of, (HFNC), 397 hyoid bone, 356, 399 296–297 high priority patients, 214 hyperacute T wave, 767 signs of, 275 Hinshaw-Cox shock hypercapnia, 193, 508 heat cramps, 181 classifi cation, 190 hypercarbia, 508 heat exhaustion, 181 HIPAA (Health Insurance Portability hyperglycemia, 555, 698–700 heat injuries, 181 and Accountability Act), 10–11, hyperkalemia, 608, 699, 780–781 heat stroke, 181 30, 98, 340 hyperoxia, 508 heave, chest palpation, 276 histaminase, 186 hyperplasia, 167 heel stick, 538–539, 578 histamine, 165, 186, 703 hyperpnea, 191, 264 HEENT, assessment of, 292–293 histamine antagonists, 703–704 hyperresonant percussion, 276, 278 Index 843 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. hypertension body temperature, 163 infants alpha-adrenergic blockers, 644 communication and, 231 blood pressure, 268 aortic stenosis, 275 injury from, 179–180 cry of, 138 beta adrenergic blockers, metabolic alkalosis, 499 development of, 135–139 644, 659 pulse oximetry, 270 obstructed airway, 412 calcium channel blockers, 663 shock and, 192–193 pulse rate, 263 high blood pressure, shunting and, 191 umbilical venous access, 580 assessment of, 290–292 hypoxic hypoxia, 179 ventilation and respiration, 136 medications, 659 hypoxic injury, 193 infarction, 180 physical exam, 267 I infection control preeclampsia, 709 ICD-10 coding (International body substance isolation, pregnancy, assessment of, Classifi cation of Diseases), 215, 216 296–297 342–343 hand washing, 178 risk factors for, 177 ICP (intracranial pressure), 192 medications for, 709–711 vasodilator therapy, 669–670 id, 132 needle safety, 535–536 hyperthermia, 162, 268 idiosyncratic reactions, drugs, 631 overview, 49–52 hypertonic solutions, 161, 556, 557 illicit drug use public health and, 120 hypertrophy, cellular, 167 airway management, 383 pulmonary treatments, 532 hyperventilation, 264, 498–499, 499, altered mental status, infections, 136, 184–185. See also 506, 773. See also respiration assessment of, 287–289 sepsis/septic shock hypnotic state, 685 drug classifi cations, 620–622 infectious transudate, 738 hypocalcemia, 781 medical restraints, 92–94 infi ltration, 575 hypocapnea, 508 narcotic antagonists, 692 infl ammatory response, 177, hypocarbia, 508 overdose, 531 186–189, 689, 700 hypodermic syringes, 534–543 patient communication, 238 infl uenza, 50 hypoepiglottic ligament, 399 patient history, 248, 249 information systems, 30 hypoglycemia, 287–289, 383, 498, respiratory acidosis, 498 informed consent, 62 698–700 scene inspection, 258 infrared analysis, exhaled gases, 433 hypoglycemic shock, 190, 231 syncope, assessment of, 283 infusion, intravenous access, 570 hypokalemia, 668, 747, 773, 774, illness, nature of, 215–216 inhaled anesthetics, 687 780–781 illness, prevention, 120–121 initial impression, 313 hypomagnesemia, 747, 780–781 immune complex, 188 injections, 534–543, 573–576, hypoperfusion, 190–193, 231, 539, immune system. See also allergies 625–627 555, 668 allergic reactions, 631 injury. See also trauma hypopharynx, 356, 369, 403 anaphylactic shock, distracting injury, 689 hyporesonant percussion, 276 medications for, 702–703 initial impression, 313 hypotension, 267, 270, 281, 555, 661 cellular physiology, 158 mechanism of, determining, hypothalamus, 163, 166 exaggerated responses, 215–216 hypothermia, 136, 162, 268, 185–189 modifi ed jaw thrust, 404 560–561, 576, 738, 781 glucocorticoids, 700–701 myocardial, 767 hypothyroidism, 702, 738 stress and, 163, 167 patient history, 344 hypotonic solutions, 161, 557 immunity, legal action, 88 prevention, 45–49, 120–125 hypoventilation, 264, 498, 499, immunizations, 49–50 reperfusion, 180 502, 506 immunocompetent, 189 trauma, assessment of, hypovolemic shock, 190, 191, immunoglobulins, 189 297–301 270, 668 implanted vascular access device “Injury in America: A Continuing hypoxemia, 276, 288–289, 293, (IVAD), 585 Public Health Problem” 295–296, 499–500 implied consent, 91 (Farrington), 121 hypoxia. See also airway; respiration incision and drainage, 188 in-line fi lters, 559–560 altered mental status, indirect statements, 236 inotropy, 166 assessment of, 287–289 IND status, drug research, 623 IN SAD CAGES, 248 atropine use, 665 in extremis, 345 insensible loss, fl uids, 554 blood gases, 508 infant mortality, 134–135 inspection, 258–259 844 Index Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. inspiratory capacity, 363 intraosseous access, 576–577, digital intubation, 445–446, 458 Institute of Society, Ethics, and the 581–582, 589–590 elastic gum bougie, 435–436, Life Sciences, 78 intravascular fl uid, 160, 554 459–460 Institutional Review Boards (IRBs), intravenous access endotracheal tubes, 427–428 62, 77 administration sets, 586 equipment, overview, 427 insulin, 531, 532, 698–700 blood samples, 569 failed, 444–445 insulin syringe, 534 cannulation, external jugular King airway, 461 insurance, health, 32, 338 vein, 569 laryngoscope, 429–430 insurance, malpractice, 88 catheter-over-needle device, lighted stylettes/translaryngeal intellectual pressures, 42 587–588 illumination, 436 intelligence, patient, 250 central venous access, 582–585 medication-facilitated, 476–485 intentional torts, 85 device categories, 563 nasogastric intubation, intercostal muscles, 362, 365 femoral line, 591–592 463–464 interfacility patient care, 4 fl uid administration, 556–560 nasotracheal intubation, 444, interferon, 189 infusion, 570 456–457 intermittent positive pressure infusion-induced hypothermia, oral endotracheal intubation, ventilation, 427 576 439–443 internal bleeding, 279. infusion rate, 571–572 orotracheal intubation, 455 See also bleeding intraosseous access, 576–577, patient preparation, 437–439, internal jugular vein, 584 581–582, 589–590 444, 453 internal locus of control, 315 intravenous injections, pediatric patients, 428, 430, International Association of Fire 573–576 453–454 Chiefs (IAFC), 6 medical vs. trauma, 554–556 post-intubation care, 450–452 International Association of pediatric patients, 579–582 rapid sequence intubation, 9 Firefi ghters (IAFF), 6 peripheral site selection, P’s, 483–485 International Classifi cation of 563–564 rescue devices, 433–435 Disease (ICD-10), 342–343 peripheral venous access securing devices, 431, International Labor Organization devices, 562–563 443, 444 (ILO), 110 physiology, 554 special circumstances, 452–453 international public health efforts, problems with, 566 stylet, 431 110–111 removing, 576 supraglottic airway devices, international system of units (SI), secondary infusions, 573 446–447 518–519 securing catheter, 570–571 surgical airways, 436–437, international units (IU), 519 site precautions, 566–567 454, 461 interpersonal communication, 8 site preparation and tracheobronchial suctioning, 465 interpretation, patient disinfection, 567–568 involuntary consent, 91–92. See also interviews, 245 venipuncture, 568–569 consent interpreters, hearing impaired, 235 intravenous fl uids, 555, 556–560 iodine solution, 702 interstitial fl uid, 160 intravenous infusions, 161, 522–524, ionizing radiation exposure, 183 intervals, ECG, 728–729, 746–747 625–627, 687 ipratropium, 646 interview techniques, 232, intrinsic rate, 725 ipratropium bromide, 532–533 237, 245 introductions to patients, 235 iron-defi ciency anemia, 706 intestines, 190, 344 intubated patients, 271, 503, 505, ischemic cascade, 180 intimate space, 232–233 533–534 ischemic hypoxia, 180 intoxication. See alcohol; drug intubation ischemic patterns, 766–767 intoxication airway physiology, 365 isoelectric line, 728, 742 intracellular water, 160–162 algorithms for, 382–388, 426 isoniazid, 695 intracranial hemorrhage, 781 automatic transport isoprenaline hydrochloride intracranial pressure (ICP), 192 ventilator, 447 (isoproterenol), 166 intradermal injection, 538 bag-valve mask, 447 isoproterenol, 645 intramuscular injections, 539–540 confi rmation equipment, isotonic solutions, 161, 556, 557 intranasal drug administration, 431–433, 444, 454 IU (international units), 519 530–531 dental appliances, 356 IV push, 573–576 Index 845 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. J L legal rights, defi ned, 74 jaundice, 279, 280 labor, childbirth, 135, 709 legislation, 28 jaw, 355–356 lacerations, 258, 289, 292–293, 298 legitimate interest, 98 jaw thrust, 218, 403 lactate dehydrogenase, 159 legitimization, patient concerns, 8 joints, 260, 289, 355–356 lactated Ringer’s solution, 556 LEMON law, intubation, 437–439 joule heat, 182 lactic acid, 159, 180, 192, 498 lethal dose (LD50), drugs, 622 journals, 10, 59 lacuane, 193 lethal weapons, 49 J point, 767 land mobile radio architecture, 326 Letterman plan, 20 jugular vein, 277, 359–360, 555, language leukocytes, 186, 601, 602 565, 569, 584 barriers to, 250 leukotrienes, 187, 646 jugular venous pressure, |
258, 274, development of, 140, 141 Levin tube, 528 279, 291 non-English speaking levodopa, 697 junctional tissues, heart, 722 patients, 232 levothyroxine, 702 jurisdiction, 84, 89 vulgar, patient use of, 246 libel, 97–98 justice, principle of, 62, 76 large box, heart rate libido, 132 J-wire, 584 calculation, 744 licensure, 27 laryngeal mask airway (LMA), 388, lidocaine, 482–483, 531, 626, 658 K 434, 446–447, 454 life expectancy, 147 kaizen, 63, 315 laryngeal muscles, 359 lifting, injury prevention, 46 kallikrein, 188–189 laryngoscope, 427, 429–430, 440–441 lighted stylets, 436 keep the vein open (KVO), IV laryngospasms, 358 light perception, 283 infusions, 522 larynx, 298, 356–357, 369, 427 limb leads, ECG, 757–759 Kefauver-Harris Act (1962), 622 last meal, patient, 344 lipid lowering drugs, 649 ketamine, 478–479 laudanum, 516 lipid peroxidation, 180 ketoacidosis, 498 law enforcement, 123 lipid-soluble drugs, 627 ketonic acid, 498 laxatives, 705 lip reading, 234–235 kidney failure, 277, 290–292, 498, leadership, 11–12 liquefactive necrosis, 193 780–781 leading questions, 247 liquid oxygen, 397 kidneys leads, ECG, 739–741, 757–759 lithium salts, 708 ACE inhibitors, 666 left anterior descending coronary liver acid excretion, 496, 497 artery (LAD), 723–724, abdominal pain, assessment beta adrenergic receptors, 166 770–771, 777 of, 279 diuresis, 667–668 left bundle branch block (LBBB), acetaminophen, 693–694 drug elimination, 629 770–771 drug metabolism, 625, fever, assessment of, 296 legal considerations 629, 695 fl uid loss, 555 advanced directives, 78, shock and, 190, 527 heart failure and, 665 96–97, 149 living wills, 97 heat stroke and, 181 borrowed servant doctrine, 87 livor mortis, 194 metabolic alkalosis, 499 civil lawsuit, process, 87–89 lobular carcinoma in situ, 167 shock and, 190, 193 confi dentiality, 97–98 loc parentis, 92 stress and, 166 criminal law, 84–85 look, listen, feel, 218–221 kidney stones, 279 destination decisions, 94, 96 look test, 216 kinematics, 313 documentation, 347 loop diuretics, 668 kinesics, 233 employment law, 98–99 lorazepam, 685–686 King LTS-D airway, 388, 434–435, Good Samaritan Act, 86 lotions, defi ned, 516. See also 446–447, 454, 461 medical restraint, 92–94 medications kinin system, 188–189 origin of law, 84 Lou Gehrig’s disease, 167, 168 knowledge base, 312 patient care reports, 338–339 lower esophageal sphincter Koch’s postulates, 109 patient consent, 89–92 (LES), 406 Korotkoff sounds, 266 pharmacology, 620–622 low priority patients, 214 Krebs cycle, 159 refusal of medical assistance, lozenges, 517. See also medications Krieger, Dolores, 233 94, 95 Luer lock, 534, 585 Kussmaul’s respiratory pattern, 264 tort action, elements of, 85–87 Lugol’s solution, 702 846 Index Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. lungs mandible, 355–356 anesthesia, 686–688 assessment, ventilated patient, mania, 708 antidysrhythmic drugs, 409–410 mannerisms, communication classifi cation of, 656–663 beta adrenergic receptors, 166 and, 233 barbiturates, 685 carbon dioxide transport, MAP (mean arterial blood pressure), benzodiazepines, 685–686 494–495 192, 193 beta-adrenergic blockers, 644, catecholamines, 643 Marfan syndrome, 134, 184 645, 659, 660–661 continuous positive airway marijuana, 704 bioavailability, 628 pressure (CPAP), 413 Marine Hospital Service (MHS), 111 bleeding disorders, 705–706 fever, assessment of, 295 marriage, 145 cancer, 711 gastric tube insertion, 529 masks, 215, 216, 400–401, cardiac emergencies, lung sounds, 276, 277 405–409, 408 overview, 647 obstructive shock, 190 Mason-Likar modifi cation, 761 central nervous system, oxygen transport, 492–494 massage, injection site, 542 684–688 patient history, 344 mast cells, 186 childbirth emergencies, pediatric, 369 master problem list, 341 708–709 respiratory acidosis, 498 mathematical conversions, cholinergic agents, 640, 665 respiratory alkalosis, 499–500 medication units, 519–520 containers, 536–537 respiratory emergency, mean arterial blood pressure (MAP), convulsions, 694–697 medications for, 644–647 192, 193, 266–268 coronary artery disease, respiratory physiology, 363–368 measles, 49–50 647–652 respiratory route, drug measurement devices, depot medications, 539 administration, 531–533 medications, 519 detoxifi cation, 628–629 shock and, 191 mechanical fl ow control devices, diabetes, 698–700 shock wave damage, 183 572–573 distribution in body, 627 shortness of breath, mechanical injury, cells, 181 drug competition, 628 assessment of, 278 mechanism of injury, 313. drug orders, elements of, transfusion-related acute lung See also injury 521–522 injury (TRALI), 607 median nerve, 566 drug reservoirs, 627–628 trauma, assessment of, 299 media relations, 11, 44 dysrhythmia, 654–656 lupus erythematosus, 185 medical command, 31 ECG readings abnormalities lymphangitis, 296 medical facilities, 94 and, 773 lymphatic system, 161 medical history, 223, 244–251, electrical storm, 661 lymphedema, 567 342–344, 555 elimination of, 629 lymphocytes, 189, 601, 602 medical intelligence, 312–313 endocrine system, 697 lymphokine, 189 medical lines, 554 enteral administration, 624–625 lysosomes, 158, 193 medical orders, 31 errors, 519, 624 medical oversight, 31 etomidate, 478 M medical records, 75, 244–245. facilitated intubation, 476–485 Macintosh blade, 430, 440–441 See also patient care report (PCR) fentanyl, 479 macrophages, 602 medical terminology, 202–205, 208 fi brinolytics, 650–652 Magill forceps, 441 medical utility, 76–77 gastrointestinal disorders, magmas, defi ned, 516. See also medication ports, 559 703–705 medications medications. See also pharmacology heart failure, 661, 665–674 magnesium sulfate, 709 absorption, 624 herbal remedies, 619 malaria, 711 acidosis and, 497 infection, 709–711 malfeasance, 86 acute coronary syndrome, injected forms, 517 malignant hyperthermia, 481 652–654 intraosseous access, 577, malignant tumors, 167 administration routes, 524–534 581–582, 589–590 Mallampati classifi cation, 438 adrenal disorders, 700–701 intravenous infusions, 522–524 malpractice, 85, 88 adrenergic drugs, 641–643 intravenous injections, 573–576 managed health care, 32 allergic reactions, 631 ketamine, 478–479 mandatory reporting, 30–31, 89 anaphylaxis, 702–703 lidocaine, 482–483 Index 847 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. medications cont. shortness of breath, mobile cellular telephones, 28, liquid forms, 516 assessment of, 279 327–328 measurement and dosing, syncope, assessment of, mobile data terminals, 328, 340. 518–520 282–283 See also documentation mechanism of injury and, 258 vulgar language and, 246 mobile subscriber units (MSU), 328 midazolam, 477–478 mentors, professional, 8, 315 modesty, patient, 258 neuromuscular blocking agents, meta-analysis, 61 modifi ed chest lead 1 (MCL1), 479–482, 641 metabolic acidosis, 498–499 740–741 nitrates, 652–654 blood gases, 508–510 modifi ed jaw thrust, 403, 404 off-label use, 623 metabolic acids, 495 MODS (multiple organ dysfunction ovarian disorders, 701 metabolic alkalosis, 499, 508–510 syndrome), 191 pain management, 688–694 metabolic disorders, 184 monoamine neurotransmitters, 165 parenteral administration, metabolic rates, 370 monoamine oxidase (MAO) 625–627 metabolism, 158, 159–160, 163, inhibitors, 641, 642, 674, Parkinson’s disease, 696–697 366–368 697, 708 past medical history, 343 metabolites, toxins, 180–181 monoamines, 707–708 patient history, 248 metaplasia, 167 mood, patient, 289 pharmacodynamics, 629–631 metered dose inhaler (MDI), 532 moral development, 144 pituitary disorders, 702 methemoglobin, 502, 507 moral obligations, defi ned, 74 prescription notations, 618 metric system, 518–519 morbidity, 179 procedural sedation, 687–688 microorganisms, infection from, Morbidity and Mortality Reports psychiatric disorders, 706–708 184–185 (MMR), 179 respiratory emergencies, microstream sample, Morbidity and Mortality Weekly 644–647 capnography, 433 Report (MMWR), 111 sedatives, 477 midazolam, 531 mores, Paramedics and, 74 solid forms, 516–517 mid-life crisis, 146–147 Moro refl ex, 136–137 thyroid disorders, 702 military EMS, 29–30 morphine, 690–691, 697 tissue binding, 628 Miller blade, 430, 440–441 mortality, 179 toxicity of, 629 mind-body connection, 43 motions, court, 89 vasopressin, 642, 664, 667–668 mineralocorticoids, 701 motion sickness, 707 volume of distribution, 628 minerals, drug sources, 616 motor function, 283 meditation, 43 minimum data set, 341 motor vehicle collisions, 47, 121 MEDLINE, 59 minority patients, 61 mountain sickness, 183 medulla, 166 minors, as patients. See children mouth, anatomy, 354–356 medulla oblongata, 365, 684, 687 minute ventilation, 363–364 movement, terminology for, 208 membrane attack complex misfeasance, 86 mucolytics, 647 (MAC), 188 mission, EMS system, 27–32 mucosal folds, 357 memory cells, 189 mistakes, response to, 7 mucous glands, airway, 360 men, fl uid balance, 160–162 mitochondria, 158 mucous membranes, 186 meniscus, injections, 534 mitosis, 133–134 multiple casualties, 347 menopause, 146, 701 mitral valve prolapse, 773 multiple organ dysfunction syndrome mental development, theories of, MMR (measles, mumps, rubella), (MODS), 191 132–133 49–50 multiple sclerosis, 185 mental imaging, 43 mnemonics multiplex radios, 326. See also radio mental status AMPLE, 343 technology airway management, 383 CHEATED, 342 mumps, 49–50 assessment of, 287–289 DOPE, intubation, 443, 454 municipal EMS service, 29 chest pain, assessment of, 277 LEMON law, intubation, murmurs, heart, 275, 284, 291, 297 communication and, 231 437–439 Murphy eye, 428, 431 drug administration, 531 OPQRST, 313, 342 Murphy’s sign, 281 fever, assessment of, 293, for patient history, 247–248 muscarine poisoning, 166 295–296 3-3-2 rule, intubation, muscarine receptors, 165–166, 640 patient history, 248 437–439 muscle atrophy, 167 848 Index Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. muscle relaxation, 43 National Association of State EMS negligence per se, 89 muscles Offi cials (NASEMSO), 26 neonates, 135 breakdown of, 160 National Centers for Injury neostigmine, 482 larynx, 357–358, 359 Prevention and Control, 121 neostigmine bromide, 640 rigor mortis, 194 National Commission for Protection nerve agents, 640 thoracic structures, 364–365 of Human Subjects of Biomedical nerves, injections, 574 thorax, 361–363 and Behavioral Research, 62 nervous system trachea, 360 National Emergency Number alpha-adrenergic blockers, 644 muscle wasting diseases, 167 Association, 28 beta adrenergic blockers, 644 muscular dystrophy, 167 National EMS Core Content, 26 neurotransmission, 639–640 musculoskeletal system, 285–287, National EMS Education Program overview, 638–639 289–290, 292. See also bones; Accreditation, 27 respiration, 364, 365–366 muscles National EMS Education Standards stress and, 42 mushrooms, poisonous, 166, 640 (NEMSES), 6, 27 toddlers, 139 myocardial infarction, 274–277 National EMS Scope of Practice neurogenic shock, 180 myocardial injury, 765–769 (NEMSSOP), 26 neuroleptics, 687 myocardial ischemia, 766–767 National Formulary (NF), 619 neurological examination myocarditis, 773 National Health and Nutrition altered mental status, myocardium, 720 Examination Survey (NHANES), 60 assessment of, 287 myoglobulinuria, 181 national healthcare systems, 32 chest pain, assessment of, 277 myosin, 194 National Highway Safety Act, 22 extremity pain, assessment MyPyramid, 41 National Highway Safety and Traffi c of, 290 myxedema, 702, 738 Administration (NHSTA), 121 HEENT, assessment of, 293 N National Highway Traffi c Safety high blood pressure, Nadar, Ralph, 121 Administration (NHTSA), 10, 25 assessment of, 292 NAD (no apparent distress), 345 National Institute for Health (NIH), pregnancy, assessment of, 297 nail polish, 501 19, 111 syncope, assessment of, naloxone, 531, 617 National Institute of Medicine 282–283 names, addressing patients, 245 Report, 7 neuromodulators, 689 narcotics, 383, 479. See also illicit National Library of Medicine, 59 neuromuscular blocking agents, 165, drug use; medications National Registry of Emergency 479–482, 641 nares, 293 Medical Technicians, 6 neuromuscular system, 139–140 nasal airway, 411 National Registry of Emergency neuropeptide neurotransmitters, 165 nasal cannula, 397, 503 Medical Technicians (NREMT), neuroreceptors, 164, 165–166, 639 nasal fossae, 354–356 6, 27 neurotransmitters, 164–165, 639 nasal medications, 526 National Research Act (1974), 62 neurovascular assessment, 279 nasogastric tubes, 451, 463–464, 528 National Rural Health Association neutrophil chemotactic factor, 186 nasopharyngeal airway, 398–399, (NRHA), 7 neutrophils, 186–187, 602 411. See also airway National Standard Curriculum new media, 11 nasopharynx, 354–356 (NSC), 27 niacin, 649 nasotracheal intubation, 427, 428, National Trauma Registry, 121 nicotine, 534 444, 456–457. See also intubation natural disasters, 110, 113 nicotinic receptors, 165, 640 National Academy’s Institutes of natural rights, defi ned, 74 nitrates, 531, 534, 652–654, 670 Medicine, 112 nature of illness, 313 nitric oxide, 647–648 National Association of Emergency nebulizers, 533–534 nitroprusside, 670 Medical Technicians (NAEMT), neck, trauma, 298 no apparent distress (NAD), 345 6–7 necrosis, 180, 193, 767–768 nociceptors, 689 National Association of EMS needle cricothyroidotomy, 448–449 nomogram, acid-base interpretation, Educators (NAEMSE), 27 needle cricothyrotomy, 437 509–510 National Association of EMS needles, 534–536, 562–563, 563, non-depolarizing (competitive) Physicians (NAEMSP), 6, 25 576–577 neuromuscular blockers, National Association of EMS State negative pressure ventilation, 365 481–482, 641 Directors (NAEMSD), 25, 26 negligence, 85 non-economic damages, 87 Index 849 Copyright 2010 |
Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. non-English speaking patients, on-line medical control, 31 Fick principle, 179–180 232, 250 onset of symptoms, 342 homeostasis and, 158 nonfeasance, 86 open-ended questions, 236 metabolism, 366–368 non-malefi cence, 76 operant conditioning, 133 pediatric patients, 370 nonrebreather face mask operational competence, 11 peripheral oxygen saturation (NRFM), 398 operation preparedness, 25 (SpO2), 260 nonspecifi c ST changes, 774 opiates, 516, 531, 534, 689–690 pulse oximetry, 269–270 nonsteroidal anti-infl ammatory opiods, 479, 617, 620–621, 704 reperfusion injury, 180 drugs (NSAIDs), 693–694 OPQRST, symptom pattern, 342 supplemental, shock and, nonverbal behavior, 233 OPQRST AS/PN, 247 192–193 norepinephrine, 164, 165, 639, opsonization, 188 transport in body, 492–494 641–642, 674, 708 oral drug administration, 527 oxygen-free radicals, 168, 181 normal saline, 161, 556 oral endotracheal intubation, oxygen-powered ventilation normal sinus rhythm, 747–749 439–443 devices, 401 normocardiac rate, 744–745 oral medications, 526–527 oxygen radicals, 193 nose, 292–293, 295, 354–356, orders, medications, 521–522 oxyhemoglobin curve, 163 530–531 orientation, patient, 217, 289. oxytocin, 702, 709 nosebleed, 293, 526, 531 See also mental status P nosocomial infections, 178 orogastric tubes, 451, 528 pacemaker, cardiac, 655, 725 notary public, 88 oropharyngeal airway, 398–399, 411. packed red blood cells (PRBCs), nuclear radiation, 182 See also airway 603–604 null hypothesis, 60, 61 oropharynx, 368 pain number prefi xes, medical orotracheal intubation, 427, 455. anesthesia, 686–688 terminology, 203 See also intubation assessment of, 247, 260 Nuremberg code, 62, 77 orphan drugs, 623 chest pain, 274–277 nurses, public health, 19, 111 orthostatic vital signs, 271–272, 285 communication about, 230 nutrition, 40–41 OSHA (Occupational Safety and documentation, 342 nutritional defi ciencies, 184 Health Administration), 46, 112 extremity pain, assessment of, nutritional fl ow, 160, 555 osmosis, 160–161 289–290 nystagmus, 283, 695 osmotic diuretics, 669 infl ammation and, 187 O osmotic pressure, 161 injections, 541–542 obesity osteomyelitis, 577 management of, 688–694 adolescence and, 143 osteoporosis, 147 patient assessment, 218 ECG and, 738 otic medication, 526 pain management, 8 injections, 535 otitis media, 293 palatine tonsils, 356 intubation and, 438, 439 otoscope, 293 palliative care, 97, 149, 711 medications and, 631 outcomes, prevention programs, 125 palmar grasp refl ex, 136–137 metabolic disorders, 184 ovarian disorders, 701 palpation overview, 40–41 overcrowding, 110 chest, 276–277, 278 observational study, 60–61 overdose, drugs, 531, 629, 690, 708. physical exam, 259–260, 261 obstructive shock, 190 See also drug intoxication pregnancy, assessment of, 296 occupational health, 110, 112 over-the-counter medications palpitations, heart, 745 Occupational Safety and health (OTC), 617. See also medications; pancreas, 190. See also insulin Administration (OSHA), 112 pharmacology pancreatitis, 773 Ockham’s razor, 314 oxygen. See also airway pancuronium, 482 odansetron, 704 acid-base disorders, 497–500 pandemics, 110 off-label use, drugs, 531, 623 acidosis and, 497 panic attack, 42 oils, drug sources, 616 advanced directives and, 97 papillary muscles, 284, 721 ointments, defi ned, 516. assessment methods, 500–510 paradigm blindness, 63, 315 See also medications brain need for, 9 paradoxical respiration, 299 omega loop, 571 capnography, 270–271 paraglossal approach, omissions, documentation, 340 chest pain, assessment of, 276 intubation, 440 oncotic pressure, 161 delivery devices, 397–398 paralysis, 167 850 Index Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. paralytics, 476–477 current health status, 247 dosing, medication, 522 Paramedic, defi ned, 26 documentation, 344–345 injections, 542–543 Paramedic fi eld diagnosis, 8, 312. general impression, 216 intraosseous access, 581–582 See also clinical decision making mental status, 217–218 intubation, 428, 430, 453–454 paramedicine overview, 214, 216 phlebotomy, 578–582 core values, 7–8 priority decision making, pediatric shootings, 122 defi ned, 4–5 222–223 peer relations, children, 141 educational systems, 6–7 patient autonomy, 75, 89–92, 96–97 peer reviewed journals, 10, 59 hallmarks of profession, 5–6 Patient Bill of Rights, 74, 75 pelvis, 299, 300 role of paramedic, 8–12 patient care report (PCR), 88, penumbra, 766–767 Paramedic—patient relationship, 7 338–342 peptic ulcers, 703 paranoid thoughts, patients, 289 patient concordance, 315 percussion parasites, infection from, 184–185, patient consent, 89–92, 346 abdominal pain, assessment of, 186, 709–711 patient history, 223, 244–251, 342– 279, 281 parasympathetic nervous system, 344, 555 fever, assessment of, 295 42, 164–166, 638–639 patient position lungs, 276 parasympathomimetic agents, 640 airway and, 218 physical exam, 260, 261, 262 paregoric, 689 cannulation, external jugular sinuses, 292–293 parenteral drug administration, vein, 569 trauma, assessment of, 299 530–534, 625–627 gastric tube insertion, 529 percutaneous central venous parents, 138–139, 145, 147 head-tilt, chin lift, 439 catheters (PCVC), 583 parietal pleura, 364 hepatojugular refl ux, 277 percutaneous cricothyrotomy, Parkinson’s disease, 168, 696–697 injections, 540 436–437, 449–450 partial pressure, oxygen, 367 intubation, 438–439 performance improvement, 315–316 partnership, with patients, 7 orthostatic vital signs, 271–272 perfusion, 9, 166, 180, 193 past medical history, 246, 343–344 rectal drug administration, 530 pericardial effusions, 738 patellar tendon, 283, 284 semi-Fowler’s position, 274 pericardial rub, 276 patented drugs, 623 terminology for, 208 pericardial tamponade, 738 pathogenesis, 176, 178–179, 185–189 patient relationship, 7 pericarditis, 275, 773, 781 pathogens, 184–185, 535–536 patients pericardium, 720 pathologic cell atrophy, 167 family and friends, working peripheral edema, 274, 279, 291, pathophysiology with, 237–238 296–297 cell injury, 179–181, 193 intubation preparation, peripherally inserted central death, 193–194 437–439 catheter (PICC), 583, 585 defi ned, 176 number of, 216 peripheral nerve exam, 282–283, 292 disease as a process, 178–179 self-protective behaviors, 237 peripheral nervous system, 638 etiology of disease, 176–178 sensitive topics, peripheral neuropathy, 167 genetic disorders, 184 communication about, peripheral oxygen saturation iatrogenic disease, 178 249–251 (SpO2), 260 immune reactions, 185–189 Patient Self-Determination Act peripheral pediatric venous infection, 184–185 (1990), 97 access, 581 metabolic disorders, 184 pattern recognition, ECG, 741–747 peripheral vascular resistance (PVR), morbidity and mortality, 179 PDCA (plan-do-check-act), 9 42, 192 necrosis, 193 peak expiratory fl ow, 364, 371 peristalsis, 190 physical causes, cell injury, peak-load staffi ng, 30 peritoneum, 279, 281, 295 181–183 PEARLS model, 7 persistent vegetative state (PVS), 78 shock syndrome, 190–193 pecking order of shock, 191 personal development patient abandonment, 86 pediatric patients adolescence, 142–144 patient advocacy, 11 airway anatomy and conception to childbirth, patient assessment physiology, 368–370 133, 134 airway, 218 airway management, 415 early adulthood, 144–145 breathing, 218–221 blood samples, 569 infants, 135–139 circulation, 221–222 convulsions, 530 late adulthood, 147–149 Index 851 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. personal development cont. physical examination intravenous access, 554 middle adulthood, 146–147 abdominal pain, assessment of, long bones, 576–577 middle childhood, 141–142 279–281, 282 respiration, 363–368 newly born, 135 altered mental status, stress, 163–167 preschool children, 139–141 assessment of, 287–289, 290 temperature regulation, theories, 132–133 auscultation, 259 162–163 personal digital assistants (PDA), capnography, 270–271 physostigmine, 640 328, 340. See also documentation chest pain, 274–277 Piaget, Jean, 133, 140, 141, 143 personal protective equipment, 48 documentation, 344–345 Pickwickian syndrome, 184 personal rights, defi ned, 74 extremity pain, assessment of, PIER, 10 personal space, 233 289–290, 291 piggyback infusions, 573 personnel, management of, 30 fever, assessment of, 293, pitting edema, 274 perspiration, 554 295–296, 297 pituitary gland, 166, 702 pertinent negatives, symptoms, 343 focused exam matrix, 272–273 placebos, 60 pH, 495, 497–500 general exam, 273–274 placenta, 133, 135, 627, 709 phagocytosis, 186–187 HEENT, assessment of, 292–293 plan-do-check-act (PDCA), 9, 46 pharmacogenoics, 617 high blood pressure, plantarfl ex, feet, 285–286 pharmacological therapeutics. assessment of, 290–292 plantar refl ex, 283, 284 See medications inspection, 258–259 plant sources, drugs, 615–616 pharmacology. See also medications orthostatic vital signs, 271–272 plaque, arterial, 647–648 drug classifi cation, 617–619 overview, 258 plasma, fresh frozen, 604 drug information sources, pain, 268–269 plasma cells, 189 619–620 palpation, 259–260 plasma protein reservoirs, 627 drug sources, 615–617 percussion, 260 plasmin, 650–652 drug terminology, 617 post-event physicals, plasminogen, 650–652 herbal remedies, 619 Paramedic, 44 platelet plug, 648, 650–652 history of, 614–615 pregnancy, assessment of, platelets, 601, 602, 604, 711 legal developments, 620–622 296–297, 298 pleura, anatomy of, 362–365 medication errors, 624 pulse oximetry, 269–270 pleural effusion, 276 new drug development, shortness of breath, pleural rub, 276 622–624 277–279, 280 plural forms, medical terminology, off-label use, 623 skin color and condition, 268 204–205 pharmacodynamics, 629–631 syncope, 282–287, 288 pneumonia, 278, 287–288, 295, 427 pharmacokinetics, 624–629 trauma, assessment of, pneumotaxic center, 366 principles of, 624 297–300, 301 pneumothorax pharynx, 354–356 vital signs, 260–268 airway management, 453 phenobarbital, 685, 694, 695 physician extenders, paramedic altered mental status, phenothiazines, 704, 707, 747 role as, 11 assessment of, 288 phenotype, 133–134 physician—patient relationship, 89 barotrauma, 183 phenoxybenzamine, 644 physicians, direction by, 31 ECG readings, 738, 773 phenytoin, 539, 646, 695 Physician’s Desk Reference percussion, 276, 278 pheochromocytoma, 660 (PDR), 619 shock, 190 phlebotomy, 566, 577–582 Physician’s Order of Life Sustaining pocket masks, 400–401, 408 phosphate, 193, 495 Treatment (POLST), 97 point of service (POS), 32 photo burns, 182 physiological stressors, 42 poisoning physical abuse, 249 physiologic atrophy, 167 carbon monoxide, 502 physical development physiology cell injury, 180–181 adolescence, 142–143 airway, pediatric, 369–370 communication and, 231 early adulthood, 145 cellular, 158–160 cyanide, 180, 181, 498, 670 late adulthood, 147 cellular adaptation, 167–168 ferritin intoxication, 706 middle adulthood, 146 defi ned, 158 mushrooms, 166, 640 middle childhood, 141 fl uid balance, 160–162 radiation poisoning, 183 preschool children, 139–140 homeostasis, 158 syrup of ipecac, 704 852 Index Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. polio, 49–50 prehospital research, 61 prostate gland, 167 poliomyelitis, 167 pre-induction agents, protective custody, 92 pollution control, 109 anesthesia, 687 protective personal equipment, 532 POMR (problem-oriented medical preparedness, operational, 25 proteins, cell membranes, 161 recordkeeping), 341 preschool children, 139–141. protocols, 31, 58–61, 315, 345–346, pons, 366 See also children 380–382. See also algorithms, care popliteal pulse, 262 prescription drugs, 617. See also protozoa, infections from, 184–185 portable radios, 326. See also radio medications; pharmacology proxemics, 232–233 technology prescription notations, 618 proximal tubule diuretics, 668 position, patient pressure, injury from, 183 proximate causation, 87 airway and, 218 pressure, oxygen, 367 prudent layperson standard, 32, 339 cannulation, external jugular pressure, ventilation, 406 psychiatric emergencies, 92–94, 248, vein, 569 pressured speech, 289 289, 706–708 gastric tube insertion, 529 pretrial discovery, 88 psychosexual theory, 132 head-tilt, chin lift, 439 preventative maintenance, psychosis, 706–707 hepatojugular refl ux, 277 vehicles, 46 psychosocial development injections, 540 prevention, illness and injury, 108, adolescents, 143–144 intubation, 438–439 120–124 early adulthood, 145 orthostatic vital signs, 271–272 primary assessment infants, 138 rectal drug administration, 530 airway, 218 late adulthood, 148 semi-Fowler’s position, 274 breathing, 218–221 middle adulthood, 146–147 positional asphyxia, 93–94 circulation, 221–222 middle childhood, 141–142 positive pressure ventilation, current health status, 247 preschool children, 140 365, 427 general impression, 216 theories of, 132–133 posterior pituitary gland, 166 mental status, 217–218 psychosocial pressures, 42 posterior tibial pulse, 262 overview, 214, 216 psychosocial theory, 132–133 post-event physicals, 44 priority decision making, psychotic thoughts, patients, 289 postmortem changes, 193–194 222–223 psychotropic medication, 772 postpartum hemorrhage, 709 primary infusions, 573 psyllium, 705 post-traumatic stress disorder primary rhythm, 746 pT wave, 728 (PTSD), 45 prime wave, 728 puberty, 142–144 postural hypotension, 555 primidone, 695 public access, 28 potassium, 499, 668, 780–781 PR interval, 729, 747 publications, public health, 111 potassium-sparing diuretics, 669 Prinzmetal’s angina, 774 public education, 10 potentiation, drugs, 630 prions, 184–185 public health care, 18–20, 108–113, povidone, 567 privacy, |
patient information, 30, 75, 120–121 power of attorney, 97 97–98, 340 Public Health Service (PHS), 111 predictable injury pattern, 313. problem-oriented medical public information offi cer (PIO), 10 See also injury recordkeeping (POMR), 341 public relations, 11 preeclampsia, 709 procainamide, 658 public safety access point (PSAP), 28 preferred provider organization procedural sedation, 687–688 public safety communications, (PPO), 32 procedures, research overview, 328–332 prefi xes, medical terminology, 203 58–61 public space, 233 pregnancy process server, 87 public trust, 85 assessment of, 296–297 professional appearance, 12 PubMed, 59 childbirth medication, 708–709 professional development, 10 pulmonary artery, 367–368 documentation, 347 progesterone, 701 pulmonary embolism, 190, 773 drug administration, 627 prognosis, defi ned, 178 pulmonary system, 139. See also hydantoins and, 695 progress notes, 341 lungs; respiration minute ventilation, 366 pronator drift, 284 pulmonary treatments, 532–533 overview, 134 propylthiouracil, 702 pulsatile masses, 281 protozoa infections, 711 prospective research, 59 pulse, 221–222, 260–263, terbutaline, 645 prostaglandins, 187 284–285, 291 Index 853 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. pulseless electrical activity Rapid Infusion Catheter (RIC), 449 residuals, disease, 178 (PEA), 745 rapid sequence intubation, 477 resistance, stress and, 163 pulse oximetry, 269–270, 409–410, rate counter, ECG, 737 resource management, 30, 76–77 500–503, 507 reactive oxygen chemicals, 180, 181 respect, 7 pulse pressure, 266–268 reasonable accommodations, 99 respiration. See also airway punitive damages, 87 rebound tenderness, 281 airway, pediatric, 368–370 pupillary reaction, 293, 298 receptive aphasia, 231 airway anatomy, 354–363 Pure Food and Drug Act (1906), 620 receptors, drugs, 630 altered mental status, Purkinje fi bers, 722–723 reciprocal changes, ECG, 769 assessment of, 287–288 pursed lip breathing, 265–266 recovery, defi ned, 178 carbon dioxide transport, purulent exudate, 188 rectal drug administration, 530 494–495 pus, 188 red blood cells (erythrocytes), 162, chest pain, assessment of, putrefaction, 194 179, 601, 602, 603–604. See also 276–277 p value, 60 blood distress, infants, 136 P wave, 728, 746. See also ECG reentry phenomenon, 660 fever, assessment of, 293, (electrocardiogram) referred journal articles, 10 295–296 pyelonephritis, 296 referred pain, 688–689. See also pain Fick principle, 179–180 pyrexia, 163, 498, 499, 693. See also refl ection, patient interviews, 245 high blood pressure, temperature, body refl exes assessment of, 291 pyrogenic reaction, 575 anesthesia and, 687 medications, respiratory pyrogens, 163 gag refl ex, 359 emergencies, 644–647 pyruvate acid, 159 Hering-Breuer, 364 oxygen, assessment methods, pyruvic acid, 498 infants, 136–138 500–510 Q pregnancy, assessment of, 297 oxygen transport, 492–494 QRS complexes, 728, 743–744, syncope, assessment of, patient assessment, 219–220 765–766, 770–771. See also ECG 282–283, 283 physical exam, 263–266 (electrocardiogram) refusal of medical assistance (RMA), physiology of, 363–368 QT interval, 729, 747, 772 94, 95, 346 pregnancy, assessment of, 296 quadrageminy, 746 regulations, 84 respiratory failure, 191 quality assurance (QA), 9, 88, 338 regulators, oxygen, 397 respiratory patterns, 264 quality improvement, 9, 88 regurgitation, 404–405 respiratory system, patient quarantine, 108 relational terms, medical history, 344 questions, 217, 236, 237, 247. terminology, 208 shock and, 191 See also history, patient relative bradycardia, 747 shortness of breath, quickening, 134 release of information, pretrial 277–279, 280 quinidine, 657–658 discovery, 88 trauma, assessment of, 300 Quinlan, Karen Ann, 96 remodeling, heart, 665 respiratory acid, 495, 496 Q wave, 728, 765, 767–768, 769. renal compensation, acids, 497 respiratory acidosis, 498, 508–510 See also ECG (electrocardiogram) renal failure, 181, 190 respiratory alkalosis, 499–500, See also kidneys 508–510 R renin, 166, 193 respiratory infections, 136, 278, race, risk factors for disease, 177 renin-angiotensin-aldosterone 287–288, 295, 427 racemic epinephrine (EP), 166 mechanism, 665, 666 respiratory route, drug radial bone, 566 reperfusion injury, 180 administration, 531–533 radial pulse, 221–222, 260–263 reproduction, 133, 134 respondeat superior, 87 radiation burns, 182 rescue devices, intubation, 433–435 resting membrane potential, radiation poisoning, 183 research 641, 725 radio frequency radiation (RFR), 182 absence of, 63 restraints, use of, 85, 92–94 radio technology, 322–327 ethical concerns, 61–62, 77 restrictive cardiomyopathy, 738 radio waves, 182 overview, 58–61 resuscitation, withholding, 194 rales, 191, 278 paramedic role in, 10 reticular activating system randomized clinical trials, 59 patient care reports, 338 (RAS), 684 rapacuronium, 482 types of, 60–62 retrospective research, 59 854 Index Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. return of spontaneous circulation saphenous vein, 565 senile dementia, 147–148 (ROSC), 30 SARS (Severe Acute Respiratory sensory system, aging and, 147 reverse R wave progression, Syndrome), 176 separation anxiety, 138 770, 776 satellite phones, 325 sepsis/septic shock, 166, 191, 192, reverse use (rate) dependent scalenes, 364 293, 295–296, 557, 575, 579, 700 drugs, 656 scalp vein access, 580–581 septal hematoma, 293, 295 review of systems, 343–344 scanners, 328 serial vital signs, 222 rhabdomyolysis, 181 scene evaluation serotonin, 165, 186, 639, 708 rheumatic fever, 185 assessing, 214 settlements, legal action, 88 rheumatoid arthritis, 185 body substance isolation, Severe Acute Respiratory Syndrome Rh factor, 605 215, 216 (SARS), 176 rhythm, heart, 263, 741–747. See hazards, 47–49, 92–94, 214, severity, symptoms, 342 also ECG (electrocardiogram) 346–347 sex chromosomes, 134 ribs, 219, 265–266, 276–277, 361–363 mechanism of injury, nature of sexual advances, patient, 250 right bundle branch block illness, 215–216, 258 sexual assault, 89 (RBBB), 771 medical records, 341 sexual behavior, 143, 249 right coronary artery (RCA), 724 number of patients, 216 sexual harassment, 99 rigor mortis, 194 overview, 214 sexual innuendo, 237 Ringer’s solution, 556 physical exam, 273 sexually transmitted disease risk factors, disease, 177 priority decision making, (STD), 143 risk management, 46 222–223 shallow respiratory pattern, 264 rocuronium, 482 schizokinesis, 230 shared decision making, 315 “Role of EMS in Injury Prevention” scleral icterus, 280 shivering, 162 (NHSTA), 121 scleroderma, 185 shock rooting refl ex, 136–137 scope of practice, 9 anaphylactic, 180, 185, root words, medical terminology, scopolamine, 707 190, 642 202, 204 script, decision making process, 313 cardiogenic, 166, 180, 190 Rovsing’s sign, 281 scrotum, 274 decompensated, 192 rub, heart rhythm, 275 scurvy, 184 distributive, 190 rubella, 49–50 search and rescue teams, 30 endocrine, 190 3-3-2 rule, intubation, 437–439 seat belt safety, 123 hemorrhagic, 192 rules and regulations, 84 seat belt sign, 299 hypoglycemic, 190 running the line out, 562 sebaceous glands, 186 hypovolemic, 190 run of ventricular tachycardia, 746 secobarbital, 685 neurogenic, 180 rural settings, 30 secondary assessment. See physical obstructive, 190 R wave, 728, 770, 776. See also ECG examination pulse points and, 263 (electrocardiogram) secondary infusions, IV, 573 shock syndrome, 185–193 S sedation, 507, 684–686, 707 treatment, 192–193 SAFE-R model, 43 sedatives, 477 shock-liver, 190 safety seizure, 297, 344, 531, 694–697, shock waves, explosions, 183 emergency response, 47 742, 747. See also convulsions shortness of breath, 248, 277–280 scene hazards, 47–49, 92–94, Seldinger technique, 584 shunting, blood, 166, 191 214, 346–347 selective serotonin re-uptake sickle-cell disease, 134, 177, 184 vehicle safety, 46 inhibitors (SSRIs), 708 sidestream sample, capnography, salicylates, 692–693 self-awareness, 232 433, 503 saline laxatives, 705 self-determination, 75, 89–92, 96–97 sighing respiratory pattern, 264 saline lock, 570 self-evaluation, 9 sign language, 235 saline solution, 556 self-regulation (biofeedback), 43 SI (international system of units), saliva, 186 Selye, Hans, 42, 163 518–519 salts, drug sources, 616 Semmelweis, Ignaz, 178 simple negligence, 85 salvo, 746 senescence, 147 Sim’s position, 530 SAMPLED history, 246 senescent cells, 168 single-blind studies, 60 sanitation, 110 Sengstaken-Blakemore tube, 528 sinoatrial node (SA), 722 Index 855 Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. sinus bradycardia, 747. See also social space, 233 status epilepticus, 531, 694–697. bradycardia sodium chloride, 161 See also convulsions sinus dysrhythmia, 748–749. See also sodium-potassium pump, 159, 181 statute of limitations, 89 dysrhythmia soft palate, 403 statutes, 84 sinuses, 292–293, 354–356 somatic death, 193–194 STD (sexually transmitted sinus of Valsalva, 723–724 somatic pain, 688–689. See also pain disease), 143 sinus rhythm, normal, 747–749 somatotropin, 166 sterility, IV solutions, 557–558 sinus tachycardia, 747. See also sovereign immunity, 88–89 sternal retractions, 265–266 tachycardia spacer, inhalers, 532 Sternberg, Robert, 145 SIR (special incident report), 347 spaces, ECG, 728–729 sternocleidomastoid muscle, 364 SIRS (systemic infl ammatory special incident report (SIR), 347 sternum, 361–363, 364 response syndrome), 191 specialization, EMS, 30 steroids, 531, 700–701 situational awareness, 12 Specialty Care Transport (SCT), stethoscope, 259 situs inversus, 762 9, 30 stewardship, 11 skin speech, assessment of, 289 stigma, prevention programs abdominal pain, assessment speedballing, 531 and, 124 of, 281 spike, 558 stochastic effects, radiation, 183 altered mental status, spinal column stomach, 190, 528. assessment of, 288–289 cervical spine, 298, 404, See also abdomen chest pain, assessment of, 438–439 stoma management, 452 276–277 injuries, modifi ed jaw thrust, stool softeners, 705 as defense mechanism, 186 300, 301, 404 strain, 42 ECG lead placement, 741, 760 thoracic vertebrae, 362 streaking, 296 extremity pain, assessment of, toddlers, 139 Streptococcus infections, 185 289–290 trauma, assessment of, stress, 41–45, 145, 163–167 fever, assessment of, 296 300, 301 stressors, 42 jaundice, 279, 280 spinal cord injury, 167, 284 stroke late adulthood, 147 spine board, 443 altered mental status, liver failure, 279 spirits, medications, 516. See also assessment of, 287 peripheral sensation, 283 medications cellular atrophy, 167 shock and, 191 spleen, 190, 191 ECG and, 747 Skinner, B. F., 133 spontaneous abortion, 133 high blood pressure, slander, 98 squared out method, 570–571 assessment of, 290–292 sleep apnea, 184 SRS-A (slow acting substances of respiratory acidosis, 498 slide clamp, 559 anaphylaxis), 187 syncope, assessment of, 284 slip-tip adaptors, 534 SSRIs (selective serotonin re-uptake ST wave, 61, 729, 765–766, slow acting substances of inhibitors), 708 767, 769, 773. See also ECG anaphylaxis (SRS-A), 187 standard drug order, 521 (electrocardiogram) SLUDGEM, muscarine ingestion Standard Guide for Providing subarachnoid hemorrhage, 773 symptoms, 166 Essential Data Needed in Advance subcutaneous emphysema, 277 smack, 531 for Prehospital Emergency subcutaneous injections, 539. smallpox, 50 Medical Service, 341 See also injections small volume nebulizer (SVN), standard of care, 86 subendocardial ischemia, 767 533–534 standards, education, 27 sublingual drug administration, 527 smell, sense of, 283 standards, professional, 6–7 subpoena, 88 smooth muscles, 186 standing orders, 31 substituted judgment, 62 sniffi ng position, intubation, 438–439 Starling’s law, 665, 721 succinimides, 695 snowballing, 531 star of life, 27 succinylcholine, 165, 476–477, 479 SOAP notes, 341 static electricity, 760 sucking refl ex, 136–137 social clock, 145 statins, 649 suction, airway management, social health, 110 statistics, research, 60 402–403, 411–412, 427, 452, 465 social learning theory, 133 status asthmaticus, 645–647. sudden cardiac death (SCD), 655, social norms, 74 See also asthma 656, 659, 777 856 Index Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. suffi xes, medical terminology, 203 systems review, 343–344 improving, 232–238 suicidal patients, 92–94, 143, 148, system status management (SSM), 30 overview, 230–231 289, 343 systole, heart auscultation, 274 therapeutic index, drugs, 622 summarization, patient systolic blood pressure, 266–268 therapeutic level, drugs, 626 responses, 237 systolic heart failure, 665–674 therapeutic privilege, 91 summary dismissal, 89 T therapeutic touch, 8, 233 summary judgment, 88 tablets, 517. See also medications thermal burns, 182 summons, 87 tachycardia thermometers, 524 sun poisoning, 183 bronchodilators, 166 thiazides, 669 superego, 132 defi ned, 262 thioamide derivatives, 702 suppositories, 517. See also dehydration, 555 thiopental, 685 medications ECG readings, 744–745, 747, third spacing, 162 supraglottic airway, 434 779–780 Thomas |
Table of Contents Title Page Copyright Page PREFACE Acknowledgements CHAPTER 1 - THE EVOLUTION OF THE HUMAN RUNNER Evolution of Running Physiology of Runners The Future of Running CHAPTER 2 - CARDIOVASCULAR AND CARDIORESPIRATORY COMPONENTS Cardiovascular and Cardiorespiratory Systems Performance Training Progression CHAPTER 3 - THE RUNNER IN MOTION Running Gait Cycle ABC Running Drills CHAPTER 4 - ADAPTATIONS FOR FOR SPEED AND TERRAIN Event-Specific Body Characteristics Effects of Terrain and Other External Factors CHAPTER 5 - UPPER TORSO Choosing Resistance Repetitions Breathing Schedule CHAPTER 6 - ARMS AND SHOULDERS Specific Training Guidelines CHAPTER 7 - CORE Specific Training Guidelines CHAPTER 8 - UPPER LEGS Specific Training Guidelines CHAPTER 9 - LOWER LEGS AND FEET Specific Training Guidelines CHAPTER 10 - COMMON RUNNING INJURIES Specific Training Guidelines CHAPTER 11 - ANATOMY OF RUNNING FOOTWEAR Why Wear Running Shoes? History of 20th-Century Running Shoes Components of Running Shoes Barefoot Running Summary CHAPTER 12 - FULL-BODY CONDITIONING Water Running Plyometrics EXERCISE FINDER ABOUT THE AUTHORS Library of Congress Cataloging-in-Publication Data Puleo, Joe. Running anatomy / Joe Puleo, Patrick Milroy. p. cm. ISBN-13: 978-0-7360-8230-3 (soft cover) ISBN-10: 978-0-736-09183-1 (soft cover) 1. Running--Training. 2. Running--Physiological aspects. 3. Running injuries--Prevention. 4. Sports medicine. I. Milroy, Patrick. II.Title. GV1061.5.P85 2010 796.42--dc22 2009035764 ISBN-10: 978-0-736-09183-1 (print) ISBN-13: 978-0-7360-8230-3 (print) Copyright © 2010 by Joe Puleo and Patrick Milroy All rights reserved. Except for use in a review, the reproduction or utilization of this work in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including xerography, photocopying, and recording, and in any information storage and retrieval system, is forbidden without the written permission of the publisher. This publication is written and published to provide accurate and authoritative information relevant to the subject matter presented. It is published and sold with the understanding that the author and publisher are not engaged in rendering legal, medical, or other professional services by reason of their authorship or publication of this work. If medical or other expert assistance is required, the services of a competent professional person should be sought. Acquisitions Editor: Laurel Plotzke; Developmental Editors: Mandy Eastin-Allen and Cynthia McEntire; Assistant Editor: Laura Podeschi; Copyeditor: Anne Rogers; Graphic Designer: Fred Starbird; Graphic Artist: Tara Welsch; Cover Designer: Keith Blomberg; Photographer (for illustration references): Neil Bernstein; Photo Asset Manager: Laura Fitch; Visual Production Assistant: Joyce Brumfield; Art Manager: Kelly Hendren; Associate Art Manager: Alan L. Wilborn; Illustrator (cover): Jennifer Gibas; Illustrators (interior): Precision Graphics and Jennifer Gibas; Printer: United Graphics Human Kinetics books are available at special discounts for bulk purchase. Special editions or book excerpts can also be created to specification. For details, contact the Special Sales Manager at Human Kinetics. Printed in the United States of America 10 9 8 7 6 5 4 3 2 1 The paper in this book is certified under a sustainable forestry program. Human Kinetics Web site: www.HumanKinetics.com United States: Human Kinetics P.O. Box 5076 Champaign, IL 61825-5076 800-747-4457 e-mail: humank@hkusa.com Canada: Human Kinetics 475 Devonshire Road Unit 100 Windsor, ON N8Y 2L5 800-465-7301 (in Canada only) e-mail: info@hkcanada.com Australia: Human Kinetics 57A Price Avenue Lower Mitcham, South Australia 5062 08 8372 0999 e-mail: info@hkaustralia.com New Zealand: Human Kinetics P.O. Box 80 Torrens Park, South Australia 5062 0800 222 062 e-mail: info@hknewzealand.com Europe: Human Kinetics 107 Bradford Road Stanningley Leeds LS28 6AT, United Kingdom +44 (0) 113 255 5665 e-mail: hk@hkeurope.com E4782 PREFACE Beginning with a chapter on the evolution of the human runner, Running Anatomy endeavors to educate runners about how and why their bodies work as they do during the movements of running. Running Anatomy explains not only how the soft tissues and bones interact to produce movement, but why they do so and what you can do to maximize your own personal running goals. By detailing the mechanisms of movement through illustrations, we hope to show, in a simple format, what happens when your body engages in running. The goal of this book is threefold. First, the illustrations in this book are meant to aid the runner in understanding the anatomy impacted when the runner is in motion. By calling out the anatomy associated with the running motion, we hope to further the runner’s understanding of how bones, organs, muscles, ligaments, and tendons work to move the body. The anatomical illustrations that accompany the exercises are color-coded to indicate the primary and secondary muscles and connective tissues featured in each exercise and running-specific movement. Then, after detailing the hows and whys of running, we focus on the significance of strengthening your body through strength training devised for performance enhancement. The text in each chapter further explains the function of the anatomy shown in the illustrations. Finally, the strengthening exercises included in each chapter will improve running performance and help to keep the runner injury-free by eliminating anatomical imbalances that often occur naturally but are exacerbated by the muscular-skeletal demands of running. The ultimate goal is to create a strength-training program that is logical and easy-to-use but also effective in improving running performance. Since injuries often occur as a result of repetitive movement, understanding how and why the body moves may be a simple way to enhance performance and prevent injury. Our intent is to enhance your running experience and performance by helping you understand the anatomy of running and develop a clearly defined strength-training program. ACKNOWLEDGMENTS Many people contributed to this book in many different ways. Jack Kraynak, Jay Carlin, Rob Weinmann, Dale Luy, Ken Deangelo, and Bill Preston were my coaches and mentors. Bob Kirkner, Dr. Carolyn Peel, Bill Bender, Scott Conary, Dave Salmon, Cassy Bradley, Abby Dean, Jay Johns, Sean Mick, Patty Deroian, Terry Luzader, Dave Welsh, Chris Ganter, Suzanne Dorrell, Sharon Smith, Jay Friedman, Mike Fox, Travis Stewart, Frank Iwanicki, and Robin England were training partners and guinea pigs. Capt. David Litkenhus, Lt. Col. Steven Peterson, Dr. Gregory Ng, Brian Walton, Harvey Newton, Bran-don Risser, Myrna Marcus, Bob Gamberg, Bob Schwelm, Todd Williams, Dave Shelburne, Paul Slaymaker, Steve Dinote, Graig White, the members and staff of the Rutgers University-Camden track and field team, and the Haddonfield Running Company provided professional support and friendship. Models Brandee Neiderhofer, Jon Salamon, Lyndi Puleo, Anthony Witter, and Jorge Ramos gave their time and talents to make the illustrations possible. The Spa Fitness Center in Pennsuaken, New Jersey, and owner Tom Loperfido allowed us to shoot the reference photos. The staff at Human Kinetics—Laurel Plotzke, Leigh Keylock, Mandy Eastin-Allen, Laura Podeschi, Neil Bernstein, Jen Gibas, and Cynthia McEntire—guided the publication process. Special thanks to my wife, Lyndi, and children, Gabe, Anna, and Sophia, for sharing me with this project for the past two years. Also, my efforts are in honor of my grandfather Joseph A. Puleo, Sr., and my father, Joseph A. Puleo, Jr. Joe Puleo My writing skills were developed through the advice of various editors of Runners World (UK), for whom I was medical adviser for 25 years, and the help and encouragement of the staff at Human Kinetics, without whom this project would never have got off the ground. I could not have completed this project without the love and understanding of my wife, Clare, and the support of my family and friends, many from the running world. Dr. Patrick Milroy CHAPTER 1 THE EVOLUTION OF THE HUMAN RUNNER Haile Gebrselassie once said, “Without running there is no life.” The sheer joy expressed by Gebrselassie about his running is shared by millions around the globe. It surpasses language and cultural barriers, so a stranger abroad can invariably change into shorts and running shoes, find a trail, and meet kindred spirits enjoying life with the same enthusiasm. Running ranks highly among ways of combining pleasure with health promotion. As civilization has progressed, the need for people to run for survival has been tempered by the development of new skills so that the average human can now enjoy leisure time in a way that the majority of our ancestors would have found at the very least impractical, and quite possibly fatal. Although the ability to run was once quite literally a matter of life and death, the social development of the biped means that running has taken on a new character. It has become a conduit for the expression of human competition, of socialization, and of scientific experiment and development. It is probably the most natural form of exercise that does not involve aggressive or antisocial techniques or require expensive equipment. Any able-bodied human should be able to enjoy it. Although the first purpose of this book is to enable you to understand the function of the anatomy of the body involved in running, the greater aim is to add training exercises and techniques that any runner can use to enhance his or her own sporting satisfaction. Running better does not necessarily involve running faster. If this book allows you to complete your runs in a more relaxed and less distressed manner than previously, and if following the exercise schedules reduces the incidence of pain and injury, then that is surely a positive gain. Not only will you be able to look back on your previous run with pleasure, but the anticipation of the next is likely to be far more positive as well. In the past 40 years, an entire industry has developed around the sport, although the practice of running stretches back for many thousands of years. Clothing and shoes, diet and physiology, and the surfaces on which and the environment in which we run have all undergone research, experimentation, and review in this short epoch. In much the same way that the coming of the “Iron Road” of railways some 200 years ago changed the way in which we lived, so running has entered the everyday lives of millions of people and with very few exceptions has benefited the majority. Although it is impossible to completely ignore the other interlinked factors that make a runner what he or she is, this chapter traces the evolution of anatomy as it affects the runner, researches the characteristics and physique that produce success, and even tries to predict the makeup of the perfect runner, if such an individual could ever exist. In the past, many learned authors have speculated on the ultimate running performance, only to find it bettered. We would like to envisage the makeup of the athlete who could produce that unbreakable record, and then in the subsequent chapters guide you toward making and breaking that goal. Evolution of Running The running skills of humans evolved as a response to predators who also vied with humans for sustenance. This was before our brains developed and we were able to think our way out of trouble. Those who could run the fastest not only got to the food first and had the biggest and most nutritious portions, but also were able to leave the quickest if danger appeared. Those who were unable to run were invariably the first to fall by the wayside because of an inability to obtain sufficient food, or because they lacked time to eat it, or because they fell victim to predators as a result of their lack of mobility. It might be interesting to conjecture how fast our predecessors would have been able to run if they had not developed their brains and learned more cunning ways to avoid danger. However, the concurrent use of brain skills to manufacture weapons with which to hunt meant that our forebears had to rely less on pure speed for survival, and the ability to run flat out became less of a necessity and more of a virtue. The communities in those times were largely tribal, and chiefs had skills over and above the majority, so the ability to run fast would figure strongly as he or she sought respect, much of which could be gained through competition, which could include running races. Eventually, the survivors passed on the genetic makeup that produced speedy legs to their offspring, and because the need to be able to run at speed was still required, faster runners continued to evolve. In those times, pure upper-body strength was generally needed more than litheness, so those peoples for whom running had become a less important element of their life skills would probably not have looked much |
like competitive runners as we see them today (figure 1.1). These were people who spent their lives in physical endeavor, so they probably had a physique equivalent to the modern gym attendee, who regularly works out on a broad program of exercises but avoids specific sport-related repetition. At some time, running evolved to have other uses. Although horses were the principal carriers of messages, sometimes people could be more efficient. Some 2,500 years ago, Pheidippides ran from Marathon to Athens to deliver news of victory in battle against the invading Persian army, though he did little to promote it as a leisure activity, dropping dead as he finished the run. Today, people and horses have an annual organized race in Wales to test the theory about which is the faster species. These early civilizations were able to enjoy sports, and one development was the organized Olympic Games, which honored the Greek gods and included running races over various distances. They lasted until AD 394 but were eventually banned because of their pagan origins. Until relatively recent times, women did not run anywhere near as much as men, partly because they were not participating in the same kinds of foraging and defense activities; rather, they were expected to produce children, usually the more the better and one after another. Time was then used to feed and teach these offspring the basic skills needed for survival until the mature males took over for the more advanced tutoring. The ability to run might still have been necessary to avoid danger, although advances in methods of transportation would have lessened the need even for this. Figure 1.1 Comparing the physical build of (a) a runner from the past with (b) a contemporary runner. Hard evidence of both competitive and noncompetitive running between Roman times and the Middle Ages is hard to come by. It may well have happened, but it was not recorded by the scribes of the time who had far more important items to chronicle, so it has become lost in the mists of history. Once they had established the basics for living, people from those times were more concerned with territorial gain and religion than events that would have done little to enhance their lives. If any time was given to leisure pursuit, running would have had to compete with throwing and wrestling events, weapon skills, and the inevitable drinking competitions, among many others. Some 14th-century texts contain references to running races held across open country, and there is evidence to suggest that competition developed from games based on hunting. In the 18th century, a new sport had emerged in which two or more horse riders would race each other to a distant church steeple. By the 19th century, simple foot races called steeplechases were organized along the same lines. These races were promoted further by the fee- paying schools and universities in the United Kingdom, who also ran “paper chases” in which a “hare” would leave a trail of paper for the “hounds” to follow. This led to the formation of the amateur Harrier Clubs for road and cross-country running that still exist today. Once again women played no part in this social convention, decreeing that it was inappropriate and demeaning to the upper classes, and the poorer majority were far too busy simply trying to survive. During the second half of the 18th century, walking competitions between gentlemen’s servants gave way to men racing against time over longer distances. One of the more popular goals involved covering at least 100 miles in less than 24 hours. Those who achieve this are still called centurions in a flashback to Roman times. Other contests involved covering one mile in each of 1,000 successive hours. (This is more than 40 straight days!) The early 19th century saw the return of races between men, and town-to-town events, accompanied by heavy gambling, for a while became the most popular sport in England. The winners of these races were those who adapted to the generally horrific environmental circumstances and lack of nutritional variety that existed at the time. Disease was rife, life expectancy was short, and diet relied in the main on whatever seasonal local supplies were available. Any training for the events as recognized in the 21st century was nonexistent, and the pedestrians would consume large quantities of meat, often raw, and alcohol, frequently in large quantities, before and during competition. In fact, training specifically for a race was considered to hinder performance because it might exhaust their energies. It was not that they were unfit, as the competitors invariably came from the laboring masses for whom a 12-hour day of physical toil was the norm, rather than from the much smaller ranks of those with sedentary jobs. The establishment of the modern Olympic Games was of little interest to the majority of the world’s population, who had no means of entering or enjoying competition, even if they knew of it; until well into the 20th century, the Games remained the prerogative of the rich and otherwise idle, who disdained most preparation for the events. Some pioneers such as Paavo Nurmi and Hannes Kolehmainen put thought into how their racing performances could be improved and utilized the most basic sport science, but it was only in the second half of the 20th century that disciplines that could be recognized as scientific were applied to running, such as those done by Arthur Lydiard. Lydiard was different: He trained alongside his protégés, asking them to do no more or fewer miles than he, and led them through a regime that intrigued the world. It was LSD—long slow distance—for everyone. Percy Cerutty used new techniques including sandhill running to win his students Olympic gold medals. Running and science have had a symbiotic relationship because runners have become unintentional guinea pigs for physiological testing. When statistics have demonstrated that runners have veered away from some expected normal values, scientists have been able to use the results to explain the physiology of the heart, circulation, lungs, and other organs. Extrapolation of the findings has led to progress in many medical specialities. Intertwined with this have been the advances in dietary knowledge. In basic terms it might prevent a runner from the consequences of eating a large meal before exercise, and at its most sophisticated, elite athletes often have an integral dietary program prepared as part of a whole season of competition. Medicine could never have developed to the extent it has without the participation of the running community any more than runners could have become faster without sport science. Running hit the headlines as a leisure activity for the general populace only after the mass publicity and television coverage that accompanied the New York and London marathons in the late 1970s. In these races there was a large number of newcomers to the sport in which the emphasis on speed was replaced by jogging at little more than walking pace. It would be an exaggeration to call the majority of them competitors. This development was not only tolerated but also even encouraged as the races became a mixture between the opportunity to raise money for charitable causes and fancy dress competitions. In terms of speed, the successful runners were those who had prepared themselves best both physically and mentally. It was noted that faster runners rarely carried excess weight, and the perception of running as a health benefit grew as parallel advances in science demonstrated that obese and sedentary people had a lower life expectancy. Race winners had usually run many miles in training before competition, although grossly excessive mileage, as in the case of British 10,000-meter world-record holder Dave Bedford, could lead to painful and career-ending injuries. It became understood that running well was not simply about quantity, but the quality of the mileage was also a decisive factor, so multiple theories of optimal training regimes abounded, none of which has yet been shown to be superior to the others in all circumstances. Physiology of Runners As more nations entered competition, ethnic variations in ability appeared. Afro-Caribbean athletes showed themselves to be the preeminent sprinters, whereas those from higher altitudes became the fastest endurance athletes, their bodies having adapted to a decreased oxygen concentration in inhaled air. The act of sprinting fast uses nearly all the muscles of the body during the event. A still photograph of the top exponents at full speed will show taut neck muscles and bulging eyeballs, not exactly the first areas to be considered when running! But if these muscles, in whatever small way, are used to increase speed, then these muscles must be trained for the event in exactly the same way as the massive thighs that provide the explosive power and high knee lift more usually associated with sprinting. Conversely, the best long-distance runners became almost pitifully thin, especially in the largely underused upper limbs, as it was realized that the less weight that they carried, the less energy would be expended in moving their bodies efficiently for mile after mile. However, one enemy of the distance runner is dehydration, a catalyst for both illness and injury, so adaptation to conserve and absorb water, especially in warmer climates, was at odds with the perceived need to be emaciated. Low fat stores, thin and sinewy muscles, and a low mass of other soft body tissues are not conducive to transporting large volumes of fluid internally during a run. The core temperature of the body needs to remain as close as possible to 98.6 degrees F (37 degrees C), not only to work most efficiently, but also, and more important, to survive. The energy burned when running produces heat, and it is by the mechanism of sweating that the core temperature is maintained. If the body is dehydrated, this cannot occur, so at worst a life-threatening hyperthermia may develop as the body temperature rapidly soars. This may help to explain why some winners of distance races can be comparatively well built, because they are able to store larger quantities of fluid to provide for the event. Science shows that performance deteriorates precipitously as the runner becomes overheated and dehydrated, so as with the tortoise and the hare, the winner may be the runner who has prepared best for the whole distance and not relied on pure speed to win the day. Transposing the body types and events quickly demonstrates the impracticality of either entering the other’s competition. The sprinter would quickly tire as he carried his comparatively heavy body for more than a few hundred meters, even if he could store sufficient fluid, whereas the undermuscled distance runner would immediately be at a disadvantage in an event requiring brute strength and power. These are extreme examples, but in general most events attract successful competitors who have comparatively similar physiques. It is interesting to consider how rare it is that more than one world record is held by a single competitor; where it is, the events tend to require very similar speeds and skills. Thus, Michael Johnson simultaneously held the 200- and 400-meter records, and Haile Gebrselassie the 5K and 10K, but for success at the highest level, the Olympics and world championships, very few runners enjoy the luxury of being able to prepare for, let alone win, more than one event. Women have been latecomers to the running scene. Races for women longer than 400 meters were not introduced to the Olympic Games until 1964 because it was considered, without any scientific proof, that they might suffer some unspoken medical ailment if they were to “strain” themselves. Once it was shown that they thrived in competition, their advancement was so rapid that by 1984 they were allowed their very own marathon at the Los Angeles Olympics. Anatomically, women are generally disadvantaged compared to their male counterparts (compare figures 1.2 and 1.3), especially where the long, light levers that make up the lower limbs are concerned, but physiologically they are in some ways better prepared, especially for ultradistance running. Because they have proportionately more fat as a percentage of body weight compared to their male counterparts, they have greater reserves of energy and stored fluid to call on, although it may take days rather than hours of competition for this to emerge. |
It is in ultradistance racing that the performance of women comes closest to men. With increasing distance, the difference between the sexes in statistical terms in time run becomes less and less marked, so it may well be that one day a woman will win an open race purely as a result of better physiological efficiency. Women are disadvantaged by relatively short thighs, which become exaggerated by their wider hips and bring the pelvis closer to the ground, resulting in a reduction of stride length. Stride length is perhaps the factor with the most effect on the speed of running. Although the fastest runners take no more than double the number of strides of the slowest over a given unit of time, their stride length may be up to four times greater. Although the abdomen of the male largely consists of the intestinal organs, which are involved in fluid balance and retention, that of the woman also has to accommodate the relatively bulky uterus and reproductive organs, limiting the volume available for the bowels. These are not large differences, perhaps even only 1 percent or 2 percent, but they also determine the differences between the relative athletic performances of the two sexes. Add to that breasts and the limitation of smaller chests and lung capacity, as well as smaller feet, which mean that part of the mechanical leverage of propulsion is reduced, further handicapping women when pure speed is the consideration. However, as the male distance runners have shown, small size is not necessarily a disadvantage, and the physiological differences that become more marked in favor of women with greater time and distance run may ultimately lead to an equalization between the sexes over the longest distances. Figure 1.2 Male runner: (a) front view; (b) side view. Figure 1.3 Female runner: (a) front view; (b) side view. Once the genetic core of the body has been established, there is only so much that each individual can do to develop his or her physique as a running machine. Even if one discounts artificial aids to body shaping, such as liposuction or steroid drugs, there are certain limits to the adaptation of the adult human form. No mature adult can lose or gain height voluntarily, and exercise training and dieting will only change or mature physique within the limits of capacity, such that although muscles develop as a result of exercise, there are individual limits to the amount of exercise that any single person can tolerate. So the 280-pounder, whose previous leisure activities had been purely nutritional, can expect to reduce his weight and change his shape by exercising to develop a runner’s physique. However, skin has limits both to elasticity and in its ability to retract once overstretched, so the excess will remain visible however assiduously that individual maintains the training program. The Future of Running A problem with genetic differences is that competition can never be between physical or physiological equals. This leads inexorably to the vexing question about what aids to improved performance may be considered both legal and sporting. This book deals solely with training methods. One factor in the improvement of running performance that is unquestionably lawful is simple leisure training. Until the last 30 or so years of the 20th century, almost all books written about running were biographies or ghosted autobiographies of the great retired runners who were hoping to make a few cents by passing on the secrets of their successes. Most of the books dealt with the races, although some had fascinating accounts of the runners’ preparations—and all too often the lack of it! Although the majority of those competitors were amateurs, at least in name, the elite runners of today are as much professionals as lawyers or doctors. Running for them is a full-time occupation for which they put in hours of preparation, travel around the world to compete, and are paid regularly by sponsors and promoters for their efforts. However, the average participant in the marathon explosion of the 1980s had little desire to run as far or as fast as the Kuts, Shorters, Zatopeks, and Coes of preceding generations. Running had become a socially acceptable leisure activity, which helped to counteract the similar growth in eating away from home. Running a few pleasurable miles with some friends and then replacing the calories in an equally enjoyable fashion became the new modus vivendi. Competition ceased to be the only goal of the runner, and running could be enjoyed for itself and the feel-good factor it produced. However, although the leisure runner became happy to commune with nature in his or her own particular fashion, it did not end all desire to improve performance, whether it be in speed or the distance covered. Running magazines began to appear on the shelves, which not only listed races and their results but also delved into nutrition, training, fluid intake and output, and all the little nuances that became part of a runner’s world. The effect of running on health, medicine, and even the psychology of the sport became regular dinner-table discussion topics. The desire to gain further health benefits and improvement from running can be advanced only if there is an understanding of the mechanism of running. Which muscles are needed in order to run, and how do they work? What part do the heart, lungs, and circulation play in this process? What are tendons, ligaments, and bursas, and why is running sometimes painful? This book sets out to answer all these questions. It also explains anatomy, the structural science dealing with all the phases of the running stride, how the muscles are employed, and the exercises that will improve strength, power, and endurance. The determined competitor also needs an appreciation of basic physiology, without which the muscles cannot function, so they may reap the full benefits of accepted science. Our hope is that by following this guide, some of today’s leisure runners may become the Olympians of tomorrow. CHAPTER 2 CARDIOVASCULAR AND CARDIORESPIRATORY COMPONENTS Improvement in running performance hinges on many factors. Specifically, running training benefits the cardiovascular and cardiorespiratory systems, which should, in turn, lead to an improvement in running performance. However, this improvement can be curtailed by neglecting or abusing the musculoskeletal system through inappropriate training—too much mileage at too fast a pace. Even intelligent training can exacerbate muscle imbalances and anatomical shortcomings. Incorporating strength training into a holistic plan for performance enhancement makes sense on many levels. A well- designed strength program promotes running efficiency through a better, more effective gait. A well-designed running program following some simple, proven tenets or best practices improves running economy by improving cardiovascular and cardiorespiratory efficiency. This chapter explains the general concept of running training via the cardiovascular and cardiorespiratory systems, and how positive anatomical changes can occur as a result of an educated, intelligent approach to training. Cardiovascular and Cardiorespiratory Systems The cardiovascular system is a circulatory blood delivery system involving the heart, blood, and blood vessels (veins and arteries). Put simply, the heart pumps blood. The blood is carried away from the heart by arteries and returned to the heart by veins (figure 2.1). Figure 2.1 Blood flows through the chambers of the heart. The cardiorespiratory system involves the heart and lungs. Air is inhaled by breathing through the mouth and nose. The diaphragm and other muscles push the air into the lungs, where the oxygen contained in the air becomes mixed with blood (figure 2.2). Figure 2.3 shows the muscles that work during respiration. The interplay between the two systems works when the heart pumps blood to the lungs through the pulmonary arteries. This blood is mixed with the air (oxygen) that has been inhaled. The oxygenated blood is delivered back to the heart via the pulmonary veins. The heart’s arteries then pump the blood, now complete with oxygen-rich red blood cells, to the body’s muscles (figure 2.4) to promote movement—in this example, running. Figure 2.2 Oxygen exchange in the lungs. Figure 2.3 Muscles that aid in respiration. How can running performance improve as a result of this interplay between the cardiovascular and cardiorespiratory systems? Simply, the more developed your cardiovascular and cardiorespiratory systems are, the more blood flow your body produces. Greater blood flow means more oxygen-rich red blood cells are available to power your muscles and more plasma is available to aid in creating energy through a process called glycolysis. Figure 2.4 Circulation of blood through the heart, lungs, and muscles. Other factors such as neuromuscular fitness, muscular endurance, strength, and flexibility are involved in improving running performance. Coupled with the strong foundation of well-developed cardiothoracic systems (the heart and lungs are located in the thorax region of the body, hence the term cardiothorax), these other factors will help to produce sustainable improvements in performance. The science described in the preceding paragraphs becomes exercise science, and a useful primer for improving running performance when applied to a training model. The following discussion of training is rooted in the anatomy and physiology of the cardiovascular and cardiorespiratory systems. Performance Training Progression Traditional training progressions consist of a well-developed base, or introductory, period consisting of easy runs of gradually increasing duration and strength training consisting of lighter weights and higher repetitions. Normally this period is followed by a slightly shorter but still significantly lengthy duration of running strength training (threshold training and hills) and strength training incorporating increasing resistance. The final phase is defined by a brief period of high-intensity ( V O2 max) running coupled with a maintenance period of resistance training and planned rest (taper). The entire training progression ends with a competitive phase of racing, which seems incredibly short given the amount of time spent attaining the fitness to race. This training progression, also known as a training cycle, is then adapted based on its success or failure and race distances to be completed in the future and repeated, incorporating a well-defined rest period at the end of each cycle, for the duration of the runner’s performance-based running career. Please note that this is by no means the only concept of how running training should be structured. Ideas such as adaptive training and functional training (Gambetta’s Athletic Development, Human Kinetics) are successful approaches to running training; however, the nuances of those training philosophies are not outlined in this book. Often, apparent differences in training philosophy boil down to simple semantics. Since training language is not codified, coaches do not always understand and apply terminology the same way. Our goal is to present an overall concept of the training progression in a simple but thorough manner without arguing the merits of different approaches. Base, or Introductory, Training The concept of base, or introductory, training is relatively simple, but the application is slightly more nuanced. Most coaches would agree that the pace of running during this phase is always easy and aerobic (based on the consumption of oxygen), not strenuous and anaerobic (using the oxygen present), and that the volume of training should gradually increase with down, or lesser-volume, weeks used to buffer the increase in volume, aid in recovery, and promote an adaption to a new training load. One systematic approach using a three-week training cycle incorporates four to six days of running training with a weekly increase in volume of 10 percent from week 1 to week 2; week 3 returns to the volume of the first week. For injury prevention, the weekly long run should not be more than 33 percent of the week’s total volume. Two or three strength-training sessions emphasizing proper form and movement, not volume of weight, would complement this running training. For a runner who is training for a race longer than a 10K, this phase of the training cycle is the lengthiest of a training progression because of the slower (relative to speed and muscle development) adaptations to training made by the cardiothoracic systems. Because relatively slow-paced aerobic runs take longer, they require the repeated inhalation of oxygen, the repetitive pumping of the heart, and the uninterrupted (ideally) flow of blood from the lungs to the heart and from the heart to the muscles. All of these actions aid in capillary development and improved blood flow. Increased capillary development aids both in delivering more blood to muscles and in the |
removal of waste products from muscles and other tissue that could impede the proper functioning of the muscles. However, these adaptations take time. The development of a distance runner may take a decade or more, while the development of faster-paced running can occur in half the time. A training program that ignores or diminishes the importance of the base training component is a training program that ignores the tenets of exercise science. Without an extensive reliance on easy aerobic running, any performance-enhancement training program is destined for failure. A common question is how long the base period should last. This seemingly simple question does not have a simple answer, but the best reply is that the base period needs to last as long as the athlete needs to develop good running fitness and musculoskeletal strength based on his or her subjective interpretation of how easy the daily runs feel, but not so long that the athlete becomes bored or unmotivated. A good guideline for experienced runners who are training for races longer than 10K is six to eight weeks. Experienced runners training for 10K races or shorter distances need four to six weeks. For beginning runners, the base period takes longer, even making up the bulk of their first four to six months of running. Another common question is how fast the athlete should run. Short of getting a lactate threshold or stress test, which normally indicates approximately 70 to 75 percent of maximum heart rate or 70 percent of V O2max, pace charts help determine aerobic training paces based on race performances (Daniels’ Running Formula, Second Edition, Human Kinetics). They are extremely accurate and offer explanations of how to use the data effectively. An emphasis on base, or introductory, training does not mean that other types of training are ignored or diminished in importance. The other types of running training—tempo, lactate, threshold, steady-state, hill, and VO2 max—are relegated to their specific roles in a well-designed training program. Also, neuromuscular development is needed to allow fast performances to occur. These other types of training are meant to sharpen and focus the endurance developed during the base, or introductory, phase. However, because these other types of training also strengthen the cardiovascular and cardiorespiratory systems, they play an essential role in improving performance. The best approach to strength training during this phase is to perform multiple sets of 10 to 12 repetitions of exercises for total-body strength development. Specifically, at this stage of training, functional strength is less important than developing muscular endurance for the whole body. If this is an athlete’s first strength-training progression, the proper execution of the exercise becomes paramount. If an athlete is revisiting strength training after a rest period, becoming reacquainted with the physical demands of combining a running and strength-training program should be the goal. Strength training should be performed two or three times per week; however, one day a week should be entirely free of exercise, so the other workouts need to be performed either on running days after the runs or on the other off days from running if following a four- or five-day-a-week running plan. Threshold Training The concept of lactate threshold (LT) often associated with tempo-based running is a conversation point for many exercise physiologists, running coaches, and runners. The science of the concept, the lexicon to describe it, and the appropriate duration and pace of the effort offer endless possibilities for debate and argument. All too often an athlete’s successful performance leads to the supposition that his or her interpretation of threshold training (if it is a cornerstone of the program) is the appropriate interpretation and therefore must be copied by the masses. We do not endeavor to make any definitive statements about lactate threshold protocols. We apply the term threshold (please feel free to substitute lactate threshold, anaerobic threshold, lactate turn point, or lactate curve) to describe the type of running that, because of the muscle contractions inherent in faster-paced training, produces a rising blood-lactate concentration that inhibits faster running or lengthier running at the same speed (figure 2.5)—or, less scientifically, a comfortably hard effort that one could sustain for approximately 5 to 6 miles (8 to 10 km) before reaching exhaustion. It is very close to 10K race pace. Lactate—not lactic acid—is a fuel that is used by the muscles during prolonged exercise. Lactate released from the muscle is converted in the liver to glucose, which is then used as an energy source. It had been argued for years that lactic acid (chemically not the same compound as lactate, but normally used as a synonym) was the culprit when discussing performance-limiting chemical by-products caused by intense physical effort. Instead, rather than cause fatigue, lactate can actually help to delay a possible lowering of blood glucose concentration, and ultimately can aid performance. Threshold training also aids running performance because it provides a greater stimulus to the cardiothoracic systems than basic aerobic or recovery runs, and it does so without a correspondingly high impact on the musculoskeletal system because of its shorter duration. By running at a comfortably hard effort for 15 to 50 minutes (depending on your goal race and timing of the effort in your training program), you can accelerate the rate at which your cardiothoracic systems develop. Tempo runs, which are often referred to interchangeably with lactate threshold runs, cruise intervals, and steady-state runs, which are slightly slower than tempos, are types of threshold workouts, just at slightly different paces and durations. Ultimately, the objective of a lactate-type run, a measurement of 4 mmol of lactate if blood was drawn at points during the run, would be accomplished performing these runs instead of an easy aerobic run, which would produce almost no lactate. A good resource on tempo-type training is Jack Daniels’ Running Formula (Human Kinetics, 2005). The author recommends paces and durations of effort based on the athlete’s current fitness and race distances to be attempted. Although less stressful on the runner’s body than V O2 max efforts and races, threshold runs in any form (lactate threshold, tempo runs, cruise intervals, repeat miles) require longer periods of recovery than daily aerobic or recovery runs. Most nonelite runners should perform threshold-type runs no more than once a week during this phase of the training progression, and need to treat them as hard efforts. They should be preceded by an easy run plus a set of strides (faster running at 40 to 60 meters [44 to 66 yards]) the day before, and an easy or easy and long run the following day. Keep in mind that easy running still makes up the majority of this phase of training. The introduction of threshold-type training to the progression usually is the only difference from the introductory phase. Figure 2.5 Oxygen consumption relative to exercise intensity. Strength training at this phase of a training progression is highly important and highly individual. The emphasis should be on countering the athlete’s weakness and on functional exercises that directly correlate to running faster. For example, if a female runner lacks arm strength, an emphasis on arm exercises with lower reps (four to six) and higher weight (to exhaustion) would be called for. Also, if she was training for a 5K, functional hamstring strength would be important, so instead of performing hamstring curls, which emphasize only the hamstrings, the dumbbell Romanian deadlift and good morning exercises are more powerful exercises because they involve more of the anatomy (hamstring and glute complex) involved in the running gait. The hamstring curls should be performed in the base phase of training to develop general strength. Two strength-training workouts per week will suffice because of the intensity of the training. The muscle fibers must have a period of rest to repair themselves so they can adapt to an increasing workload. V 2 max Training Many exercise physiologists consider V O2 max and·V O2 max training to be the most important components of a comprehensive running program; however, this view has been challenged by some of the younger coaches who are not scientists but have had success in running and coaching. Regardless of bias, V O2 max-specific workouts are a powerful training tool for improving running performance—after performing the training leading up to it. V O2 max is the peak rate of oxygen consumed during maximal or exhaustive exercise (see figure 2.5). Various tests involving exercising to exhaustion can be done to determine a V O2 max score (both a raw number and an adjusted one). Once a V O2 max score is obtained, a runner can develop a training program that incorporates training at heart rate levels that equate to V O2 max levels. The training efforts, or repetitions, would not necessarily end in exhaustion, although they can, but would reach the heart rate equivalent of the V O2 max effort for a short period, approximately three to five minutes. The goal of this type of training is multifold. It requires the muscles incorporated to contract at such a fast pace as to be fully engaged, aiding in the neuromuscular component by placing a premium on nervous system coordination of the muscles involved in running at such a fast rate. Most important, it requires the cardiovascular and cardiorespiratory systems to work at peak efficiency to deliver oxygen-rich blood to the muscles and to remove the waste products of the glycolytic (energy-producing) process. Training at V O2 max levels is obviously a powerful training tool because of its intense recruitment of many of the body’s systems. It is important to note that a V O2 max training phase needs to be incorporated at the appropriate time in a training cycle for the runner to fully benefit from its application. Despite some athletes’ reporting success by reversing the training progression and performing V O2 max workouts at the beginning of a training cycle, the most opportune time to add V O2 max training to a performance-based training plan is after a lengthy base period of easy aerobic or recovery training and a period of threshold training geared to the specific event to be completed. Rest is an important component of this phase since it aids in adaptation to the intense stimulus of the V O2 max workouts. Do not be fooled into thinking that intense workouts and multiple races without rest is an intelligent training plan. It may deliver short-term success, but ultimately will lead to injury or excessive fatigue. The strength training performed at this stage should be a set of exercises that are highly functional and specific to the event being contested and the literal strength of the runner. For example, a marathon runner who has a strong core would focus on his or her core with multiple sets of 12 reps. The exercises are equally divided between abdominal exercises and lower back exercises to ensure balance. The emphasis is on muscular endurance. A 5K runner whose focus is speed would continue with the lower-rep, higher-weight routine of the threshold phase, emphasizing the upper legs, core, and upper torso. Results of the Training Progression Model As in math, each training phase builds on the by-products of the completion of the preceding phase. They are not isolated blocks, but an integrated system. For example, a completed base, or introductory, phase leads to increased capillary development, resulting in more blood volume, musculoskeletal enhancement, and, theoretically, a more efficient gait. Threshold training furthers the performance of the runner by advancing the development of the cardiothoracic systems, increasing the adaptation of the musculoskeletal system through faster muscle contractions, and heightening the body’s neurological response to stimulus (faster-paced running). Anaerobic training (using oxygen already present) has little practical application to distance running, and for most nonelite runners does not factor into the training progression. When these conditions have been met, the runner can easily begin a short course of high-intensity V O2 max training. The specifics of pace, duration, and rest are found in many training manuals, and the specific application of this type of training varies by individual. By following the strength- training recommendations for each phase of the running training progression, a runner is really preparing his or her body for the rigors of a goal race or races. The result of following a training program based on the development of |
the cardiothoracic systems is better performance through an improved “engine” (the heart and lungs) and a stronger “chassis” through strength training. Whether V O2 max is determined by the exhaustion of the heart first or the muscles first, the development of the cardiothoracic systems will permit the point of exhaustion to be reached (measured in heart rate) at a faster pace and allow a greater distance to be covered. This is a visible way that improvement in performance can be measured. CHAPTER 3 THE RUNNER IN MOTION How do humans run? Is running just a faster version of walking? Is there a proper running form? Can I improve my running form? These are questions that many runners ask running experts, be they MDs, PhDs, running coaches, or fellow runners with more experience. The answers to these questions are complicated, but ultimately answerable, with a little knowledge of exercise science. This chapter explains the hows of running. Ultimately, an explanation of the gait cycle is worthy of doctoral study by researchers studying the biomechanics of running. The overview presented here provides runners with a basic understanding of the anatomy involved, the biomechanics that engage and disengage the anatomy, and the kinesthetic results that occur from initiating the running motion. The drills included in this chapter are designed to aid the runner in perfecting the running form by fine-tuning the gait cycle. Running Gait Cycle Running can be understood by using an analysis of the gait cycle. Unlike walking, which is defined by having both feet simultaneously in contact with the ground during a cycle, running is characterized by having both feet off the ground during a cycle (a cycle is defined as the period between when one foot makes initial contact with the ground until the same foot reconnects with the ground). The two phases of the gait cycle are the stance, or support, phase and the swing phase. When one leg is in the stance phase, the other is in the swing phase. The stance phase is marked by the foot’s initial contact with the ground (foot strike), midstance through toe-off and takeoff. This phase has been measured at approximately 40 percent of the gait cycle; however, for elite distance runners and sprinters it represents considerably less of the total phase. The swing phase begins with the float, which morphs into the forward swing or swing reversal, and finishes with the landing or absorption, which begins the next cycle. In the illustration (figure 3.1), the right leg is in the stance phase (making contact with the ground), and the left leg is in the swing phase, preparing to make contact with the ground. Figure 3.1 The gait cycle: (a) initial contact, (b) stance phase, (c) takeoff, and (d) forward swing phase. Stance Phase The quadriceps group, specifically the rectus femoris, is heavily active before initial contact. Once contact is made, the muscles, tendons, bones, and joints of the foot and lower leg function to dissipate the impact of the landing. Specifically, as described in chapter 9, three related but separate foot movements occur. The subtalar joint inverts and everts, the midfoot abducts or adducts, and the forefoot dorsiflexes and plantarflexes. Ideally, through this interaction of the anatomy of the lower leg, a small amount of pronation, the inward collapsing of the rear foot, occurs. This pronation helps dissipate the shock of the landing by spreading the impact over the full surface of the foot at midstance. An underpronated foot at midstance is less prepared to cushion the impact of landing because only the lateral aspect of the foot is in contact with the ground. This type of biomechanics can lead to chronically tight Achilles tendons, posterior calf strains, lateral knee pain, and iliotibial band tightness (all covered in chapter 10). Conversely, an overpronated foot at midstance can result in tibia pain, anterior calf injuries, and medial-side knee pain because of the internal rotation of the tibia. Neither extreme, a high rigid arch that underpronates or supinates or a low hypermobile arch, is ideal. Mild to moderate pronation is normal and very effective at combating impact stress. Swing Phase After the initial contact and midstance positioning, the hamstrings and hip flexors, the quadriceps, and the muscles of the calf (gastrocnemius and soleus) work in conjunction to allow a proper takeoff. While one leg is moving through its gait cycle, the other leg is preparing to begin a cycle of its own. Having already contacted the ground, this leg begins its forward motion as a result of the forward rotation of the pelvis and the concurrent hip flexion caused by the psoas muscles. As the leg passes through the forward swing phase, the hamstrings lengthen, limiting the forward extension of the lower leg, which had been extended by the quadriceps. The lower leg and foot begin to descend to the running surface as the torso accelerates, creating a vertical line from head to toe upon impact. Note that two cycles, one by each leg, are happening simultaneously. As one foot takes off the ground to begin its swing phase, the other leg is preparing to begin its stance phase. The dynamic nature of the running movement makes isolating the anatomy involved difficult because, unlike in walking, potential energy (the energy stored within a physical system) and kinetic energy (the energy of a body resulting from its motion) are simultaneous. Essentially, the anatomy involved in running is constantly turned on both as agonists, muscles that are prime movers, and antagonists, muscles with opposing or stabilizing motion. In walking, the muscles are either one or the other during the gait cycle. The role of the core during the stance phase is identical to its role in the swing phase, providing stability for the upper body, which allows the pelvis to twist and rotate in its normal manner. Because the gait cycle is defined by each leg moving through the stance or swing phase simultaneously, stabilizing the pelvis so it can function appropriately is an important task. A more lengthy discussion of the core is found in chapter 7, but suffice it to say that an unstable core could potentially lead to injury because of the gait cycle being negatively impacted. The arms also function to stabilize and balance, but in a slightly different way. Each arm counterbalances the opposite leg, so when the right leg swings forward, the left arms swings, and vice versa. Also, the arms counterbalance each other, keeping the torso stable and in good position and ensuring that arm carriage is forward and back, not side to side in a swaying motion. Poor arm carriage ultimately costs the runner both by hindering running efficiency (stride length is shortened as a result of the legs “following” the swaying arms and rocking slightly) and running economy (poor form requires a dramatic increase in energy consumption). Given the explanation that the gait cycle can be understood as each leg performing a cycle simultaneously, and that the same anatomy (i.e., muscles, tendons, and joints) are performing multiple functions simultaneously, it is reasonable to assume that a breakdown, or failure, in the kinetic chain is likely. This breakdown usually occurs because of inherent biomechanical imbalances that are exacerbated by the dynamic repetition of the running motion. For example, the quadriceps group and the hamstrings group are both involved in the landing phase of the gait cycle. The quadriceps group serves to extend the leg and the hamstrings limit flexion at the knee. Because the quadriceps group is dramatically stronger, the hamstrings must be able to work at their optimal capacity for the movement to be fluid. If the hamstrings group is weakened or inflexible, an imbalance exists that will ultimately lead to an injury. This is just an obvious example of the injury potential of anatomical imbalances. To counteract this scenario and others, this book offers a comprehensive strength-training regimen. The exercises are geared to complement each other by developing both the agonist and antagonist muscles as well as strengthening joints. ABC Running Drills Other than with strength training, how can running form and performance be improved? Because running has a neuromuscular component, running form can be improved through form drills that coordinate the movements of the involved anatomy. The drills, developed by coach Gerard Mach in the 1950s, are simple to perform and cause little impact stress to the body. Essentially, the drills, commonly referred to as the ABCs of running, isolate the phases of the gait cycle: knee lift, upper leg motion, and pushoff. By isolating each phase and slowing the movement, the drills, when properly performed, aid the runner’s kinesthetic sense, promote neuromuscular response, and emphasize strength development. A properly performed drill should lead to proper running form because the former becomes the latter, just at a faster velocity. Originally these drills were designed for sprinters, but they can be used by all runners. Drills should be performed once or twice a week and can be completed in 15 minutes. Focus on proper form. A Motion The A motion (figure 3.2; the movement can be performed while walking or more dynamically as the A skip or A run) is propelled by the hip flexors and quadriceps. Knee flexion occurs, and the pelvis is rotated forward. The arm carriage is simple and used to balance the action of the lower body as opposed to propelling it. The arm opposite to the raised leg is bent 90 degrees at the elbow, and it swings forward and back like a pendulum, the shoulder joint acting as a fulcrum. The opposite arm is also moving simultaneously in the opposite direction. Both hands should be held loosely at the wrist joints and should not be raised above shoulder level. The emphasis is on driving down the swing leg, which initiates the knee lift of the other leg. Figure 3.2 (a) A motion 1, (b) A motion 2, and (c) A motion 3. B Motion The B motion (figure 3.3) is dependent on the quadriceps to extend the leg and the hamstrings to drive the leg groundward, preparing for the impact phase. In order, the quadriceps extend the leg from the position of the A motion to potential full extension, and then the hamstrings group acts to forcefully drive the lower leg and foot to the ground. During running the tibialis anterior dorsiflexes the ankle, which positions the foot for the appropriate heel landing; however, while performing the B motion, dorsiflexion should be minimized so that the foot lands closer to midstance. This allows for less impact solely on the heel, and because the biomechanics of the foot are not involved as in running, it does not promote any forefoot injuries. Figure 3.3 (a) B motion 1, (b) B motion 2, and (c) B motion 3. C Motion The final phase of the running gait cycle is dominated by the hamstrings. Upon impact, the hamstrings continue to contract, not to limit the extension of the leg but to pull the foot upward, under the glutes, to begin another cycle. The emphasis of this exercise (figure 3.4) is to pull the foot up, directly under the buttocks, shortening the arc and the length of time performing the phase so that another stride can be commenced. This exercise is performed rapidly, in staccato-like bursts. The arms are swinging quickly, mimicking the faster movement of the legs, and the hands come a little higher and closer to the body than in either the A or B motions. A more pronounced forward lean of the torso, similar to the body position while sprinting, helps to facilitate this motion. Figure 3.4 (a) C motion 1, and (b) C motion 2. CHAPTER 4 ADAPTATIONS FOR FOR SPEED AND TERRAIN Every runner has a vision of the perfect run—beautiful views; a gentle, cooling breeze; a benign, perhaps slightly downhill surface; and a loving companion. Sadly, the real world is rarely like that, and we all have to make do with some sort of compromise on these fronts. The weather may be wet, windy, and cold; the surface rutted and uneven; the view industrial; and the companion a rival. In such circumstances one’s body and mind have to adapt to the prevailing conditions—either that or give up completely! This chapter deals with the adaptations that |
can be made to cope with everything our sport throws at us. Although we have used athletes from the extreme ends of the running spectrum to illustrate the points, most runners will find a compromise somewhere between the various limits that are discussed. Event-Specific Body Characteristics When you attend a track and field meet, it is not too difficult to make an educated guess about the events in which most competitors will compete. The sprinters and high hurdlers are often so physically developed that they appear muscle-bound. Generally, the bodies of the 400-meter to 1,500-meter athletes become progressively less well built and smaller in stature the further the distance raced. Finally, the long-distance runners may seem unnaturally thin or even undernourished, even if their performance in a race soon belies this. That you are able to tell roughly what type of body image fits which runner indicates that the diversity of training for an event has created structural differences in the runner. It is perhaps easiest to consider the two extremes—that of the 100-meter sprinter and the marathon runner. Not only is the latter perhaps some 10 years older, but also the years of training will have shaved most of the surplus fat from his or her torso. The sprinter may also carry minimal fat, but appears to be a much more physical presence, for not only is he or she likely to be taller, but the rib cage of the short-distance runner is covered by layers of structural muscle as well, augmented by the training program, which the marathoning counterpart lacks. In the upper body, the arms are part of the sprinting mechanism. No one could envisage sprinting without a lot of arm action, yet for the distance runner the arms are little more than a means of balancing, to such an extent that it is not unusual to see runners who are trying to relax running with their arms dangling by their sides and only starting to use them in a finishing sprint. That said, it is quite common for runners to complain of arm pain at the end of a long race, especially if they have given no thought at all to preparation for several hours of repetitively swinging each shoulder through the few degrees of movement that has been required for the effort. That the arms are needed for balance is demonstrated clearly by the hill runner, who will invariably speed downhill with arms held quite widely open, even though this is partly to prevent injury in case of a fall. Further differences occur in the stride length (figure 4.1). Sprinting is all about high speed. The legs can only be moved so many times a second, but anyone who can cover more ground with each stride will move further ahead of the field in an equal number of strides. The difficulty is in the repetition of the long strides, for the energy expended is far greater than that involved in taking shorter paces, which explains why sprinters do not win long-distance races. To gain the extra reach, the thighs need to be stronger, so they become bulkier and heavier, which limits their flexibility and can eventually become self-defeating if taken to extremes. Accessory muscles in the lower abdomen and pelvis also develop to help lift the thighs higher. For the same reason, the knees flex more at sprinting speed and the calves may touch the hamstring muscles when sprinters are in full flight. Figure 4.1 Physical adaptations to different running speeds: (a) shuffle; (b) finishing kick or sprint. Effects of Terrain and Other External Factors The sprinter has little to worry about underfoot. For the past 40 years the majority of tracks have been built with a rubbery surface, which aids elastic rebound after landing. These were a source of considerable injury when first introduced because of the shock of the bounce-back and the Doppler effect on the untrained muscles and Achilles tendons. Training on these tracks as they have become more numerous has helped to reduce incidence of injury. This is not the case for longer-distance runners after they leave the track. Roads themselves vary from hard concrete to soft tarmac; even standing water changes the forces produced on landing. All of these alter the shock waves and response within the lower limbs particularly. Even more difficult is the adaptation by the hill or mountain runner, who not only has to ascend and descend vertically (figure 4.2), but may also have to run slopes diagonally. This produces excessive forces not only on the lower limbs (figure 4.3), as the ankle joints need to prepare for constant inversion and eversion, but also on the knees and hips and the pelvis. The consequence of this may be a scoliotic, or twisted, lower back, which will soon become painful unless steps are taken to prepare for this type of running. Hills are the ultimate test of the ability to stay upright while running. If the runner is unstable, he or she will soon topple over. Those blessed with a low center of gravity have a head start, although their inherently short legs may not deliver a long stride. A thin torso is a factor under the control of the runner because it may lower the center of gravity; reducing weight overall also makes it easier to lift the body vertically. Flexibility of the spine, particularly the lumbar area, is also a virtue because the climber needs to incline into the slope and the descender needs to lean backward to avoid the center of gravity from being moved forward horizontally by the running action. It follows that the hips have to be more flexible to compensate for the decreased range of motion in the spine that the need to lean causes. Although the muscles that are used to run hills are the same, the emphasis changes. The erector spinae and iliopsoas have more work to do while climbing because a tilted spine requires more effort to hold it stable than a vertical one, where the vertebrae generally just sit on top of each other. Descent places greater stresses on the anterior muscles of the calves and thighs, which have to absorb the impact of landing as well as the effect of gravity. Because running on flat surfaces cannot adequately prepare any runner for hills, some of the training should involve climbing, even if stairs alone are used. Downhill training is more difficult if the runner lives on flat terrain, although as a last resort, stepping, both up and down, can give some experience of the problems and training for hills, especially if maintained for several minutes. Climbing muscles in the calves and anterior thighs can be strengthened using the exercises in chapter 9. Figure 4.2 Running (a) up an incline or (b) down a decline requires physical adaptations. Figure 4.3 The lower legs and feet must adapt to (a) inclines and (b) declines. Cross-country running is sufficiently global to boast its own world championships, though all too often they are run on grassy parkland surfaces. The real aficionados prefer six miles or more of deep, gluelike mud from which they have to lift their legs out with each stride while attempting not to slip backward on the treacherous ground. Although the choice of footwear may aid movement, it does little to prepare for the increasingly exhausting effort that each stride demands compared to the rebound found on the roads. Bends and corners present their own difficulties. Runners have to lean into the corner at a right angle (figure 4.4), or they will fall flat on their sides. Indoor tracks are half the length of those outdoors and are steeply banked to allow runners to lean less obviously and be able to concentrate on staying in their own lanes as they double back through 180 degrees. Bend running stresses the lateral outer side of the lower limbs; the fasciae latae, the peroneal muscles, and the lateral ligaments of both outer knee and ankle have to take the extra force induced when turning. The medial side of the inner leg is similarly affected. Running indoors on the boards for the first time has been an awakening for many experienced runners who thought they knew it all! The shoes also have to absorb the lateral forces, so laterally rippled shoes that grip mud when running forward will give no help when the foot slides outward when a sharp corner is turned. Figure 4.4 Runners have to lean into corners on banked indoor tracks. Many roads have a camber, so if a runner persists in running along one particular side of the road, he effectively gives himself a leg-length difference; that is, one leg (that nearer the middle of the road) will appear shorter than the other, and the pelvis will inevitably be tilted. In order to compensate for this, the pelvis has to incline so the lumbar spine corrects itself by twisting to become vertical. If a runner needed a recipe for low back pain, this is it! As we cannot recommend running down the middle of the road either, local knowledge of heavily cambered roads or alternating sides may help to reduce the problem. For all these varied events, some training in near-competitive situations is invaluable. Although he wasn’t preparing for a running event, British racewalker Don Thompson prepared for the sapping humidity and heat of Rome in July for the 1960 Olympic 50K race by steaming himself in a heavy tracksuit with kettles of boiling water in the modest bathroom of his home. The result: an unexpected gold medal. This is an extreme example that we would strongly discourage following, but in general, practicing in conditions that resemble competition is unlikely to do any serious harm, especially if adequate time is left for recovery and lessons from the experience are learned. It may not be entirely possible for runners to simulate race conditions. The domination of long-distance races by Africans in the 21st century may be partly a result of evolution, but that itself is influenced by living at altitude and by a lifestyle that demands that they may need to run 5 or 10 miles each way to school in order to be educated. If the kids in Western civilizations had to do the same, might not they have similar successes? All training has to rely on the facilities available. A town-dwelling mountain runner is unlikely to have suitable slopes to train on at his doorstep. He or she can prepare to run at certain speeds, and may even use the stairs in a high-rise block to simulate some of the climbing action. It is more difficult to practice for a rugged, slippery, or stony surface, where a major objective is to avoid injury. It is at this point that thought about both preparation and the desired outcome is needed. If a run is likely to involve a diagonal downhill section, then the best results will come if the runner has added flexibility and strength to withstand the forces generated by the impact of landing many times on a foot that will be inverted and twisted inwardly. This stretches the ligaments on the outside of the ankle and the knee, and yet more shock is absorbed by the muscles on the outer side of the limb. Conversely, the other limb, higher up the slope, has the inner side stressed. If the runner realizes that this is going to occur, exercises to stretch and strengthen the appropriate soft tissues can and should be introduced into the training program. The way in which the body adapts to speed and terrain can be influenced by the training program used. Many years ago some runners trained using LSD—long slow distance. Unfortunately, this only made them good at running long distances slowly and led them to other problems in the form of overuse injury. It is not only human bodies that react badly to wearisome repetition; machines are not much different and also break down with long-term continuous use. One method of prevention is to vary the programs used. As sprinters have shown, fast running is about training the whole body. Some of this means running fast, but a large proportion of the program requires neither racing shoes nor a track. |
It should be no different for distance runners, who should exercise specific parts as well as their whole bodies. Hills and rough and uneven surfaces can all be faced with more confidence if the body is prepared, especially if certain weaknesses are known. A cross-country runner who is aware that he or she loses ground in thick mud can perform exercises and training drills to strengthen the thigh muscles needed to haul him or her through. In each chapter of this book we have produced disciplines to cover all these eventualities, help you to adapt to the sort of running that you want or even may have to do, and aim to make you a better runner. If you are unable to adjust to the speed and terrain that you encounter during your runs, not only will the performance factor be lowered, but there is every chance that the enjoyment will disappear with it as well. External factors must be another consideration. No one in their right mind would wear a pair of spiked shoes for a road race, but the choice of clothing and shoes for the race may well help to determine the outcome. On a warm day, well-ventilated, airy, and pale-colored attire helps to reduce heat buildup from various external and internal sources. In contrast, warm protective clothes may help reduce the greater risk of injury that colder temperatures may induce. Although very light shoes are suitable for a short-distance race, a heavier pair may give more cushioning and protection to the lower limbs and back over a longer distance despite the weight increase. The composition of the shoe is an important factor in maximizing the value of a run. The upper parts of shoes fail to be waterproof after a heavy rainfall, though some materials will limit the ingress of water sufficiently to prevent the otherwise strong possibility of blistering and other skin conditions. The weight of the shoe should probably be in inverse proportion to the distance to be run. The grip on the ground underfoot is paramount. Spikes gain the best purchase but will ruin feet if used on tarmac or concrete, where rubber-based compounds have the most elasticity and facilitate a good rebound effect. On softer but still firm terrain, such as grass, spikes are ideal, but some runners prefer the sole to have a waffle or even a ridged effect where the ground is likely to be muddy (figure 4.5). Snow and ice present their own difficulties with the maintenance of grip. Spikes are often best, but then the runner has to beware of frostbite. Where hills and their often rocky surfaces are involved, there is debate as to which are the best shoes to provide grip for both uphill and downhill running, yet have sufficient cushioning to stop the landing at up to 10 times body weight from damaging heels and metatarsals. Experience will eventually allow the runner to decide on the most suitable shoe for any particular surface, and we discuss shoes more fully in chapter 11. Figure 4.5 Proper shoes help a runner keep his footing on muddy or gravelly surfaces. It is no coincidence that the fastest sprinters in the world make the majority of their appearances and all of their fastest runs in the summer months. Once the temperature drops below the mid-60s (F; high teens C), flexibility is lost in the ligaments and joints of the lower limbs and the blood flow through muscles will decrease as a result of the cooling. This is a certain recipe for injury, especially because winter preparation probably contained a large percentage of indoor training in warm clothing to simulate summer temperatures during which muscle volume and strength were built up. Sprinters require this body muscle bulk for the explosion of power needed in their events. This can only be obtained by repetitive training in muscle-friendly ambient temperatures with increasingly heavy weights and drills, which eventually produce the muscle definition so admired and effective in their events. Watching a slow-motion image of sprinters shows how they run with every muscle available. Look not only at their legs, but also watch the shoulders, arms, neck, and even the lips of a sprinter running flat out to visualize how the winner is the one who has trained each of these elements individually and hardest. Usain Bolt did not just happen! Even if you do not have a coach with whom to discuss your objectives, there is nothing to stop you from jotting these ideas down to discuss with fellow runners. If you plan a race while on vacation, forethought about the conditions—both the weather and the terrain—could pay dividends. It could be a flat race but with one big climb up or down, or both. This will require an adaptation of your speed for that segment of the run, so acceleration during the training sessions at the appropriate point and a simulation of the hill will help your body to strengthen itself for the contest ahead. We have given you exercises to help prepare yourself for such conditions—we cannot anticipate the conditions themselves, which remain your responsibility. If you follow the ideas, your body should adapt optimally to your running needs and enable you to achieve your full potential. CHAPTER 5 UPPER TORSO Anyone who understands the function of a bellows or an accordion will soon grasp the anatomy of the thorax, commonly known as the chest. Bellows and accordions have evolved over many years as a way to move air under pressure and produce an air current or musical sounds. The principal bony architecture of the chest (figure 5.1) consists of 12 thoracic vertebrae, each placed one on top of another, but interlocked by ligaments and other soft tissues in such a manner that there can be movement in anterior (front) and posterior (rear) directions, limited lateral (side) motion, and a degree of rotation that allows the torso to twist. Emerging from the side of every thoracic vertebra are two bony ribs that encircle the body and meet at the front, the majority of them forming the sternum, or breastbone. Figure 5.1 Bony structures of the torso: ribs, sternum, and vertebrae. Although the outside or posterior of the vertebrae are supported by the erector spinae muscles, which run the length of the spine, each rib hangs from the one above, held together by the intercostal muscles, much in the fashion of a venetian blind. Without further structural support, these would be unstable, so the trapezius, latissimus dorsi, rhomboid, teres group, shoulder stabilizers, and pectoralis major and minor (figure 5.2) all aid in the maintenance of the relative position of the ribs. At the base of this dome, with attachments to the lower ribs, lies the vast diaphragm, encircling the base of the thorax. Further stability is given by the abdominal muscles, rectus abdominis, the external oblique, and serratus anterior. Running makes far greater demands on the body for oxygen than does sedentary life. The diaphragm uses a bellowslike action as it contracts to draw air into the lungs. At the same time, the intercostal muscles relax, only to contract strongly as expiration occurs, during which time the diaphragm relaxes and is drawn up into the thorax. Using this push-pull endeavor, the lungs fill with air and empty to maintain the oxygen needs of the runner. Figure 5.2 Upper torso: (a) front view and (b) back view. As well as their action in the mechanisms of breathing, the muscles of the thorax have a limited but significant part to play in forward motion. The best way to appreciate this is to view an approaching runner in slow motion. As the thigh moves forward with each stride, the pelvis rotates slightly, first one side, and then the other. This twists the spine a little and would cause instability within the abdomen and thorax if unchecked, so a small but significant tensing and relaxation of the thoracic musculature helps not only to maintain the vertical component, but also to correct variations that are caused by forward motion of anything up to 20 miles per hour (32 k/hr). The muscles that are attached to the shoulders and humerus, particularly the pectorals and teres, are also moved passively when the arms swing fore and aft with each stride. If they contract actively, they too will help move the upper arms to a small extent as they oppose the pull of the deltoid (figure 5.3). The importance of these muscles in running lies with the “weakest link” presumption—that the power of the runner is dependent not on the strength that he can produce but on which facet of his running body tires first. If the muscles of the thorax are undertrained and fatigued, they will be unable to perform their functions and so reduce the efficiency of the running action and the runner himself. If the thoracic muscles lose strength and power, not only is the breathing action compromised, but also the auxiliary actions to support the spine and aid the arm movement will be weakened, leading to an inevitable slowing. Having watched runners for many years, it is surprising how many feel that they can only improve if they increase the pace or quantity of their training. Many do not realize that the limits to their running will always be related to the weakest part of their body. The legs may be capable of a mile in under four minutes, but if the lungs do not have the capacity to provide oxygen to those legs, then they are only going to be able to achieve the speed allowed by the lungs, and not that of which the legs may be capable of under other circumstances. To avoid this disparity, the diaphragm and all the supporting muscles need to be just as fit as those of the lower limbs. These muscles become fatigued by exercise in exactly the same way as do all other muscles, so it seems logical that they need to be as highly trained as any other group of muscles involved in exercise. It is for that reason that the training exercises included here should be considered as important as all those that are prescribed for the legs. Figure 5.3 The deltoid. Choosing Resistance Initially, choose weights for each exercise that provide a moderate amount of resistance but that allow for the strength-training movement to be performed by maintaining proper technique for the entire set of repetitions. The weight should be increased as strength improves and adaption becomes apparent through easier performance of the exercise; however, the weight should never be so heavy that proper technique is compromised, even on the final few repetitions of a set. Factors such as which part of the anatomy is being strengthened also factor into the decision on weight used. For example, the pectoral muscle is large, and therefore can handle a large amount of work. The triceps, comprised of three much smaller muscles, fatigues quite quickly when it is the primary muscle group used; however, because the triceps is involved secondarily in many upper-body exercises, it will already be slightly fatigued before any triceps-specific exercises are performed. One triceps-specific exercise per strength-training session that involves the arms should suffice to strengthen the triceps sufficiently. Conversely, multiple chest exercises or many sets of the same exercise will be needed to sufficiently fatigue the larger pectoral muscle. Repetitions The amount of repetitions should vary based on the strength-training goal of the exercise and the objectives of the entire strength-training workout for that day. For example, two sets of 20 dumbbell presses and a set of 30 push-ups may function as an entire chest workout on a Monday, but on Friday, one set of 12 repetitions with a heavier weight than lifted Monday, followed by two sets of 10 repetitions of incline barbell presses and three sets of 15 push-ups may be what is called for. A general rule to follow is that the heavier the weight, the fewer reps performed, and vice versa. Breathing Exhale when forcibly moving the weight and inhale when performing the negative movement or resisting the weight. When generating movement, exhale; when resisting movement, inhale. The speed of each exercise should be as fluid and controlled as possible and should be in relationship |
to the breathing pattern. An accepted breathing pattern is four seconds for the resistance (inhalation phase) and two seconds for the movement (exhalation phase). Schedule A varied resistance-training routine works best. The concept of work plus rest equals adaption has a caveat. The work must change over time both in quantity of work (amount of resistance) and in quality of work (type of exercise) to ensure continued strength gains. For each segment of the body examined in this book, we have provided multiple exercises, some with variations, that can be used to create a multitude of different strength-training sessions all geared toward strengthening the anatomy that is most involved in running. By changing exercises, the number of sets and repetitions, and the exercise order, runners can tailor their strength-training sessions to meet their fitness needs and time constraints. No workout need be longer than 30 minutes, and two to three sessions per week can dramatically enhance a runner’s performance by strengthening the specific anatomy used during run training and racing. We are not suggesting that just lifting weights will make you a better runner. We are suggesting that through proper strength training, your anatomy will be strengthened, and this resultant strength will aid running performance by eliminating muscle imbalances that impede the gait cycle, help in respiration, and help eliminate injuries that result from muscle imbalances. Dumbbell Press Execution 1. Lie supine (back down) on a bench with legs steepled and feet on the bench. There should be a small, natural bend in the lower back so it does not touch the bench. A dumbbell should be held in each hand, at chest level. 2. Press the dumbbells upward to full extension. When full extension is reached, immediately lower the dumbbells slowly to the original position. 3. Repeat the movement, keeping in mind the stable position of the back against the bench. Muscles Involved Primary: pectoralis major, triceps, anterior deltoid Secondary: biceps, rectus abdominis SAFETY TIP For the physioball dumbbell press variation, the weight of the dumbbells should be reduced because of the relative instability of the physioball versus the bench, but after becoming comfortable with the movements, dumbbell weight can be added. Running Focus As mentioned earlier in the chapter, the muscles of the chest become fatigued by exercise in exactly the same way as do all other muscles, so developing these muscles through a simple exercise like the dumbbell press is both easy and beneficial. This exercise recruits the abdominal group more than the barbell bench press because the torso requires stabilization as a result of the independence of each dumbbell. It targets the pectoral muscle group and uses the abdominal group as stabilizers. The stronger the abdominal and pectoral group are, the better the posture of a distance runner in the latter stages of a race or training run, as well as the cardiovascular benefit of improved respiration. The better the upper-body posture of a runner, the more efficient the gait cycle is, aiding the runner by not wasting precious energy on poor running mechanics. VARIATIONS Rotadet Dumbbell Press Dumbbell Press on Physioball This variation develops the sternal head of the pectoral groupIt helps fully develop the pectoral group. The use of the physioball enhances the role of the abdominal group as stabilizers for the exercise. Incline Barbell Press Execution 1. Lie on a 45-degree incline bench. With arms extended almost to their full extension, grip the barbell a little wider than shoulder width. 2. Fully extend the arms, removing the barbell from the rack. Lower the barbell in a straight line to the upper chest. 3. Press the barbell up, in a straight line, back to the original position without locking the elbows. Muscles Involved Primary: pectoralis major, triceps, anterior deltoid, serratus anterior Secondary: biceps, rectus abdominis SAFETY TIP Use of a spotter is highly recommended to help with removing and placing the barbell back on the stays of the bench. Because of the inclined nature of this exercise, there is more shoulder involvement—specifically, the rotator cuff. If any pain is felt in the shoulder, discontinue the exercise and perform only the flat dumbbell press. Running Focus Similar to the dumbbell press in the muscles engaged, the incline press also involves the serratus anterior, adding to the development of the upper body. By adding variation to a strength-training routine through the use of different exercises that stimulate muscle growth in the same area, a runner can avoid becoming bored with a regimen. Because the strength-training component is meant to complement and enhance run training, performing new exercises helps keep the training fresh. Dumbbell Fly Execution 1. Begin by lying supine on a bench with legs steepled and feet on the bench. There should be a small, natural bend in the lower back so it does not touch the bench. Arms are extended perpendicular to the body with 5 to 10 degrees flex in the elbows. Hands grip the dumbbells, palms facing inward. 2. Lower the weight slowly, focusing on the stretch of the pectoral muscles while maintaining bent elbows, until the upper arms are outstretched and in the same plane as the bench top. 3. Return the weight to the starting position as if you were hugging a barrel. Control the dumbbells so they do not touch at the top, but are separated by 2 or 3 inches. Muscles Involved Primary: pectoralis major Secondary: biceps, deltoid, extensor digitorum SAFETY TIP Note that you begin the exercise with the dumbbells extended, not outstretched. Lifting the dumbbells to begin the exercise can be difficult if heavy weight is used, and starting in the outstretched position places the deltoids and biceps in an awkward position. Also, do not lower the arms past the plane of the bench top for fear of injury. TECHNIQUE TIP ▶ When returning the weight to the overhead position, do not push the weight with your hands or overly engage your deltoids. Your pectorals should do the lifting. Running Focus The emphasis on strengthening the pectoral muscles has been noted in all the exercises listed in this chapter. However, the benefits of the dumbbell fly include the stretching of the pectoral muscles, specifically during the negative, or lowering, phase of the exercise. This stretching helps expand intercostal muscles between the ribs, allowing for better respiration. Essentially, the more the muscles of the chest are expanded, the easier it is to inhale oxygen. This is reflected in the large rib cages of elite marathoners like Ethiopian Haile Gebrselassie and American Ryan Hall. Their chests always seem expanded when they run, most likely to accommodate their exercise-enlarged lungs. Push-Up Execution 1. Start in a prone position, arms bent, slightly wider than shoulder-width apart, but in a straight line with the outsides of the shoulders. 2. Push away from the floor in a single, controlled movement, keeping your body in one slight upward plane (from feet to head) until your arms are fully extended. Exhale while performing the push-up. 3. Lower your body slowly by bending at the elbows until the chest is parallel and touching or near touching the floor. Inhale during this phase of the exercise. Muscles Involved Primary: pectoralis major, triceps, anterior deltoid Secondary: biceps, latissimus dorsi, rectus abdominis Running Focus The push-up is the purest strength exercise. No machines. No weights (other than your own body weight). One fluid movement. It is not complicated unless you add variations (incline push-up and push-up on physioball), but it is a highly effective exercise for developing upper-body strength. Push-ups benefit a runner by strengthening the upper body and abdominals, ensuring proper posture. The technique involved in completing a push-up is similar to the position of the upper body during running, so the exercise reinforces correct posture. Multiple sets of push-ups can be done, but like any strength-training activity, push-ups should not be done daily, but following a rest period that allows for the mending of the muscle fibers used during the push-up session. VARIATIONS Incline Push-Up Incline push-ups shift the emphasis of the exercise to the upper chest and the muscles of the shoulders. A greater number of push-ups can be performed, so incline push-ups are a good exercise to begin with if regular push-ups are difficult. Because the exercise is easier, you may be tempted to accelerate the motion, but resist this temptation. The rotator cuff is more involved in incline push-ups, and accelerating the motion could lead to a shoulder injury. Push-Up on Physioball Decline push-ups shift some of the emphasis to the upper back. Using a physioball while performing this exercise requires core stabilization, so this exercise aggressively targets secondary muscle groups. Try to keep your hips from sinking toward the ground during the execution of the push-up. Maintain a rigid posture. If this is difficult, use a smaller physioball, which makes the exercise easier. UPPERBACK Pull-Up Execution 1. Use an overhand (palms forward) grip and hang from the pull-up bar, getting a full stretch. 2. Pull your body weight upward using a fluid motion. 3. When the chin reaches bar height, lower your body in a controlled movement back to almost full extension of the arms. Feet should not touch the floor during repetitions. Muscles Involved Primary: latissimus dorsi, teres major, rhomboid Secondary: biceps, pectoralis major Running Focus The pull-up is the yin to the push-up’s yang. It is simply performed, but powerful in providing strength benefits. It helps strengthen the upper back, and as distance runners can attest, a strong upper back makes for better running posture during the later stages of a training run or long race. The U.S. Marine Corps and other branches of the military use the pull-up (and push-up) to measure the fitness of their soldiers. A perfect score is 20 pull-ups in one minute. Pull-ups are a difficult exercise. To aid in starting the exercise, stand on a box to begin the first rep. Do only the amount of pull-ups that can be done with a fluid, controlled movement. Do not wriggle or bounce. Often pull-ups are called chin-ups. Some trainers distinguish between pull-ups and chin-ups based on the grip (palms outward or inward), but for others the difference is simply semantic. VARIATION Reverse-Grip Pull-Up Use an underhand (palms facing toward you), shoulder-width grip. Hang from the pull-up bar, getting a full stretch. Pull your body weight upward using a fluid motion. When the chin reaches bar height, lower your body in a controlled movement back to almost full extension of the arms. Feet should not touch the floor during repetitions. The reverse-grip pull-up involves the biceps more than the overhand-grip pull-up. Given the relatively small size of the biceps, performing this exercise is more difficult than with the overhand grip because the biceps can fatigue quickly. The two pull-up exercises can be alternated during a strenuous upper back workout, or they can be done on different days as part of a general workout. UPPER BACK Machine Lat Pull-Down Execution 1. Using a weight machine, face the bar with your legs under the pads and grip the bar using a wide grip. Arms are fully extended. Palms face away from the body. Your upper body is slightly rotated (shoulders back) to accommodate the exercise motion. 2. In one continuous motion, pull the bar down, with elbows back and chest out until the bar reaches the upper chest. 3. Gradually allow the arms to return to full extension while resisting the weight during the negative phase of the exercise. Muscles Involved Primary: latissimus dorsi, teres major Secondary: triceps, deltoid TECHNIQUE TIP ▶ The lat pull-down will cause significant muscle mass to develop in the upper back if heavy weight is used as resistance. It is recommended to perform the exercise with lighter weight than the maximum and to complete multiple sets of higher repetitions. Running Focus The lat pull-down motion is not a normal running movement, so how does this exercise aid running performance? Like the chest and upper back exercises previously illustrated, the lat pull-down helps performance by strengthening muscles (latissimus dorsi and teres major) that support and stabilize the body’s thorax and aid in respiration and posture. The strengthening of the upper back helps counterbalance strength gained from performing the exercises targeting the chest, creating a torso that is balanced, and helps with maintaining |
an erect posture throughout a lengthy training or racing session. This is a good exercise to perform during the introductory phase of training. VARIATION Reverse-Grip Lat Pull-Down This exercise emphasizes the role of the biceps as well as the latissimus dorsi and teres major. We recommend completing this exercise on a day when strengthening the arms is the focus of the workout. If you perform the lat pull-down first, you may need to change the weight load to perform the reverse-grip variation since the latter minimizes the role of the larger shoulder and upper back muscles. UPPER BACK One-Arm Dumbbell Row Execution 1. Kneel with one leg on a flat bench. Use the same-side hand (non-weight-holding hand) for support by placing it on the bench. The weight-holding hand is dropped below the bench top, arm extended down. 2. Grip the weight and, in a smooth, continuous motion initiated by the muscles of the upper back and shoulder, pull the dumbbell upward until the elbow is bent at a 90-degree angle. Exhale while performing the row. 3. Gradually lower the weight along the same path that the dumbbell traveled upward. Muscles Involved Primary: latissimus dorsi, teres major, posterior deltoid, biceps, trapezius Secondary: erector spinae, rectus abdominis, external oblique, internal oblique TECHNIQUE TIP ▶ The movement of the exercise has been likened to that of sawing wood with a hand saw. Running Focus This is an easy exercise to perform, and it benefits multiple muscles. Specifically, because a relatively heavy weight can be used (once good form is established), a lot of strength gains can occur. The development of the deltoid and trapezius will help with head position and arm carriage. Specifically, strength in these muscle groups will aid in developing a powerful arm carriage during track sessions, help fend off fatigue during longer workouts and races, and help maintain good running form during trail runs on difficult (rocky or hilly) terrain. An important element of this exercise is the isolation of the upper back and shoulder muscles used. Although the abdominal group engages to stabilize the body, emphasis should be placed on the role of the latissimus dorsi, trapezius, deltoid, and biceps. UPPER BACK Bent-Over Row With Barbell SAFETY TIP Always maintain the natural curve in the lower back while performing this exercise, especially if lifting heavier weight. Do not round the back. Execution 1. Stand with legs shoulder-width apart, leaning forward at the waist, knees slightly bent, and arms hanging down, clasped to the barbell with a traditional grip, shoulder-width apart. 2. Pull the barbell to the chest, still in a bent position, until your elbows are bent parallel to the chest. 3. Return the weight to the starting position and repeat. Muscles Involved Primary: latissimus dorsi, trapezius Secondary: triceps, deltoid Running Focus Muscle imbalances are prevalent in runners, predominantly between the four muscles of the quadriceps group, between the quadriceps group and hamstring muscles, and, more generally, between the legs (left versus right). Muscle imbalances of the upper body are often not addressed in strength training for runners because the practical shortcomings of such imbalances are not assumed to affect running performance. However, an imbalance between the “push” muscles of the chest and the “pull” muscles of the upper back can have a dramatic impact on gait because the forward lean or lack thereof changes the degree of lift the quadriceps group can generate during the forward swing phase. A lack of lift as a result of too much forward lean can inhibit the speed of running, especially during faster-paced training. The speed not created by the normal lift of the gait cycle can be compensated for with faster turnover, but the resulting emphasis on aerobic capacity because of poor posture can have an adverse effect on performance if the athlete’s aerobic fitness is subpar. Hence, the anatomy of running plays a major role in performance despite its seemingly secondary role in fitness development. Specifically, if a large muscle group is strengthened (e.g., the pectorals through “push” exercises), the agonist muscles (in this case, those of the upper back) must be equally strengthened. VARIATION Wide-Grip Bent-Over Row With Barbell A wider grip allows you to work the muscle at a different angle. In this case, it does not change the main muscle group worked. Some athletes with longer arms prefer the wider grip because it feels more natural. Maintain the natural curve in the lower back. CHAPTER 6 ARMS AND SHOULDERS Sir Murray Halberg, a New Zealander, won the Olympic 5,000-meter run with a withered arm that was the result of an earlier sporting accident. Even people who lack arms are perfectly capable of running, and often do so very well. However, arms are a necessary part of a smooth running motion; each arm not only aids the balance of the runner, but also assists forward movement by acting as a counterbalance when the opposite leg drives away from the ground. To test this, try leading with your right hand and right leg at the same time—at best, it will feel unnatural; at worst, you will fall over! A further example is to watch a sprinter coming out of the blocks—a high knee lift accompanies exaggerated arm action for the first dozen strides, and then the arms continue to pump away for the rest of the sprint. Distance runners would waste energy by driving the arms in this fashion; as economy of effort to save energy is all-important, so their arms hang fairly loosely, usually with elbows bent to 90 degrees or so with the hands relaxed beyond the wrist joints. Sprinters’ fingers are straight and more tense as they drive each stride, a marked difference, so arms have a serious part to play in successful running, though in distinctly different manners for the type of run being attempted. The arms are attached to the body at the shoulder joint, which is a shallow ball and socket to permit maximum movement through as close to 360 degrees as possible. This is quite effective, although the disadvantage of such mobility is an unstable joint that can be easily damaged. The ligaments that hold the shoulder in place have to be elastic enough to allow movement, so the stability of the joint relies on the strength of the retaining muscles. It may be helpful to have a reminder of Newton’s third law of motion: For every action, there is an equal and opposite reaction. If a muscle contracts and pulls the shoulder in one direction, then one or more other muscles will need to lengthen to allow this to happen. Strong muscles with good tone will tend to separate a joint if those opposing it are weak and undeveloped. This is never truer than with the shoulder joint. The ball of the shoulder joint, at the upper end of the humerus, is located in the shallow glenoid labrum, or cavity, itself a part of the winged scapula that surrounds the posterior portion of the upper chest. From the runner’s point of view, it is beneficial simply to know the muscles that maintain the position of the humeral head (figure 6.1) and which ones can be strengthened to improve running motion. The movement of the legs when they take large strides requires a similarly large movement of the arms backward and forward to balance the action. In sprinting especially, the arms and shoulders play a large part in propulsion, and a sprinter who is losing a race will often tense his or her shoulders as they go backward though the field. Anatomically, strong shoulders aid both strength and balance in the runner, so the exercises that follow are quite as important as those for the lower limbs. Tired arms and tense shoulders lead to a less fluent arm swing and a short stride that then uses unnecessary energy. The endurance that strength training of the upper limbs provides could make the hundredth of a second difference between success and a lifetime of disappointment. Figure 6.1 Upper arm: (a) back and (b) front. The outermost layer is formed by the triangular deltoid muscle. It arises from the clavicle, or collarbone, and part of the top of the scapula to cover the whole joint and be inserted into the middle of the humerus, where its contractions pull the arm out sideways into abduction. It opposes gravity. The complicated pattern of muscles underneath it have developed to enable movement in most planes. This matters little to runners, whose arms merely need to move no more than 45 degrees fore and aft, with minimal sideways movement. These muscles need to be strong rather than elastic. A complicated web holds the arm to the shoulder: The supraspinatus braces the head of the humerus; the infraspinatus, subscapularis, and teres major and minor form a rotator cuff both to connect together and stabilize the shoulder. Below the shoulder are the biceps, triceps, and brachialis muscles. Their primary function is moving the elbow joint, but some fibers are attached around the shoulder, giving even greater stability to that joint. The extensor and flexor muscles of the forearm (figure 6.2) rotate the wrist inward and outward and also move the wrist and fingers. The flexors bend the joints in and the extensors open them out. More detailed knowledge of this anatomy is not the province of the runner, though their strength and flexibility undoubtedly are, so the exercises to promote this are all of relevance in increasing running speed. Once again, any weakness will slow the runner, so the arms, particularly in power sprints, must have endurance equal to that of the legs. This explains why the physique of a sprinter’s upper limbs is not unlike that of a boxer. Evolution has led to the use of arms when running, first to help stabilize the body and then to keep it upright as each leg moves. You should study a steeplechase runner in slow-motion replay to view how the arms help the body prepare for each takeoff, flight, and landing over the hurdles. Second, strong upper limbs not only aid in the production of full power when sprinting but also help the shoulders relax. When the shoulders tense, the runner inevitably slows. In short, a sprinter without arm movement is not a sprinter! One other point to bear in mind is that the legs are unable to run with full efficiency if the arms are not involved in the running action. The effect of this could be that strong legs want to speed up toward the end of a run, but are handicapped by upper limbs that have not been trained for the task. So when the arms fatigue, stride length and rate lessen and the runner slows. Figure 6.2 Forearm: (a) front and (b) back. Specific Training Guidelines While performing biceps exercises, remember to keep your back straight; do not rock to help lift the weight. Choose a weight that does not hinder the smooth motion of the curl, and choose a lighter weight rather than a heavier weight to start. Also, keep your elbows fixed and close to your body, emphasizing the biceps and not the shoulders. Most runners, if they do arm exercises at all, will emphasize the biceps exercises. We have emphasized the triceps to help balance the muscular strength of the arms. Both biceps and triceps exercises can be performed with smaller amounts of resistance. Since distance runners need to be able to swing their arms steadily in the later stages of a long run or race, not to suddenly produce power, the emphasis should be on a larger number of repetitions (18 to 24) because the emphasis is on muscular endurance. For mid-distance runners or sprinters, 8 to 12 repetitions of a heavier weight will suffice. A good order for a sample arm workout would be the narrow-grip barbell curl, double-arm dumbbell kickback, and reverse wrist curl. Alternating Standing Biceps Curl With Dumbbell Execution 1. Stand with feet shoulder-width apart and knees slightly bent. Arms should hang straight down from the shoulders, holding dumbbells with the palms inward. 2. In one smooth motion, concentrating on using the biceps and not the hand, curl one dumbbell upward, completing a full range of motion. 3. Using a slow, fluid movement, lower the dumbbell in the |
opposite direction of the curl. Feel the stretch as the dumbbell returns to its starting position. Repeat the exercise with the other arm. Muscles Involved Primary: biceps, brachialis, anterior deltoid Secondary: brachioradialis, flexor carpi radialis TECHNIQUE TIPS ▶ The upper arm should be fixed at the elbow; as the dumbbell passes 90 degrees, the upper arm should not move with it. ▶ Look sideways into a mirror, noting whether the elbow is staying fixed and there is little or no swaying (to aid in focusing on using the biceps brachii). SAFETY TIP This is a simple exercise that can go awry when too much weight is attempted. The ideal weight is heavy enough to provide resistance throughout each rep and set of reps, but not so heavy that poor form eventually occurs. Do not throw the weight by engaging your upper back muscles. The biceps dominates the movement. Running Focus It seems odd that runners need to develop biceps strength. Most distance runners appear emaciated, with thin arms and legs; however, this does not mean that their biceps are not strong. Developing strength is different from adding mass. The biceps exercise, when performed with enough resistance to stimulate strength gains and done with higher repetitions in conjunction with a strenuous running program, will promote functional strength endurance without added mass. Because the goal of the arms, for a distance runner, is to balance the runner from side to side and counterbalance the movements of the legs, the biceps should not fatigue during a grueling training or racing session. Strength endurance is paramount, and performing 12 to 18 repetitions and multiple sets of this exercise will help develop this type of strength. VARIATION Barbell Curl With Variable-Width Grip Barbell curls can be done with a normal shoulder-width grip, a narrow grip, or a wide grip. The narrow grip emphasizes the biceps brachii more than the other grips, while the wide grip incorporates the anterior deltoid (the large muscle encapsulating the shoulder). All three grips are appropriate, and a complete biceps workout can be completed by using just this exercise, incorporating one set of each grip. Alternating Standing Hammer Curl Execution 1. Stand with feet shoulder-width apart. Arms hang straight down from the shoulders, holding dumbbells with the palms inward. 2. In one smooth motion, concentrating on using the biceps, not the hand, curl one dumbbell upward until it touches the shoulder, completing a full range of motion. The upper arm should be fixed at the elbow; as the dumbbell passes 90 degrees, the upper arm should not move with it. 3. Using a slow, fluid movement, lower the dumbbell in the opposite direction of the curl. Feel the stretch as the dumbbell returns to its starting position. Repeat the exercise with the other arm. Muscles Involved Primary: biceps, brachialis Secondary: forearm extensors SAFETY TIP Avoid throwing the weight. Focus on the contraction of the biceps. TECHNIQUE TIPS ▶ The upper arm should be fixed at the elbow; as the dumbbell passes 90 degrees, the upper arm should not move with it. ▶ Look sideways into a mirror, noting whether the elbow is staying fixed and there is little or no swaying (to aid in focusing on using the biceps brachii). Running Focus Similar in execution to the biceps curl—only the hand position is changed—the hammer curl develops strength in the biceps and, to a lesser extent, the brachialis. Performed during the same strength-training session at the end of the biceps set, the hammer curl is a fatigue-inducing exercise that also promotes joint flexibility because of its resistance over a full range of motion. Often, runners complain of sore biceps during and after a race of a shorter duration with more intense effort. Because of the increased force of the arm carriage, a greater demand is placed on the muscles of the upper arm. By performing the biceps exercises, runners can stave off the fatigue during a race and shorten recovery time between reps during a workout. VARIATION Seated Double-Arm Hammer Curl While seated on the edge of a flat bench, feet flat on the floor, back erect, and arms hanging down with a dumbbell in each hand, palms inward, perform the hammer-curl motion with both arms simultaneously. This exercise involves the coordination of both arms, and may cause fatigue a little quicker than when alternating arms. Dumbbell Lying Triceps Extension Execution 1. Lie on a flat bench with both feet on the bench. The torso should be stable. Arms are bent 90 degrees at the elbow, shoulder-width apart. Hold a dumbbell of an appropriate weight with both hands, palms inward. 2. Extend the forearms to full extension. 3. Lower the arms to the initial position slowly, resisting the weight. Muscles Involved Primary: triceps SAFETY TIP Have a spotter place the weight in your hands and hold the weight in place until you begin the exercise. If there is not a spotter, begin the exercise with the arms in the extended position, and perform the negative (lowering the weight) action as the first movement. Running Focus The introduction to this chapter emphasized the importance of the arms in balancing and counterbalancing during running. The triceps exercises listed in this section serve to balance the recommended biceps exercises, creating a well-developed and strengthened upper arm. The muscles of the forearm are involved as secondary movers. The only movement occurs at the elbow joint, precipitated by the engagement of the triceps. VARIATION Barbell Lying Triceps Extension Instead of using a dumbbell, using a barbell to perform the same exercise works well. Execute the exercise the same way, and follow the same safety instructions. Single-Arm Dumbbell Kickback With Bench Execution 1. Kneel on a flat bench with one leg. Keep the spine and torso in a straight line with your head. Establish a stable base of support with the non- weight-bearing hand pressed to the bench, and the opposite-side leg extended with the foot on the floor. The weight-bearing arm is bent at about a 90-degree angle with the palm inward. 2. Extend the forearm backward from the elbow, using the triceps muscles to instigate the movement in a slow, fluid fashion. Keep the elbow in a fixed position parallel to the torso, not higher. Exhale during this motion. 3. Upon straightening the arm, allow the weight to return the arm to 90 degrees by providing gentle resistance. Inhale during the return. Muscles Involved Primary: triceps Secondary: infraspinatus, supraspinatus, deltoid, pectoralis major TECHNIQUE TIP ▶ It is important not to vary elbow position during the exercise. Keep the elbow tight to the body and fixed. Try to avoid dropping the shoulder to help push the weight backward. Running Focus The dumbbell kickback is primarily a triceps exercise, but it recruits the infraspinatus and the supraspinatus muscles of the shoulder. Because the initiation of the arm swing during running takes place in the shoulder, strengthening the triceps and shoulder via this exercise helps ward off arm fatigue and bad posture, two energy-sapping scourges of good performance. VARIATION Double-Arm Dumbbell Kickback The double-arm variation does not require a bench. From a standing position, bend over at the waist so your torso is close to parallel to the floor, feet shoulder-width apart, and grasp a dumbbell in each hand with the arms hanging downward. Perform the kickback movement with both arms simultaneously. The exercise uses the same muscles as the single-arm kickback using a bench, and will incorporate the core muscles of the abdomen and lower back to stabilize the body. Machine Reverse Push-Down Execution 1. Standing with your feet narrower than shoulder-width apart, grasp the short, straight bar attached to a cable (on a pulley attached to the machine) with palms upward (underhand grip). The forearms are extended at approximately 75 degrees to the elbows, which remain fixed at your sides throughout the exercise. 2. In a smooth, uninterrupted motion, push the forearms downward in full extension, keeping the elbows fixed in their original position and close to the body. Exhale throughout the motion. 3. Allow the weight to return to the original position by resisting the pull of the cable gradually and in a smooth manner. Inhale during this part of the exercise. Muscles Involved Primary: triceps, forearm extensors Running Focus The reverse push-down mainly works the triceps, but it has the added benefit of also working the forearm muscles because of the underhand grip. This exercise marks a nice transition from the triceps-dominated extension and kickback into the next exercises, wrist curls, which predominantly work the forearm muscles. The triceps muscles and the extensor muscles of the forearms will fatigue quickly during the exercise as they do during a shorter distance race (5 to 10K), when using the arms becomes a means of propelling the legs during surges and effecting a finishing push. Wrist Curl and Reverse Wrist Curl Execution for Wrist Curl 1. Lean forward on a flat bench with your forearms resting on the bench. The wrists and hands should extend off the bench. Palms should be facing up with a barbell of a light weight resting forward of the palms with the fingers gently closed around the bar. 2. Raise the barbell by raising your hands, involving only the muscles of the forearms and hands, through a full extension. 3. Return the weight to its original position, gradually resisting the barbell as it moves downward. Execution for Reverse Wrist Curl 1. Lean forward on a flat bench with your forearms resting on the bench. The wrists and hands should extend off the bench. Palms should face downward with a barbell of a light weight gripped securely by the palms and fingers. 2. Raise the barbell by raising your hands, involving only the muscles of the forearms and hands, through a full extension. 3. Return the weight to its original position, gradually resisting the barbell as it moves downward. Muscles Involved Primary: forearm flexors, forearm extensors TECHNIQUE TIPS ▶ Focus on a full stretch of the muscles, but do not allow the barbell to snap down. ▶ If it is difficult to rest your forearms on the bench, you can rest them on your legs. Running Focus After gradually incorporating the extensor and flexor muscles into the strength-training routine, use wrist curls and reverse wrist curls to emphasize these muscles. During the course of a four-hour marathon, each arm will swing approximately 22,000 times. Although the movement is initiated by the larger muscles of the shoulders, the upper arms and the forearms are involved in the arm carriage. Specifically, each forearm is held at approximately 90 degrees to the upper arm to counterbalance the action of the opposite-side leg. During the course of 22,000 arm swings and four hours of being held aloft (fighting gravity), fatigue is bound to set in, creating a chain reaction of biomechanical adjustments resulting in poor form and wasted energy. By performing the strength-training exercises for the arms, this fatigue and its chain reaction of bad results can be mitigated, if not eliminated—hence, less wasted energy, and hopefully faster times and better performances. CHAPTER 7 CORE Running for pleasure was a long way down the list of priorities that determined how the pelvis would evolve in humans. The bones that form it are principally in place as a protective structure for the developing fetus, a need not shared by men, in whom a narrower pelvis forms the platform from which the legs unite with the rest of the body parts and have developed to accommodate locomotion. Six major bones form the pelvis, two each of ilium, ischium, and pubis (figure 7.1a). Although these bones are solidly joined to each other with no discernable laxity, each ilium meets the lowest part of the spine, the sacrum, posteriorly at the large sacroiliac joints, where there can be considerable movement. This is most noticeable during childbirth, when hormonal influences cause the ligaments that bind the joint to relax to such an extent that the joint may become subluxed, or partially dislocated, with considerable instability and possible consequences for the female runner. Above the sacrum are the five lumbar vertebrae, which have an important function in keeping the whole skeletal structure stable. As well as these two joints, each pubis is linked at the front by the symphysis pubis at |
the lowest point of the abdomen. This is a more solid fibrous connection, but sometimes liable to damage in a slip or fall or as a result of chronic overtraining, for it forms the pivot and point of maximum force and corresponding weakness between the legs and torso. Figure 7.1 Pelvic bones and muscles: (a) bony structures; (b) pelvic floor muscles. On the side of each ilium is a depression that forms the hip, known as a ball-and-socket joint. Its shape has developed in order to combine maximum stability with the greatest possible range of movement. The shoulder is similar but shallower and has a far greater likelihood of dislocation under load. The head of the femur forms the ball; movement of the joint is limited by the bony surrounds of the acetabulum, or socket, and also by the density and elasticity of the surrounding muscles and tendons. If the pelvis is viewed from above as an oval-shaped clock, the two sacroiliac joints are fairly close together at the 11 and 1 o’clock areas, the hips at 4 and 8, and the symphysis at the 6 o’clock site. If one of these joints is moved, then another has to change position to compensate. This becomes important when running, for the pelvis is swung from side to side and twisted during the gait cycle, which has an effect on all the structures in and around it. Forming a floor to the pelvis is the levator ani (figure 7.1b), which, for those with some knowledge of Latin, does just that. It lifts the anus and cradles all the other internal organs that fill the pelvis so that they do not collapse through the pelvic outlet. Weakness of the levator ani will predispose people to degrees of incontinence, and it is a muscle that requires training and toning just like any other. Running increases the pressure inside the abdomen, so any frailty may produce unwanted physical symptoms. The other pelvic muscles have a dual function to stabilize and move the legs from their pivot at the hip joints. The stability is aided by some large ligaments, which are relatively inextensible, though with good breadth of movement. Running from the lumbar vertebrae and the interior of the ilium are the iliopsoas muscles, which pass through the pelvis, forming soft walls for the internal organs, to the inside of the femur below the hip joint. Over the lumbar vertebrae, they are counteracted by the erector spinae muscles, which stabilize the spine externally. The iliopsoas is a strong flexor of the hip and pulls the thigh up toward the abdomen. The bulk of the buttock is formed by the glutei, three layers of muscle that slope down the outside of the back of the ilium at 45 degrees. Contraction of the outer layer, the gluteus maximus, extends and rotates the hip joint outward. It continues down the outside of the thigh as the tensor fasciae latae (see chapter 8 for more about this). The gluteus medius and minimus, underneath it, insert into the top of the femur at the greater trochanter, where their action is to pull the thigh outward, known as abduction, with the hip joint acting as a fulcrum. Runners with low back pain are frequently diagnosed with piriformis syndrome. The piriformis muscle lies alongside the gluteus medius, and pain probably occurs because of its close proximity to and irritation of the sciatic nerve. It both stabilizes and abducts the hip joint. Because the hip joint is so mobile, there have to be groups of muscles to counteract the forces produced by those that originate around and above the pelvis. These primarily pull the hip backward, abduct, and rotate it outward. The opposing muscles are those of the upper leg, which often have more than one function. The hamstrings—semimembranosus, semitendinosus, and biceps femoris—all arise from the lower pubic bone (figure 7.2) and travel down the back of the thigh and behind the knee joint as its flexor (the lower limbs are discussed in more detail in chapter 8). Their upper leg function is to extend the hip backward. The opposite of abduction is adduction, and the three adductors, magnus, longus, and brevis, together with the gracilis, all pull the thighs together. They arise from the inside of the pubis and are inserted along the inner border of the length of the femur. As well as the iliopsoas, the rectus femoris and the other quadriceps muscles also extend over the hip joint, and when contracted, have a flexing action on the femur. Figure 7.2 Lower core through upper leg: (a) back; (b) front. Muscles may be distinct entities, but often merge into one another and when dissected can be difficult to separate. The running action is repetitive, so that muscles with even slightly different functions may oppose each other during the running cycle and actually produce negative frictional forces. Where this may happen, a small fluid-filled sac called a bursa may form, the largest of which is over the greater trochanter, known as a trochanteric bursa. This may become inflamed and sore. Returning to the pelvis and its adjacent organs, the abdomen, unlike the chest, does not have a bony architecture to stabilize it. The vertical height is maintained by the lumbar vertebrae. The responsibility for stability falls to the abdominal contents, which exert a counterpressure to a surrounding circular wall of muscles formed by the rectus abdominis, which extends from the base of the rib cage centrally down to the pubic symphysis and bone (figure 7.3). Outside this and lying diagonally are the external and internal oblique and the transversus abdominis muscles, which have three functions: to abduct and rotate the trunk, to flex the lumbar and lower thoracic vertebrae forward, and to contain the abdomen. When running, these muscles alternately lengthen and shorten as the pelvis moves not only from side to side, but also twists, rises, and falls relative to the surrounding body parts. In addition, they have a function to aid respiration at high rates, working in conjunction with the diaphragm and ribs, which is particularly noticeable if the runner is reduced to panting. Thus, they have multiple roles, all of which may be required at the same time, and will perform better if well and thoroughly trained. Figure 7.3 Rectus abdominis and surrounding muscles. Rather than being active exercisers while running, the lower back muscles and lumbar vertebrae have more of a stabilizing passivity. First and foremost, they must maintain an upright posture, tempered by the need to accommodate for hills, where the upper body must lean backward or forward to counteract gravity upending the runner. The encircling musculature must allow rotation, body lean around corners, and lateral movement on any diagonally sloping surface, so they will contract and expand to maintain this stability. These complex movements have to coexist in conjunction with all the other variations in posture that occur as the legs move, the lungs breathe, and the abdominal contents shift to accommodate ingested fluid and nutrients during the run. Intrinsic strength, particularly of the muscles that surround the lumbar vertebrae, should be considered an essential in every runner because any weakness is liable to escalate into other areas. Specific Training Guidelines For the core exercises that require the movement of body weight only, multiple sets can be performed with many repetitions. All body-weight exercises should be slow and deliberate. Without extra resistance, the emphasis should be less on moving weight and more about perfect movement. High repetitions are a great way for a runner to develop muscular endurance, which benefits long-distance runners; however, strength development to aid power only comes from using heavier resistance. Choosing what weights to use (when applicable) and how many or how few repetitions are to be performed is a function of the goal of the workout, and in the macro sense, the performance goal of the runner. Core exercises should be performed at all stages of the training progression. Since many are body-weight bearing only, requiring no additional load, they can be performed three or four times per week. LOWER BACK AND GLUTES Back Extension Press-Up Execution 1. Lie prone on the ground with arms in the push-up position and legs outstretched. Keep the body rigid and in a straight line. 2. Press up the arms only until the torso is off the ground. Hold this position for 10 to 15 seconds, breathing throughout. 3. Lower the arms, bending at the elbows, and return to the original position. Muscles Involved Primary: erector spinae, gluteus maximus Secondary: hamstrings, rectus abdominis, external oblique, internal oblique Running Focus This a very simple exercise to perform. Not to be confused with a synonym for the push-up, the press-up extension of the lower back helps strengthen the muscles and tendons of the erector spinae, and acts as the antagonist for the rectus abdominis muscle. This exercise both strengthens and stretches the support structure of the sacral and lumbar spine, helping the pelvis rotate and twist properly, and mitigating the forward tilt of the pelvis if too many abdominal strengthening exercises have been performed, leading to an imbalance between the abdominals and muscles of the lower back. Unfortunately, an emphasis on the core exercises can become an emphasis on the abdominals, with little attention paid to the muscles of the lower back and the glutes. Without strong glutes and a supportive lower back, the hamstrings often can’t generate sufficient muscular power despite their having been strengthened properly. Essentially, the strongest muscles are only as strong as the weakest link on the kinetic chain allows. The proper movement of the pelvis is critical in the gait cycle. A misalignment of the pelvis due to muscle imbalances between the abdominal muscles and the muscles of the lower back can cause injuries that impede running performance despite good cardiothoracic fitness. LOWER BACK AND GLUTES Lumbar Hyperextension/ Alternating Arm and Leg Raise Execution 1. Lie prone on the ground with arms and legs outstretched. Keep the body rigid and in a straight line. 2. Raise the left arm and the right leg three to four inches off the ground. Hold this position for 10 to 15 seconds, breathing throughout. 3. Lower the left arm and right leg, and raise the right arm and left leg simultaneously. Muscles Involved Primary: erector spinae, gluteus maximus Secondary: hamstrings, rectus abdominis, external oblique, internal oblique TECHNIQUE TIPS ▶ This exercise can also be performed on a Roman chair, where gravity plays a greater resistance role. Because Roman chairs are rarely around when you need them, performing this exercise on the ground works as well. ▶ All the movement should be generated by the muscles of the lower back and glutes. SAFETY TIP Performing this exercise requires hyperextension of the back. Normally, this is not a problem, but for runners with chronic back pain or disc issues, press-ups are safer. Running Focus Lumbar hyperextensions can be performed in many ways. The goal of the lumbar extension is to strengthen and stretch the muscles of the lower back, glutes, and, to a lesser extent, the abdominals to help provide the appropriate pelvic tilt during the running gait cycle. A misaligned pelvis causes a chain reaction of misalignment, resulting in poor running form and wasted energy. Not only do the muscles of the back, abdominals, and glutes have to work in unison, but they also must work to balance each other and still generate enough strength to perform the exercise. This is very similar to how the core works when running. Because the pelvis is rotating and twisting, the core must dynamically stabilize, reacting to terrain shifts, turns, and missteps. VARIATION Lumbar Hyperextension on Physioball Using a physioball changes the dynamic of the lumbar hyperextension. By only using one hand for balance (and, after mastery, no hands), there is a neuromuscular (proprioceptive) component added to the exercise. Ultimately, the goal of this exercise is to not include a balance hand. Balance can be maintained on the physioball from mastering the form of the exercise and strengthening the muscles of the core so that they can be activated when needed. Runners tend to overlook proprioceptive exercises because there is not much visible effort, rather small, subtle movements that help create more fluid running. LOWER BACK AND GLUTES Hip |
Abductor Machine Execution 1. Sit in a proper seat position, with machine pads on the outsides of the knees. 2. Press outward using the abductor muscles (outsides of the legs). Emphasize reaching a full range of motion. 3. Return to the original position by gradually resisting the weight. Muscles Involved Primary: gluteus medius, gluteus maximus Secondary: tensor fasciae latae, quadriceps TECHNIQUE TIPS ▶ The motion should be fluid, but with consistent effort throughout. ▶ The more upright the backrest, the more the emphasis on the gluteus medius. ▶ Avoid trying to overextend the exercise. Don’t force the legs higher laterally than your hip naturally allows. Focus on pressing the legs apart using only the targeted muscles of the gluteus. Running Focus The abductor exercise can be done during the same workout as the adductor exercise; it is easy to change the pad positions on the machine, but its emphasis on the glutes makes it a better fit with the exercises for the glutes and lower back. Many runners, especially those who underpronate, complain of piriformis pain at some point in their running careers. Because of its location, the piriformis muscle is difficult to stretch. However, abduction exercises aid in preventing and treating piriformis pain and sciatica by stretching and strengthening the gluteus medius, which is connected. ABDOMINALS AND PELVIS Floor Sit-Up Execution 1. Lie on the back with knees steepled, feet pressed to the floor, and hands gently touching the back of the head, but not clasped. 2. Raise the torso by rounding the back one vertebra at a time while pressing the pelvis down to floor. Raise the torso only 45 degrees before lowering the back to the floor. 3. Inhale, and gradually lower the torso to the floor one vertebra at a time. Muscles Involved Primary: rectus abdominis, external oblique Secondary: quadriceps, tensor fasciae latae TECHNIQUE TIP ▶ Sit-ups can be performed with a partner holding down the feet of the person performing the exercise. It makes the exercise easier, but allows more reps to be performed. SAFETY TIP Don’t clasp, but gently touch the hands behind the head because it is easy to pull the head and torso up by using the muscles of the arms. Running Focus Because the quadriceps and hamstrings counterbalance each other, so do the muscles of the abdominals and lower back. To avoid muscle imbalances and potential injury, it is important to perform abdominal exercises after performing the strength-training exercises for the lower back described in the first part of this chapter. The sit-up should not be performed for speed, but in a relatively quick, fluid manner. The lowering of the torso should be done slowly, with attention to the work the abdominals are doing. The rectus abdominis is the dominant muscle affected by sit-ups. It controls the flexion of the abdomen. Because almost all abdominal exercises work the rectus abdominis, a single set to failure can make up the start of an abdominal set. The proper movement of the pelvis is critical to the gait cycle. A misalignment of the pelvis due to muscle imbalances between the abdominal muscles and the muscles of the lower back can cause injuries that impede running performance despite good cardiothoracic fitness. VARIATION Oblique Twist A simple variation on the sit-up involves twisting the torso using the oblique muscles by attempting to touch the elbow to the opposite hip. A set of 12 can be done all on one side and then the other, or each rep can alternate sides. ABDOMINALS AND PELVIS Hanging Leg Raise SAFETY TIP This exercise can put a lot of stress on the shoulder. Limit the number of reps if the shoulder is compromised. Execution 1. Hang from a pull-up bar with palms facing forward. Emphasize lengthening, feeling gravity exerting its force on your spine. 2. Using a controlled movement, bring the knees up toward the chest. Keep the torso from swinging. 3. Gradually return to full extension and continue to repeat. Muscles Involved Primary: rectus abdominis, external oblique, iliopsoas Secondary: latissimus dorsi, serratus anterior Running Focus The hip flexor muscles, specifically the iliopsoas, fatigue greatly during the course of a long run or race on a course that has the same terrain throughout. The repetitive nature of running is exacerbated with few terrain changes, and smaller muscles fatigue quickly. By strengthening the iliopsoas and the other hip flexors, runners can delay the onset of this fatigue. Also, when the terrain is hilly, requiring a lot of lifting throughout a run, weaker muscles will fatigue quicker, and gaining solid footing becomes harder. VARIATION Hanging Leg Raise With Twist The standard hanging leg raise affects the external and internal oblique, but adding a twist to the side increases the role of these abdominal muscles that are responsible for rotation and lateral flexion of the torso. As was mentioned in the introduction to this chapter, the oblique muscles help to twist, allowing for terrain adjustments, and they aid respiration by working in conjunction with the diaphragm and ribs. ABDOMINALS AND PELVIS Dumbbell Side Bend Execution 1. Stand with good posture, feet shoulder-width apart. Hold a dumbbell in one hand with the arm extended downward. The other hand is placed behind the head with the elbow out. 2. Bend at the waist in the direction of the hand holding the dumbbell, allowing the weight to pull the side down gradually. 3. Complete a set of 12 reps and then switch the dumbbell to the other hand and repeat. Muscles Involved Primary: external oblique Secondary: rectus abdominis, quadratus lumborum Running Focus Balancing the abdominal muscles is the goal of this exercise. Most abdominal exercises focus on the large muscle of the abdominals, the rectus abdominis. The side-to-side movement of this exercise helps develop the external oblique, also strengthened in the hanging leg raise with twist. The strengthening of the external oblique helps minimize the side-to-side listing at the end of a fast race or hard effort in a speed workout. Because the smaller muscles of a large muscle group—that is, the abdominals—fatigue easier than the large rectus abdominis, it is important to do exercises that specifically target the smaller muscles so that they maintain their relative strength and do not become dominated by the larger muscle. The practical application of this exercise is to eliminate the side-to-side rocking of the upper body during the gait cycle. While a leg length discrepancy could cause this rocking, the usual culprit is poor abdominal strength, especially weak oblique muscles. The inability of the abdominal muscles to maintain erect posture causes an awkward side-to-side motion generated by a pelvis that is not aligned. ABDOMINALS AND PELVIS Single-Leg V-Up Execution 1. Lie flat on the back with your hands reaching back behind your head. One leg is steepled and the other is raised approximately six inches off of the ground. 2. Leading with the chin and chest, engage the abdominals, raising up as in a sit-up, but also raise the leg that is off the ground, meeting the hand at its apex. 3. Recline to the initial position. Muscles Involved Primary: rectus abdominis, transversus abdominis, iliopsoas Secondary: hamstrings, gluteus maximus Running Focus This exercise is dynamic and quickly fatigues the abdominal muscles and the iliopsoas. Because of the incorporation of both the upper body and lower body, there is more of a whole-body movement that more closely resembles a running movement than some of the other exercises in this chapter. Performed to failure, this exercise and its variation with a medicine ball can be an entire abdominal workout, especially if done as the final exercise in a strength-training session. VARIATION Single-Leg V-Up With Medicine Ball The use of the medicine ball works the abdominals harder because of the added weight. Since the medicine ball is held away from the abdominals, even a five-pound ball feels heavy as a result of its distance from the fulcrum (the abdominal muscles). Also, the coordination of the movement with the added weight helps develop coordination, a skill not gained when just running in a forward motion. CHAPTER 8 UPPER LEGS There is no real division between the core and the upper leg; all the limbs merge seamlessly into each other. Some of the pelvic muscles help movement and stability of the leg, and vice versa. The same occurs at the knee, where muscles are described as crossing over two joints, so they influence the action and steadiness of the joints. The upper leg (figure 8.1), or femur, is inserted via the hip joint into the pubis and ischium. The other bone of the upper leg, the patella (knee joint), is really a pulley. It runs in a groove at the lower end of the femur to help guide the extending forces of the quadriceps muscles around the knee. Figure 8.1 Bony structures of the upper leg. The primary function of the quadriceps group (figure 8.2a) is to extend the knee. From the outside to the center line, the vastus lateralis, rectus femoris, vastus intermedius, and vastus medialis combine at the superior pole of the patella and straighten the knee joint with a pull through the patellar tendon on the upper part of the tibia. Contraction of this, the largest muscle group in the body, also pulls the knee toward the chest. It is particularly relevant to the sprinter, who gains extra stride length with big quadriceps contractions; however, this high knee lift wastes energy in a long-distance run, so the hip and knee have much smaller ranges of motion when covering longer distances. The role of the quadriceps in the running action is therefore twofold, though the intent of both movements is to increase the stride length (see figure 3.2 on page 23). If at the same time the knee is fully extended and the quadriceps muscles exert the maximum flexion to the hip, not only is the stride length maximized, but the added time in the air will also allow the momentum already generated to propel the body farther forward. Much the same goes for the hamstring muscles (figure 8.2b), which also span the two joints but act in an opposite manner to both extend the hip and flex the knee. The semimembranosus, semitendinosus, and biceps femoris have some congruity in the center of their bulk, having arisen from different points within the pelvis, but then separate behind the knee and are inserted into the rear of the tibia and fibula. Contraction of the hamstrings drives both the upper and lower leg backward, a movement that tends to be exaggerated in a sprinter (see figures 3.3 and 3.4 on pages 24 and 25). Increased knee flexion would be inefficient to a distance runner; a greater percentage of the hamstring motion for a distance runner occurs at the hip. It may be helpful to consider each full hamstrings group as two separate half muscles. This may sound paradoxical, but although it is the upper portion that links over the hip joint as an extensor muscle, the lower portion both flexes and limits extension of the knee. There is, of course, no actual physical distinction within the muscle groups when they are microscopically examined; the difference is purely functional. In the distance runner the hamstrings have a limited range of motion over both the hip and knee joint, although their contraction is very powerful over these small angles. Figure 8.2 Upper leg: (a) front and (b) back. It may seem strange that the knee needs to be able to twist, but how else would a runner turn corners or cope with uneven terrain? The knee (figure 8.3) has two collateral ligaments on the inside and outside that allow it to hinge to and fro, but rotation depends on the half-moon-shaped menisci, also known as cartilages, which are placed between femur and tibia and spread weight through the knee joint. They also allow the bones to twist on each other. An anterior and posterior cruciate ligament within each knee, placed in a crosslike shape, obstruct excessive forward and backward movement of femur and tibia on each other. It should be stressed, however, that these ligaments are there to guide knee movement and play only a small part in maintenance of knee stability, which depends mostly on the strength of the muscles. The thigh muscles |
need both strength and flexibility, each of which can be improved by exercise. The maintenance of a balance between the two is also vitally important because being muscle-bound will do little for pliability; the converse is equally true in that lack of muscle bulk will cause relative weakness. Figure 8.3 Knee ligaments and tissue. Specific Training Guidelines Protection of the knee joint while performing some of the following upper leg exercises is an important consideration. Because both the quadriceps and hamstrings groups of muscles attach to the knee, and the knee joint twists to adapt to terrain variations, turns, uphills, and downhills, there is constant stabilization and relaxation of the joint. The lunge exercises are difficult to perform initially, so care must be taken to perfect the motion with lighter weight before increasing the resistance. A machine-aided exercise helps protect the joint, but it has a fixed range of motion that does not make it the best functional exercise. The exercises listed for the upper legs are good introductory and strength (threshold) phase exercises. However, they should not be done during the final phase of training, which emphasizes V O2 max. During the final phase, substitute the plyometric exercises listed in chapter 12 to meet a runner’s needs without overly fatiguing the muscles. ADDUCTOR FOCUS Hip Adductor Machine Execution 1. Sit in a proper seat position, with machine pads on the insides of the knees. 2. Squeeze inward on the pads. The motion should be fluid but with consistent effort throughout. 3. Return to the original position by gradually resisting the weight. Muscles Involved Primary: adductor longus, adductor brevis, adductor magnus, gracilis Secondary: vastus medialis TECHNIQUE TIP ▶ Avoid pushing the weight with the feet. Focus on bringing the legs together with the adductor muscles. Running Focus The adductor exercise can be used in a strength-development regimen or as a rehabilitative regimen that requires ancillary muscles to be developed without undue stress on the knee joints. Many knee problems are caused by an imbalance of the four quadriceps muscles, which cause tracking issues for the patella. The adductor exercise strengthens the adductor muscle group specifically and the vastus medialis secondarily, preventing the patella from tracking too laterally. Developing strength in the adductor group and the quadriceps muscles of the upper leg aids in the powerful extension during the propulsive phase of the running gait. To prevent imbalances in the quadriceps, perform the abductor exercise on the same piece of equipment, as described in chapter 7. QUADRICEPS FOCUS Machine Leg Extension Execution 1. Sit in the leg extension machine in the appropriate position. Keep the knees in line with the fulcrum of the weight lever and the back straight. Grasp the handles on both sides of the seat, but do not squeeze. 2. After choosing an appropriate weight, extend, but do not hyperextend, both legs through a full range of motion with a fluid motion. 3. At full extension, lower the legs gradually, resisting the weight while inhaling deeply. Muscles Involved Primary: quadriceps Secondary: tensor fasciae latae, sartorius TECHNIQUE TIP ▶ Avoid hyperextending the knees and rocking the body to help lift the weight. Running Focus The machine leg extension is a fantastic exercise because it is simple to perform and has a great impact on quadriceps strength. It develops the four muscles of the quadriceps equally (rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius) and aids in keeping the patella tracking correctly. For runners suffering from a patellofemoral injury, the full extension needed for this exercise will unduly stress the patella. To help develop the quadriceps, a modified version of the exercise using a short arc (only the final 15 to 20 degrees of the exercise) helps off-load the patella. This exercise is a must during the introductory phase of training due to its general strength-building power. VARIATION Machine Leg Extension With Short Arc The leg extension with short arc variation is an excellent exercise for developing quadriceps strength if there is knee pain due to patellofemoral syndrome. The only drawback is that it is not a full range-of-motion exercise; however, once the knee pain dissipates, the full extension exercise can be completed. HAMSTRING FOCUS Machine Lying Hamstring Curl Execution 1. Lie prone on a hamstring curl machine. The pads of the machine are situated at the Achilles tendon. Hands are outstretched, holding onto the handles of the bench. Keep the head centered with the chin slightly off the bench. 2. Focusing on the hamstring muscles, slowly but fluidly pull the weight upward. 3. Return the weight to the starting position by gradually resisting the downward motion of the lever. Muscles Involved Primary: hamstrings Secondary: gluteus maximus, gluteus minimus, gastrocnemius SAFETY TIP Some common mistakes made while performing this exercise are pulling strongly on the handles to help aid the motion of the exercise, lowering the weight too quickly, and slamming the weight into the glutes to finish the repetition. Running Focus As the counterpart to the machine leg extension, the lying hamstring curl works the large muscles of the hamstrings, helping to balance the quadriceps muscles of the front of the leg. The hamstrings come into play during the recovery phase of the gait cycle, as the lower leg bends at the knee, pulling the leg upward toward the glutes. The hamstrings group is not as strong as the quadriceps group, but it must be diligently strengthened or an imbalance between the quadriceps and hamstrings could occur. It is not common for distance runners to experience hamstring tears or pulls, but it is common for distance runners to suffer from hamstring tightness because of problems in the lower back. Also, many knee injuries are related to weak hamstrings. One complaint about the hamstring curl is that it works only the hamstrings and not the hamstrings and glutes, which work together in the gait cycle. While true, this is less significant if the exercise is performed in the base, or introductory, phase of training, where the emphasis is more on general strengthening and less on functional work, and where other exercises can work the glutes. Dumbbell Lunge Execution 1. Stand with legs shoulder-width apart, with good posture. Each hand is holding a dumbbell that is relatively light. 2. Take a small step forward with one leg, lowering your hips as you step so that your quadriceps are parallel to the ground and your lower leg is at a 90-degree angle at the knee. Your rear leg provides balance. 3. Return to the original position by pushing upward, after reaching parallel, with the same leg that made the initial step. Repeat the exercise for a full set of reps on one leg, or switch legs after a rep with each leg. Muscles Involved Primary: quadriceps, hamstrings, gluteus maximus Secondary: rectus abdominis, external oblique SAFETY TIP One caution for this exercise is to not allow the kneecap to extend past the toes of the lead foot while performing the movement. The possibility of injuring the knee because of its relatively vulnerable, unstable position while performing a difficult, anaerobic exercise is real. This is a wise rule to follow for most people; however, in a few runners with longer femurs, it is difficult not to extend past the toes. Practice the exercise in front of a mirror, and if your form is spot-on and your knees extend past your toes, so be it. Running Focus The lunge is a difficult exercise to master quickly. Like the squat, a similar movement, it develops strength throughout the core, hamstrings, and quadriceps, but mastering the proper form is difficult. It is important to master the technique before adding weight. A barbell instead of dumbbells can be used, but holding the barbell on the shoulders is an unnatural hand position for a runner. Keeping the hands low while holding the dumbbells is normally more comfortable for runners. This exercise fits nicely in the second, or strength (threshold), phase of training. It is functional and, with the added weight of the dumbbells, can develop significant strength. VARIATION Lunge With Long Step By taking a longer step, the gluteus medius and gluteus maximus of the leg that is forward are strengthened more than with a regular step, and the iliopsoas and rectus femoris of the back leg are stretched. Machine Incline Leg Press Execution 1. Sit with the feet placed close together (narrower than shoulder-width apart) on the bottom part of the footplate. The back and the head are pressed against the back pads. The safety catch should be on. Flip the safety outward, rendering the weight active. The legs should be prepared to support the weight before the safety is released. Inhale. 2. Concentrating on the hips, glutes, and quads, extend the legs in a fluid movement to full extension by extending both knees. 3. Return to the starting position by gradually flexing the knees, allowing the weight to slowly lower back to the original position. Muscles Involved Primary: quadriceps, gluteus maximus Secondary: gastrocnemius, biceps femoris SAFETY TIP This exercise allows for a greater weight to be used because of its reliance on a machine; however, be careful not to add too much weight until proper form is established. TECHNIQUE TIP ▶ Do not hurry the movement, which results in the weight moving past the full range of motion and bouncing back to the legs. Running Focus The machine incline leg press is a safe exercise to perform, and it can increase strength in the quadriceps and glutes quickly because relatively heavy weights can be used because of the incorporation of the machine. Instead of using energy and strength by heavily incorporating stabilizing muscles (abdominals and adductors), the exercise effectively isolates the quads and glutes, strengthening both sides of the upper leg, helping to avoid muscle imbalances and potential injury. Altering foot position on the footplate will change the muscle groups impacted. To incorporate more of the glutes, place your feet at the top of the footplate. Due to its emphasis on the large muscle groups, this exercise creates explosive power for runners. Therefore, it is best used by runners training for shorter events such as a 5K or for track racing in sprints or middle-distance events. The exercise is suitable during the introductory phase of training for all runners because it is a general strength exercise, not a functionally-specific strength exercise. Bent-Leg Good Morning Execution 1. Stand with good posture, feet shoulder-width apart, grasping a barbell of light weight across the shoulders. 2. Lower the torso by bowing at the waist. The back should be lowered in a single plane, maintaining the lumbar (lower back) curvature. The glutes push outward during the motion. Inhale during the downward movement. 3. Return to the standing position by raising the torso, focusing on the rotation of the pelvis. Muscles Involved Primary: hamstrings, gluteus maximus Secondary: gastrocnemius, external oblique, internal oblique Running Focus Many distance runners complain that they feel chronic tightness in the lower back because of the accumulated mileage they have run in training. The jarring impact of a heel strike plus a lack of flexibility has caused many a runner to discontinue training and find another sport. How can you alleviate such a problem? Exercises like the bent-leg good morning, which actually strengthens and stretches the hamstrings in one exercise, work well. Again, like most of the exercises in this book, the bent-leg good morning is a simple exercise to perform, and it has multiple benefits. Aside from strengthening the hamstrings and glutes, it also helps stretch these muscles, helping to loosen the connective tissue between the muscles and the bones of the lower back and the pelvis. This kinetic chain also affects the knees because a more supple lower back pulls less on the hamstrings, in turn allowing the kneecaps to track normally. VARIATION Straight-Leg Good Morning The good morning can be performed with straight legs, but runners with chronically tight hamstrings should perform the exercise with bent legs because of the emphasis on hamstring flexibility. Once greater flexibility is attained, the straight-leg version can be incorporated. Dumbbell Romanian Deadlift Execution 1. Stand with feet slightly apart and legs slightly bent, with each arm extended downward holding a dumbbell with an overhand grip. There is a slight natural curve in the lower back. 2. |
Gradually bend at the waist, lowering your back in a single plane while maintaining the natural curve in the back, with the dumbbells almost scraping the quads and knees as you bend. 3. Return to the upright position once you can no longer lower the weight. Muscles Involved Primary: hamstrings, gluteus maximus Secondary: erector spinae TECHNIQUE TIP ▶ The dumbbells should not reach the floor. The slight curve in the lower back should prevent that much movement. Running Focus This intense exercise emphasizes the upper legs, specifically the hamstrings and glutes. It is extremely functional in that it works the muscles the way they work when running, more so than the hamstring curl. As has been noted previously, the balance between the larger quadriceps group and the hamstrings is the key to extension and propulsion during the gait cycle. To ensure uninterrupted training, avoidance of injury can be almost guaranteed by performing exercises like the dumbbell Romanian deadlift that help stretch and strengthen the back of the upper legs. Also, given the demands of fast-paced running on the hamstrings, fast-twitch muscle fibers of the hamstrings are best trained with higher-intensity exercises like the dumbbell Romanian deadlift. Squat Execution 1. Using a squat rack, slide under the barbell and center the barbell on the deltoid and trapezius muscles, not the vertebrae of the neck. Feet should be shoulder-width apart and splayed slightly. 2. Inhale deeply, expanding the chest. Maintain the natural curve in the lower back while straightening up and lifting the barbell off the rack. 3. Establish proper position by taking a few steps backward, repositioning the feet and reestablishing the accentuated curve in the lower back. 4. Look toward a point above head level, and initiate the squat action by bending forward at the hips, which will lower the rear. When the thighs are parallel to the floor, straighten the legs and return to the initial position while exhaling. Muscles Involved Primary: quadriceps, gluteus maximus, gluteus medius, gluteus minimus Secondary: hamstrings, external oblique, gastrocnemius Running Focus The squat is primarily a quadriceps exercise, but because of its stability demand, it also helps strengthen the core, hamstrings, and muscles of the lower leg. Heavy weight can be lifted, but it is not necessary to make this exercise effective. Squats should be performed during the same session as the dumbbell Romanian deadlift or the good morning to create balance between the front and back of the legs. Like the machine incline leg press, the squat creates explosive power due to its emphasis on the large muscle groups. Therefore, it is best suited for runners training for shorter events such as the 5K or for track racing in the sprints or middle distance events. Because it is a general strength exercise, not a functionally-specific strength exercise, it is suitable during the introductory phase for all runners. Its emphasis on core stability can aid all runners at every phase of the training progression. VARIATION Single-Leg Squat With Dumbbells This exercise aids in developing the adductor muscles of the inner thigh. Stand about two to three feet in front of a bench with a dumbbell in each hand. Place the top of one foot (laces of the shoe down) on the bench behind you. Lower your body until the forward leg is bent 90 degrees at the knee and the knee of the rear leg is almost touching the ground. Push back up using the quadriceps muscles of the forward leg. After performing a set of 12 on one leg, switch legs. The weight of the dumbbells does not need to be heavy. Initially, until good form is established, no added weight is necessary. CHAPTER 9 LOWER LEGS AND FEET Any structure that will pass the test of longevity must have a strong, secure, and preferably wide base. The human being is certainly not a pyramid, which is the perfect example of such a design, yet to remain upright the human has to survive with two stable lower limbs, augmented by relatively large feet, over a fairly narrow base. The tibia (figure 9.1) is the major weight-bearing bone of the lower leg. It is splinted by the thinner fibula, which becomes more relevant at the ankle, where it forms the outer part of this hinged and curved joint. The muscles attached to these bones control the movement of both the ankle and the metatarsals and phalanges that form the foot. The ankle joint itself moves almost entirely in the anterior-to-posterior plane, but the seven bones that form the tarsus are placed so that there can be both inversion and eversion of the foot at the midtarsal and subtalar joints. This allows each foot to turn inward and outward to accommodate for uneven or slippery ground underfoot. Figure 9.1 Bony structures and soft tissues of the lower leg and foot. Only three bones on the undersurface of the foot make contact with the ground. Under the heel is the calcaneum, and the first and fifth metatarsal heads complete the triangle. Between this tripod of bones is a complex consisting of the talus, cuboid, navicular, and three cuneiform bones, which lie in opposition to each other in such a way that they can be raised to form a longitudinal, or lengthwise, arch to each foot with the five metatarsal bones. Not only do they have to change position to compensate for variations underfoot, but they also allow the feet sideways movement. The tarsal bones form the apex of a bony arch, and when viewed from the ends of the toes appear to rotate on each other to enable the feet to move in or out. It is by this movement that walking or running on the inside or outside of the feet is possible. The power from the calves to push forward comes from the two muscles of the posterior compartment (figure 9.2). The soleus is the deeper muscle and combines with the gastrocnemius to form the Achilles tendon, which is inserted into the calcaneum. Their contraction pulls this bone and thus the whole foot backward. A deeper layer of muscles provides flexion to the metatarsals and toes. These are the flexor digitorum longus, flexor hallucis longus, and tibialis posterior. They provide plantarflexion to the foot and, because they cross several joints, to the ankle as well. The anterior, or extensor, compartment of the leg lies between the tibia and fibula and is surrounded by a relatively inelastic fibrous sheath. Within it are contained the tibialis anterior, extensor digitorum longus, and extensor hallucis longus muscles. These pass through the front of the ankle and are inserted into the tarsal, metatarsal, and toe bones in order to raise them or lift them up, an action known as dorsiflexion. These do not have to generate the same power as the posterior calf muscles for most activities, so they are less developed and weaker. Further lateral stability to the ankle and rear foot is provided by the peroneal muscles, which arise from the fibula and pass around the lateral side of the ankle joint to be inserted into the outer metatarsals. Very powerful forces are generated through the Achilles tendon. If it is injured, it tends to be very painful because of its well-developed nerve supply and heals slowly because of poor blood flow. Much the same can be said of the plantar tendon, or fascia, which spreads from the front of the calcaneum and is inserted at the bases of the five metatarsals. It is an unyielding sheet of fibrous tissue whose weakest point is at the heel. If the foot is viewed two- dimensionally from the inside, the plantar tendon provides the horizontal base to the triangle completed by the tarsal and metatarsal bones. Figure 9.2 Lower leg and foot: (a) back and (b) front. This anatomy must be considered on a functional basis, and watching a slow-motion recording of a foot landing and taking off is invaluable in understanding the motion involved in each stride. The initial plant of the foot is known as the heel strike, after which the foot turns a little inward, with the weight of the body progressively passing down the outer side of the foot before landing is completed on the ball formed by the metatarsal bases. Fewer runners meet the ground first with their toes, sometimes because of an inability to dorsiflex sufficiently. This lack of heel strike may be due to genetic or structural causes. Most people can run on their toes only for a very short time and distance because the work of plantarflexion is taken over by the comparatively weak toe flexors rather than the powerful calf muscles working through the pivot of the calcaneum, especially if dorsiflexion is limited. Once the foot is flat, the movement continues in reverse; during takeoff, the heel lifts off first, rolls inward along the outer metatarsals, and ends with the final push-off from the ball of the foot. During this action, all the muscles will contract or expand in a regular rhythm, though not at the same time. At this juncture we need to demystify the superstitions that have developed around feet that are pronated or supinated. There are three related but separate elements to movement within the foot. At the subtalar joint, the foot inverts and everts, or turns inwardly or outwardly. At the midfoot, there is abduction or adduction, where the movement is solely in the horizontal plane, while at the forefoot, the movement is principally up and down, in dorsiflexion, which somewhat confusingly describes an extension of the foot, or plantarflexion. Pronation describes a compound movement of these joints, where there is eversion at the subtalar joint, abduction (i.e., outward horizontal movement) at the midfoot, and dorsiflexion at the forefoot. Supination describes the opposite movement of each joint. Every foot, with every stride, exhibits some of these actions. When they become excessive, the runner may have difficulties that lead to pain or injury. Excessive pronation when the foot is flat on the ground, where the longitudinal arch of the foot leans excessively inward and the toes point outward, will stress the tibia by internally rotating it and the ligaments between the bones of the midfoot by stretching them, affecting the ability of the inverting muscles of the feet to perform efficiently. Supination describes the opposite action, in which the outside of the runner’s foot takes the weight of landing on the ground. The tibia is disproportionately externally rotated, and the effect of the extra strain on the peroneal muscles may also spread to the iliotibial band. (In chapter 11 we demonstrate how appropriate footwear may minimize the distress that overpronation and supination may pose to the serious runner.) Because of the strains imposed when the feet are excessively overmobile, a severely supinated foot may prove too much of a handicap for a distance runner, though many of the fastest runners in the world have overcome this potential disability. Another anatomical variation concerns those with high, rigid, longitudinal arches, who may also but not necessarily supinate, and those with flat arches with or without excessive pronation. For both of these types of feet, the lack of flexibility is likely to lead to a mechanical disadvantage in that they may be slower runners than they otherwise might. Specific Training Guidelines Some of the standing exercises are performed or can be performed unilaterally, meaning one leg at a time. This type of movement can significantly strengthen the targeted muscles by recruiting all the major leg muscles, weaker ones included, to establish balance while properly performing each exercise. As mentioned in chapter 5 and thoroughly examined in chapter 7, exercises that require stability engage the core muscles of the abdomen, lower back, and hips to maintain proper form. Performing most freestanding exercises unilaterally helps ensure that the specific muscles targeted plus the core muscles recruited develop strength and, with enough reps, muscular endurance. CALF AND ACHILLES Single-Leg Heel Raise With Dumbbells Execution 1. Stand on a platform with one foot touching the platform with only the ball of the foot and the toes. The midfoot and the heel are not touching the platform. Hold the other leg at a 90-degree angle at the knee, from the hip, not touching the platform. Both hands should be holding dumbbells, with the |
arms extending straight down along the hips and sides of the quadriceps. 2. Maintaining proper posture, an erect upper body stabilized by the engagement of the abdominal muscles, rise up (plantarflexion) on the foot on the platform. Do not hyperextend the knee. The leg should be straight or slightly bent at approximately 5 degrees. 3. Lower the foot (dorsiflexion) back to the beginning position. Complete to tolerance each set and then repeat the exercise using the other leg. Muscles Involved Primary: gastrocnemius, soleus Secondary: tibialis anterior, peroneus brevis, flexor digitorum longus Soft Tissue Involved Primary: Achilles tendon TECHNIQUE TIP ▶ The exercise should be performed until the calf muscles begin to burn. Do not perform to fatigue unless performing only one set. One to three sets will suffice, with the amount of weight held being a variable that can change the effect of the workout. Running Focus The single-leg heel raise exercise should be a staple of every runner’s strength-training regimen because it is a simply-performed exercise with very little equipment, and because it is a multipurpose exercise. Specifically, it can be performed to develop strength, which aids in injury prevention, and it can be used as a rehabilitation exercise if the Achilles tendon or calf muscles have been injured. The exercise should not be performed if a runner is still suffering the initial effects of the injury, but can be safely performed after the onset of the injury if some healing, determined by a subjective evaluation of the pain level or the evaluation of an objective image (MRI), has taken place. As described in chapter 10, adding an eccentric, or negative, component of the exercise (lengthening of the muscle) adds value to this specific calf and Achilles tendon exercise. Eccentric motions have value because the muscle can handle a lot more weight eccentrically contracting. It is also hypothesized that muscle strengthening is greatest when performing eccentric-contraction movements and that eccentric contractions are better suited to develop a muscle’s fast-twitch fibers. CALF AND ACHILLES Machine Standing Heel Raise TECHNIQUE TIP ▶ The upper body should be erect and the abdominal muscles should be engaged to maintain proper form. Execution 1. Stand under the shoulder pads of the machine so that there is a small amount of flex at the knees. The upper body should be erect and the abdominal muscles should be engaged to maintain proper form. Arms should be placed on the handles next to the shoulder pads. A light grip should be used. 2. Elevate the heels (plantarflexion) until both feet are only touching the platform with the metatarsals and toes; however, the toes should be relaxed and the emphasis should be on the extension of the calf muscles. 3. Lower the heels until a full stretch of the calves is felt. Repeat. Muscles Involved Primary: gastrocnemius, soleus Secondary: tibialis anterior, peroneus brevis Soft Tissue Involved Primary: Achilles tendon Running Focus The standing heel raise is another exercise designed to strengthen the complex of calf muscles (gastrocnemius and soleus) and the Achilles tendon. Its emphasis is more on the gastrocnemius, the larger portion of the calf, than the soleus, but it does work the smaller muscle also. This exercise can be done during the same workout as the single-leg heel raise to really fatigue the calf muscles, or it can be done independently of the other exercises when the goal of the workout is to perform one exercise per body part. The Achilles tendon and calf muscles take on much of the shock absorption and deflection after heel strike. When a runner races in lightweight shoes with a lower heel height than traditional trainers, the impact becomes more pronounced. To help minimize impact and aid in propulsion by moving the foot through its cycle, all runners should include exercises to develop calf strength in their training. These exercises can be performed during any stage of the running progression, with special emphasis during the racing phase if no injury has occurred. VARIATION Machine Seated Heel Raise Similarities between the anatomy affected by the standing heel raise and seated heel raise abound, but it is the emphasis on the soleus muscle that differentiates the two exercises. When sitting, the gastrocnemius muscle is less involved in the exercise, allowing the soleus, despite its smaller size, to become the dominant calf muscle. The strengthening of the soleus aids in the propulsive force of the takeoff phase of the running gait cycle. It also aids the runner who races (or works out) in racing flats to overcome calf pain and Achilles tendon strain during and following a race or a workout. The lower heel height of the flat or spike forces the Achilles tendon to stretch more than in running shoes. A strengthened and stretched soleus muscle helps prevent injury to the Achilles tendon by mitigating the extra stretch. FEET Plantarflexion With Tubing Execution 1. Sit on the floor with legs fully extended in front of the body. A length of surgical tubing, an end in each hand, should extend underneath the foot, wrapping around the ball of the foot where the metatarsal heads are located. The tubing needs to be taut, with no slack, before the exercise begins. 2. Extend (plantarflex) the foot to full extension. 3. At full extension, hold the position for one second before pulling the tubing backward in a smooth, continuous fashion. The foot will be forced to dorsiflex and return to its initial position. 4. Repeat the push and pull of the exercise, adjusting tension throughout, until fatigue. Muscles Involved Primary: tibialis posterior, flexor hallucis longus Soft Tissue Involved Primary: posterior talofibular ligament, calcaneofibular ligament Running Focus In chapter 4, a discussion of the adaptations required for running at different speeds and terrains offers some insight into the role of the feet and ankles in running performance. This exercise promotes strength and flexibility of the foot and ankle to prevent injury when running on uneven terrain and aids in the support phase of the gait cycle. Because this exercise is not weight bearing, it can be performed daily. It can function as a rehabilitative exercise to overcome an ankle sprain, or it can stand alone as a strengthening exercise to promote improved strength and flexibility. Because the exerciser controls the tension of the surgical tubing, the exercise can be made as difficult or as easy as possible for each repetition. The emphasis should be on a smooth but explosive movement with the appropriate resistance being provided by the tautness of the tubing, which can easily be adjusted by applying or lessening tension through gradually pulling or releasing the ends of the tubing held in each hand. FEET Dorsiflexion With Ankle Weights TECHNIQUE TIP ▶ The speed of the movement is not fast, but the muscles of the foot and the tendons of the ankle need to be dynamically engaged. Execution 1. Sit on a table with knees bent and lower legs dangling. An ankle weight providing appropriate resistance is secured around the midfoot. The upper body is erect with hands by the sides providing balance only. 2. In a smooth but forceful motion, the foot dorsiflexes (points upward and back) toward the tibia to full extension. The lower leg remains bent at 90 degrees and does not swing to aid the foot and ankle in moving the weight. 3. Gently lower (plantarflex) the foot (it does not need to be fully extended) and repeat the exercise to fatigue. Switch the ankle weight to the other foot and repeat the exercise. Muscles Involved Primary: tibialis anterior Soft Tissue Involved Primary: anterior talofibular ligament, calcaneofibular ligament, plantar tendon Running Focus This is another non-weight-bearing foot and ankle exercise that can be done daily both as an injury rehabilitation exercise as well as to improve strength and flexibility. The amount of weight of the ankle cuff can be varied to fine-tune the goal of the exercise. For example, a heavier weight performed fewer times with fewer sets emphasizes the strengthening of the anatomy affected. A lighter weight allows for more repetitions and sets, which aids the flexibility and endurance of the anatomy affected. VARIATION Dorsiflexion With Tubing This exercise can also be done with tubing, like the plantarflexion exercise. It can actually be done alternately by first plantarflexing the foot against the resistance of the tubing, and then immediately resisting when the tubing is pulled toward the body, until it is fully flexed and ready to plantarflex again. FEET Foot Eversion With Elastic Band Execution 1. Sit on a weight bench with the legs fully extended so that only the Achilles tendons, ankles, and feet are off the bench. Support the body by placing both hands on the bench behind the body. Wrap an elastic band tautly around both feet, which are plantarflexed, soles down, leaving approximately six inches of space between the feet. 2. Rotate the feet inward, dropping the big toes, and pushing outward with the feet against the resistance of the band. Hold for three to five seconds. 3. Relax the feet, rest for three to five seconds, and repeat. Muscles Involved Primary: peroneus longus, peroneus brevis, extensor digitorum longus Running Focus As mentioned in the introduction to this chapter, pronation happens as a result of movements on three planes, not just one. One of these movements is the eversion of the foot; during plantarflexion, eversion is controlled mainly by the peroneus longus, and in dorsiflexion, the peroneus brevis. This exercise is performed in the plantarflexed position because it is an easier movement, particularly for a runner who is an overpronator. Underpronators, also called supinators, benefit from this exercise because it is not the natural motion of their feet. FEET Foot Inversion on Bosu Ball Execution 1. Step onto a properly inflated Bosu ball with the dome side up. Establish foot position to ensure a properly balanced body. 2. While standing on the Bosu ball with feet in an inverted position, perform any standing exercise from the book (see the Running Focus section that follows for details). 3. Fatigue sets in quickly, so stepping onto a flat surface as a break between reps on the Bosu ball can be taken as needed. Muscles Involved Primary: tibialis posterior Secondary: extensor hallucis longus Running Focus Bosu balls are touted by fitness trainers as a tool for developing balance and proprioception. The development of balance and proprioception benefits the runner racing and training off-road, and the improved ankle strength and flexibility derived from the inverted position of each foot on the ball supports each foot through the gait cycle. The exercise performed is less important than the emphasis placed on maintaining balance on the Bosu ball. Given the curvature of the dome, the feet are in an inverted position on the ball throughout the exercise. For example, performing squats with dumbbells would be a good exercise to promote strengthening of the feet and ankles in the inverted position. Another less dynamic exercise would be to perform dumbbell curls. Or you could do one set or multiple sets of each. The emphasis is on the inverted position of the foot, but combining it with another exercise makes for a time-saving compound movement. The use of the Bosu ball also adds a twist to normal strength-training exercises like dumbbell curls and dumbbell squats, making for a more varied and enjoyable strength-training routine. However, some exercises should not be performed on the Bosu ball. Specifically, exercises that require placing a lot of weight and torque on the knee joints (e.g., full squats with heavy weight) should be avoided. CHAPTER 10 COMMON RUNNING INJURIES If this book had been written without thought for any downside to running, we would have done readers a great disservice. It would be naive in the extreme to imagine that it is possible to run and exercise in a more efficient manner without meeting some of the pitfalls that almost every runner encounters at some time. Some of these are beyond human control, but others are certainly preventable if thought is given to the long-term aim of the training program. If the exercises in this book are followed, the time allocated both to exercise and to running will increase. One handy rule is never to step up either the mileage or the time spent running by more |
than 5 to 10 percent per week. This cannot apply in the initial stages of a training schedule, where less than 10 miles a week are run, but above these levels, this guide will help to prevent overuse injuries. Pain is probably the best warning sign of injury, but it may appear in a variety of forms. Although the suffering that occurs during a tough training session is probably ultimately beneficial in the improvement of performance, the experienced runner will soon learn to recognize pain in other parts of the anatomy that does not disappear when the exercise has ended. External factors that may induce injury include the surface run on and the clothing and shoes worn by the runner. The force of landing with something like three to four times your body weight onto concrete affects the joints much more than a more forgiving and softer surface like sand or even snow. Too many runners use only one side of a road and forget that the camber will pitch them toward the sidewalk and cause a tilt to the pelvis, which may translate into a twisted lower back or strain to the ligaments of the ankle joint. Running demands thought just as much as other sports that require different skills. It is too easy to be dazzled by a new pair of running shoes, which cause blistering on the first occasion on which they are used, simply because you forgot to break them in. All shoes and clothing should be worn in but not worn out! Because the diagnosis of injury is likely to be complex, any unexplained pain or symptom should be rapidly assessed by a professionally qualified doctor. However, a considerable number of commonsense first aid measures can and should be taken in the early stages of injury. It would seem sensible to follow the guidelines that any doctor would use. First, take a history. Ask yourself these questions: Was the injury sudden, or did it build up over a series of runs? Does it cover a small area, or is it more diffuse? Does it hurt to touch? Does it disappear with rest? There are countless more questions, but the object is to make you think about the injury. Next, a doctor will look at the injury. Observation can distinguish asymmetry, swelling, discoloration, and so on. You can do the same in a mirror. Only this stage of examination by gentle palpation, followed by active and passive movement, will elucidate the cause. By this stage there may be a differential diagnosis, a choice of likely and then less common causes. If the diagnosis is pretty much certain, first aid treatment can begin; if not, further tests can be arranged after a visit to the doctor. To a certain extent these can run concurrently, as treatment can be started while test results are awaited. If the results suggest a different diagnosis, then treatment can be amended. The diagnosis and treatment phases of an injury should be interrelated and reciprocal so that if the one is questionable or ineffective, then the other can be reviewed and reassessed. The areas of the body that are likely to suffer most from running are the lower back, the groin, the muscles of the leg, the knee and ankle areas, and the feet. The tissues that suffer most are joints, bones, ligaments, muscles, and tendons. Some choice! A typical muscle tear is most likely to occur if the runner overstretches between two joints, especially if a halfhearted warm-up procedure has been used. The pathology behind this is that a blood vessel inside the muscle will be pulled beyond its limits, burst, relatively flood the area with blood, and stop bleeding only when the counterpressure exerted by the surrounding soft tissues or strapping is equal to that of the blood seeping out. The pressure of this bleeding causes pain in the soft tissues and is always a good indicator of injury. Cooling is another major factor that speeds up healing, so the rapid application of an ice pack to any acute injury, muscle or otherwise, is unlikely to do much harm; if it limits the swelling, it may well reduce the time spent in recovery. Statistically, the back and the knee are the most commonly injured sites for runners. A runner’s back pain will usually be localized to the lower lumbar and sacral areas (figure 10.1), and all too often it is a result of repetitive training with a lack or loss of low back flexibility, accompanied by attempts to run through the pain. It may be related to poor posture, a real or artificial difference in leg length (such as what occurs with the camber running referred to earlier), or a sudden move to hill work. If there is any suggestion that the pain is referred down either leg or is associated with numbness or weakness of the limb, then this could signify a more serious condition such as a prolapsed intervertebral disc, for which a more urgent medical opinion should be sought. Much the same is true of the knee (figure 10.2). An injury followed by swelling or locking within the joint, especially if this happens rapidly over a few hours, is not a simple runner’s knee and needs prompt diagnosis. Runners are more prone to patellofemoral pain as a result of the failure of the patella to glide through the center of the groove at the base of the femur rather than severe internal disruption as might occur with a skiing or football injury. When we stand, our knees and ankles are usually together, but the hip joints can be separated by 12 inches or more. The effect is that when the quadriceps muscles contract, the forces of nature pull the patella laterally and twist it within the femoral groove. The vastus medialis muscle counteracts the pull of the outer quads, but can do so only if it has been strengthened and developed suffi-ciently, which requires it to be exercised with the knee locked and extended. If pain can be localized, it is easier to diagnose the cause. Pain on the outside of the lower thigh is in all probability a result of iliotibial band (ITB) syndrome, in which this piece of generally inelastic connective tissue rubs against the lateral condyle of the femur. If appropriate exercises to stretch it fail, podiatric adjustment of shoes and insoles may bring about a cure. Figure 10.1 (a) Lumbar region of the back; (b) vertebrae. Figure 10.2 Knee. This treatment may also help with the foot pain of metatarsalgia. With a dropped longitudinal arch (known as pes planus, or flat feet), constant landing on a particular bone in the foot and a pull on the surrounding ligaments can be extremely painful, but proper support to the arch with exercises for the intrinsic muscles of the feet may dissipate the pain rapidly. Pain associated with bones is deeper and more resistant to analgesia than that from the soft tissues. One particularly important cause of bone pain is the so-called stress fracture, which can be equated with metal fatigue or the crack that can occur in a china cup. (Figure 10.3 shows the most common sites of stress fractures in runners, in the tibia and fibula.) The fracture is undoubtedly present, but the opposing surfaces remain together because of surface tension and the binding from soft tissues. It is characterized by “crescendo” pain, which worsens with increasing distance run; it most commonly but not exclusively affects the lower leg or foot, and it stops only when the run finishes. On the next run it will begin earlier and worsen sooner. If this symptom is ignored, it may proceed to a complete fracture, with all the potential for disability of any broken bone, and will take at least double the time of a stress fracture to heal. Any runner with these symptoms who suspects a stress fracture is strongly advised to stop running immediately and seek a definitive diagnosis. Figure 10.3 Common sites of stress fractures in the tibia and fibula. Plantar fasciitis is often such a painful condition that it commonly prevents any running at all. The weakest part of this sheet of fibrous tissue that runs between the heel and the metatarsal heads (figure 10.4) is at the heel, where it becomes injured through chronic overuse, ill-fitting shoes, or sudden stretching from an irregularity in the running surface. The typical sufferer will wince when the underside of the heel is even lightly touched. If the exercises in this chapter are ineffective, then a physician’s steroid injection can produce a cure. Figure 10.4 Foot: (a) underside showing plantar fascia; (b) medial side. If an Achilles (figure 10.5) or any other tendon is injured, healing is delayed by the poor blood supply to these tissues. Although the diagnosis may not be too difficult—the tendon becomes locally tender and stiff, especially if stretched—there has been much dispute concerning the best method of treatment. Current opinion tends toward a regimen of extensive stretching, which needs to be repeated endlessly even after a cure has been effected in an attempt to prevent recurrence. To be of value, a stretch should be uncomfortable rather than painful, held for between 15 to 30 seconds, and never used in a jerky or unstable position, such as the performance of a quadriceps stretch by standing on one leg. Figure 10.5 Tendons, bones, and muscles of the lower leg and foot. Note, however, that self-diagnosis of any sporting injury is fraught with danger. Every injury is different in some way from every other and each requires individual assessment and management. It would be irresponsible of us to attempt to manage injury in a book that is aimed at improvement, so the preceding paragraphs should encourage you, the runner, to be aware that your body is not just a mean, well-oiled speed machine but, like all machinery, may need a little fine-tuning! Specific Training Guidelines Warm up by doing some light running before performing the stretch. If the stretch is part of a rehabilitation of a tight iliotibial band and running is not an option, walk or perform a warm-up exercise for the legs for 10 minutes to promote blood flow. There are many supposedly therapeutic treatments for running injuries, and many methods of performing those treatments. For example, the role of stretching in running training is widely debated. How often, what body parts to stretch, and how long to hold the stretch are some of the questions most runners ask running experts. Because the emphasis of this book is anatomy and strength training, an in-depth examination of these topics and the unraveling of the mysteries of stretching are left to you. We offer some best practices, but we also believe in the authorship of your own running training system. Attempt the strength-training and rehabilitation exercises prescribed in this book, and supplement these with others that your experience has proven successful. ITB Stretch Execution for Standing ITB Stretch 1. Stand next to a wall. Cross the outside leg in front of the inside leg (closest to the wall). Press a hand against the wall for support. 2. Lean the inside hip toward the wall, touching the wall if possible. Both feet should remain flat on the ground. 3. Hold the static stretch for 15 to 30 seconds. Repeat multiple times. Switch sides. Execution for Sitting ITB Stretch 1. Sit on the floor with one leg extended and the other leg crossed at the knee, knee in the air, and foot firmly on the ground. The opposite hand is supporting the knee joint. 2. Gently press the outside of the knee that is crossed toward the opposite armpit. 3. Hold the static stretch for 15 to 30 seconds. Repeat multiple times. Switch sides. Muscles Involved Primary: gluteus maximus, tensor fasciae latae Soft Tissue Involved Primary: iliotibial band Running Focus As mentioned in chapter 9, tight iliotibial bands are normally a result of supination, not overpronation. The inversion of the foot can cause tight calves, lateral knee pain, and tight iliotibial bands. Even pronators who are overcorrected by their stability shoes or orthotics, essentially creating underpronation, can suffer from this injury. Performing the standing and sitting iliotibial band stretch will help stretch this thick band |
of soft tissue, preventing the painful rubbing over its attachment at the lateral femoral epicondyle. These stretches can be performed several times a day. Proprioceptive Standing Balance Execution 1. Stand between two walls, one on each side. Extend the arms sideways at shoulder height for balance. Do not use the walls to balance unless needed to prevent falling. 2. Lift one knee until it is at a 90-degree angle with the hip and the tibia is at a 90-degree angle to the femur. Close your eyes. 3. Hold the position for 15 to 30 seconds. Lower the leg and repeat with the other leg. Perform multiple reps. Muscles Involved Primary: peroneus longus, peroneus brevis Soft Tissue Involved Primary: plantar tendon Running Focus This exercise has a neuromuscular and physiological component. It may take a while to establish proper balance, but the foot and lower leg are working to find equilibrium, so the exercise is productive even if you don’t find balance immediately. Standing Calf Stretch Execution 1. Stand, facing a wall with one leg extended backward, foot planted on the ground. The other leg, flexed at the knee, has the foot planted on the ground straight down from the hip. Arms are extended forward at upper-chest height, shoulder-width apart. Hands are placed on the wall. 2. Press gently into the wall and gradually press the heel of the extended leg into the floor. A stretch should be felt through the length of the gastrocnemius. 3. Stretch statically for 15 to 30 seconds and repeat multiple times, or switch legs after every rep. Muscles Involved Primary: gastrocnemius, soleus, hamstrings Running Focus Runners with neutral or underpronated biomechanics often suffer with tight calves. This stretch helps alleviate the pain of a chronically injured calf and also helps prevent calf injuries by keeping the muscle supple. Standing Heel Raise With Eccentric Component Start position. Finish position. Execution 1. Stand with both feet on a step with the heels off the step. Hands are pressed against the wall in front. 2. Raise up onto the metatarsal heads of both feet to full extension (plantarflexed). 3. Lower gradually to full extension (dorsiflexed). Muscles Involved Primary: gastrocnemius, soleus Soft Tissue Involved Primary: Achilles tendon TECHNIQUE TIP ▶ Do not forcefully dorsiflex; it will place too much stress on the Achilles tendon. Running Focus This exercise both concentrically contracts (shortens) the calf muscle during plantarflexion and eccentrically contracts (lengthens) the muscle during dorsiflexion. As mentioned in chapter 9, including an eccentric, or negative, component adds value to this specific calf and Achilles tendon exercise. Studies have found that performing exercises with an eccentric component actually shortens the time it takes to heal an injury. Hamstring Stretch Execution 1. Sit upright lengthwise on a bench in a stable position. The leg with the hamstrings to be stretched is on the bench, and the other leg is placed on the floor with the foot flat to help stabilize the position. Place a towel or soft roll under the knee to be stretched with the knee bent no more than 5 degrees, and rest the heel lightly on the bench. 2. Move the torso forward toward the bench and flex at the hip joints to stretch the hamstrings. Maintain the position for 10 seconds or so, then slowly unwind. (There is no need to stretch out with the arms or to grasp the shin. This may lead to poor posture and an ineffective stretch!) Repeat three times. Alternate both legs in turn. Muscles Involved Primary: hamstrings Secondary: piriformis TECHNIQUE TIP ▶ There is no need to perform a hamstring stretch with the knee straight for specifically increasing hamstring muscle flexibility. When the leg is straightened, the tendency is for the stretch to be taken up more by the tendons and less by the hamstrings. Running Focus There are some runners whose particular style is to “pitter-patter” along with a short stride. Even if they are successful, this sort of running does them no favors if the race speeds up or a final sprint is involved. This exercise helps to increase the stride length without putting more strain on the lower back and sacroiliac regions. It should enable the stride length to be maintained longer as the runner tires, and eventually lead to improved performance. Seated Knee Press Execution 1. Sit upright in a comfortable position with room to extend the legs and knees. The back should be against a solid, supportive object. Both knees are slightly bent, heels on the floor. 2. Slowly straighten one knee in an attempt to push the back of that knee into the ground. Hold this position for six seconds. 3. Relax and allow the knee to flex slightly back to its resting position. Repeat the exercise but with the opposite leg. Do 10 repetitions with both knees. Muscles Involved Primary: vastus medialis Secondary: rectus femoris, vastus lateralis, vastus intermedius, hamstrings, gastrocnemius Soft Tissue Involved Primary: posterior cruciate ligament, hip joint ligaments TECHNIQUE TIP ▶ If you perform this correctly, you should have a pulling sensation at the back of the knee, and a visible bulge will appear above and medial to the knee as the vastus medialis is contracted and its bulk develops. Running Focus Knee pain is the greatest source of difficulty for most runners; runner’s knee is the biggest culprit. This exercise strengthens the vastus medialis muscle and counteracts the slightly lateral (outward) pull of the other quadriceps muscles, which tends to cause patellofemoral pain as the bone shifts in the femoral groove. There is no nonoperative cure other than the development of the vastus medialis muscle, so this should be an essential exercise in every runner’s training program. Knee-to-Chest Stretch Execution 1. Lie on your back on a firm but comfortable surface. 2. Use the quadriceps to lift and bend the knee to 90 degrees, then grasp behind the knee with both hands and pull it toward the chest so that you feel a pulling sensation in the lowest part of the back and upper buttocks. At the same time, resist the urge to flex the other hip, but push it down onto the surface. 3. Hold the position for 15 to 30 seconds and repeat no more than five times, two or three times per day. Alternate with the other leg. Muscles Involved Primary: hamstrings Secondary: piriformis, erector spinae Running Focus The lower back is usually ignored as a vital element of running until pain develops. By then it may be too late to correct. This exercise and those that follow give the lower back flexibility and strength. This is particularly important when climbing or descending hills. If the back can accommodate the changes of gradient, the stride length will also be increased by this flexibility in the hips and lower back. As with all stretching exercises, the aim should be to achieve discomfort without pain. Wall Press Execution 1. Stand approximately 18 inches from a wall with feet shoulder-width apart, toes pointed inward. 2. Press your pelvis to the wall, adjusting the distance from the wall and the angle of the toes to gain the best stretch of the soleus. Keep your heels on the floor. 3. Hold stretch for 15 to 30 seconds and repeat. Muscles Involved Primary: soleus, gastrocnemius, tibialis anterior Running Focus Shin splints, or diffuse anterior lower leg pain, can be either soft-tissue related or bone (tibia) related. Both problems usually stem from overpronation; however, the soft-tissue variety is normally associated with midfoot horizontal plane abduction. This exercise can help prevent muscle pain in the anterior compartment of the gastrocnemius. This exercise can be performed multiple times daily and is effective when done regularly. Ankle Plantarflexion Execution 1. Sit upright on a comfortable, hard-backed chair. The foot is initially flat on the floor, with the knee bent about 45 degrees or so, depending on the height of the chair. Raise the heel off the ground, then invert the foot as though pointing the toes like a ballet dancer. Hold the position for 15 seconds and repeat up to 10 times, two or three times per day, with both feet. With tubing. 2. Place the chair in a position where a piece of flexible elastic such as Theraband can be attached to an immovable object on a wall in a loop. Sit in the same stretched position as previously and put the elastic around the midfoot farthest away from the wall. Use this as resistance to ease the foot farther into inversion and pull against it, strengthening the tibialis anterior muscle. Hold the position for 15 seconds and repeat up to 10 times, two or three times per day, with both feet. Muscles Involved Primary: tibialis anterior Running Focus The importance of the tibialis anterior muscle is in the flexibility it gives to the ankles and feet. It is very involved in increasing stability when running on uneven terrain because it helps to adjust the position of the foot and therefore the leg. As such, any prolonged hill or undulating rough ground will bring it increasingly into use. If untrained, it will tire rapidly and slow the runner down, as well as increase the risk of a sprained ankle. When strengthened, it will also help to limit the pronation and supination of the foot, the cause of further problems for the runner. Partial Sit-Up Execution 1. Lie on a firm, supportive surface on your back with both knees bent and feet flat on floor. Have the hands resting loosely on or hovering slightly above the thighs. 2. Lift the arms a couple of inches and slowly raise the head and shoulders off the floor. Reach with both hands toward the knees and attempt to hold the position for 10 seconds. Repeat five times. Concentrate on performing the exercise smoothly without jerking; just as important, also ensure a slow return to the resting position between stretches. Muscles Involved Primary: rectus abdominis Secondary: transversus abdominis, external oblique, internal oblique Running Focus It is impossible to overemphasize the importance of a stable core for a runner. Weak abdominal muscles cannot help support the back. If the torso crumples under the weight of the upper body, running becomes difficult and painful. This exercise also helps to preserve the link between the abdomen and the lower limbs, and it adds some strength to the knee lift, which in turn will enable the stride length to be maintained. Seated Straight-Leg Extension Foot out. Foot straight up. Foot in. Execution 1. Sit on the floor with your arms behind you for support and one leg outstretched. In the early stages the ankles should not have weights attached, but as you become more adept, you may wish to attach up to 10 pounds of weight incrementally to improve strength. 2. Turn the foot outward and slowly lift the leg, locked straight but not hyperextended at the knee, until it is no more than six inches off the floor. Hold for 10 seconds, then, equally slowly, lower the ankle to the ground and rest. Repeat the exercise 10 times for 10 seconds and alternate with the opposite leg. The foot position can be changed to work all the muscles of the quadriceps evenly. Muscles Involved Primary: vastus medialis Secondary: rectus femoris, vastus intermedius, vastus lateralis Soft Tissue Involved Primary: medial collateral ligament, patellar tendon TECHNIQUE TIP ▶ At first this may seem difficult, which is why you should not attach weights. The upper leg may well develop a tremor when first exercised in this fashion, but as strength is acquired, this will reduce and the whole exercise becomes easier. Running Focus If sports medicine clinics banned runners with knee pain, they would become very lonely places! Unfortunately, too many coaches place far too much emphasis on general quadriceps development and fail to comprehend the role of the vastus medialis in stabilizing the knee and the prevention of patellofemoral pain. This is the most effective way of producing the increase in strength and power in this muscle to ward off the demon of anterior knee pain. CHAPTER 11 ANATOMY OF RUNNING FOOTWEAR Runners who assiduously perform the strength-training regimen outlined in chapters 5 through 9 of this book, arrange their training to conform to the basic tenets of an intelligent training program as explained |
in chapter 2, and take the time to perform the injury-prevention exercises described in chapter 10 can still be stymied in their efforts to improve running performance. Simply by wearing the wrong training shoes or the wrong orthotic device for his or her foot type, a runner may short-circuit his or her well-intentioned efforts to improve. This chapter endeavors to present some sound wisdom about footwear and orthotic selection by presenting an overview of how and why running shoes are constructed for particular biomechanics and how runners can choose the right footwear and orthotics for their specific needs. Why Wear Running Shoes? Running shoes work for running because they are designed and manufactured to meet the demands of bearing three to four times the body’s weight on impact, are designed for the biomechanics of running that are outlined in chapter 3, and are biomechanically (and, to a lesser extent, terrain) specific. Running shoes are designed on lasts, or forms that are models of the human foot. These lasts have shapes ranging from curved to straight with variations on the degrees of the curve, which make the shoes appropriate for the various foot shapes of runners. The term last also applies to the methodology of construction. A combination-lasted shoe stitches the upper fabric underneath a cardboard heel to provide stability. A slip-lasted shoe stitches the upper directly to the midsole, ensuring flexibility. A full-board-last (cardboard from heel to toe) shoe is the most stable lasting technique but currently is almost nonexistent in shoe manufacturing. Theoretically, curved slip-lasted shoes are designed for higher-arched, rigid feet, whereas straight combination-lasted shoes are designed for flatter, more flexible feet. Because flat feet tend to pronate (the inward rolling of the rear foot, controlled by the subtalar joint) more than high-arched feet, straight- lasted shoes, with the aid of stability devices embedded in the midsole, help limit the rate and amount of pronation. Conversely, runners who underpronate should wear curved to slightly curved slip-lasted shoes, which allow the foot to generate as much pronation as possible to help aid in shock absorption. Many runners err in choosing shoes because they do not know what foot type they have. If an underpronator trains in stability shoes, predictable injuries like calf pain, Achilles tendinitis, and iliotibial band syndrome will occur. If an overpronator trains in a cushioning-only shoe, stress injuries (including fractures) to the foot, tibia, and the medial knee likely will occur. For most runners, a qualified employee at a running specialty store can evaluate foot biomechanics, possibly by using a treadmill and a video camera, and successfully recommend multiple shoe models that, in theory, will prevent injury and provide a pleasurable ride. Occasionally, evaluating the foot becomes tricky due to motion not seen clearly by the naked eye, and a slow-motion camera may be needed to ascertain true foot movement. This is rare and usually not found in recreational runners due to lower training volume and velocity. Understand that biomechanics can change; what was once corrected may no longer be a problem, and new problems can arise. History of 20th-Century Running Shoes The history of the running shoe in the 20th century begins with Spalding’s introduction of the long-distance running shoe. The company outfitted the 1908 U.S. Olympic marathon team in its models, and based on observations of the marathon and the shoes’ performances, it created a line of marathon shoes in 1909. Both high-top and low-top shoes with a pure gum sole and leather uppers were “full finished inside so as not to hurt the feet in a long race.” Within five years, the gum rubber sole had been replaced by the leather sole, and the research and marketing of running shoes had begun in earnest, albeit in fits and starts. Although Spalding continued tinkering with its running shoe models, the intrigue in running shoes sparked by the 1908 Olympic marathon in London gave way to a fascination with track spikes, particularly those manufactured by the Dassler brothers of Germany. Worn by Jesse Owens in the Munich Olympics, the spiked shoes were little more than a soft leather upper sewn to hard leather soles with permanent “nails” built into the soles to provide traction on the dirt tracks. An interest in production of running shoes was rekindled in the United States in the mid-1960s through the mid-1970s, which ushered in the era of the running specialty business. Facing competition from the Japanese-imported Tiger running shoes, Hyde, New Balance, and Nike all began production of serious running shoes. The features of the new shoes were a higher heel, midsole cushioning material (EVA), and nylon uppers. In some cases, the shoes were well made; in most cases, they were not. By the late 1970s, Runner’s World began lab-testing the running shoes, and the manufacturers were forced to improve the quality of their shoes or lose market share. This change in the mind-set of the companies began a period of intense competition (that still lasts today) to provide the best fit with the most cushioning, stability, and durability in a shoe that looks good. Components of Running Shoes This section describes the components of the running shoe and their significance for the runner. The emphasis is on finding the right shoe, from a biomechanical and a fit standpoint. One part of the equation without the other could lead to injury. When purchasing shoes, remember that the cost of the shoe does not ensure its success. For one runner, an expensive shoe may only deplete his bank account without aiding performance; for another, the shoe may be expensive and perfect. Your foot type, shape, and biomechanics determine what is best when it comes to shoes. Upper The upper of a running shoe (figure 11.1) is the material that covers the top and the sides of the foot. It can be made of multiple pieces of fabric sewn or glue-welded together, or it can be made of a one-piece, seamless material. All current running shoes are of human-made materials (nylons) for breathability, comfort, and weight reduction. Leather is no longer used because of its lack of breathability, nonconforming shape after repeated use, weight, and cost. The front of the upper is referred to as the toe box of the shoe (figure 11.2). It takes its shape from the last of the shoe (the form the shoe is built on), but its style is determined by the shoe designer to meet the needs of the shoe wearer. The toe boxes of many of the shoes built recently are wider and deeper to accommodate the higher-volume feet that seem to have become more prevalent as the second running boom has corralled more recreational runners with larger frames into the sport. The midfoot of the shoe’s upper can be designed in conjunction with or independently of the lacing system (e.g., ghillie lacing) to allow for various upper fits. Occasionally, companies will attempt a nonsymmetrical lacing pattern ostensibly designed to improve the fit of the upper and remove “hot spots” (pre-blister-forming areas) from developing on the foot during running. Figure 11.1 Lateral view of shoe: upper, midsole, and outsole. Figure 11.2 Upper. The design of the upper of the shoe determines the fit of the shoe—not the length of the shoe, but how the shoe envelops the foot. This is important because if the shoe fit is improper, the biomechanical needs of the runner may not be met. Only when the fit of the shoe is spot-on can the function (be it stability, motion control, or cushioning) work as designed. For example, if the fit of the upper is too baggy in the midfoot, excessive pronation can occur despite the presence of a medial support. The lack of a proper fit renders the stability device ineffective in combating the pronation it was designed to limit. Injuries can occur—in this case, tibial pain—even if a runner wears a shoe that is the correct category for his or her foot type. This scenario often leads to disenchantment when purchasing shoes because of the confusion resulting from following the suggestions and guidelines and still not getting relief from pain. Here is a general point when purchasing shoes: If the shoe doesn’t fit your foot well, it isn’t the best shoe for you, regardless of whether its biomechanics are matched to your foot type. For example, it could be argued that for a mild overpronator, a cushioned shoe that fits perfectly is more stable than a mild stability shoe that is too roomy. In conjunction with proper fit, a heel counter embedded in the upper material ensures a secure, mildly stable ride when running. Heel counters (figure 11.3) are hard plastic devices that stabilize the rear foot, helping the foot through the normal cycle of heel strike, midfoot stance (avoiding excess pronation), forefoot supination (the outward rolling of the forefoot), and toe-off from the smaller toes of the foot. Heel counters can be removed in shoes manufactured for underpronators, but the possibility of Achilles tendinitis is increased because of the increased movement of the calcaneus and the subsequent pulling on the Achilles tendon. Figure 11.3 Heel counters and heel clefts. Midsole The midsole of a running shoe (figure 11.4) is made of EVA (ethylene vinyl acetate) or rubberized EVA used to cushion or stabilize the ride of the shoe during foot strike. Developed in the early 1970s as a cushioning material to rival polyurethane (which is denser and heavier), EVA has been combined with other proprietary cushioning materials such as air and gel as well as engineering designs like wave plates, footbridges, cantilevers, and truss systems to minimize impact shock generated during the foot strike and to guide the foot through its normal path. The holy grail of midsole technology has been to find a material that provides a moderately soft ride and has the durability to withstand compression, which limits the life span of the shoe. A reasonable expectation for a running shoe’s life is 350 to 500 miles. The development of a midsole that could provide 750 miles of consistently comfortable running would be a boon both to runners and to the manufacturing company that patented the material. Figure 11.4 Midsole. The current crop of rubberized midsoles provide dramatically better cushioning than their “sheet” EVA predecessors from the 1970s, but there is an environmental cost associated with producing the material. Traditional EVA midsoles take approximately 1,000 years to entirely biodegrade. Some running shoe manufacturers are marketing eco-friendly “green” midsoles that are touted as environmentally sound because they degrade 50 times faster in a traditional landfill environment. Most runners look at the outsoles of their shoes to determine whether the shoes need to be replaced. Unfortunately, when the outsole of a running shoe has worn away enough to show significant wear, the midsole has been long compromised in providing cushioning. Because midsoles provide cushioning, they also absorb and dampen the shock of impact. During a 30-minute run, each shoe lands on the ground approximately 2,700 times. That is multiplied by an impact force of three to four times a runner’s body weight, so it’s amazing that no more than a two-inch-thick wedge of EVA can withstand approximately 150 of these training runs before being replaced. The midsole is also the part of the shoe that contains the various stability devices designed to prevent pronation. These devices are always placed on the medial side of the shoe, usually between the arch and the heel. The devices are located in this area to counter the effects of pronation, which is mainly controlled by the subtalar joint that is located in the area of the foot closest to this part of the shoe. Occasionally a shoe will be produced with forefoot posting (to prevent late-stage pronation of the forefoot), but this is a nontraditional method of design. Posting of the lateral side of the shoe is never done because increasing the rate and degree of pronation is problematic for pronators (leading to increased tibia discomfort) and needless for underpronators (a cushioned shoe allows for the foot to pronate as it needs to). Outsole The outsole of a running shoe (figure 11.5) has evolved dramatically from a materials standpoint from the gum rubber of the 1908 Spalding marathon trainers. The outsole (the part of the shoe that actually touches |
the road) is made of carbon and blown rubber composites used jointly to make for a durable yet appropriately flexible ride. Most runners strike the lateral heel of the foot upon impact. Hence, manufacturers place the most durable carbon rubber in this area of the shoe to ensure longevity of the outsole. Despite the added durability of the carbon rubber, excessive wear will still appear in that area of the shoe for most runners. This is to be expected and does not indicate a proclivity toward overpronation or underpronation. It simply means the runner is a heel striker. If the outsole is completely worn through in the forefoot of the shoe, the midsole cushioning was compromised long before, and the shoe is worthless as a shock-absorbing entity. Because the outsole of the shoe lasts much longer than the midsole cushioning, using outsole wear as a guide for when to replace your running shoes is erroneous. The best method of measuring the life of a shoe requires little work. Pay attention to the mileage on your shoes by keeping a log or quick estimation of miles per week multiplied by weeks of training, and after approximately 350 miles, replace your shoes when you begin to have aches or pains in your legs that you did not have for the first 350 miles of the shoe’s life. Normally, if a shoe model is not correct for a runner’s biomechanics, weight, flexibility, or foot shape (all factors that determine the best shoe), discomfort or injury will occur within the first 100 miles of running. Thus, the wrong shoe should rarely be confused with an old shoe. Figure 11.5 Outsole. Shoe manufacturers are constantly altering the strike path of a shoe’s outsole and the surface pattern of the rubber to improve comfort and durability. Although these aims of the manufacturers seem to be worthwhile, the role of aesthetics in shoe design cannot be ignored. At every phase of design and development, the aesthetics of the shoe, its attractiveness to the consumer, must be weighed against the practicality of building the shoe and the effectiveness of the shoe for running purposes. Often the aesthetics of the shoe take precedence, and a much-hyped shoe proves to be a performance dud—albeit a dud with an expensive advertising campaign. Insoles and Orthotics Runners want to wear comfortable running shoes that help prevent injuries; however, because running shoes are not custom-made, there will always be a bit of a compromise when it comes to fit. Because each runner’s foot is unique and not even symmetrical with the other foot, it becomes apparent that accommodations may be needed in order to enhance a running shoe’s fit and its function. To customize the fit and function of their shoes, runners turn to insoles and orthotics. Each pair of running shoes comes with an insole. It is made of EVA or a material combined with EVA to add comfort (shock absorption) and to aid the fit of the shoe. It costs less than 50 cents to manufacture, and it is mostly useless. It is removable, and for a good reason. Most runners remove the inexpensive insole and replace it with a more cushioned or more stable insole that actually has some resemblance to the shape of the human foot. In the past decade, over-the-counter replacement insoles have become a serious revenue generator for running specialty stores. The proliferation of these stores has led to more retail outlets for the sales of insoles, and the insole manufacturers have responded by producing good-quality products for less than $30. It seems a bit redundant to spend $90 on a pair of shoes and $30 on a pair of insoles when you could just buy a $120 pair of running shoes. The true value of the insole is that it customizes the shoe to the runner’s foot. Thus, the $90 shoe feels closer to a perfect fit than the $120 shoe because it more closely resembles a shoe made from a mold of the runner’s own foot. Not only does the insole aid fit, but current insoles also help correct for poor biomechanics. They can be posted to compensate for pronation factors or high-arched to help prevent plantar fasciitis. They do work well, but they are not for every runner. Many runners can do without insoles because they do not have major biomechanical problems that their training will exacerbate. For those runners who have run a lot of miles in their lives, are training at a high volume, or have chronic injuries, insoles are a viable option. For those runners who do not find relief with an over-the-counter insole, the next step is to visit an expert (certified pedorthist or podiatrist) to obtain custom-made orthotics. An orthotic device is meant to correct an anatomical or biomechanical abnormality. In theory, an orthotic device realigns the foot strike, which, in turn, alleviates any imbalances or weaknesses through the kinetic chain of events initiated by running. Do orthotics work? Sometimes. Upon visiting a podiatrist or certified pedorthist, a runner should expect the following procedure to occur before an orthotic device is produced. The specialist should take a thorough history of running injuries, shoes worn, and remedies attempted. Measurements of leg length and an evaluation of joint mobility should be completed. X-rays can be taken, but they are often not necessary. After evaluating the feet, the specialist will proceed to make plaster molds of them. The doctor will place each foot in a “neutral” position and wrap plaster-soaked strips of gauze around each one. The most important step is placing the foot in the neutral position. This position is the key element in producing an orthotic that works well. Because the goal of an orthotic is to correct, the foot must be in the neutral position so a cast can be fabricated that shows any corrections to be made. The difference between the runner’s foot and the appropriate position of the runner’s foot when in neutral is the correction that needs to be made. When the cast is sent to an orthotics lab to produce the orthotic, a technician will evaluate the cast and take more measurements. From the “negative” cast, a “positive” model is created from plaster and is ground to the specifications provided by the doctor. A hard orthotic is fabricated from thermoplastic and filled with cushioning material. It is posted medially no more than 4 degrees to help position the foot in neutral at midstance. It is covered by a thin layer of synthetic material. A soft orthotic, also referred to as an accommodative orthotic, is more of a custom-made arch support than a posted orthotic. Its goal is less medial stabilization for pronation and more arch support for a runner with high, rigid arches. Normally, a running orthotic will be full length, replacing the insole of the shoe. It is not uncommon for a laboratory to offer a three-quarter-length orthotic. Because most rear-foot motion issues can be alleviated with a three-quarter-length orthotic, logic would dictate that the weight-saving inherent to a three- quarter-length orthotic would be welcome. Unfortunately, the lack of a continuous surface under the complete length of the foot leads runners to fabricate their own system of completing the orthotic. Purchase an orthotic with a full-length cover. The litmus test of a well-constructed orthotic is twofold. Does it fit comfortably into a running shoe (although it may be a different, larger shoe than you were wearing), and does the orthotic device eliminate the running injuries it was created to combat without causing other injuries? The answer should be a resounding yes! If not, contact your doctor for a follow-up appointment to reevaluate the orthotic. The pairing of an orthotic device and a running shoe is a combination of art and science. If a hard, corrective orthotic is worn, a neutral cushioned shoe that encompasses the orthotic well and provides a good fit may suffice in eliminating any overpronation injuries. If a stability shoe is still needed with a hard, corrective orthotic, take caution to avoid the possibility of overposting the foot. This marriage of a stability shoe and corrective orthotic is a possible recipe for iliotibial band syndrome, an injury usually associated with underpronators who stay on the lateral aspect of their foot through the foot strike, creating tightness in all the muscles and soft tissue laterally from the foot to the hip. At the first sign of pain on the lateral side of the knee or tightness in the hip area, reconsider the use of a stability shoe and corrective orthotic. Underpronators who wear accommodative orthotics should continue to wear cushioned shoes. The only caveat, and this is true for overpronators with orthotics as well, is that an extra half size may be needed in order to fit the orthotic into a running shoe. The orthotic replaces the insole that comes with the shoe, but it is higher in volume and thus needs to be fit properly so that the biomechanics it is meant to promote during running can proceed seamlessly. Barefoot Running Barefoot running could have been included in chapter 9’s list of exercises to strengthen the foot because that is essentially what barefoot running does best (along with developing some proprioceptive awareness). But daily barefoot training is not really a substitute for running in shoes. Given that most runners log the majority of their miles on asphalt, concrete, treadmills, and gravel-strewn trails, running barefoot daily seems a bit painful at the least; however, running without shoes does have many practical applications when used as a supplement to running training, much like the strength-training exercises outlined in chapters 5 and 6 of this book. It should not replace traditional (with shoes) training. The argument has been made that many African runners have trained barefoot and have had success (native South African Zola Budd is a famous example), but the counterargument is that all the world records are held by shoe-wearing runners. Proponents of barefoot running tout the muscular strength gained through barefoot running, which is an accurate assessment in the proper context. Advocates of barefoot running also tout the psychological release derived from running on sand and lush grass, which may also be because sand and lush grass are normally found in places more likely to be idyllic, although it is a tenuous connection to aiding running performance. The best reason to do some barefoot running on lush grass or hard-packed sand (not more than twice a week and no more than 100 meters straight for a total of 400 meters per session to begin) is to train the muscles of your feet to work differently than they do when running shoes are worn. Barefoot running forces the feet to work, preventing atrophy in the muscles of the foot that function the same way during every run in running shoes with or without orthotics. The antiorthotic movement in running espouses mixing in barefoot running and running in neutral shoes for overpronators to force the foot to strengthen itself to prevent future injuries. Just as the exercises in this book have detailed how to strengthen your body to improve running performance, barefoot running can help strengthen your feet to withstand the countless training miles required of them. As with all strength training, if you feel pain while barefoot running, stop. Summary The ultimate goal of a well-designed and constructed running shoe and orthotic device is to promote injury-free and comfortable running. Extra cushioning to limit the impact forces of the foot strike, stability devices adding medial posting to limit pronation generated by the subtalar joint, and transitional EVA densities to ease the transition from heel strike to midstance are all designed to meet this goal. Appropriate footwear and orthotic devices (matched to a runner’s biomechanical needs), when combined with the strength-training program for the lower leg and foot presented in chapter 9, should eliminate all leg and foot injuries. One caveat is that the running shoe and orthotic must be appropriate to the foot that wears it, and the shoe and orthotic device must be replaced when its cushioning, stability, and accommodative properties are compromised. Normally, a running shoe can be expected to last at least 350 miles, an aftermarket insole should last through every other shoe purchase, and a custom |
orthotic should last at least two years (although the cover may need to be replaced). Trained employees at running specialty stores can help runners match current running shoes with the appropriate foot types and match feet with nonprescription insoles that provide similar protection as orthotic devices, but are not custom-made by a podiatrist. The effectiveness of any running shoe and orthotic device hinges not just on biomechanics but also on fit. A well-constructed shoe that is the right biomechanical choice for a runner may not function correctly if the shoe is ill-fitted to the foot. When purchasing a shoe, make sure the shoe is neither too long or too short, nor too wide or too narrow. Also, try the new shoes with the orthotic device to be worn in order to replicate the fit of the shoe-and-insert combination. Remember, if it doesn’t work in the store, it is not going to work on the road, trail, or track! CHAPTER 12 FULL-BODY CONDITIONING Chapters 5 through 9 of this book deal with strength training and the specific anatomy affected by properly performed resistance exercises. This chapter deals with alternative forms of exercise that complement the strength-training exercises detailed in the previous chapters. Specifically, this chapter examines water running and plyometrics as performance-enhancing training tools for runners. Full-body conditioning is an important training element because it can diminish the injury potential that a repetitive, high-impact exercise such as running can have on the musculoskeletal system. By substituting a deep-water running session for a land running session, you can avoid countless tons of force on the body’s anatomy without a concurrent loss in cardiovascular stimulation. Also, incorporating plyometrics into a training plan strengthens muscles, aiding the ability to withstand the impact of accumulated running training miles. It also helps in recovery from injury (when performed at the appropriate time), and it can improve running economy. Water Running Most runners have been introduced to water running as a rehabilitative tool for maintaining cardiorespiratory fitness after incurring an injury that precludes dryland running. However, runners should not assume that aquatic training’s only benefit is injury rehabilitation. Running in water, specifically deep-water running (DWR), is a great tool for preventing overuse injuries associated with a heavy volume of aerobic running training. Also, because of the drag associated with running in water, an element of resistance training is associated with water running that does not exist in traditional running-based training. Although shallow-water running is a viable alternative to DWR, its benefits tend to be related to form and power. Although the improvement of form and power is important, it comes at a cost. Because shallow-water running requires impact with the bottom of a pool, it has an impact component (although the force is mitigated by the density of the water). For a runner rehabbing a lower leg injury, shallow-water running could pose a risk of injury. More important, balance and form are easier to attain in shallow-water running because of a true foot plant. Fewer core muscles are engaged to center the body, as in DWR, and there is a resting period during contact that does not exist in DWR. For our purposes, all water-related training exercises focus on DWR. In performing a DWR workout, proper body positioning is important (figure 12.1). The depth of the water should be sufficient to cover the entire body: Only the tops of the shoulders, the neck, and the head should be above the surface of the water. The feet should not touch the bottom of the pool. Runners tend to have more lean body mass than swimmers, making them less buoyant; therefore, a flotation device will be necessary. If a flotation device is not worn, body position can become compromised and an undue emphasis is placed on the muscles of the upper body and arms to keep the body afloat. Once buoyed in the water, assume a body position similar to dryland running. Specifically, the head is centered, there is a slight lean forward at the waist, and the chest is “proud,” or expanded, with the shoulders pulled back, not rotated forward. Elbows are bent at 90 degrees, and movement of the arms is driven by the shoulders. The wrists are held in a neutral position, and the hands, although not clenched, are more closed than on dry land in order to push through the resistance of the water. (See figure 12.2 for an example of poor body position during DWR.) The strength gained from performing wrist curls and reverse wrist curls (see chapter 6) are beneficial for this. Figure 12.1 Proper body position for deep-water running. Leg action is more akin to faster-paced running than general aerobic running because of the propulsive force needed for overcoming the resistance caused by the density of the water. The knee should be driven upward to an approximate 75-degree angle at the hip. The leg is then driven down to almost full extension (avoiding hyperextension) before being pulled upward directly under the buttocks before the process is repeated with the other leg. During the gait cycle, the feet change position from no flexion (imagine standing on a flat surface) when the knee is driving upward to approximately 65 degrees of plantarflexion (toes down) at full extension. This foot movement against resistance both facilitates the mechanics of running form and promotes joint stability and muscle strength as a result of overcoming the resistance caused by drag. Due to the unnatural training environment (water) and the resistance created when driving the arms and legs, improper form is common when beginning a DWR training program. Specifically, it is common to make a punting-like motion with the forward leg instead of snapping it down as shown in the B motion on page 24. This error is due to fatigue of the hamstrings from the water resistance, resulting in poor mechanics. To correct this error, rest at the onset of the fatigue, and don’t perform another repetition until the time goal is met. Do not try to push through it. You won’t gain fitness, and you will gain poor form. Figure 12.2 Incorrect body position for deep-water running. Figure 12.3 shows a DWR technique that most closely resembles dryland running form. It is the best technique for facilitating proper running form while training in deep water. A high-knee alternative does exist (figure 12.4), but it is less effective in mimicking the nuances of proper running form. Instead, it more closely resembles the form used on a stair-stepping exercise machine. There is little running action other than the lift phase and therefore very little muscle involvement. DWR is effective because it elevates the heart rate, similar to dryland running. And because of the physics of drag, it requires more muscular involvement, thus strengthening more muscles than dryland running does without the corresponding overuse injuries associated with such training. Specifically, it eliminates the thousands of impact-producing foot strikes incurred during non-DWR running. DWR is easily integrated into a running training program either as a substitute for an aerobic run, lactate, or V O2max effort or as a supplemental workout, such as a second running workout of the day. Because pace is easily controlled by speeding up or slowing down leg turnover, adjusting efforts based on heart rate or perceived effort is simple. Studies have found that heart rates during water running are about 10 percent lower than during land running, so a heart rate of 150 beats per minute (bpm) during water running equates to a heart rate of 165 bpm on land. Also, perceived effort is greater in water because of the combination of greater muscle involvement and the warmer temperatures of most pools. Because running for an hour in the pool is boring to most runners, we recommend 50 minutes in a pool as a good substitute for an on-land easy run; fartlek and interval-type efforts should be the emphasis of DWR training. Also, multiple intense efforts akin to speed work on land can be performed weekly because of the lack of ground impact. The following are two sample DWR workouts. Figure 12.3 Deep-water running, traditional form. Figure 12.4 Deep-water running, high-knee form. Sample Lactate Workout The goal of this workout is to elevate the blood-lactate accumulation. At the end of each subsequent repetition, muscle fatigue should be increasingly present because the one-minute rest does not allow full recovery. This is not an easy workout, but it would not be a true speed session. Warm-up: 15 min easy running + 4 × :30 @ 5K race pace (perceived effort) 2 × 10 min @ 10K race pace (perceived effort) with 1 min recovery jog 1 × 15 min @ 10K race pace (perceived effort) with 1 min recovery jog Cool-down: 10 min easy running SampleV O2max Workout The goal of this workout is to simulate 5K race effort. Because pace can’t be replicated in a pool, the emphasis of the workout is on perceived effort. Heart rate can be used; if you know your training zones from an LT test and you own a waterproof heart rate monitor, the exact effort can be substituted. Rest is given to allow for proper form on each repetition. Note that, as in running on dry land, body position is an important component of running efficiency. Good body position (as described and illustrated earlier in the chapter) leads to a more productive workout. This would be a moderately hard effort for a trained runner and a difficult effort for a beginner. Warm-up: 15 min easy running + 4 × :30 @ 5K race pace (perceived effort) 5 × 2 min @ 5K race pace (perceived effort) with 2 min recovery jog 3 × 3 min @ 5K race pace (perceived effort) with 3 min recovery jog 3 × 2 min @ 5K race pace (perceived effort) with 2 min recovery jog Cool-down: 10 min easy running Plyometrics The term plyometrics is mysterious to many distance runners, although it is a common training tool for many elite distance runners, middle-distance runners, and sprinters, most professional athletes, and many athletes rehabilitating from injuries. For the noninitiated, it sounds like, and at times is represented as, a hyperspeed method of improving performance. Just perform plyometrics, drink amino acid-laced recovery drinks, and voilà, instant performance improvements. By definition, plyometrics means measurable increases, in this case through body-weight exercises. Because it is the use of strength, not raw strength, that contributes to speed development, plyometric exercises have one main goal: the conversion of strength to speed by generating a large amount of force quickly. Plyometric exercises train the neurological and muscular systems to increase the speed at which the body’s strength can be used. By performing plyometric exercises, runners can measurably improve running performance, but not in the way they may think. A by-product of the development of muscular power is an improvement in running economy. Running economy is the cost, or amount of oxygen, required to maintain a defined pace. The less oxygen used to maintain a certain pace relative to other runners or your previous measurement, the better the running economy. It does not quantify the efficiency of running form (the terms are often confused), although running form may affect running economy. Plyometric exercises trigger improved running economy through recruitment of muscle fibers in a way that distance training does not. A plyometrically trained athlete’s muscle contractions are shorter in duration; because less strength is required to perform the contraction (a result of both increased strength and neurological development), running economy improves. This chain of events leads to faster performances caused by the delay of muscle fatigue. But, unlike DWR, plyometrics cannot be substituted for running training to improve performance for distance runners. Although DWR has an impact on LT and V O2max, plyometric exercises train the neuromuscular systems with almost no impact on the cardiothoracic systems described in chapter 2. Without running training, plyometric training could not sustain improvements in running performance. There is debate about the phase of training in which plyometrics should be incorporated. There are no definitive answers, but we suggest one plyometric session per week during lactate training and two sessions per week during V O2 max training. The workout should be done before the LT or V O2 max workout takes place, in a separate training session |
Endobronchial Ultrasonography Companion DVD This book has a companion DVD with: • A searchable database of 36 video clips showing procedures described in the text • All clips are referenced in the text where you see this icon: Endobronchial Ultrasonography Noriaki Kurimoto MD, PhD Professor of Chest Surgery Department of Surgery St Marianna University Kawasaki City Kanagawa Prefecture Japan David I. K. Fielding MB, BS, FRACP, MD Director of Bronchology Department of Thoracic Medicine Royal Brisbane and Women’s Hospital Brisbane, QLD, Australia Ali I. Musani MD, FCCP, FACP Associate Professor of Medicine and Pediatrics; Director Interventional Pulmonology National Jewish Health Associate Professor of Medicine University of Colorado School of Medicine Denver, CO, USA A John Wiley & Sons, Ltd., Publication Disclaimer: This eBook does not include ancillary media that was packaged with the printed version of the book. This edition first published 2011 © 2011 by Noriaki Kurimoto, David I. 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No warranty may be created or extended by any promotional statements for this work. Neither the publisher nor the author shall be liable for any damages arising herefrom. Library of Congress Cataloging-in-Publication Data Kurimoto, Noriaki. Endobronchial ultrasonography / Noriaki Kurimoto, David I. K. Fielding, Ali I. Musani. p. ; cm. Includes bibliographical references and index. ISBN 978-1-4051-8272-0 1. Bronchi–Cancer–Ultrasonic imaging. 2. Endoscopic ultrasonography. 3. Bronchi–Ultrasonic imaging. I. Fielding, David I. K. II. Musani, Ali I. III. Title. [DNLM: 1. Bronchi–ultrasonography. 2. Bronchoscopy–methods. WF 500 K96e 2011] RC280.B9K87 2011 616.99'423–dc22 2010019095 A catalogue record for this book is available from the British Library. This book is published in the following electronic formats: ePDF 9781444314373; Wiley Online Library 9781444314366 Set in 8.75 on 12 pt Meridien by Toppan Best-set Premedia Limited 01 2011 Contents Dedication, vi 8 EBUS-Guided Peripheral Pulmonary Nodule Biopsy, 73 Foreword, vii 9 Diagnosis of Peripheral Pulmonary Lesions Using Preface, viii Endobronchial Ultrasonography with a 1 An Overview of Endobronchial Guide Sheath, 89 Ultrasonography, 1 10 Endobronchial Ultrasonographic Analysis 2 Anatomy of Mediastinal and Hilar Area, 16 of Airway Wall Integrity and Tumor Involvement, 96 3 How to Perform Endobronchial Ultrasonography, 26 11 EBUS in Interventional Bronchoscopy, 111 4 Endobronchial Ultrasound-Guided Transbronchial 12 Future Directions for Endobronchial Needle Aspiration (EBUS-TBNA), 36 Ultrasonography, 118 5 Tips and Diffi culties in EBUS-TBNA, 52 13 Case Reports, 120 6 Endoscopic Ultrasound-Guided Mediastinal Appendix: Videos, 160 Lymph Node Aspiration for Lung Cancer Index, 162 Diagnosis and Staging, 59 7 Qualitative Analysis of Peripheral Pulmonary Lesions Using Endobronchial Ultrasonography, 62 Companion DVD This book has a companion DVD with: • A searchable database of 36 video clips showing procedures described in the text • All clips are referenced in the text where you see this icon: v Noriaki Kurimoto MD To my wife and children: Mayumi, Satoshi, Wataru, Misturu, and Manabu David Fielding MD To my wife and children: Siobhan, Josie, Alison, Eveline, and Michael Ali I. Musani MD To my wife and children: Lubna, Sara, and Sef vi Foreword How nice it is for us to be able to learn from this text- by a tireless and enthusiastic surgeon, Dr. Kurimoto, book the up- to - date knowledge and techniques of whom I thank for his friendship and encouragement, echobronchoscopy. which I will always appreciate. The main part has been written by Professor N. The two coauthors, Drs. D. Fielding and A. Musani, Kurimoto. The few years during which I worked with are both leading bronchoscopists, and good friends of Dr. Kurimoto in the Department of Chest Surgery St. mine. Many times we shared knowledge and desire in Marianna Univerisity School of Medicine was very the bronchoscopy, especially in echobronchoscopy, fruitful, especially because we could feel that we were with each other at St. Marianna University. I am in contributing to our specialty by developing the theory the position to congratulate an epoch making publica- and technique of echobronchoscopy. As soon as Dr. tion in this attracting fi eld. Kurimoto joined us, it became routine for a lobe just removed in the theater to reach the pathology section Hiroaki Osada, M.D. by being carried in Dr. Kurimoto’ s own hands for a Professor Emeritus redo echobronchoscopy. St. Marianna University School of Medicine This book shows what those lobes have taught us Kawasaki Japan regarding how exact the preoperative diagnosis had Chair of the World Association for Bronchology been, or why the original lesion had been undiagnosed. and Interventional Pulmonalogy The essence of this book is the product brought about August, 2010 vii Preface Gastrointestinal and genitourinary ultrasound tech- Endobronchial ultrasound has truly revolutionized nologies have gone through dramatic improvements the diagnosis and staging of lung cancer and many and growth over the last three decades. However, the other diseases of the mediastinum and lungs. We feel pulmonary applications of ultrasound, endobronchial honored to have been a part of its development and ultrasound (EBUS), started much later, in the early dissemination. 1990 ’ s. We sincerely hope that our book will help physi- In the fi rst half of this book we present a compre- cians learn the technique of endobronchial ultrasound hensive review of the principals of ultrasound and and its applications to its fullest. its application in thoracic medicine. We summarize We would like to thank Mr K. Hirooka and Mr K. mediastinal anatomy, the basic technique of needle Nishina of the Ultrasound Development Group at aspiration of lymph nodes, and how to perform suc- Olympus Optical Co. Ltd, and Ms. Cathryn Gates of cessful endobronchial ultrasound guided transbron- Wiley - Blackwell for her editing assistance. We would chial aspiration. We also discuss the use of peripheral also like to express our gratitude to Dr F. Tanaka of ultrasound for the localization of pulmonary nodules, the Hyougo Medical University Department of Thoracic and the role of endobronchial ultrasound in interven- Surgery and Dr R Amemiya of the Ibaraki Prefectural tional pulmonology. This book is an evidence- based Central Hospital for the illustrations used in this book. refl ection of our collective experience of hundreds of Without their invaluable assistance, this book would thousands of cases. not have been possible. The second half of this book focuses on the correla- tion of EBUS images with the histology and pathology August 2010 of mediastinal lymph nodes and pulmonary nodules. Noriaki Kurimoto In our experience, careful and methodical analysis of David I. K. Fielding ultrasound images of these structures could predict the Ali I. Musani benign vs. malignant nature of these structures with signifi cant sensitivity and specifi city. viii 1 An Overview of Endobronchial Ultrasonography 2 Iizuka 1992: Evaluation of airway smooth muscle Introduction (A History of Endobronchial contractions in vitro by high - frequency ultrasonic Ultrasonography) imaging [3] . 3 Ono 1992: Bronchoscopic ultrasonography in the Endobronchial ultrasonography (EBUS) is a diagnostic diagnosis of lung cancer [4] . modality whereby a miniature ultrasonic probe is 4 Goldberg 1994: US - assisted bronchoscopy with use introduced into the bronchial (tracheal) lumen, pro- of miniature transducer - containing catheters (deline- viding tomographic images of the peribronchial (peri- ation of central and peripheral pulmonary lesions) [5] . tracheal) tissue. Endoscopic ultrasonography (EUS) 5 Becker 1995: Endobronchial ultrasonography – a is already an indispensable technique for examining new perspective in bronchology? (tracheobronchial the gastrointestinal tract, particularly the stomach and wall 7 - layer structure) [ 6] . large intestine. Applications of EUS include assessment 6 Kurimoto 1999: Assessment of usefulness of endo- of the depth of tumor invasion, detection of lymph bronchial ultrasonography in determination of depth node metastases, tumor staging, and fi ne needle of tracheobronchial tumor invasion (tracheobronchial aspiration (FNA) under EUS guidance. wall 5 - layer structure) [ 7] The fi rst reported clinical use of a narrow gauge ultra- Based on these studies, the present applications of sonic probe was for intravascular ultrasonography by EBUS are: Pandian et al. [1] in 1988. The history of EBUS began a Determination of the depth of tumor invasion of the with the report by H ü rter et al. [2] of endobronchial tracheal/bronchial wall (allocation of patients to local- ultrasonography of the lung and mediastinum in 1990. ized endobronchial treatments such as photodynamic Since then, development and research has been carried therapy (PDT). out mainly by Becker (Germany) and ourselves (Japan). b Identifi cation of the location of a peripheral lung EBUS probes are typically of the 20 MHz radial type. lesion during bronchoscopic examination (more accu- Tissue penetration of the ultrasound waves is there- rate than fl uoroscopy in determining contact between fore of the order of 2– 3 cm, in other words, EBUS lesion and bronchus, thereby reducing abrasions, provides a tissue cross - section image with a radius of the time to determine biopsy sites and duration of 2 – 3 cm centered on the trachea or bronchus. fl uoroscopy). Some important EBUS reports include the c Qualitative diagnosis of peripheral lung lesions and following: differentiation between benign and malignant lesions. 1 H ü rter 1990. Endobronchial sonography in the d Determination of position and shape of peribron- diagnosis of pulmonary and mediastinal tumors [in chial structures, particularly lymph nodes (at the time German] [2] . of transbronchial |
needle aspiration). e Determination of spatial relationship between bron- chus and lesion in the short axial image of the Endobronchial Ultrasonography, 1st edition. bronchus (if the bronchus is situated near the center By Noriaki Kurimoto, David I. K. Fielding and Ali I. Musani. of the lesion, the lesion may have arisen from the Published 2011 by Blackwell Publishing Ltd. bronchus). 1 Endobronchial Ultrasonography Problems arising from the application of EBUS Wavelength Wavelength until now, and the results of studies, include the following: 1 Standardization of how the layers in the tracheo- bronchial wall structure are interpreted (how many layers do you see?). High frequency Low frequency 2 Changes in the layer structure of the tracheobron- chial wall with the use of higher frequencies, e.g. Figure 1.1 Relationship between frequency and wavelength. 30 MHz. 3 Evaluation of the accuracy of qualitative diagnosis, and differentiation between benign and malignant lesions, from EBUS images of peripheral lung lesions. Speed of Sound 4 Evaluation of peribronchial lymph node metastases. Sound travels through a variety of materials such as 5 Comparison of the diagnostic accuracy of EBUS- air and water (hereafter media), and the speed at guided FNA and unguided FNA cytology and which it travels through each medium is the speed of histology. sound for that medium. The speed of sound through 6 A worldwide standard nomenclature for this the human body is generally considered to be 1530 m/s, technique. although the actual speed of passage varies for differ- EBUS allows us to examine the state of the bronchial ent organs and tissues. wall and extramural tissue that we are unable to visu- alize with bronchoscopy alone. This book will present Production of Ultrasound Images an overview of EBUS with reference to actual clinical Transmitting and Receiving Ultrasound cases. Waves (Figure 1.2 ) Ultrasonic probes used in medical ultrasonography use a sensor that transforms electrical signals into Principles of Ultrasonography ultrasound, and ultrasound into electrical signals. When an electric signal is applied to the electrode of What is A Sound Wave? the ultrasonic transducer (also oscillator/transformer), Defi nition of Ultrasound ultrasound waves are transmitted from the surface In general, ultrasound refers to sound wavelengths of the device, and when ultrasound waves are greater than 20 MHz that cannot be heard by the received by the device surface, an electrical signal is human ear. There are considerable variations in the generated. range of frequencies audible to humans, however, so we often defi ne sounds in terms of their purpose. In Propagation and Attenuation of this case, ultrasound is “ sound not intended for Ultrasound Waves humans to hear ” . The ultrasound waves produced by the ultrasonic transducer travel through a medium; this is called Frequency and Wavelength propagation. As the soundwave is propagated, the The frequency of a sound tells us whether it is high energy of its oscillations is absorbed and scattered, and or low in pitch. The unit of frequency is hertz (Hz), becomes steadily weaker. This phenomenon is called defi ned as the number of oscillations per second. For attenuation. In general, the higher the frequency, the example, a sound with a frequency of 20 MHz has greater is the attenuation rate. Medical ultrasonogra- 20 × 106 oscillations per second. Medical ultrasound phy equipment uses high frequencies that do not equipment produces sounds with a frequency between propagate well through the air due to the high attenu- 2 MHz and 50 MHz. The wavelength is the length of a ation ratio. A medium such as water is therefore soundwave, and varies inversely with the frequency, needed between the ultrasonic transducer and the so the higher the frequency the shorter the wave- object of study to allow effi cient propagation of ultra- length (Figure 1.1 ). sound waves. 2 CHAPTER 1 An Overview of Endobronchial Ultrasonography Ultrasound transducer Ultrasound transducer Transmit ultrasound Receive ultrasound Figure 1.2 Transmitting and receiving ultrasound waves. Add electrical signals Generate electrical signals Medium A B C D Ultrasound transducer 1 Transmit pulse wave 1 2 2 2 3 2 Penetrate 3 Attenuate 4 4 Reflect 4 4 5 Receive 5 Figure 1.3 How an Ultrasound image ultrasound image is made. Refl ection and Penetration and receive ultrasound pulses (electronic scanning). As with light, a proportion of ultrasound waves are This method of ultrasound imaging is called B- mode refl ected at the boundary between different media, (B is for brightness). and a proportion penetrate the boundary. The ultra- sonic processor uses these refl ections to construct Resolution images. Axial Resolution The ultrasonic transducer emits pulses of ultra- An ultrasound pulse wave has a defi nite length, so a sound, and receives the ultrasound pulses refl ected boundary between media has a defi nite width on from the boundaries between media (Figure 1.3 ). The an ultrasound image. If we reduce the distance ultrasonic processor calculates the positions (distance between the two boundaries of a medium, the pulse from the probe) of boundaries between media based waves from the two boundaries will overlap, making on the time between transmitting and receiving ultra- it diffi cult to distinguish the two boundaries on the sound pulses, and converts the strength of the return- ultrasound image. The ability to distinguish between ing pulses into the brightness of the image. objects on an ultrasound image is called the resolu- Following the above steps alone gives information tion, and the resolution in the direction traveled by about a body along a single line, so we obtain a two - the ultrasound pulse is the axial resolution. In general, dimensional image by moving the ultrasonic trans- the higher the frequency the shorter the ultrasound ducer (mechanical scanning) or using a linear array of pulse, so distance resolution improves with higher multiple ultrasonic transducers that sequentially emit frequencies (Figure 1.4 ). 3 Endobronchial Ultrasonography Medium A Medium B Medium C Ultrasound transducer High frequency Ultrasound image Low frequency Ultrasound image Figure 1.4 Difference in axial resolution between different frequencies. High frequency Large size Small size Low frequency Figure 1.5 Pulse wave Difference of transducer size Difference of frequency spreading. Lateral Resolution Resolution in the direction perpendicular to the direc- High frequency tion traveled by the ultrasound pulse, in other words in the direction the probe moves or in the direction of the array of transducers, is called the lateral resolu- tion. The ultrasound pulse wave emitted by the trans- ducer gradually spreads out as it propagates through a medium. The degree of spread depends on the trans- Low frequency ducer size (aperture area) and the frequency. As the transducer size and/or frequency increases, the degree of spreading decreases (Figure 1 .5 ). Lateral resolution improves with decreased spread (Figure 1.6 ). Figure 1.6 Lateral resolution. 4 CHAPTER 1 An Overview of Endobronchial Ultrasonography Depth Penetration appropriate image quality adjustment is performed. Ultrasound waves are attenuated as they propagate The fundamentals of image quality adjustment are through a medium, so they can only reach a certain gain, contrast and sensitivity time control (STC). distance. Ultrasound images can therefore only be attained for a certain distance from the ultrasonic Gain probe. This distance is called the depth penetration (or Gain, also called brightness, is the mechanism for penetration). The depth penetration also depends on adjusting the overall brightness of the ultrasound the frequency and the transducer size (aperture area). image. Adjustment of the gain increases or decreases The attenuation rate of an ultrasound wave increases the entire ultrasound signal (the signal from the ultra- as its frequency increases, so depth penetration sonic transducer converted for display on the monitor) improves as the frequency decreases (Figure 1.7 ). As evenly. Changes in the gain make the entire image the aperture area of the ultrasonic transducer increases, brighter or darker, but do not alter the differences it can emit a stronger pulse, and it can also convert in brightness between light and dark sections of the weaker received pulses into electrical signals. Depth image (Figure 1.8 ). penetration therefore increases as the transducer size increases. Contrast Contrast is the mechanism for adjusting the difference Image Quality Adjustment in brightness between light and dark sections of the Even when using an ultrasonic probe appropriate to image. Adjustment of the contrast makes the greatest the task, its abilities cannot be fully harnessed unless changes in the sections of the image with the strongest Medium A B C D E Ultrasonic transducer Attenuation: heavy High frequency Ultrasound image Attenuation: slight Low frequency Figure 1.7 Differences in depth Ultrasound image penetration at different frequencies. Increase Increase Decrease Decrease Figure 1.8 Adjustment of gain (brightness). Strength of ultrasound signal Position on the monitor 5 Brightness on the monitor Brightness on the monitor Endobronchial Ultrasonography ultrasound signal, in other words changing the con- sor amplifi es the ultrasound signal according to the trast mainly alters the brightness of the lighter sections current distance from the probe (the time for the ultra- of the image, and the darker sections are changed but sound pulse to return to the transducer) (Figure 1.10 ). little. Increasing the contrast of an ultrasound image By altering the degree of amplifi cation, adjustment of yields an image with enhanced differences between STC can make the ultrasound image lighter or darker light and dark areas, whereas decreasing the contrast according to the distance from the probe (Figure 1.11 ). yields an image with minimal differences between light and dark areas (Figure 1.9 ). Procedure for Image Quality Adjustment Image quality adjustment should be conducted in Sensitivity Time Control accordance with the properties of the ultrasonic proc- Sensitivity time control (STC) also known as time gain essor, monitor and printer. Adjustment of gain (bright- compensation (TGC), is the mechanism for adjusting ness) and contrast are performed in the following the gain according to the distance (depth) from the manner: ultrasonic probe. As shown in Figure 1.7 , attenuation 1 Switch on the system, and bring up an image on the of the ultrasound wave increases with the distance monitor (Figure 1.12 ). from the probe, so ultrasound signals from distant 2 Adjust the brightness and contrast controls of the (deep) regions are weaker than those from near monitor so that the gray scale bar in the ultrasound (shallow) regions. In order to correct this and make the image is displayed with smoothly varying gradations overall image as even as possible, the ultrasonic proces- (Figure 1.13 ). Increase Increase Decrease Decrease Figure 1.9 Adjustment of Strength of ultrasound signal Position on the monitor contrast. In case that STC is; 1~2cm: –1 3~4cm: +1 4~5cm: +2 0 1 2 3 4 5 cm 0 1 2 3 4 5 cm Distance from transducer Distance from transducer Figure 1.10 STC default settings. Figure 1.11 Adjustment of STC. 6 Brightness on the monitor Amplitude ratio of ultrasound signal Brightness on the monitor Amplitude ratio of ultrasound signal CHAPTER 1 An Overview of Endobronchial Ultrasonography 3 Adjust the brightness and contrast controls of the printer so that the gray scale bar in the printed image Gain Gray scale bar corresponds closely to the monitor image. 4 Adjust the gain, contrast and STC of the ultrasonic Contrast processor according to the study subject and purpose of the study. When the EU - M30 system is used with a 20 MHz ultrasonic probe, images with appropriate gradations can be obtained by setting the gain to between 10 and 13, the contrast to between 2 and 5, and the STC to all zero (center position). Figure 1.12 Monitor image (EU- M2000 endoscopic ultrasound system). Equipment Endoscopic Ultrasonic Probe In this section, we will introduce the equipment used by the author, manufactured by Olympus Corporation. The frequencies and outer diameters of the endo- scopic ultrasonic probes we use are shown in Table 1.1 . Since the resolution and depth penetration of an ultrasonic probe are dependent on the frequency and size of the transducer (as the outer diameter of the probe increases, the size of the ultrasonic transducer also increases), the probe needs to be selected to suit the aim of the procedure. Ultrasound examinations can be performed using either the balloon (the probe contacts the object Figure 1.13 Adjustment of gray scale bar. of study through a balloon fi lled with medium) Table 1.1 Ultrasonic probes Model name Maximum |
outer diameter F requency Compatible biopsy channel UM - 2R 2.5 mm 12 MHz 2.8 mm or more UM - 3R 2.5 mm 20 MHz 2.8 mm or more UM - 4R 2.4 mm (2.0 mm at proximal side) 20 MHz 2.6 mm or more UM - S20 - 20R 1.7 mm (2.0 mm at proximal side) 20 MHz 2.2 mm or more 2.55 mm (incl. guide sheath SG - 201C) 2 .6 mm or more UM - S30 - 20R 1 .7 mm (2.0 mm at proximal side) 30 MHz 2.2 mm or more 2.55 mm (incl. guide sheath SG - 201C) 2 .6 mm or more UM - S30 - 25R 2.5 mm 30 MHz 2.8 mm or more UM - BS20 - 26R 2.6 mm (incl. balloon sheath MAJ- 643R) 20 MHz 2.8 mm or more UM - S20 - 17S 1.4 mm (1.7 mm at proximal side) 20 MHz 2.0 mm or more 1.95 mm (incl. guide sheath SG - 200C) 2 .0 mm or more 7 Endobronchial Ultrasonography or direct contact method (the probe makes direct or a rigid bronchoscope with an instrument channel contact with the object of study). The method is of 11.5 Fr or more. usually selected according to whether the object of The direct contact method does not require a study is centrally or peripherally situated, and probe balloon, so the probe is passed directly down the bron- selection is also made according to the region being choscope instrument channel. examined. When the balloon method is used, the UM - BS20 - Bronchoscope 26R ultrasonic probe (which can be inserted in a bron- Having selected the ultrasonic probe in accordance choscope instrument channel with a diameter of at with the aim of the investigation and the region being least 2.8 mm) is generally used (Figures 1.14, 1 .15 ). examined, it is then necessary to select a broncho- Other probes can also be used in the balloon method scope suitable for use with that probe. In particular in combination with the balloon sheath MH - 246R when the balloon method is selected, care must be (Figure 1 .16 , outer diameter 3.6 mm). This will require taken to prepare a bronchoscope with an instrument a special bronchoscope such as the BF- ST49, with an channel diameter of at least 2.8 mm. Table 1 .2 shows instrument channel with a diameter of at least 3.7 mm, the endoscopes compatible with the various probes. Ultrasonic transducer O-ring Balloon Balloon sheath MAJ-643R Ditch Ultrasonic probe UM-BS20-26R Balloon sheath MAJ-643R Balloon sheath connector MAJ-667 Balloon applicator MAJ-564 Ultrasonic probe UM-BS20-26R Adapter Figure 1.14 Structure of Balloon sheath connector mounting section UM - BS20 - 26R. Figure 1.15 Distal end of UM - BS20 - 26R with balloon sheath. Figure 1.16 UM - BS20 -2 6R with balloon sheath (MH - 246R). 8 CHAPTER 1 An Overview of Endobronchial Ultrasonography Table 1.2 Compatibility between bronchoscopes and ultrasound probes Bronchoscopes Guide sheath method Direct contact method Balloon method UM - S20 - UM - S20 - UM - UM - S20 - UM - UM - UM - UM - 2R/3R 17S 20R/ S20 - 17S 20R/ 4R 2R/3R BS20 - UM4R + MH - 246R UM - S30 - UM - S30 - UM - 26R UM - S20 - 20R 20R 20R S30 - 25R UM - S30 - 25R BF - 200/240 * 1 Yes No Yes Yes No No No No BF - P200/P240 * 1 BF - 6C240 * 1 BF - 160/MP160F * 2 BF - P150/P160/P180 * 2 BF - Q180 * 2 BF - Q180 - AC * 2 BF - 260/6C260 BF - MP60 BF - P260F (2.0 mm CH) BF - 30 * 1 Yes No Yes Yes No No No No BF - 40 BF - P30/P40 * 1 BF - P60 BF - 20D/P20D * 2 BF - PE/PE2 * 2 (2.2 mm CH) BF - 1T200/1T240 * 1 Yes Yes Yes Yes Yes No No No (2.6 mm CH) BF - 1T30/1T40 * 1 Yes Yes Yes Yes Yes Yes Yes No BF - 1T240R * 1 BF - 1T150/1T160 * 2 BF - 1T260 BF - LT30 BF - 1T20D * 2 BF - TE/TE2 * 2 (2.8 mm CH) BF - 1T60/1T180 * 2 Yes Yes Yes Yes Yes Yes Yes No (3.0 mm CH) BF - XT20/XT30 * 1 Yes Yes Yes Yes Yes Yes Yes N o BF - XT40 BF - XT160 * 2 (3.2 mm CH) BF - ST40 * 1 Yes Yes Yes Yes Yes Yes Yes Yes (3.7 mm CH) * 1: Discontinued model. * 2: Not available in Japan. 9 Endobronchial Ultrasonography (a) (b) Figure 1.18 Ultrasound image obtained with the EU- M2000. Figure 1.17 Endoscopic Ultrasound Center (EU- M2000), Probe Driving Unit (MH - 240). Select a bronchoscope which can be used with an ultrasonic probe. When the balloon method is selected, it is necessary to use an endoscope that has an instru- ment channel diameter of 2.8 mm or more. Ultrasonic Processor and Probe Driving Unit Figure 1.19 Ultrasound Center (EU- M30S). Ultrasound images are obtained by attaching the endo- scopic ultrasound probe to the Endoscopic Ultrasound Center EU - M2000 (Figure 1 .17a) via the Probe Driving Unit MH - 240 (Figure 1.17b ). Preparations The EU - M30 videoconverter system is fully compat- ible with both videoscopes and fi berscopes, and its Required Equipment subscreen function allows simultaneous display of Ultrasonic probe (sterilized). both ultrasound and endoscopic images on the one Balloon sheath. monitor, or switch between images (Figure 1 .18) . The Balloon sheath connector (for attachment of the EU - M30 ultrasonic processor is compatible with fre- balloon sheath to the probe). quencies from 7.5 to 30 MHz, can be used for distance 3 - way stopcock with extension tube. and area calculations, and is compatible with gastroin- Sterile water or physiological saline, 20 mL. testinal endoscopic ultrasound (EUS) and a variety of 20 mL syringe. endoscopic ultrasonic probes. It is highly compact, and fi ts on the standard endoscopic equipment trolley. Assembling the Balloon Probe The EU - M30S (Figure 1.19) ultrasonic processor is Using the Endoscopic Ultrasound designed for use with miniature probes. It is equipped Probe UM - BS 20 - 26 R with a probe drive unit as standard, and the main unit The advantages of this probe are that it can be used is compact and highly portable. This probe - dedicated with fl exible bronchoscopes with a standard instru- system makes it easy to obtain high quality ultrasound ment channel with a diameter of at least 2.8 mm images, and includes full image quality adjustment (BF - IT20, IT30, IT40, IT240R), and balloon defl ation functionality. has become simpler. 10 CHAPTER 1 An Overview of Endobronchial Ultrasonography Figure 1.21 Push the O- ring into the groove. Figure 1.20 Probe main unit (above), probe inside balloon sheath (below). Assemble the balloon probe in accordance with the instructions in the manual provided. a Pass the balloon sheath connector from the probe tip down, and fi x it to the balloon sheath connector attachment on the probe. b Insert the balloon sheath from the probe tip, and Figure 1.22 Balloon infl ated with water. press the balloon sheath clasp into the balloon sheath connector. c The optimum position for the ultrasonic transducer is not in the center of the balloon, but rather the g After all air in the balloon has been eliminated, fi x transducer should just protrude from the base of the the probe by hand through the balloon, and push the balloon (Figure 1 .20) . This allows the transducer to O - ring on the balloon tip into the groove in the probe rotate within the maximally expanded portion of the tip, by hand or using a balloon applicator (Figure balloon when it has been infl ated. 1.21 ). Once the balloon has been fi lled with water, d Draw up 15 mL of sterile water (or physiological and checked for leaks and air bubbles, preparation is saline) into the syringe, fi ll the 3- way stopcock exten- complete (Figure 1.22 ). sion tube with water, and attach the extension tube to the balloon sheath connector inlet. Connection of the Probe to the Driving Unit e Pull back on the syringe to create negative pressure, Insert the connection pin of the ultrasonic probe into drawing out as much air as possible from between the the connector on the driving unit, pointing the pin at balloon sheath and probe. After performing this step the 12 o’ clock position. three times, slowly release the negative pressure and then slowly fi ll inject sterile water into the balloon. Connecting the Power and Data Entry f Continue to push the syringe plunger with the Only turn on the power to the Ultrasound Center after balloon tip pointing upwards, fi lling the balloon with the probe has been connected. The ultrasonic probe water. Although a small bubble of air will enter the will be damaged if it is connected when the power is balloon, the tip of the balloon is separate, with a hole on. After the power has been connected, switch the in it. Pulling the balloon in the direction of the tip, monitor to the ultrasound input, and enter the express the air and water in the tip. patient ’ s identity number, age and name. 11 Endobronchial Ultrasonography Checking the Image process, hold the probe at a point 2 or 3 cm away from Unfreeze and rotate the ultrasonic probe. If it is the instrument port with each hand in turn. It is working properly, multiple echoes with fi ve to seven important to be aware that there are two places with layers will be seen centered on the probe. If multiple greater resistance within the instrument channel, echoes are not seen, the probe may be disconnected between the instrument port and the distal end of or there may be air bubbles in the medium in contact the bronchoscope. The fi rst site is 4 – 5 cm from the with the probe. instrument port, where the suction and instrument channels join, and the second is 2– 3 cm from the bron- Inverting the Image choscope tip, where the instrument bends. When Next press the “ Image Direction ” switch to change the resistance is high at either site and the probe is diffi cult monitor image from normal to inverse. This inverts to pass, then the probe should be removed and jelly the ultrasound image so that left and right are the reapplied, and if that fails, remove the bronchoscope same as the endoscopic image, to an image seen from from the patient and reinsert the probe. the rostral direction. In gastrointestinal EUS, the normal ultrasound image is seen from the caudal Operating the Probe direction, for easy comparison with computer tomog- Advance the probe to a point slightly distal to the site raphy (CT) scans, but in EBUS it is desirable for the of interest. Inject 1 – 3 mL of sterile water (physiological directions in the ultrasound image to coincide with the saline may also be used with the UM- BS20 - 26R), image from the bronchoscope, for the purposes of FNA infl ating the balloon while scanning so that it contacts from the tracheobronchial lumen. The normal mode the bronchial wall circumferentially. The optimum is only used in special situations, such as for compari- volume of water is that which just achieves circum- son with CT images. ferential contact with the bronchial wall. Over- infl ation can cause compression of bronchial wall structures or bursting of the balloon. Operation Then, while scanning and capturing images (always make a videorecording), retract the probe from deep Anesthesia (distal) to superfi cial (proximal). The important point In principle, anesthesia for EBUS is the same as for to remember about scanning is to retract the probe regular bronchoscopic examinations. It should be kept very slowly. If necessary, ask the patient to hold their in mind, however, that until the operator has become breath while scanning. Advancing the probe from more experienced, procedures will tend to be some- superfi cial (proximal) to deep |
(distal) can cause what longer in duration. When EBUS is performed in damage to the probe, and should be avoided. conjunction with another procedure, such as laser- induced fl uorescence endoscopy (LIFE), then intrave- nous anesthesia may be used, allowing spontaneous Tips for Achieving Optimum respiration. An important consideration for the anes- Ultrasound Images thetist is to confi rm, under direct observation using To obtain clear, easily understandable images: the laryngoscope, that local anesthetic spray is applied a Rotate the ultrasound image so that it corresponds directly to the pharynx and larynx, in particular to the to the endoscopic images. vocal chords. After bronchoscopic examination of the b To assess the depth of tumor invasion, the ultra- trachea and bronchi, local anesthetic is further applied sound pulse must penetrate the tracheal/bronchial to the bronchus (bronchi) into which the balloon wall perpendicularly. probe will be introduced. Rotate the Ultrasound Image So that It Inserting the Probe Corresponds to the Endoscopic Images Apply xylocaine jelly liberally to the distal end of the i A t a bifurcation (e.g. the opening of the right upper balloon probe, and slowly insert it into the instrument lobe bronchus), we can line up the direction so that channel of the bronchoscope. During the insertion the balloon is not in contact with the bronchial lumen 12 CHAPTER 1 An Overview of Endobronchial Ultrasonography on the endoscopic image, with no echo on the EBUS pulmonary artery runs anteriorly to the right main image. bronchus and right middle lobe bronchus, from 10 ii F or example (Figure 1.23) , in the left ultrasound o ’ clock to 2 o’ clock (Figure 1 .24 right). Identify the image below, the direction has no echo, because the position of these structures, and rotate the EBUS balloon is not in contact with the bronchial lumen, image accordingly. and direction is from 4 to 6 o ’ clock. In the right endo- scopic image, the balloon is not in contact with the bronchial lumen and direction is from 2 to 4 o ’ clock. To Assess the Depth of Tumor Invasion, To match up the images, we need to rotate the EBUS Obtain Images with the Ultrasound image anticlockwise 45 ° . Pulse Penetrating the Tracheal/ iii R otate the EBUS image according to the relative Bronchial Wall Perpendicularly positions of the bronchial tree and the esophagus and If the fi rst layer (marginal echo, refl ected at the great vessel. boundary between tissues) is highly echoic, the image When scanning from the lower part of the trachea can be said to be derived from an ultrasound pulse to the left main bronchus, the esophagus is located penetrating the tracheal/bronchial wall nearly per- at the 6 o’ clock direction (Figure 1.24 left). The right pendicularly (Figure 1.25 ). Right pulmonary artery Opening of right upper bronchus Opening of right upper bronchus Figure 1.23 Tips for achieving optimum ultrasound images. Rotation of the ultrasound image so that it corresponds to the endoscopic images. Right pulmonary artery Esophagus Figure 1.24 Tips for achieving optimum ultrasound images. Rotation of the EBUS image according to the relative positions of the bronchial tree and the esophagus and great vessels. 13 Endobronchial Ultrasonography Figure 1.27 Aspiration Needle (NA- 201SX -4 022, Olympus). Figure 1.25 Tips for achieving optimum ultrasound images. To assess the depth of tumor invasion, obtain images with the ultrasound pulse penetrating the tracheal/bronchial wall perpendicularly. The arrows in the fi gures indicate a highly echoic fi rst layer, with a clearly lineated layer structure in that region. Figure 1.28 Ultrasonic bronchoscope with needle. bronchoscope has a working channel with a diameter of 2.0 mm; we can insert the disposable biopsy instru- ment with a 22 G needle (Figure 1 .27 , NA- 201SX - 4022, Olympus) through the working channel (Figure 1.28 ). After the convex probe is covered by the balloon, saline is injected into the balloon, fi lling its inner space. Figure 1.26 Ultrasonic bronchoscope (BF- UC160F, Olympus). This bronchoscope is connected to the ultrasound unit (EU- C60) and the power switch turned on (Figure 1.29 ). Equipment of E BUS Guided The scope shows us the target lesion for TBNA Transbronchial Needle Aspiration beyond the bronchial wall. The transducer provides ( EBUS - TBNA ) longitudinal planes of peribronchial areas, and the ultrasonographic image shows us real - time movement The curved array transducer is combined at the tip of of the TBNA needle. the bronchoscope for EBUS - TBNA (Figure 1 .26 , BF - As this convex bronchoscope has an oblique forward UC160F, Olympus). This convex bronchoscope con- viewer, there is a little diffi culty when inserting this sists of an oblique forward viewer with a convex scope through the vocal cord. Observing the 12 o’ clock transducer mounted in front of the lens. The convex direction of the vocal cord, the tip of the scope is transducer is 7.5 MHz and covered by a balloon . The straight and it is easy to enter the trachea. 14 CHAPTER 1 An Overview of Endobronchial Ultrasonography 6 Becker H . Endobronchialer Ultraschall - Eine neue Perspektive in der Bronchologie. Ultraschall in Med 1996 ; 17 : 106 – 112 . 7 Kurimoto N , Murayama M , Yoshioka S , et al. Assessment of usefulness of endobronchial ultrasonography In deter- mination of depth of tracheobronchial tumor Invasion. CHEST 1999 ; 115 : 1500 – 1506 . Frequently Asked Questions Figure 1.29 Ultrasound processor (EU - C2000). 1 Which generation of the bronchial tree needs the balloon to visualize the bronchial wall using EBUS? References A: From trachea to sub- sub or sub- sub - subsegmental bronchus, the balloon is necessary to obtain excellent 1 Pandian N G , K reis A , B rockway B , et al. U ltrasound images using EBUS. angioscopy: real - time, two dimensional, intraluminal 2 Could the miniature probe reach the subpleural area? ultrasound imaging of blood vessels . Am J Cardiol A: Yes, the miniature probe of 1.4 – 2.5 mm in diameter 198 ; 62 : 493 – 494 . expands to the subpleural area 2 H ü rter T h , H anarath P . E ndobronchiale Sonographie zur Diagnostik Pulmonaler und Mediastinaler Tumoren. 3 Which probe could penetrate the tissue deeper, a 20 MHz Dtsch Med Wschr 1990 ; 115 ; 50 : 1899 – 905 . probe or 30 MHz probe? 3 Iizuka K , Dobashi K , Houjou S , et al. E valuation of airway A: 20 MHz probe could. As the frequency decreases, the smooth muscle contractions in vitro by high - frequency depth penetration of the ultrasound pulse is increased. ultrasonic imaging . Chest 1992 ; 102 : 1251 – 1257 . 4 What are tips for achieving satisfactory visualization of 4 Ono R , Suemasu K , Matsunaka T . Bronchoscopic EBUS using the radial probe? Ultrasonography in the diagnosis of lung cancer. J pn J A: The probe should be located at the center of the lumen Clin Oncol 1993 ; 23 : 34 – 40 . of the bronchial tree. As the ultrasonic waves penetrate 5 Goldberg B , S teiner R , L iu J , et al. U S - assisted bronchos- the bronchial wall perpendicularly, excellent images are copy with use of miniature transducer- containing cath- visualized. eters . Radiology 1994 ; 190 ; 1 : 233 – 237 . 15 2 Anatomy of Mediastinal and Hilar Area relationship between the peribronchial organs and the Overview of Ultrasound Imaging of the bronchial tree, as seen when we pull the probe from Right and Left Bronchi While the Radial the right and left lower lobe bronchi up to the left and Probe is Being Pulled out right main bronchi, respectively. To fully understand EBUS, it is essential to understand the positional rela- EBUS images are cross- sectional images of planes per- tionship between the peribronchial organs during pendicular to the long axis of the tracheobronchial visualization while the probe is being pulled out. tree. These images are used to assist endoscopic treat- ments, so ultrasound images are generally displayed looking from the rostral direction, so that left and right Right Bronchi (Figure 2.1 ) match with endoscopic images. The positional relationship between the peribron- Right Lower Lobe Bronchi chial organs in EBUS images taken from the trachea When the balloon is infl ated in the right basal bron- corresponds to those in a reversed CT image (CT scans chus, the inferior pulmonary vein (V6) passes on the are cross- sectional images looking from the caudal dorsal side of the bronchus (1), whereas anterior to direction). EBUS images taken distal to the bifurcation the bronchus the pulmonary artery divides into A8, of the left and right main bronchi, however, are cross- A9 and A10, positioned between 9 o ’ clock and 2 sectional images of planes perpendicular to the long o ’ clock. axis of the bronchus, and therefore have a different As the probe is pulled back, A8, A9 and A10 meet at positional relationship between the peribronchial the 12 o’ clock direction and the direction of the pulmo- organs from the CT images. nary artery changes gradually to 3 o ’ clock (2, 3). When In clinical practice, when EBUS is performed for the probe is pulled further back, it approaches the bifur- centrally located lesions, the balloon is infl ated distal cation of B6. An area that does not contact the balloon to the lesion, and images are obtained while pulling appears on the bronchial wall, from where the ultra- the probe proximally (superfi cially). The reasons for sound is refl ected. As a result, the image of the layer this are that it is diffi cult to push the probe distally containing the bifurcation of B6 at 5 o ’ clock is lost. (deeper) with the balloon infl ated, and by pulling the Pulling the probe back further, the opening of the probe proximally, cross - sectional images of planes middle lobe bronchus, indicated by refl ection of the perpendicular to the long axis of the bronchus can be ultrasound pulse (because the balloon loses contact obtained without bending the probe. with the bronchial wall at the bifurcation), appears at In this part of the chapter, using schematic diagrams 12 o’ clock. The pulmonary artery has gradually moved and ultrasound images, we will describe the positional round to the 2 o ’ clock position (4). From the Right Intermediate Bronchus to Endobronchial Ultrasonography, 1st edition. the Right Main Bronchus By Noriaki Kurimoto, David I. K. Fielding and Ali I. Musani. As the probe is pulled from the distal intermediate Published 2011 by Blackwell Publishing Ltd. bronchus to a point immediately below the origin of 16 CHAPTER 2 Anatomy of Mediastinal and Hilar Area PA V6 V6 Upper part of V6 Right lower bronchus PV PA PA Opening of right middle lobe Center of intermediate trunk PA PA Figure 2.1 Right bronchi. PA: pulmonary artery; PV: pulmonary vein; Right main bronchus V6: pulmonary vein for segment 6. Upper part of intermediate trunk (opening of upper bronchus) 17 Endobronchial Ultrasonography the upper lobe bronchus, the pulmonary artery crosses As the probe is pulled back, it approaches the bifur- the bronchus from the right to the left (5, 6, 7). In the cation of B6. An area that does not contact the balloon central section of the intermediate bronchus, the appears on the bronchial wall, from where the ultra- superior pulmonary vein can sometimes be seen ante- sound is refl ected. As a result, the image of the layer rior to the pulmonary artery (5). containing the bifurcation of B6 at 7 o’ clock is lost. When the probe is pulled further back, the origin of Pulling the probe back further, the opening of the the upper lobe bronchus is indicated by refl ection upper lobe bronchus, indicated by refl ection of the of the ultrasound pulse (because the balloon loses ultrasound pulse (because the balloon loses contact contact with the bronchial wall at the bifurcation) at with the bronchial wall at the bifurcation), appears at 3 o ’ clock (7). 11 o’ clock (3). The pulmonary |
artery is located below Pulling the probe back further, A1+ 3, originating the origin of the upper lobe bronchus. from the pulmonary trunk, can be seen crossing hori- zontally anterior to the right main bronchus. Retracting Left Main Bronchus the probe further, the origin of the left main bronchus The distal section of the left main bronchus is charac- at the carina is indicated by refl ection of the ultra- terized by the left pulmonary artery at 10 o’ clock, the sound pulse at 9 o ’ clock. descending aorta at 7 o ’ clock, and the left atrium from The key to reading EBUS images is to recognize the 1 o’ clock to 3 o’ clock (4, 5). As we enter the central anatomy of the peribronchial organs as the probe is section of the left main bronchus, the left atrium dis- retracted from the right lower lobe bronchus to the appears, and the esophagus appears at 6 o’ clock. The right main bronchus. subcarinal (#7) lymph node is often visible medial to the esophagus (6). Right Side When the probe is pulled further back, the origin of Right basal bronchus: inferior pulmonary vein, V6 the left main bronchus at the carina is indicated by (6 o ’ clock); PA7- 10 (2 o’ clock). refl ection of the ultrasound pulse (because the balloon Right lower bronchus: PA6- 10 (2 – 3 o ’ clock). loses contact with the bronchial wall at the bifurca- Right intermediate bronchus: right pulmonary artery tion) at 3 o ’ clock. (12 o ’ clock). The key to reading EBUS images is to recognize the Right main bronchus: right upper lobe pulmonary anatomy of the peribronchial organs as the probe is artery (12 o ’ clock). retracted from the left lower lobe bronchus to the left PA: pulmonary artery. main bronchus. 1 V6. 2 Upper part of V6. Left Side 3 Right lower bronchus. Left basal bronchus: inferior pulmonary vein, V6 (6 4 Origin of right middle lobe bronchus. o ’ clock); PA8- 10 (9 o’ clock). 5 Middle part of intermediate bronchus. Left lower bronchus: PA6 - 10 (10 o ’ clock); superior 6 Upper part of intermediate bronchus. pulmonary vein (1 – 4 o ’ clock) 7 Right main bronchus (origin of right upper lobe Left main bronchus (distal): left pulmonary artery (10 bronchus). o ’ clock); aorta (7 o’ clock); left atrium (1– 3 o ’ clock). Left main bronchus (proximal): left pulmonary artery (10 o’ clock); aorta (7 o’ clock); left atrium (1– 3 Left Bronchi (Figure 2.2 ) o ’ clock); esophagus (6 o ’ clock). PA: pulmonary artery. Left Lower Lobe Bronchi 1 Left V6. When the balloon is infl ated in the left basal bronchus, 2 Left lower bronchus. the inferior pulmonary vein (V6) passes on the dorsal 3 Origin of left lower bronchus. side of the bronchus, whereas the A8, A9 and A10 4 Lower part of left main bronchus. branches of the pulmonary artery meet at 9 o’ clock 5 Left main bronchus (LA, PA, Ao). (1, 2). 6 Left main bronchus (esophagus, #7LN). 18 CHAPTER 2 Anatomy of Mediastinal and Hilar Area PA PA V 6 Left V6 Left lower bronchus PA PV PA LA Ao Opening of left upper bronchus Lower part of left main bronchus PA LA Ao Eso #7LN Figure 2.2 Left bronchi. Ao: aorta; Eso: esophagus; LA: left atrium; LN: lymph nodes; PA: pulmonary artery; PV: pulmonary vein; V6: inferior Left main bronchus (LA, PA. Ao) Left main bronchus, pulmonary vein. (esophagus, #7LN) 19 Endobronchial Ultrasonography Ultrasound Imaging of Mediastinal and #7 LN : Subcarinal Lymph Node (Figure 2.3 ) Hilar Lymph Nodes for EBUS- TBNA by the For approaching #7 LN, the convex bronchoscope is Convex Bronchoscope inserted into the right main bronchus. While scanning at the 9 o’ clock direction, we can confi rm the largest To carry out EBUS- TBNA procedures successfully, the area of the #7 LN. While rotating right handed and bronchoscopist should have a good understanding of scanning at the 11 o ’ clock direction, we can observe ultrasonographic images of the peribronchial vessels the right main pulmonary artery. and lymph nodes. Ascending aorta Superior vena PA #6 cava Left lower bronchus #5 #10 Left upper Right upper #5 PA bronchus A3 PA #4 #4 A1+2a+b Right upper A6 A1+2c #10 #2 bronchus #10 Azygousvein Descending aorta Esophagus #7LN PA Figure 2.3 Subcarinal lymph node. PA: pulmonary artery. (From Bronchoscopy, 1st ed. Tokyo, IGAKU-SHOIN, 1998, p. 45 with permission.) 20 CHAPTER 2 Anatomy of Mediastinal and Hilar Area 11 R LN : Right Intralobar Lymph Node ning at the 12 o’ clock direction, we can confi rm the (Between Right Lower Lobe Bronchus and largest area of the #11R LN. While rotating right Right Middle Lobe Bronchus) (Figure 2.4 ) handed and scanning at the 3 o’ clock direction, we For approaching #11R LN, the convex bronchoscope can observe the right pulmonary artery. is inserted into the right basal bronchus. While scan- [Anterior] rt. middle PA V5 PA rt. middle PV V4b rt. superior PV #12 V4a rt. upper PV #11 A8 V8 [Medial] A2b [Lateral] #12 rt. middle bronchus B7 B8+9+10 V9+10 rt. inferior PV A9+10 B6 V6 #9 A6 #10 [Posterior] Figure 2.4 Right intralobar lymph node. PA: pulmonary artery; PV: pulmonary vein. (From Bronchoscopy, 1st ed. Tokyo, IGAKU-SHOIN, 1998, p. 48 with permission.) 21 Endobronchial Ultrasonography 11 R LN : Right Intralobar Lymph Node located at the 12 o ’ clock direction from the intermedi- (between the Right Intermediate Trunk ate trunk. While scanning at the 12 o’ clock direction, and Right Upper Lobe Bronchus) (Figure 2.5 ) we can confi rm the largest area of the #11R LN. While For approaching #11R LN, the convex bronchoscope rotating left handed and scanning at the 9 o’ clock is inserted into the right intermediate trunk. On the direction, we can observe the right main pulmonary bronchoscopic fi ndings, the right upper bronchus is artery. [Anterior] rt. upper PV rt. main PA PA V1 2 V3 V #11s B3 3 #10 A [Medial] #10 [Lateral] B1 #7 A1 B2 #12 rt. intermediate trunk #10 rt. upper bronchus [Posterior] PA Figure 2.5 Right intralobar lymph node. PA: pulmonary artery; PV: pulmonary vein. (From Bronchoscopy, 1st ed. Tokyo, IGAKU-SHOIN, 1998, p. 47 with permission.) 22 CHAPTER 2 Anatomy of Mediastinal and Hilar Area 11 L LN : Left Intralobar Lymph lobe bronchus. While scanning at the 12 o’ clock direc- Node (Figure 2.6 ) tion, we can confi rm the largest area of the #11L LN. For approaching #11R LN, the convex bronchoscope While rotating left handed and scanning at the 10 is inserted into left basal bronchus. On the broncho- o ’ clock direction, we can observe the right pulmonary scopic fi ndings, the left upper lobe bronchus is artery. located at the 12 o ’ clock direction from left lower B3 B1+2 3 V1+2 V [Anterior] A1+2C B4 #12 #12 B5 V4+5 #12 #12 A6 B6 V6 It. superior PV #13 B8 B9+B10 [Posterior] It. superior PV PA Figure 2.6 Left intralobar lymph node. PA: pulmonary artery; PV: pulmonary vein. (From Bronchoscopy, 1st ed. Tokyo, IGAKU-SHOIN, 1998, p. 46 with permission.) 23 Endobronchial Ultrasonography 4 L LN : Lymph Node (Figure 2.7 ) o ’ clock direction, we can confi rm the largest area of the For approaching #4L LN, the convex bronchoscope is #4L LN. While pushing the scope to the distal site about inserted to the distal site of the trachea. On the bron- 1 – 2 cm, we can observe the left main pulmonary artery. choscopic fi ndings, the left side of the trachea is located While pushing the scope to the proximal site about at the 12 o ’ clock direction. While scanning at the 12 1 – 2 cm, we can observe aortic arch. ascending aorta PA #6 Left lower bronchus #5 #10 Left upper #3 bronchus A3 Left PA #4 #4 A1+2a+b A6 A1+2C #10 #7 #2 Descending aorta Esophagus PA Aorta Aorta Figure 2.7 Left lower paratracheal nodes. PA: pulmonary artery. (From Bronchoscopy, 1st ed. Tokyo, IGAKU-SHOIN, 1998, p. 45 with permission.) 24 CHAPTER 2 Anatomy of Mediastinal and Hilar Area 4 R LN : Lymph node (Figure 2.8 ) scanning at the 2 o ’ clock direction, we can confi rm For approaching #4R LN, the convex bronchoscope is the largest area of the #4R LN. While scanning 4R LN, inserted to the distal site of the trachea. On the bron- we can observe the superior vena cava (SVC) just choscopic fi ndings, the membranous portion of the below. While pushing the scope to proximal site about trachea is located at the 6 o’ clock direction. While 1 – 2 cm, we can observe the aortic arch #4R LN. Ascending aorta Superior vena cava PA #6 Left lower bronchus #5 SVC #10 Left upper #3 Right upper PA bronchus A3 #4 # A1+2a+b Right upper A6 A1+2C #10 #7 bronchus #2 #10 SVC SVC Azygous vein Descending aorta Esophagus Figure 2.8 Right lower paratracheal nodes. PA: pulmonary artery; SVC: superior vena cava. (From Bronchoscopy, 1st ed. Tokyo, IGAKU-SHOIN, 1998, p. 45 with permission.) Frequently Asked Questions 1 On the right bronchus, what is most useful for recognizing A: By rotating the convex probe right - handed or left- handed, the direction of the peribronchial organs? the margin of a lymph node may not be continued. By A: At the intermediate bronchus and the right main bronchus, rotating the convex probe right- handed or left- handed, the the right pulmonary artery is located at the 12 o’ clock margin of a vessel may be continued. Power Doppler mode is direction. also useful to differentiate a lymph node from vessels. 2 On the left bronchus, what is most useful for recognizing 4 How do you avoid bleeding during EBUS - TBNA? the direction of the peribronchial organs? A: We should avoid puncturing the great vessels (PA, PV, A: At the left main bronchus, the esophagus is located at the or aorta) and the bronchial artery, particularly when the 6 o ’ clock direction. bronchial artery is located between the bronchial wall and 3 How can one differentiate a lymph node from vessels the target lymph node. I recommend checking the route of during EBUS - TBNA? the needle before puncturing. 25 3 How to Perform Endobronchial Ultrasonography however, and must be used with a bronchoscope with Introduction a big channel (BF - ST40, working channel diameter: 3.7 mm). In recent years, I usually use a thinner I commenced endobronchial ultrasonography (EBUS) 20 MHz mechanical radial ultrasonic probe (UM- BS - in August 1994. Initially, I performed EBUS using a 20 - 26R, Olympus) with a balloon - tip sheath (MH- radial probe without a guide sheath for the diagnosis 676R, Olympus) through the 2.8 mm diameter of peripheral pulmonary lesions. Guide sheaths working channel of a fl exible bronchoscope (BF - became available in 1996 to aid in the accurate iden- 1T260, Olympus). These probes are able to connect tifi cation of the location of peripheral pulmonary with the Endoscopic Ultrasound System (EU- M 30 lesions. Another early application of EBUS was the and EU - M 2000, Olympus). radial probe with a balloon to visualize the layer struc- tures of the tracheobronchial wall. In recent years, the Preparation of the Balloon Probe use of convex probes combined with the broncho- (Video clip 3.1) scope for EBUS guided transbronchial needle aspira- The ultrasonic probe is inserted into the balloon sheath. tion (EBUS - TBNA) has rapidly expanded in many The probe and sheath are fi xed in place by the connect- countries. Here I will describe the equipment used for ing unit. A 25 mL syringe containing about 15 mL of EBUS using a radial probe and EBUS - TBNA, and some saline is connected to the injection port in the connect- tips for various procedures. ing unit. Most of the air between the inner surface of the sheath and the outer surface of the probe is removed in two or three aspirations using the 25 mL syringe. Balloon Probes for Central Lesions Saline |
is injected from the syringe into the sheath and the balloon at its tip, infl ating the balloon to a diameter Air always inhibits the visualization of ultrasound of about 15 mm with saline fi lling the balloon. When images. Beyond the subsegmental bronchi, the outer the tip of the balloon is slightly compressed, a small surface of the probe fi ts snugly to the bronchial amount of air is collected in the uppermost part of the surface. A balloon probe is needed to obtain ultra- balloon and withdrawn into the sheath. This completes sound images of central lesions located between the the preparation of the balloon probe. trachea and subsegmental bronchi using EBUS. Performing E BUS Using A Balloon Probe Equipment (Figure 3.1 ) We use fl exible bronchoscopes (1T - 40, 1T- 240R, For some time, I used a 20 MHz mechanical radial Olympus) with a working channel 2.8 mm in diameter ultrasonic probe (UM - 3R, Olympus Optical Co., Ltd, for all EBUS procedures using a balloon probe. Tokyo, Japan) with a balloon - tip sheath (MH- 246R, Suffi cient local anesthetic is applied to the bronchi that Olympus). The diameter of this sheath is 3.6 mm, the balloon probe will make contact with, to avoid the patient coughing during the procedure. The balloon probe is inserted into the working channel of the bron- Endobronchial Ultrasonography, 1st edition. choscope, advanced beyond the lesion, and then By Noriaki Kurimoto, David I. K. Fielding and Ali I. Musani. infl ated with the minimum amount of saline required Published 2011 by Blackwell Publishing Ltd. to obtain an EBUS image of the entire circumference 26 CHAPTER 3 How to Perform Endobronchial Ultrasonography Probe Central Peripheral (balloon method) (direct contact method) UM-3R+MH246R 3.7 mm(BF-XT30,40) 2.5 mm; UM-3R 1.7 mm; UM-S20-20R Esophagus UM-BS20-26R+MAJ 643R 1.4 mm; UM-S20-17S 2.8 mm(BF-1T30,40) Figure 3.1 Radial probes for EBUS. Balloon method for central lesions: we use a thick ultrasonic probe (UM- 3R, 20 MHz, Figure 3.3 Orientation of the radial probe. Orientation of the 2.5 mm diameter) covered by a balloon sheath (MH - 246R), or a 12 o ’ clock position does not correspond to the bronchoscopic thin ultrasonic probe (UM - BS20 - 26R, 20 MHz, 2.0 mm diameter) 12 o ’ clock orientation. The peribronchial anatomy gives us the covered by a balloon sheath (MAJ- 643R). Direct contact method correct angle to rotate the EBUS image. On this image at the for peripheral pulmonary lesions: we use a thick ultrasonic left main bronchus, the location of esophagus is located probe (UM - 3R, 20 MHz, 2.5 mm diameter), a thin ultrasonic posterior to the left main bronchus, providing the correct probe (UM - S20 - 20R, 20 MHz, 1.7 mm diameter), or thinner orientation for the radial probe. ultrasonic probe (UM- S20 - 17S, 20 MHz, 1.4 mm diameter). Orientation of the 12 o ’ clock position does not cor- 5 respond to the bronchoscopic 12 o ’ clock orientation. 3 Comparison of bronchoscopic images and the EBUS image makes it expedient to rotate the EBUS image 1 (Video clip 3.2). The peribronchial anatomy gives us the correct angle to rotate the EBUS image (Figure 3.3 ). We therefore routinely rotate the EBUS image to give the same orientation as the bronchoscopic image. The balloon probe is withdrawn gradually to enable acquisition of EBUS images in the short axis of lesions and the tracheobronchial wall. Figure 3.2 EBUS image obtained using a balloon probe. The Tips for Successful EBUS Using balloon probe is inserted into the bronchoscope working A Balloon Probe channel, and infl ated with the minimum volume of saline 1 Keep the probe in the center of the balloon. needed to obtain an EBUS image of the entire circumference of 2 Assess the depth of the tumor center at a site where the bronchial wall. The cartilaginous portion of the extra - the fi rst layer is a thick hyperechoic layer. pulmonary bronchus is visualized as fi ve layers (arrows indicate Keeping the probe in the center of the balloon allows the fi rst, third and fi fth layers). the ultrasound wave to enter the bronchial wall per- pendicularly. The layers of the bronchial wall can be visualized clearly where the fi rst layer is a thick hyper- of the bronchial wall (Figure 3.2 ). Scanning is per- echoic layer, with the ultrasound pulse penetrating formed while retracting the probe slowly from deep the bronchial wall perpendicularly [1] . (distal) to superfi cial (proximal). Advancing the probe Because the balloon covers the lesion, it is sometimes from superfi cial (proximal) to deep (distal) can cause diffi cult to ascertain whether an often thin bronchial damage to the probe, and should be avoided. lesion, visible bronchosopically, has been actually been 27 Endobronchial Ultrasonography covered by the balloon to allow successful ultrasound scanning. There are two ways of solving this problem. Improved procedure Original procedure The fi rst is to place the defl ated balloon directly against the lesion to confi rm its presence, then re - infl ate the 4 mm balloon and scan the entire 360 ° circumference to accurately identify the position of the lesion. The other Thin GS Thick GS outer diameter: 2 mm outer diameter: 2.5 mm method is to infl ate the balloon and make a 360 ° cir- cumferential scan, then pull back the balloon slightly UM-BS20-20R into instrument channel, moving the bronchoscope tip UM-BS20-17R 1.7mm 1.4mm so that it indents the balloon, directly observing through the saline - fi lled balloon the positions of the probe transducer and lesion, and then identifying the lesion in the ultrasonic images (Video clip 3.3). Figure 3.4 Equipment used in EBUS using a guide sheath (EBUS - GS). In the original procedure, we used a thick guide Performing E BUS Using a Guide sheath 2.5 mm in diameter and an ultrasonic probe 1.7 mm in diameter. In the improved procedure, we use a thin guide Sheath (E BUS - GS) for Peripheral sheath 2.0 mm in diameter, an ultrasonic probe 1.4 mm in Pulmonary Lesions diameter, and a thin bronchoscope 4 mm in diameter. Fluoroscopy is not able to confi rm whether forceps have reached the site for endobronchial brushing and Equipment (Figure 3.4 ) transbronchial biopsy (TBB). EBUS cannot create We use two miniature ultrasonic probes (UM - S20 - 20R, images of normal air - fi lled lungs, but it can delineate UM - S20 - 17R; 20 MHz, mechanical radial, Olympus) peripheral pulmonary lesions because only small with outer diameters of 1.7 mm and 1.4 mm, respec- amounts of air come into contact with the probe. The tively. Probes are connected to an Endoscopic exploration of some bronchi with the miniature probe Ultrasound System (EU - M30, EU - M2000, Olympus). allows us to determine, more defi nitively than with The Guide Sheath Kit ( K - 201 - 202, K - 203 - 204,Olympus fl uoroscopy, which bronchus should be selected for Optical Co., Ltd.) contains a guide sheath (1.95 mm, endobronchial brushing and TBB. EBUS is also useful 2.55 mm outer diameter, respectively), a disposable for examining lesions that are diffi cult to visualize by brush (BC - 204D - 2010, BC - 202D - 2010: 1.4 mm, fl uoroscopy (e.g. lesions behind the mediastinum or 1.8 mm outer diameter, respectively), and disposable diaphragm, ill- defi ned opacities, small lesions, and biopsy forceps (FB - 233D, BC- 231D - 2010: 1.5 mm, lesions behind other TBB). EBUS clearly identifi es 1.9 mm outer diameter, respectively). which bronchus is most closely related to the lesion and should be subjected to biopsy. Using fl uoroscopy, Preparation for E BUS - GS (Video clip 3.4) the probe appears at a slight distance even when it is 1 A bronchial brush (BC - 202D - 2010, BC - 204D - 2010, adjacent to the lesion, as demonstrated by the defi ni- Olympus), or biopsy forceps (FB - 231D, FB - 233D, tive diagnosis of adenocarcinoma by endobronchial Olympus) for transbronchial biopsy (TBB), is intro- brushing at the site using EBUS. This suggests that the duced into the specially made guide sheath, so that area at the margins of the lesions contains more air, the tip of the forceps reaches the far end of the sheath so the margins may appear normal on fl uoroscopy, to facilitate manipulation. The forceps are marked at leading to underestimation of the size of the lesion. the near end of the sheath using the stopper during Since 1996, we have deployed the ultrasonic probe bronchoscopy. in a guide sheath with the active part of the probe 2 A miniature probe is introduced into the guide sheath protruding from the tip, identifi ed the location of the (SG - 201C, SG- 200C, Olympus) until the tip of the lesion ultrasonically, and then passed instruments probe including the 2 mm long transducer just pro- such as brushes and biopsy forceps down the guide trudes from the far end of the sheath. Then, the probe sheath to collect cytology or tissue specimens [ 2] . and the sheath are bound together at the proximal 28 CHAPTER 3 How to Perform Endobronchial Ultrasonography end of the sheath with the stopper so that the tip of the reaches the proximal end of the sheath (Figure 3 .5 – 3). probe remains positioned at the far end of the sheath. A few vigorous back - and - forth movements of the brush are made under fl uoroscopic guidance to collect How to Perform EBUS - GS a sample on the brush. We use a fl exible fi beroptic bronchoscope (BF 1T- 30, After the brush is withdrawn, the biopsy forceps are 40, 240R, 260, P260F) for all procedures. once again introduced into the sheath until the stopper After the bronchoscope is advanced beyond the on the surface of the forceps reaches the end of the vocal cords, all segments of the bronchial tree are sheath. The forceps cusps are opened, the forceps are visualized. Based on the radiographic fi ndings, the advanced 2 or 3 mm into the lesion and the cusps miniature probe with the guide sheath is negotiated closed under imaging guidance. After an adequate into the bronchus of interest. That is, by careful study biopsy specimen is obtained, it is placed in formalin. of the CT and the segment where the lesion lies, the The guide sheath is left in place for about 2 minutes subtending bronchus is chosen. With small lesions, to put pressure on the biopsy site to control bleeding. choosing the correct bronchus can be diffi cult and a The procedure is concluded after confi rmation that list of possible 5th or 6th order candidate bronchi can haemostasis has been achieved. be made by the bronchoscopist before the procedure. The probe is advanced until it reaches a point where the operator feels resistance, and is then pulled back Evaluation of the Diagnostic Yield for scanning (Figure 3.5 – 1). Once an EBUS image of Using E BUS - GS for Peripheral the lesion has been obtained and the location of the Pulmonary Lesions [ 2] lesion has been identifi ed precisely using EBUS, the probe is withdrawn, leaving the guide sheath in place We found that the diagnostic yield for EBUS- GS (Figure 3.5 – 2). (thick guide sheath, outer diameter: 2.5 mm) was 77% Biopsy forceps or a bronchial brush is introduced (116/150 patients) overall, 81% (82/101) for malig- into the sheath until the point marked by the stopper nant lesions, and 73% (35/45) for benign lesions. Procedure of EBUS-GS Guide sheath Guide sheath Biopsy forceps Transducer 1 2 3 Tumor Tumor Tumor Figure 3.5 Procedure for EBUS- GS. (1) The probe is advanced image. (2) Once the location of the lesion has been identifi ed until it reaches a point where the operator feels resistance, and precisely using EBUS, the probe is withdrawn, leaving the guide is then pulled back for scanning. Once an EBUS image of the sheath in place. (3) Biopsy forceps or a bronchial brush is lesion has been obtained, the probe is withdrawn and a guide introduced into the sheath until the point marked by the device is inserted into the guide sheath. After searching for |
the adhesive tape reaches the proximal end of the sheath. lesion using the guide device under fl uoroscopy, the guide A few vigorous back - and -f orth movements of the brush are device is withdrawn and once again the probe is inserted into made under fl uoroscopic guidance to collect a sample on the guide sheath and another attempt made to obtain an EBUS the brush. 29 Endobronchial Ultrasonography Leison Leison Probe Probe Figure 3.6 Location of the probe in EBUS - GS for peripheral pulmonary lesions. The diagnostic yield when the probe was within the lesion on the ultrasound image Within Adjacent to was 87% (105/121), better than that of 42% (8/19) when the probe was adjacent to the lesion. The diagnostic yield was 60% (90/150) for brushing ultrasonic probe 1 mm at a time until the probe cytology, and 70% (89/128) for transbronchial biopsy. transducer enters the sheath. When the transducer The diagnostic yield when the probe was within the completely enters the guide sheath, the ultrasonic lesion on the ultrasound image was 87% (105/121), pulse will be blocked by the guide sheath, and the better than that of 42% (8/19) when the probe was ultrasound image will suddenly become darker. If the at the periphery of the lesion (Figure 3.6 ). site of this phenomenon is within the lesion, the guide No difference was seen in diagnostic yield according sheath will be placed precisely within the peripheral to lesion size, with 76% (16/21) for lesions ≤ 10 mm, pulmonary lesion. 76% (19/25) for lesions > 10 and ≤ 15 mm (p = 0.99, χ 2 ), 2 Moving the guide sheath from adjacent to the lesion 69% (24/35) for lesions > 15 and ≤ 20 mm (p = 0.41, χ 2 ), to within the lesion (Figure 3 .8 ). Diagnostic yield has and 77% (33/43) for lesions > 20 and ≤ 30 mm (p = 0.96, been reported to be superior when the probe is within χ2 ). In other words, EBUS - GS can diagnose large and the lesion than when it is adjacent to the lesion [2] . small lesions with equal accuracy. A high diagnostic With 4 mm diameter bronchoscopes as commonly yield of 74% (40/54) was also achieved with lesions used presently, when we introduce the probe into the ≤ 20 mm, that cannot be detected using fl uoroscopy. selected sub - subsegmental bronchus to delineate a We are now achieving favorable diagnostic results lesion using EBUS, the probe is sometimes placed adja- with the introduction of ultrasonic probes in smaller cent to the lesion. In that case, the probe should be gauge guide sheaths via smaller diameter broncho- introduced into another sub- subsegmental bronchus scopes, following the route to the lesion determined in an attempt to place the probe within the lesion. by virtual bronchoscopy using a CT - based navigation When a lesion cannot be delineated using EBUS, the system. ultrasonic probe should be removed without moving the guide sheath, guiding device introduced into the Tips for Successful EBUS - GS guide sheath until their tips protrude (Figure 3.9 ). The These comprise tips for using a guide sheath, and tips tip of the guiding device (a hinged curette) is bent in for introducing the probe into the lesion. the direction of the lesion, and the guiding device is 1 Use of signal attenuation caused by the guide sheath then withdrawn slowly, looking for a point at which (Figure 3.7 ). This is a method of accurately placing the they move slightly towards the lesion under fl uoro- guide sheath within a peripheral pulmonary lesion. scopic guidance. The aim is to enter a bronchus leading Once a peripheral lesion has been delineated using to the lesion branching off from the initial bronchus EBUS, at the point the lesion appears at its largest and point, and if the tip of the guiding device is advanced clearest, the assistant should keep the guide sheath in this direction the guide sheath will follow, reaching stationary and after undoing the connection of the the lesion. Sometimes such a branch point can be felt ultrasound probe to the guide sheath withdraw the as a slight “ crank ” as the curette drops into a bronchial 30 CHAPTER 3 How to Perform Endobronchial Ultrasonography Guide Transducer sheath Figure 3.7 Confi rmation of the location of the guide sheath until the probe transducer enters the guide sheath. When the within the lesion. This is a method of accurately placing the transducer completely enters the guide sheath, the ultrasonic guide sheath within a peripheral pulmonary lesion. Once a pulse will be refl ected by the guide sheath, and the ultrasound peripheral lesion has been delineated using EBUS, at the point image will suddenly become darker. If the site of this the lesion appears at its largest and clearest, the assistant phenomenon is within the lesion, the guide sheath will be should withdraw the ultrasonic probe about 2– 3 mm at a time placed precisely within the peripheral pulmonary lesion. Adjacent to Within Figure 3.8 Moving the probe from adjacent to the lesion to within the lesion – method 1. When we introduce the probe into the selected sub- subsegmental bronchus to delineate a lesion using EBUS, the probe is sometimes placed adjacent to the lesion. In that case, the probe should be introduced into another sub - subsegmental bronchus in an attempt to place the probe within the lesion. 31 Endobronchial Ultrasonography Figure 3.9 Moving the probe from adjacent to the lesion to which they move slightly towards the lesion. A bronchus leading within the lesion – method 2. Top: the lesion was located in to the lesion branches off from this point, and if the tip of the right upper lobe. Left: When a lesion cannot be delineated guiding device is advanced in this direction the guide sheath will using EBUS, the ultrasonic probe should be removed without follow, reaching the lesion. This allows accurate placement of moving the guide sheath, guiding device introduced into the the guide sheath within the peripheral pulmonary lesion. Right: guide sheath until their tips protrude. Middle: The tip of the The guiding device is then removed, the ultrasonic probe is guiding device is bent in the direction of the lesion, and the reintroduced, and the lesion can be delineated. guiding device is then withdrawn slowly, looking for a point at opening. This allows accurate placement of the guide sheath within the peripheral pulmonary lesion. The guiding device is then removed, the ultrasonic probe is reintroduced, and the lesion can be delineated. The main benefi ts of EBUS - GS are as follows: 2.0 mm working channel 6.9 mm 1 The position of lesions can be accurately determined. 2 Forceps can be introduced any number of times to the same bronchial segment. 3 The internal structure of lesions can be analysed. 4 There is very little post - transbronchial biopsy bleeding. EBUS Guided Transbronchial Needle 7.5 MHz Optical system Aspiration (E BUS - TBNA ) convex forward oblique Equipment (Figure 3.10 ) We use a convex bronchoscope (BF - UC260F, 7.5 MHz, Figure 3.10 Bronchoscope used in EBUS - TBNA (BF - UC260F, Olympus) with an outer diameter of 6.9 mm. The 7.5 MHz, Olympus Optical Co., Ltd., Tokyo, Japan). 32 CHAPTER 3 How to Perform Endobronchial Ultrasonography probe is connected to an Endoscopic Ultrasound The target lesion is clearly outlined by EBUS. By System (EU- C2000, Olympus). rotating the bronchoscope on its axis slightly in both directions, the transducer at its tip will scan and How to Perform EBUS - TBNA delineate the entire target lesion. In this way, the We usually carry out EBUS- TBNA with topical pha- bronchoscopist measures the size of the target lesion ryngeal anesthesia, and sedation (e.g. midazolam). (Figure 3.11 ). First, B mode scanning determines The assistant elevates the patient ’ s jaw to maximize whether the internal echoes of the lesion to be punc- the pharyngeal space. The convex bronchoscope is tured are homogenous or heterogenous. Scanning in inserted into the pharynx. We should observe the 12 power Doppler mode should be performed for the o ’ clock position of the vocal cord in order to pass the target lesion as well as the path that the needle is larynx smoothly, as this scope has an oblique forward expected to traverse. This additional information view. should help avoid unintended puncture of interposed Another way of introducing the bronchoscope into small vessels and bronchial arteries located between the trachea is to insert an endotracheal tube, leaving the bronchial wall and the target lesion. Sometimes this in place for the duration of the procedure. An the target lesion is a lymph node with some necrotic 8.0 – 8.5 Fr endotracheal tube is placed over the com- areas, in which case optional power Doppler mode monly used bronchoscope, and the tip of the broncho- scanning will show the necrotic areas with reduced scope introduced into the trachea. With the tip of the blood fl ow to be avoided, and allow identifi cation of patient ’ s jaw elevated, the endotracheal tube is then the region with tortuous blood fl ow (1 mm vessels) introduced into the trachea using the bronchoscope as within the target lesion that is to be punctured. a guide. Intubation in this way has the advantage that The transducer must constantly be held in fi rm emergency treatment for hemorrhages can be given contact with the tracheobronchial wall during punc- even if the visual fi eld is obscured by blood on the ture. The needle is prepared immediately before punc- bronchoscope lens. ture is to be performed, and is inserted into the During assessment of the location of the lesion on working channel of the bronchoscope. We take care chest CT, the infl ated balloon containing the probe is that the edge of the outer sheath just protrudes from in contact with the bronchial wall adjacent to the the bronchoscope. The stylet is withdrawn a few cen- lesion. timeters to expose the sharp needle. A problem with Right- Left- handed handed LN PA Figure 3.11 Rotating the bronchoscope for the target lesion. The target lesion is LN clearly outlined by EBUS. By rotating the bronchoscope on its axis slightly in both directions, the transducer at its tip will scan and delineate the entire target lesion. 33 Endobronchial Ultrasonography placed against the tracheobronchial wall and the target lesion. The needle, containing the partially withdrawn stylet, is then advanced into the lesion under real time ultrasound guidance. The stylet is repositioned before it is withdrawn to remove the primary tissue plug containing superfi cial layers and bronchial cartilage from the needle (Video clip 3.6). Suction is then applied through the needle using a 10 Outer sheath of or 20 mL syringe. The needle is further advanced into the needle the lesion and moved back and forth under ultrasound control, with 5 to 10 strokes within the lesion usually Cartilage suffi cient. Suction is then equilibrated while the tip of the needle is still in the lesion. The needle is now withdrawn, and the needle and the outer sheath Figure 3.12 The tip of the puncture between cartilages. The tip of the outer sheath is then pushed toward the bronchial removed. wall, aiming for the membranous part between cartilages. In order to retrieve the tissue sample from the needle, the stylet is inserted into the needle from the currently available aspiration needles is that when the tip of the needle, and the sample will emerge from the needle is advanced, its outer sheath often protrudes needle tip. This is piled up on a piece of fi lter paper to too far with it. There is a way to overcome this problem facilitate histopathological examination. Any cellular (Video clip 3.5). The needle is pushed anteriorly material remaining inside the needle is then fl ushed within the bronchus, so that when the needle comes out using air from the syringe, and sent off for cyto- near the tip of the outer sheath the sheath approaches logical examination (Video clip 3.7). the transducer, and through the bronchoscope we can see the tip of the outer sheath suddenly drop a millimeter or so down. The needle is stopped |
at this References point, and the outer sheath is withdrawn once again 1 Kurimoto N , Murayama M , Yoshioka S , et al. Assessment until it can just be seen through the bronchoscope. If of the usefulness of endobronchial ultrasonography in we advance the needle now, puncture can be per- tracheobronchial depth diagnosis. Chest 1999 ; 115 : formed with almost no movement of the outer sheath. 1500 – 1506 . The tip of the outer sheath is then pushed toward the 2 Kurimoto N , Miyazawa T , Okimasa S , et al. Endobronchial bronchial wall, aiming for the membranous part ultrasonography using a guide sheath increases the between cartilages (Figure 3 .12) . This step is very ability to diagnose peripheral pulmonary lesions endo- important for a successful puncture. The needle is scopically . Chest 2004 ; 126 : 959 – 965 . 34 CHAPTER 3 How to Perform Endobronchial Ultrasonography Frequently Asked Questions 1 Is it always necessary to use the balloon? 5 What happens if the needle goes into a pulmonary artery A: The balloon is necessary to scan the cartilaginous portion branch? (horse -s hoe shape) of extrapulmonary bronchus for avoiding A: If the needle goes into a pulmonary artery branch, bleeding air between cartilages. The balloon is unnecessary for scanning is not usually severe. I have experienced no case of puncturing the membranous portion of extrapulmonary bronchus, and great vessels, but on animal experiments there was a little intrapulmonary bronchus. bleeding after puncturing great vessels. We should check 2 If N1 and N2 nodes are to be sampled how is this managed bleeding around the great vessel in the mediastinum by – should different needles be used for each site? EBUS. A: Ideally different needles should be used for each site. 6 How do you avoid the esophagus? However, the needle is very expensive and the fi rst puncture A: From trachea to left main bronchus, the esophagus is should be performed at the more proximal site (ex: N2). The located beside the bronchus. We can detect the esophagus lumen of the needle should be cleaned by fl ushing with containing air in the lumen. saline. 7 Which nodes are easiest to biopsy? 3 Is a standard bronchoscopy necessary before doing a convex A: The EBUS- TBNA for 11L or 11R is easiest to biopsy, probe EBUS procedure? because the bronchial cartilage around 11L or 11R is small. A: For checking a bronchial lesion before TBNA, a standard 8 Should on - site cytology be used? bronchoscopy is necessary. For EBUS- TBNA, a standard A: On - site cytology is very useful when deciding to end the bronchoscopy is unnecessary. EBUS - TBNA for a malignant lesion . 4 How much bleeding usually occurs after a TBNA? A: In most of cases, bleeding is very little (about 0– 3 mL). If bleeding is severe, the balloon is useful to press the bleeding point on the bronchus. 35 4 Endobronchial Ultrasound- Guided Transbronchial Needle Aspiration ( EBUS - TBNA ) should be referred to as the hilar nodes. Station 8 Anatomy should be called para- esophageal nodes, and should be distinguished from the subcarinal nodes, or station 7. Mediastinal lymph nodes are generally described In addition to the lymph node stations, the locations according to their anatomic location in the United of major vascular structures in relation to airways and States. In Europe, Asia, and other parts of the world, lymph nodes should be committed to memory. As they are referred to using international nomenclature. shown in Figures 4 .2 , 4 .3 , 4 .4 , 4 .5 , and 4.6 the ascend- The following diagram (Figure 4 .1 ) depicts their names ing part of the aorta lies anteriorly, along the left side and locations. It is important to learn the international of the trachea. It then descends, making a curve nomenclature of mediastinal lymph node stations around the left hilum, heading posteriorly. The main (i.e., their numbers) in order to be able to communi- pulmonary artery lies in front and just to the left of cate with surgical and international colleagues. the distal trachea and carina. It bifurcates into left and The lymph node stations easily accessible using right pulmonary arteries that travel anterior to the left endobronchial ultrasound- guided transbronchial and right mainstem bronchi, respectively. At the level needle aspiration (EBUS - TBNA) include the following of each hilum, the pulmonary arteries further divide, mediastinal stations: highest mediastinal (station 1), following the branching of the airways. At each poten- upper paratracheal (stations 2R and 2L), lower parat- tial transbronchial needle aspiration (TBNA) site, the racheal (stations 4R and 4L), and subcarinal (station location of the vessels may vary, as shown in. It is 7). The accessible hilar stations are hilar (station 10), helpful to post a chart of these fi gures in the bron- interlobar (station 11), and lobar (station 12). choscopy room and review it prior to the procedure. Some commonly encountered discrepancies between the US and international nomenclature are as follows. Lymph node station 4L is often referred to as the Transbronchial Needle Aspiration AP (aorto - pulmonary) window node in the US, instead of the lower left paratracheal nodes. In reality, the Transbronchial needle aspiration (Figure 4.7 ) has been station 5, subaortic node is the “ aorto - pulmonary used for decades, but with very inconsistent yield. Low node ” and it is not accessible by TBNA (Figure 4.1 ). yield may be related to multiple factors, including the Similarly, station 11, rather than station 10, lymph expertise of the bronchoscopist and the variation in nodes are often referred to as hilar nodes in the US. size and location of the target lymph nodes. Fear of According to the international nomenclature, station vascular punctures, often due to inadequate training 11 should be called the interlobar nodes, since it is in the technique, is probably the most common reason located below the upper lobe take - off, and station 10 for the low yield of TBNA. In order to use EBUS - TBNA to its maximum poten- tial, the bronchoscopist must fi rst hone his or her Endobronchial Ultrasonography, 1st edition. standard TBNA skills. Endobronchial ultrasound By Noriaki Kurimoto, David I. K. Fielding and Ali I. Musani. merely provides real- time images to prevent non - nodal Published 2011 by Blackwell Publishing Ltd. needle insertion. Good samples ultimately depend on 36 CHAPTER 4 Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) (c) (b) Ligamentum (a) arteriosum 3 Brachiocephalic 6 artery 1 Ao 5 Phrenic nerve PA 2 Azygos vein 4 Ao Superior mediastinal nodes 1 Highest mediastinal PA 2 Upper paratracheal 3 Prevascular and retrotracheal 4 Lower paratracheal (including azygos nodes) 10R 7 Aortic nodes 5 Subaortic (A-P window) 10L 6 Paraaortic (ascending aorta or 11R phrenic) 11L Inferior mediastinal nodes 8 7 Subcarinal 8 Pareasophageal (below carina) 9 Pulmonary ligament 12R N1 nodes 10 Hilar 12 9R 9L L 11 Interlobar 12 Lobar 13 Segmental 14 Subsegmental Inferior pulmonary ligaments N2 any ipsilateral single digit node N3 any contralateral or any supraclavicular node Figure 4.1 (a) Anterior view of mediastinal lymph node stations in relation to major airways and vascular structure. (b) Lat view of station 5 and 6 in relation to aorta and main pulmonary artery. (c) Station 3 node along trachea with close proximity to phrenic nerve. good TBNA technique, and the feeling of EBUS- TBNA Some are little stiffer than the others, depending upon is very similar to standard TBNA with the added benefi t the manufacturer (Figure 4.8 ). of visualization. Being comfortable with standard Generally, the fi rst pass should be performed with TBNA removes much of the “ mystery ” about EBUS- a small needle, such as a 22 G, to minimize the risk of TBNA, and makes clear the intuitive aspects of the inadvertent vascular puncture. Once the safety of the design of the EBUS- TBNA needle. In the following puncture site is established with the 22 G needle, one section, the knowledge and instruments necessary for may use a larger bore (19 G) or histology needle. successful TBNA are briefl y reviewed. Larger bore needles are generally required to ade- quately sample lymph nodes in diseases such as lym- Needles phoma or sarcoidosis, because tissue architecture plays TBNA needles range in size from 19 to 22 gauge (G). a pivotal role in their diagnosis. Alternatively, there is Their length usually varies between 13 to 15 mm. a double needle that has a 21 G inner needle with a 37 Endobronchial Ultrasonography Left common carotid artery Trachea Left subclavian artery Brachiocephalic artery Arch of aorta Right main bronchus Left main bronchus Descending thoracic aorta Esophagus Figure 4.2 Anatomy of trachea and major airways in relation to the arch of aorta and its main branches “ anterior view” . Trachea Ascending aorta Arch of aorta Right main bronchus Left pulmonary Right pulmonary artery artery Left main Right superior bronchus lobar bronchus Pulmonary trunk Right superior Left superior pulmonary vein pulmonary vein Right inferior Left inferior pulmonary vein pulmonary vein Figure 4.3 Anatomy of major airways in relation to aorta, pulmonary artery, pulmonary vein and their branches. 38 CHAPTER 4 Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) Trachea Right pulmonary artery Left pulmonary artery Left main bronchus Right main bronchus Right superior pulmonary vein Left superior pulmonary vein Right inferior pulmonary vein Left inferior Figure 4.4 Anatomy of trachea and pulmonary vein bilateral main stem bronchi with major vessels. Main crina Subcarinal lymph node Right main stem bronchus Pulmonary trunk Ascending aorta Left main stem Subcarinal bronchus lymph node Figure 4.6 Endotracheal and endobronchial area is highlighted to show the proper site for needle insertion for subcarinal node TBNA. Trachea 19 G histology needle that slides over it, from the same catheter. 12 11 1 Planning the Approach 10 2 The chest CT with contrast should be thoroughly 9 3 reviewed, regardless of whether or not EBUS will also be used. Often, it is helpful to reverse the CT fi lm in 8 4 order to better visualize the relationship between 7 5 6 lymph nodes, airways, and vascular structures, as they Figure 4.5 Locations of sub- carinal (station 7) lymph nodes in will be encountered during the bronchoscopy. All relation to trachea, main stem bronchi, aorta and pulmonary lymph node stations should be thoroughly evaluated artery. The anatomical clock at the bottom shows unsafe areas on the CT scan, and a strategic plan to approach differ- for needle insertion by red arrows pointing in that direction. ent stations in the order of preference should be made. 39 Endobronchial Ultrasonography In the event of potential or known malignancy, one station lymph nodes cannot be successfully sampled, should always attempt to sample the node that would one should then move to the second highest station. stage the disease at its highest level. For example, in The issue of changing the needles between different a patient with a 1 cm left upper lobe nodule (T1) and stations is still under investigation. adenopathy at left paratracheal, subcarinal, and right paratracheal stations, the fi rst target should be the Insertion Technique right paratracheal lymph nodes (N3), which, if posi- The four most common techniques for standard TBNA tive, would make the disease stage III B. Sampling needle insertion described in the literature are the so- only the subcarinal (N2) or left paratracheal (N2) called hub, jab, piggy - back, and cough techniques. The nodes would result in staging at a lower level, namely technique used is purely a matter of personal prefer- stage III A (Figure 4.9 ). This approach allows one to ence. I prefer the hub technique, mainly because it is diagnose and stage the patient appropriately in a safer and easier to teach. The “ hub ” technique (Figure single, minimally invasive, out- patient procedure and 4.10 ) involves placing the hub of the needle/catheter precludes unnecessary surgical staging. If the highest at desired site of insertion and, after watching for needle movement during a few respiratory cycles, pushing the needle out while holding the scope and the hub in place. The “ jab ” technique (Figure 4.11 ) involves fi rst advancing the needle out of the catheter and then entering the |
target area by pushing the cath- eter down while holding the scope in place. The “ piggy - back ” technique (Figure 4 .12 ) entails having the needle out of the catheter, with the catheter out of the working channel, at a fi xed distance in the airway lumen. The scope is then advanced into the target as one unit. The “ cough ” technique (Figure 4.13 ) requires a relatively awake and cooperative patient. In this tech- nique the patient is asked to cough while the needle coming out from the catheter is held in a steady posi- tion on the airway wall. The cough brings the airway wall onto the needle allowing it to penetrate the tissue. Figure 4.7 Transbronchial needle aspiration: the needle is passed through the airways wall in between the cartilage with In whichever technique is chosen, once the needle an angle as perpendicular as possible. The lymph node or mass is inside the target area, suction is applied fi rst to lying outside of the airways is traversed blindly or under confi rm the avascular nature of the insertion site. ultrasound guidance. Generally when within a lymph node suction on the Figure 4.8 A typical transbronchial needle and attached catheter. 40 CHAPTER 4 Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) N2 Jab method N3 N2 T1 Figure 4.11 Jab technique – having the needle out of the catheter and then entering the target area buy pushing the Figure 4.9 A CT slice depicting a left upper lobe nodule (T1) catheter down while holding the scope in place. and a mediastinal adenopathy at stations 4L (N2), 4R (N3) and prevascular area (N2). Piggy-back method Hub method Figure 4.12 Piggy back technique – having the needle out of the catheter while holding the catheter out of the working Figure 4.10 Hub technique – by placing the hub of needle at channel at a fi xed distance in the lumen of the airway. The desired site of insertion, the needle is pushed out while holding scope is then driven down into the target by the operator as the scope and the catheter in place. one unit. needle should meet with fi rm resistance. In case bleeding stops, another attempt can be made in differ- of bloody return, suction should be turned off imme- ent location. diately and the needle should be retracted and Once the needle ’ s location outside of a vascular removed from the working channel. Any blood from structure is verifi ed, a rapid and shallow in - and - out the puncture site should be suctioned. In general, motion is used to obtain the sample, while keeping the bleeding in these situations is minor and stops spon- bronchoscope fi xed at the patient ’ s nose or mouth. An taneously. Signifi cant bleeding is very rare. Once the assistant may help to limit the scope motion. The 41 Endobronchial Ultrasonography motion should be deliberate and swift. Attention the scope can be lacerated. The bronchoscopist should should be paid to keep the scope straight between the deliberately pause at this time to clear any secretions patient and the operator ’ s hand. If there is slack in the from the tip of the bronchoscope to allow as clear a scope, much of jabbing motion is lost before reaching view of the tip of the TBNA needle as possible to ensure to needle. I usually jab between fi ve and ten times. The that the sharp needle has been completely retracted. suction should be slowly released before pulling the needle back in the catheter, to prevent aspirating bron- Sample Handling chial cells on the way out. Once the needle is fully Rapid on- site cytology (Rapid On Site cytologic inside the catheter, the catheter should be removed Evaluation – ROSE) allows for differing additional from the working channel. Care must be taken to make biopsy with outloss in diagnostic yield, likely lower sure that the needle is fully inside the catheter when procedural risk and is cost effective [1] . If on - site cytol- going in and out of the working channel, otherwise ogy is available, the sample from the needle should be transferred directly to the slides. We usually make at least two slides from each pass, one for Diff - Quick and Cough method the other for hematoxylin and eosin (H & E). The usual air drying method is employed for the preparation of these slides. The remaining sample is pushed into a container fi lled with the saline for a cell block. The needle/catheter is purged with air and saline to prevent clotting. The entire process can be repeated in the event of a negative yield on the fi rst pass. Endobronchial Ultrasound Endobronchial ultrasound was created by modifying and miniaturizing the endoscopic ultrasound used by Figure 4.13 Cough technique – in this technique the patient gastroenterologists. Please refer to Chapter 1 of this is asked to cough while the needle is held in a steady position book for a review of the physical principals of ultra- on the airway wall. The cough brings the airway wall onto the sound. The initial version was a radial ultrasound needle allowing it to penetrate the tissue. probe (radial probe) (Figure 4 .14 ). This probe passed (a) (b) US probe Guide sheath Figure 4.14 (a) Endobronchial ultrasound balloon probe (UM- BS20 -2 6R) extending out of the working channel of a fl exible bronchoscope. The balloon over the probe is infl ated with normal saline. (b) Endobronchial ultrasound probe is extended in the lumen of the airway through the working channel of a fl exible bronchoscope. Once the balloon is infl ated, the probe can pick up the sonographic features of a mass around the airways. 42 CHAPTER 4 Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) Channel Fiber optics Transducer Scanning direction/range EBUS-TBNA scope Miniature probe (one example) Figure 4.15 Comparative structures of EBUS scope and radial the view is 90 ° and the direction of the view is 30 ° forward probe. The EBUS scope (XBF - UC260F - OL8, Olympus, Tokyo, oblique. The radial probe can pass through the working channel Japan) has a convex/linear transducer (7.5 MHz) extending ahead of the bronchoscope into the lumen of the airway. It rotates of the light source and camera. The outer diameter of the scope 360 ° and gives a circular image of objects all around it. itself is 6.7 mm whereas that of a tip is 6.9 mm. The angel of (a) (b) Figure 4.16 (a) The EBUS scope (XBF- UC260F - OL8, Olympus, Tokyo, Japan). (b) The balloon is over the transducer is infl ated with saline. through the working channel of the bronchoscope (linear scope or convex scope) and the radial probe is into the airway lumen and could rotate 360° . A its capacity to provide real - time images during TBNA. balloon sheath over the probe was infl ated with saline The EBUS scope (BF- UC260F - OL8, Olympus, Tokyo, to fi ll up the airway lumen. The saline - fi lled balloon Japan) (Figure 4.15 ) has a convex/linear transducer provided a good medium for sonic coupling between (7.5 MHz) extending ahead of the light source and the probe and the target tissue. Once the images were camera. The outer diameter of the scope is 6.7 mm, captured and recorded, the probe was pulled out of whereas the tip is 6.9 mm (Figure 4.16 ). The angle of the scope ’ s working channel to allow for insertion of the view is 90 ° , and the direction of the view is 30 ° the TBNA needle/catheter. As a result, the operator forward oblique. The convex surface should be in needed to make a mental picture of the potential direct contact of the airway wall, or the space between needle insertion site in reference to the airway and them should be fi lled with a good sound - conducting vascular structures. Hence, this was a “ blind ” tech- medium, such as saline. The ultrasound image is proc- nique, (not real- time) which limited its utility and essed in the ultrasound scanner (EU - C2000, Olympus, popularity. It did however allow for more confi dence Tokyo, Japan). A small balloon (Figure 4.17 ) mounted in less commonly needled sites such as hilar or left over the linear /convex probe is fi lled with saline once paratracheal. the probe is in the airway lumen. An extra opening In early 2000, a real - time EBUS device was intro- under the working channel, below the handle of the duced. The major difference between the EBUS scope scope (Figure 4.18 ), allows for saline to be instilled 43 Endobronchial Ultrasonography (a) (b) (c) (d) (e) Figure 4.17 (a) Balloon to go over the convex probe. (b) The pad of index fi nger over the tiny knob at the distal most aspect balloon is held between the two arms of the application forceps of the convex probe. All the bubbles should be released from at half length and reversed over it. (c) The balloon is applied the tip of the balloon after fi rst infl ation with saline before over convex probe with the wider opening of the balloon pushing the tip of the balloon onto the tip of the convex probe. sitting in the crease on the distal aspect of the convex probe. (e) Infl ated balloon on the convex probe without any air (d) Smaller opening of the balloon is pushed down with the bubbles. into and removed from the balloon. Because the assembly (Figure 4.20 ) is a stylet. Just under the camera faces 30 ° forwards and upwards, maneuvering handle bar is a white needle lock that controls the the scope in the airway can be somewhat challenging. length of the needle. The length of the needle is also I think of it as lying on one’ s back in a tunnel looking controlled by a stop bar slightly distal to handle bar. up and ahead while dragging forward. When placed at number three, the stop bar limits the The needle set- up of the EBUS scope appears rather functional length of the needle to 20 mm. Under the complex at fi rst, and requires a good understanding of stop bar is a white sheath lock. This lock allows the its operation. The needle comes out at a 45 ° angle from sheath covering the needle to be moved forward or the working channel of the EBUS scope, passing above backwards (Figures 4.21 and 4 .22 ). Usually, I advance and away from the balloon on the probe (Figure 4.19 ). the sheath to the tip of the working channel so that it The needle provided with the EBUS system is 22 G. appears on the upper right portion of the monitor However, the inner diameter of this needle is equal to screen prior to the actual insertion. This prevents the a 21- gauge needle, which allows larger, histological scope from being pushed away from the tissue when core samples. The most proximal portion of the needle trying to introduce the needle in the tissue. 44 CHAPTER 4 Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) The EBUS scope set up also includes connecting the scope via a scope cable to the control panel as shown in Figure 4.23 . Once connected and secured properly, monitor settings should be chosen for optimal picture quality. Our usual setting are depth 4 cm, penetration mode, and GI2 (contrast 2). The gain is certain at every start up of this ultrasound machine (Figure 4.24 ). Step - by - Step Endobronchial Ultrasound- Guided Transbronchial Needle Aspiration A thorough examination of the airway is performed with a conventional (non - EBUS) bronchoscope prior to EBUS - TBNA. Endobronchial lesions should be excluded which may obviate the need for EBUS- TBNA. An EBUS scope is then inserted through the oral cavity. Some experts go directly to the TBNA site, while others perform a thorough ultrasound examina- tion of the mediastinum prior to proceeding to the pre - selected site. I favor the latter approach, because the ultrasound survey often provides more practical Figure 4.18 An extra opening under the working channel port information |
about the location and accessibility of of the scope allows for infl ation of balloon over the transducer with saline. This opening is connected with the 20 cc syringe nodes, compared with the CT scan. However, one fi lled with saline via IV tubing and a stop cock. should still abide by the predetermined plan to sample lymph nodes that would, if positive, stage the disease to the highest level in the smallest number of attempts. After the ultrasound - guided mediastinal survey, and before the fi nal approach to the insertion site, the tip of the scope is placed in a large airway, where the catheter and needle are positioned at its tip (Figure 4.25 ). The catheter is pushed out to the tip of the scope by loosening the catheter lock. The catheter tip should be barely visible on the upper right portion of the monitor screen showing bronchoscopic fi ndings. This can be done either before passing the scope or when inside the bronchial lumen. The needle lock is then Figure 4.19 This fi gure depicts the relationship between the loosened and the needle is advanced out to the tip of convex probe, balloon covering the convex probe, needle the catheter. This can be demonstrated by observing a extending from the working channel and penetrating the lymph “ drop ” in the needle apparatus as the needle is node behind the airway wall. advanced with the sheath locked. From this point the sheath is pulled back to its original position just exiting from the channel tip. Once the catheter tip and needle Under the sheath lock, there is a safety adaptor to are in place, the locks are tightened and the stylet is lock the needle handle to the biopsy port. The purpose pulled back about 2 cm to allow the bevel of the needle of this lock is to prevent movement of the needle to lead. Optionally it is possible to lave the stylet assembly from the scope. fully in, as some operators report less contamination 45 Endobronchial Ultrasonography (a) Stylet Stylet knob Wire Aspiration port Needle slider Lot number Handle section Model reference label Needle adjuster Single use adapter biopsy valve (MAJ-1414) Needle adjuster knob Pull-tab Scale Stopper Connector section Sheath adjuster knob Needle attachment section Connecting-slider Insertion port Stylet distal end Boot Echo enhanced region Protective plate Needle tube Needle distal end Insertion portion/ working length Sheath Distal portion (b) Connector section Stopper Needle adjuster Aspiration port Needle slider Scale Stylet knob Connecting slider Sheath adjuster knob Needle adjuster knob Figure 4.20 (a) A complete needle assembly system for EBUS- TBNA. (b) Proximal portion of the needle assembly focusing on the needle and sheath adjuster knobs and the needle stopper to determine the functional length of the needle. with epithelial cells with this method. The target is inserting the needle. Once the tissue is penetrated, the identifi ed, and the balloon is infl ated, allowing ultra- picture returns to the screen. This image “ blackout ” sound confi rmation of the location. As shown in happens because the needle pushes the scope away Figure 4 .26 the target is kept in the center of the screen, from airway wall, leading to loss of contact between with the green dot marking the entry point on the the balloon and the tissue. This is either because the right upper edge of the screen. A brief Doppler ultra- sheath is pushing the bronchial wall away having sound examination is performed at this point, to iden- extended beyond the tip of the needle, or because tify any vascular structures in or around the target. the needle has come up against bronchial cartilage After observing respiratory movement in relation to preventing penetration. With the latter scenario the EBUS picture for a couple of respiratory cycles, the coming away and re approaching the wall at a slightly needle lock is loosened and the needle is advanced altered angle is preferred, particularly aiming at a into the tissue. An assistant should hold the scope at point “ on top of” a cartilage ring to facilitate passage the patient ’ s mouth while the needle is advanced. between the rings. Once the scope is pushed down and Often, an assistant is asked to push the scope down the needle has penetrated the tissue, the balloon forcefully, yet smoothly, to facilitate penetration. It is comes back in contact with tissue and the image not unusual to lose the image of the target while reappears. 46 CHAPTER 4 Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) Needle adjuster knob (a) (b) Sheath adjuster knob Handle section Connecting-slider (c) (d) Stylet knob 50 mm Sheath adjuster knob Handle section Figure 4.21 Different parts of a needle assembly system used with EBUS- TBNA scope. (a) The needle assembly’ s handle section showing how the connecting slider fi ts on the adaptor attached to the working channel port of the scope. (b) The connector slider is pushed backwards. Needle adjustor knob is located above the sheath adjuster knob. (c) Sheath adjuster knob is loosened by rotating counter clockwise. (d) The stylet is pulled back by holding the stylet knob. Once the needle is in the lymph node, the stylet is the pre- loaded suction syringe is connected, and pushed forward a couple of times to force out bron- suction is applied. If no blood is seen in the catheter, chial cells captured along the way. One can see the gentle jabbing is begun, as previously described, tissue and blood being pushed out of the needle on a making sure that the needle does not come out of the real - time ultrasound image. The stylet is then removed, lymph node. Five to ten long, smooth passes are made, 47 Endobronchial Ultrasonography (a) (b) (c) (d) (e) (f) Figure 4.22 Proper technique for loading the needle assembly assembly). (d) Before lowering the needle, the position of the on the scope, step - by - step. (a) The needle is passed through the needle length slide lock should be confi rmed at 3, allowing only working channel and the entire needle assembly is loaded in the about 20 mm of needle to come out of the scope. (e) The stylet special working channel cap provided with the needle kit. The is pulled back a couple of centimeters to allow the bevel of the tightening knobs should face forward. The sheath and the needle to lead. The needle is then unlocked by loosening the needle should be completely retraced by pulling their sliders all needle lock knob just prior to penetration in the tissue. Once the way up. (b) Once the needle assembly is tightly fi tted in the the target is penetrated, the stylet is pushed forward a couple working channel; the lock should be applied by sliding it of times to push out the unwanted epithelial cells captured on backwards. (c) In preparation for needle insertion, the sheath is the way. (f) Suction is applied after removing the stylet with a pushed out by loosening the sheath lock (lower knob on the locking syringe. 48 CHAPTER 4 Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) (a) (b) (c) Figure 4.23 (a) Endobronchial ultrasound processor EU - C2000. (b) Endobronchial ultrasound bronchoscope (BF- UC260F - OL8) attached to the processor. (c) Same as (b) seen in close up. Figure 4.24 Endobronchial ultrasound monitor. The basic settings and format is shown here. Detailed set up is discussed in Chapter 1 . 49 Endobronchial Ultrasonography (a) (b) (c) Figure 4.25 (a) Endobronchial ultrasound convex probe with balloon is defl ated. The angulation of the needle allows for near needle sheath pushed out of the working channel. The balloon perpendicular angle between the target and the needle. (c) is defl ated to show the safety margin between the catheter and Needle pushed out of the catheter pointing at an angle of 45° . needle that comes out of it and the probe. (b) Needle pushed The needle stays clear of the infl ated balloon. out of the catheter pointing at an angle of 45° . Again the (a) (b) Needle Lymph in the node lymph node Figure 4.26 (a) A small mediastinal lymph node is seen on EBUS monitor. (b) A needle is penetrated diagonally across the lymph node. The entry point of the needle is at the green dot on the right upper corner of the ultrasound fi eld. 50 CHAPTER 4 Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) much like picking ice. Before removing the needle genetic studies, the procedure can be concluded. from the lymph node, the suction is turned off to However, if the sample contains lymphoid material avoid collecting unwanted cells in the needle on the but no malignant cells or granulomata, one may way out. The needle is then retracted into the cathe- proceed to another TBNA of the same site or another ter. The needle assembly is unlocked at the biopsy port site. The number of aspirates performed is a matter and removed from the working channel. of personal preference. There are no randomized, The needle containing the specimen should be controlled trials to suggest that multiple punctures of taken immediately to the slides, which have been pre- same lymph node improve the yield. I generally viously laid out, labeled, and numbered. Some bron- perform at least two TBNAs at the same site before choscopists push the specimen out with the stylet onto going to the next lymph node station. If lymphoma or a fi lter paper or gauze to absorb blood and separate sarcoidosis is a strong possibility, I usually insert a 19 G the core tissue biopsy. The core tissue is then put into needle at the same puncture site, without EBUS, formalin for histopathologic examination. Some of the before proceeding to the next station. Overall, experi- specimen in the needle is pushed out onto the slides ence with this strategy for EBUS - TBNA has been very for cytologic examination by blowing air through the good. In general, post - procedure chest radiographs are needle. Sample remaining in the needle is placed into not needed following an uncomplicated TBNA. a tube containing normal saline. After the specimen has been pushed from the needle with the stylet, the stylet is cleaned with an alcohol swab to clean blood Acknowledgements clots from its surface. Another technique is to push the specimen on the slide with the stylet, then push I would like to acknowledge and thank Dr. Esther air and saline to deliver any remaining specimen into Langmack for editorial assistance, Barry Silverstein for saline for later staining and cell blocks. End paper photographic expertise and Boyd Jacobson for excel- method is used for cell block/histology after the mate- lent art work. rial for slides has been obtained. If on- site cytology is not available, the specimen retrieved in the needle should be pushed into a tube References containing normal saline. However, if on - site cytology is available, the cytologist may help determine whether 1 Baram D , Garcia RB , Richman PS . I mpact of rapid a second aspirate is needed. If malignant cells, granu- on - site cytologic evaluation during transbronchial needle lomata, or other features reveal a diagnosis, and no aspiration . Chest 2005 ; 128 ( 2 ): 869 – 875 . more tissue is needed for further confi rmation or 51 5 Tips and Diffi culties in E BUS - TBNA in this technique. The most commonly aspirated sites Tips would be the right paratracheal and subcarinal posi- tions and the anatomical relations of these two sites Wang ’ s Descriptions of TBNA Positions can be quickly gleaned from the Wang descriptions. The technique of transbronchial needle aspiration has been in the literature for over 25 years [ 1] , and there Radiological Anatomy is much useful material to be obtained from Wang ’ s The proceduralist needs to become familiar with inter- original description to facilitate transbronchial needle preting the CT scan for the presence of mediastinal aspiration. The addition of EBUS aids the practitioner and hilar lymphadenopathy. An excellent reference in confi rming the localization of the lymph node [2] , for this is Ko, 2000 [6] . In fact, with EBUS, only the as shown in early |
studies with an EBUS balloon probe. following are accessible: the highest mediastinal However, an understanding of the common locations (station 1), the upper paratracheal (station 2R and of the lymph nodes adjacent to the trachea and main 2L), the lower paratracheal station (4R and 4L), the bronchi as well as their main relationships can be subcarinal (station 7), hilar (station 10), the interlobar obtained from careful scrutiny of these early papers (station 11) and the lobar nodes (station 12). Stations [1,3] . In his papers, Wang described 11 nodal positions 5 and 6 are the subaortic and para- aortic lymph nodes starting at the anterior carina and progressing down respectively and neither of these are directly applied the main bronchi, to the subcarina and, ultimately, the to the trachea. Similarly, the number 8 and 9 lymph hilar positions. At each of these 11 sites, a description nodes are too far posterior and inferior to be accessed of the best point to insert the needle was given in by the TBNA scope. Both of these can be accessed by terms of a clock - face with respect to the bronchial endoscopic ultrasound. The number 13 and 14 seg- lumen. These 11 positions provide an invaluable start- mental and subsegmental lymph nodes are usually not ing point for the student of transbronchial needle aspi- able to be biopsied simply because the TBNA scope is ration whether using a standard TBNA needle or using too large to proceed further out the bronchial tree the convex probe and a bronchial ultrasound scope. It towards these nodes. On occasion, a number 13 might should be remembered that these numbered positions be accessible. are different from the traditional lymph node stations Some of the important vascular- relations are as described by Naruke and the American Thoracic described in Ko ’ s paper. The level 1 nodes are only Society in their classifi cations [4,5] . Even familiarity very uncommonly biopsied by EBUS- TBNA. The with two or three of these positions is adequate for important vascular relation is that this node is cranial the learning practitioner to quickly develop expertise to the brachiocephalic vein where it crosses the trachea. The station 2 para - tracheal lymph nodes are positioned below the top of the left brachiocephaic vein but above the top of the aortic arch. Station 4 Endobronchial Ultrasonography, 1st edition. lymph nodes can be divided radiographically into a By Noriaki Kurimoto, David Fielding and Ali Musani. superior and inferior subset. Superior nodes are infe- Published 2011 by Blackwell Publishing Ltd. rior to the top of the aortic arch and above the azygous 52 CHAPTER 5 Tips and Diffi culties in EBUS-TBNA vein; inferior station 4 lymph nodes are below the on right and left, the pulmonary artery can be horizontal line drawn at the superior aspect of the readily seen in the lateral position (3 o ’ clock on the azygous vein. Of course, lymph nodes in this station right, and 9 o ’ clock on the left). By rotating the scope 4 para - tracheal position can be contiguous between directly anteriorly, each of these vascular points can the superior and inferior positions. In the lower para- be avoided and the node easily visualized in this loca- tracheal position, these nodes can be classifi ed as tion just at the origin of the right or left lower lobe either 4R or 4L depending on whether they are on the bronchus. right or left of the lower trachea. The nomenclature is The fi nal tip is with hard copy fi lm or even on an important with respect to 4L as these are separated electronic copy to fl ip the fi lm horizontally so that a from the number 5 or aortopulmonary window lymph bronchoscopic type view (standing at the head looking nodes by the ligamentum arteriosum, with 4L lymph at the feet) is obtained to further visualize the likely nodes being medial to this structure. Station 10 hilar direction of needle puncture. lymph nodes are anterior and posterior to the right upper lobe bronchus. The demarcation point between Which Nodes will be Most Commonly station 4 mediastinal and station 10 hilar nodes is the Sampled? top of the right upper lobe bronchus; mediastinal Lymph nodes most commonly sampled will be the number 4 nodes are superior to this and station 10 right paratracheal and subcarinal lymph nodes and it hilar nodes are inferior to this point. Familiarity with is suggested to do just 10 or 20 cases at these two sites these positions and enlargement of lymph nodes at alone to develop familiarity with the process and this point obviously brings familiarity with the vascu- needle puncture. The number 4L position can be dif- lar relations. fi cult to access because of the sharper angle of the left In general terms, the anatomy of these major struc- main bronchus coming off the lower trachea com- tures is not nearly as variable as is seen in assessing pared to the right. As such, it is diffi cult to maintain the peripheral airways and small vascular branching good application of the EBUS balloon to the tracheo- at subsegmental levels and therefore it allows the bronchial angle and the help of an assistant to hold trainee to rapidly develop a concept of pattern recog- the bronchoscope in position can be required. To a nition [7]. The nodal positions 1, 2R, 4R, 4L, 11L, and lesser extent, this can be true at the right tracheobron- 11R and 7 all have fairly constant vascular relations chial angle in low number 4 or number 10 nodes. and, as such, a “ snap - shot ” or pattern recognition image can be used by the trainee [ 7] . For example, in Setting Up the Scope the commonest position, the number 7 subcarinal The TBNA convex probe dedicated needle made by location, it is a simple matter of demonstrating the Olympus (NA- 201SX - 4022) has a number of moving right main pulmonary artery immediately anteriorly parts with which the operator can become rapidly at the origin of the right main bronchus and turning familiar. away anticlockwise to the subcarinal position at the 9 The needle apparatus is released by unwinding the o ’ clock location. In the number 2 right paratracheal screw on the gray sleeve. By holding the apparatus position, the best known vascular relation deep to the above this sleeve between fi nger and thumb it can be lymph node would be the superior vena cava which easily pulled down in a controlled fashion to protrude can be seen as an elongated vascular structure usually the needle from the tip. Stabilize the hand on the at the 3 o ’ clock position. (This may be poorly seen if apparatus by winding the fi fth fi nger of the same hand the node is not suffi ciently enlarged.) Turning back around it below the needle apparatus. Before com- anticlockwise slightly to the 1 – 2 o’ clock position mencing the procedure, check that the needle moves brings the node into view. In the number 4 lower right freely in and out in the same way as one would paratracheal position, the superior vena cava can be prepare a simple cannula for venous cannulation. seen in its lower end, whereas at the lower end, more Immediately on completing this simple task and at all anteriorly, both the azygous vein and right pulmonary times when using the needle, the needle shaft should artery can be relatively easily seen in a commonly be pulled back until a click is felt and heard and the observed pattern. In both the number 11 positions screw on the gray sleeve retightened. This ensures that 53 Endobronchial Ultrasonography the sharp needle is fully retracted within the plastic front of the optic which is not visualized. Therefore to sheath and, as such, the needle tip is unable to damage facilitate ease of passage of the scope through the vocal the biopsy channel of the bronchoscope. Next, the cords it can be helpful for an assistant to provide ante- needle apparatus as a whole needs to be calibrated for rior jaw lift to open up full viewing of the vocal cords. length against the biopsy channel. The needle appara- If the anterior commissure is viewed it means the tus is passed into the channel and the white knob scope itself is pointed at the mid point of the cords and unscrewed to allow inward or outward movement of the scope will easily pass through. This part of the the plastic sheath. This sheath should be aligned at the procedure requires practice particularly the need to end of the biopsy channel; when this plastic sheath have the scope tip go anteriorly over the arytenoids just comes into view on the monitor it implies that the and not be caught and pushed posteriorly. In patients sheath has come out the end of the biopsy channel with crowded upper airways this can be diffi cult even and, therefore, should be fi xed in this position so that with anterior jaw lift. Similarly, when in the bronchial when the needle is protruded from the sheath it will tree to pass the main carina one would overcorrect do so from outside the biopsy channel thereby not much earlier than with a standard bronchoscope damaging it.. The sheath should not be fi xed too far where the viewing optic is at the very end of the out as this will hamper needle penetration attempts scope. For example, 2 or 3 cm before the main carina, by pushing the ultrasound transducer away from the the scope would be rotated to the right and very close wall and hampering imaging just prior to biopsy. Once to the lateral tracheal wall to facilitate passage into the this position has been found, the white knob should right main bronchus. generally not be adjusted until during the procedure. Depending on local preference anesthetic support is Now the balloon can be set up on the transducer available in some centers with the ability to intubate tip. Draw up 30 mL of saline into a Leuer lock syringe the patient either with standard ETT or laryngeal mask with fl exible giving set and 3- way tap attached. It is airway (LMA). Sarkiss et al. reported their anesthetic best to remove all air bubbles; this is best achieved by technique for EBUS - TBNA [8] . They use a number 4 drawing up the saline slowly and then expelling the LMA because it has a large internal diameter and is bubbles by holding the syringe in a vertical position the most suitable device to secure the airway and with the three way tap uppermost, gently tapping the provide adequate ventilation around the broncho- syringe as required. Having done this, one can prime scope. The outer diameter of the XBFUC 160F EBUS- the balloon channel on the scope with 2 or 3 mL of TBNA scope is 6.7 mm and 6.9 mm at the tip. These saline. The three way tap is then closed. The balloon authors used a total intravenous anesthesia (TIVA). itself then needs to be fi tted to the convex probe end TIVA was preferred over volatile anesthetics because of the scope over the ultrasound transducer. There is frequent suctioning of airway by the bronchoscopist a dedicated applicator for this. Having applied this to resulted in contamination of the procedure room the convex probe, the probe tip is held upwards and atmosphere by the anesthetic gases and also causes the fl uid syringe held downwards and 5– 10 mL of inconsistent delivery of the anesthetic gas to the saline is used to slowly fl ush through the balloon patient. channel until bubbles are removed from the balloon. They used propofol infusion at a rate of 75 µ g/kg/ Once it appears that this has been complete, the very min once intravenous catheter and standard monitor- tip of the balloon can be folded back over the dedi- ing for general anesthesia were in place. Small doses cated balloon holder at the tip of the scope. This of fentanyl or remifentanil were given for induction. should only be done once all bubbles have been An alternative to the LMA is |
an endotracheal tube removed as bubbles can no longer be removed once (8.5). The indications for ETT placement were diffi cult this has been folded into place. laryngeal mask airway placement, obesity, and severe untreated gastro- esophageal refl ux. The EBUS can Passing the Bronchoscope and Anesthesia only fi t in a size 8.5 or 9.0 mm internal diameter As described in the previous chapter the practitioner endotracheal tube. These authors used an 8.5 ETT for needs to adjust for the anterior view of the white light female patients and a size 9.0 for male patients. optic and the fact that there is about 1 cm of scope in To some extent, the endotracheal tube does make it 54 CHAPTER 5 Tips and Diffi culties in EBUS-TBNA diffi cult to oppose the convex probe against the bron- of the lower cartilage, the ultrasound balloon can chial wall because the tube brings the scope into the then be fl exed back up against the bronchial wall to center of the lumen. The ETT can be manually “ leaned ” image the fi rst pass of the needle into the node. towards the side of biopsy to some extent. Prior to performing puncture, it may be possible to In general an LMA is preferable because an ETT can push the plastic sheath in and out allowing visualiza- at times hinder in access to paratracheal lymph nodes; tion of this to occur as it indents the space between ETTs may have to be pulled back if this occurs, some- the cartilage rings, and makes it easy to pass the needle times repeatedly, to allow free access to the side of the through. tracheal wall. The second method is to simply hold the broncho- scope with the infl ated balloon against the node at its The Reach of the Bronchoscope most upper or cranial point and to gently advance Usually, it is diffi cult to access the segmental bronchi the needle into the node without any movement of with this 6.4 mm diameter bronchoscope. It is possible the scope away from the bronchial wall. The disad- to easily access the origins of the right and left main vantage of this method is that it is common for bronchi, both lower lobe bronchi. On the right, occa- the needle to come up against cartilage rings. To over- sionally it is possible to enter the right upper lobe come this problem it requires re - manipulation or rota- bronchus origin to puncture the top end of a number tion of the scope 5 or 10 ° in either direction. Again 11S lymph node. Occasionally it is also possible to this can be made easier by slightly advancing the enter the origin of the right middle lobe bronchus to plastic outer sheath and visualizing this indenting access anterior lymph nodes at this point. On the left, the top right of the ultrasound image. This method it is usually possible to access the most proximal parts might be easier to use in the more peripheral puncture of the upper division bronchus although the indica- sites such as the number 11 in the origin of each tions to do this are very infrequent and this region is lower lobe. The obvious reason being the diffi culty very vascular. Accessing the left upper lobe bronchus of fl exing the bronchoscope away from the wall and lingula are usually not possible. at these points given the small bronchial lumen diam- eter. Also the cartilage rings here tend to be less Passing the Needle through the Wall obstructive. After infl ation of the convex probe balloon a biopsy Before doing either of these methods, it is possible site is chosen, usually by selecting the most proximal to improve puncture by having the sharp needle end of the lymph node. Careful Doppler examination come to the tip of the plastic sheath before formally at this point should reveal no small bronchial artery; advancing it into the lymph node. Somewhat unex- if this is present, simply rotating the scope in an axial pectedly when the needle is protruded inside the plane should be able to remove the vessel from the plastic sheath, the sheath is elongated by this action. anticipated needle puncture track. Puncture of the That is, the sheath will move out in front of the needle tracheal wall can be done using two different methods. even though it has not been specifi cally released The fi rst and preferred method is to visually determine itself. This pushes up against the wall of the bronchus, a mark or minor vascular structure on the tracheal or and can effectively “ push ” the balloon away from the bronchial wall where the needle will be passed. This wall before the needle can be advanced. A quick is determined by fi rst using ultrasound examination method to prevent this problem has been recently showing the position of the most cranial (near) end of described by Kurimoto and others: with the scope the lymph node. The bronchoscopic white light views in the middle of the bronchus lumen away from are then carefully scrutinized to show a mark at this the wall the needle is protruded and observed exact point, obviously just above a cartilage ring. The closely. The needle will have just reached the tip of next step is to fl ex the bronchoscope a little backwards the sheath when there is a slight downward move- and away from the bronchial wall so that the needle ment of the tip of the sheath. The needle shaft is can be passed more directly straight into the wall at then left in this position and the plastic sheath with- the desired point as described. Having passed the drawn to its original position just outside the biopsy needle into this cartilaginous space, usually on the top channel. 55 Endobronchial Ultrasonography Obtaining Samples was confi rmed in 41 stations in 30 patients. Two areas It is often helpful to ask an assistant to hold the bron- of malignancy as documented by surgery were missed choscope still at the exit from the mouth as this will in two patients. Sample adequacy was 90.1% for one prevent slight movements of the scope which can aspiration and it reached 100% for three aspirations. hinder adequate visualization during insertion of the The sensitivity for differentiating the malignant from needle. Sometimes as the needle is being inserted, the benign lymph node stations was 69.8%, 83.7%, scope is pushed backwards in a cranial direction and 95.3%, and 95.3% for 1, 2, 3 and 4 aspirations respec- re - advancing the scope the 1 or 2 mm helps to regain tively. Maximum diagnostic values were achieved in the image. Because of the effect of slight movements three aspirations. The negative predictive value of it helps to have two monitors (one for EBUS and one 86.5% for one aspirate and 97.6 for four aspirates for bronchoscopic fi ndings) on continuous display respectively. These authors concluded that optimal rather than alternating the view on one monitor. results could be obtained in three aspirations per It is important to keep the full length of the needle lymph node station for mediastinal staging of the in view on the monitor during the TBNA procedure potentially operable non - small cell carcinoma. They specifi cally with reference to the distal tip of the felt that if a tissue core specimen could be obtained in needle. the fi rst or second aspiration, then two aspirations per Occasionally, once the needle has been inserted in lymph node station would be acceptable. the node, it is diffi cult to push the stylet fully in to remove cartilaginous material from the tip of the needle. This is particularly true when the broncho- Side Effects and Risks scope is more acutely angled and it is sometimes nec- essary to gently release any angulation on the Transbronchial needle aspiration biopsy as an alone bronchoscope to allow a more straight passage in of procedure has been in clinical use for at least 25 years the stylet. Care should be taken to prevent inadvertent [1] . Tolerance of this technique was summarized in bending of the stylet during reinsertions. Occasionally, 2000 [10] . The main reported risk at that time was not when two or three insertions are made, it is necessary so much to the patient as damage to the broncho- to ensure any small amounts of blood are wiped off scope. This occurred when standard TBNA needles the stylet before it is readvanced as coagulation of were inadvertently deployed whilst still within the blood on it can make it stick in the thin channel. biopsy channel, hence causing damage to the channel. Sometimes blood comes into the suction syringe in [11] . In addition to this, standard TBNA needles can aspirations of vascular lymph nodes. This can reduce be damaged by the sharp point of the needle going the diagnostic yield and therefore it is best to remove through the plastic sheath [12] . In the review of the needle without any further passes at that point. TBNA, there were two cases of pneumothorax and Some authors recommend trials of no suction on the one case of pneumomediastinum and hemomediasti- needle in this situation just relying on the “ cutting ” num [11] . There was one patient with a reported aspect of the needle to obtain the sample. In subse- purulent pericarditis after TBNA of a subcarinal mass. quent passes it may help to just do four or fi ve move- One rare complication of standard TBNA has been in ments of the needle in and out in the node as opposed advertent liver biopsy in a patient with a right raised to the usual 20. hemi - diaphragm [13] . A 2002 report noted a medias- tinal hematoma after inadvertent puncture of the How Many Aspirations Per Target Lymph aorta; his resolved spontaneously on CT [14]. Node Station? The convex probe TBNA scope was fi rst reported in This was reported by Seok Lee et al. and is clearly 2003 and, to date, very few side effects have been relevant for those situations where rapid onsite reported [ 7] . Signifi cant bleeding has not been reported cytopathological examination is not available [9] . In in any patient since the advent of EBUS - TBNA and, this study, 163 nodal stations in 102 patients with indeed, with conventional TBNA, reports have been non - small cell lung cancer were punctured. Malignancy rare. One case of perihailar hematoma has been 56 CHAPTER 5 Tips and Diffi culties in EBUS-TBNA reported from sampling a small node in vicinity of hilar tion, the patient had coughed very forcibly and vessels - care with ultrasound examination is needed because the bronchoscope was being pushed distally [15] . There is usually a small amount of blood after with the piggy - back method, it is assumed that with removal of the TBNA needle which settles spontane- the needle coming against the cartilage and the ously within half a minute or so and is usually bleeding patient ’ s coughing effort, that there was a shearing from the small bronchial vessels. Occasionally, bleed- force at the point of the needle exit from the plastic ing can occur from within the node itself, particularly sheath. It was apparent that the needle could not be in metastatic lymph nodes from tumours such as renal seen advancing on the ultrasound image and needle cell carcinoma or melanoma due to their vascularity. breakage was immediately suspected. The needle was The theoretical increased risk of bleeding in patients retracted and a standard bronchoscope was immedi- with superior vena caval obstruction has previously ately inserted. The broken end of the needle could be been raised [16] . As is often seen at EBUS- TBNA, the seen in the subcarinal position and was removed with superior vena cava is displaced out of the way by nodal standard endobronchial biopsy forceps. The recom- tissue. The convex probe TBNA needle can be with- mendations from this problem were that the piggy- drawn should there be any excess of blood come into back method should be avoided using this needle, and the needle indicating vascular puncture, however if to use the |
methods described above. There were no the node is well imaged, this is exceedingly unlikely to adverse effects with respect to the patient and there happen. The only caveat may be penetration of a small was no residual needle seen on chest X - ray immedi- bronchial artery immediately beneath the tracheal or ately following the procedure. bronchial wall and this can be quickly ruled out by Doppler imaging at the TBNA site in each case. Two recent reports concern post EBUS TBNA infec- On Site Pathology tions [17,18]. A pericardial infection followed full extension of the needle to 36 mm. Such extension The benefi ts of rapid on site cytology examination should only be used very infrequently. Another case (ROSE) in standard transbronchial needle aspiration of pneumonia following sampling of a pulmonary are well known [ 20,21] . Because fewer samples were lesion next to a bronchus occurred. In the other report required the procedure was cost effective and there- a cystic lesion was sampled in the high mediastinum fore paid for the extra expense of the cytologist ’ s as part of staging of thyroid disease [18] . An infection availability. ensued with purulent skin discharge; this settled with ROSE also offers benefi ts in EBUS - TBNA [ 22] . It is antibiotics. In both the last 2 cases antibiotics would a useful way to not only confi rm malignant cells but now be recommended post procedure. Alternatively also where nodes are likely to be benign that abundant cystic lesions should be avoided. The author has had lymphocytes can be seen at ROSE. In lung cancer one adverse event with respect to the convex probe staging with EBUS - TBNA it is usual to start by sam- TBNA needle [19] . This was a case performed by the pling N3 followed by N2 followed by N1 nodes depend- author in a patient with underlying sarcoidosis. There ing on size and accessibility [ 22] . In this respect it is were large abnormal nodes at the right paratracheal very important to not allow positive cytology speci- and subcarinal positions, both of which had been aspi- mens from one pass to contaminate a subsequent pass. rated. There had been a strongly positive PET scan Most authorities consider that simply rinsing a needle prior to the procedure and on site pathology was nega- is not adequate to prevent such contamination occur- tive for the presence of any malignancy, hence the ring. ROSE clearly can assist with this process. If an patient had four passes before the breakage of the N3 sample is positive it would be reasonable to stop TBNA needle on the fi fth pass. In retrospect, this the process there. If negative the next step would be was because the technique of needle penetration was to sample N2 nodes. It may be reasonable in these the piggy - back method as described by Wang rather circumstances to use the same needle again for the N2 than the two- step or three- step method described node, providing the initial ROSE with that needle was above. During the performance of this needle penetra- negative for malignant cells. 57 Endobronchial Ultrasonography 11 Sherling BE. Complication with a transbronchial histol- References ogy needle . Chest 1990 ; 98 : 783 – 784 . 12 Stelck MJ , Kulas MJ , Mehta AC . M aintenance of the 1 Wang K PO , T erry P B . Transbronchial needle aspiration bronchoscope and the bronchoscopy equipment. In in the diagnosis and staging of bronchogenic carcinoma . Prakash UBS , ed. B ronchoscopy . N ew York: Raven Am Rev Respir Dis 1983 ; 127 : 344 – 347 . Press , 1993 : 386 . 2 Herth F , Becker H D , Ernst A . C onventional vs endobron- 13 Mehta AC, Kathawalla SA, Fischler D , et al. Bronchoscopic chial ultrasound- guided transbronchial needle aspira- liver biopsy. J Bronchol 1994 ; 1 : 173 – 174 . tion: a randomized trial . Chest 2004 ; 125 : 322 – 325 . 14 Agli LL , Trisolini R , Burzi M , P atelli M . Mediaytinal 3 Wang KP , Brower R , Haponik EF , et al. F lexible trans- hematoma following transbronchial needle aspiration . bronchial needle aspiration for staging of bronchogenic Chest 2002 ; 122 : 1106 – 1107 . carcinoma . Chest 84 : 571 – 576 . 15 Kurimoto N . E BUS TBNA case report of hilar hematoma. 4 Narouki T . T horacic surgery. In Pearce G, Deslauriers J , Japanese Society of Respiratory Endoscopy, Yokohama Ginsberg RJ et al., eds. T horacic Surgery. N ew York : June 2010 . Oral presentation. Churchill Livingstone, 1 995 : 909 – 917 . 16 Kelly P T , Chin R , A dare N , et al. B ronchoscopic needle 5 Murray JG , Breatnach E . T he American Thoracic Society aspiration in patients with superior vena caval disease . lymph node map: a CT demonstration. E ur J Radiol J Bronchol 1997 ; 4 : 290 – 293 . 1993 ; 17 : 61 – 68 . 17 Haas AR. Infectious complications from full extension 6 Ko , J P , D rucker E A , S hepard J A , et al. CT depictions of endobronchial ultrasound transbronchial needle aspira- regional nodal stations for lung cancer staging . Am J tion . E ur Resp J 2009 ; 33 : 935 – 938 . Radiol 2000 ; 174 : 755 – 782 . 18 Steinfort DP , Johnson DF , Irving LB . Infective compli- 7 Yasufuku K , F ujisawa T . Staging and diagnosis of non- cations from endobronchial ultrasound transbronchial small cell lung cancer: invasive modalities . R espirology needle aspiration. E ur Resp J 2009 ; 34 : 524 – 525 . 2007 ; 12 : 173 – 183 . 19 Fielding D . S ifde effects of EBUS TBNA. Japnese Society 8 Sarkiss M , K ennedy M , R iedel B , et al. A nesthesia tech- of Respiratory Endoscopy, Yokohama June 2010. Oral nique for endobronchial ultrasound- guided fi ne needle presentation. aspiration of mediastinal lymph node. J Cardiothorac 20 Diacon AH , Schuurmans MM , Theron J , et al. Utility of Vasc Anesth 2007 ; 21 : 892 – 896 . rapid on site evaluation of transbronchial needle aspi- 9 Seok Lee H , Kook Lee G , Lee HS , et al. Real - time endo- rates . Respiration 2005 ; 72 : 182 – 188 . bronchial ultrasound- guided transbronchial needle 21 Baram D , Garcia RB , Richman PS . I mpact of rapid on aspiration in mediastinal staging of non- small cell lung site cytologic evaluation during transbronchial needle cancer: how many aspirations per target lymph node aspiration . Chest 2005 ; 128 : 869 – 875 . station? Chest 2008 ; 134 : 368 – 374. 22 Vincent B D , E l Bayoumi E , H offman B , et al. Real time 10 Minai , O A , D asgupta , A . M ehta A C . T ransbronchial endobronchial ultrasound - guided transbronchial lymph needle aspiration of central and peripheral lesions . In node aspiration . A nn Thorac Surg 2008 ; 85 : 224 – 230 . B olliger C T , M athur P N , eds. Interventional Bronchoscopy . Basel : Karger , 2000 : 66 – 79 . 58 6 Endoscopic Ultrasound - Guided Mediastinal Lymph Node Aspiration for Lung Cancer Diagnosis and Staging As evident from its name, endoscopic ultrasound (EUS) considered complementary to each other. When used is performed through a trans - esophageal approach together, EUS- FNA and EBUS - TBNA allow access to (Figure 6.1 ). The EUS scope, like the endobronchial almost all of the mediastinal nodes during one session ultrasound (EBUS) scope, allows for real - time ultra- of conscious sedation. However, when lymph nodes sound needle aspiration (Figures 6.2 and 6.3 ). The are potentially accessible by both modalities, the EBUS purpose of this brief chapter is to acknowledge the role approach is preferred because it also allows examina- of EUS in sampling mediastinal lymph nodes and to tion of the airways for endobronchial disease, which compare EBUS and EUS for this particular indication. may be easily missed on chest CT scans. Both EUS- An in - depth discussion of endoscopic ultrasound for FNA and EBUS - TBNA carry a very low risk of sampling mediastinal lymph nodes is beyond the scope complications. of this book. To learn more about mediastinal sampling Like EBUS - TBNA, EUS - FNA may be performed as with EUS, one should review the gastroenterology an out - patient procedure. It is usually carried out with literature. the patient under conscious sedation. The needle used Endoscopic ultrasound - guided fi ne- needle aspira- for EUS- FNA is typically 19 or 22 G. The 19 G needle tion (EUS- FNA) of mediastinal lymph nodes to stage provides the benefi t of allowing a core biopsy, which lung cancer has been performed since the 1990s. improves diagnostic accuracy in diseases such as sar- Posterior and inferior mediastinal nodes are easily coidosis and lymphoma. In a meta- analysis, the sen- accessible by EUS - FNA (Tables 6 .1 and 6 .2 ). Mediastinal sitivity of EUS - FNA was 81 – 97% and specifi city was lymph node stations accessible by EUS- FNA include 83 – 100% for the diagnosis of posterior mediastinal stations 4L (Left lower paratracheal), 7 (subcarinal), 8 lymphadenopathy in non- small cell carcinoma lung (para - esophageal), and station 9 (inferior pulmonary [1] . The major limitation of EUS- FNA was its high ligament). Superior mediastinal (stations 1, 2, 3, and false negative rate. Recent studies comparing PET scan 4R), N1 (stations 10, 11, 12, 13 and 14), subaortic with EUS- FNA for posterior mediastinal adenopathy (station 5) and the para- aortic node (station 6) are not have shown that the EUS- FNA is better than PET scan accessible by EUS - FNA. in staging lung cancer [ 2] . These studies suggest that In comparison, the lymph node stations accessible there is a high false positive rate for PET scanning; by EBUS - TBNA include stations 1, 2, 3, 4, 7, 10, 11, therefore, EUS- FNA can confi rm the benign or malig- and 12. Endobronchial ultrasound- guided fi ne- needle nant status of these lymph nodes. aspiration (EBUS- TBNA) for lung cancer staging has Endobronchial ultrasound - guided fi ne- needle aspi- been performed since the early 2000s. ration appears to have greater sensitivity and specifi city Because they can access different mediastinal lymph than EUS - TBNA. In a case report of 70 patients with node stations, EUS- FNA and EBUS- TBNA should be mediastinal (58 patients) and hilar (12 patients) aden- opathy, EBUS - TBNA for differentiating benign from malignant nodes had a sensitivity of 95.7%, specifi city Endobronchial Ultrasonography, 1st edition. of 100%, and accuracy of 97.1%, respectively [3] . By Noriaki Kurimoto, David I. K. Fielding and Ali I. Musani. A recent multicenter trial of more than 500 patients Published 2011 by Blackwell Publishing Ltd. showed EBUS- TBNA to be a very sensitive and specifi c 59 Endobronchial Ultrasonography Distal end of the endoscope Trachea Distal end of the sheath Superior mediastinal nodes Echo enhanced region Bronchoscope Needle distal end Figure 6.3 Cartoon depicting endoscopic ultrasound via the esophagus. The real- time images of a mass or node outside the Inferior mediastinal walls of the esophagus allow fi ne - needle aspiration. nodes Esophagus Table 6.1 Lymph node stations Location S tation Superior mediastinal nodes Figure 6.1 Endoscopic ultrasound scope in the esophagus Highest mediastinal 1 behind the trachea. The subcarinal and para- esophageal lymph Upper paratracheal 2 nodes are easily accessible by endoscopic approach with Pre - vascular and retrotrachael 3 ultrasound - guided fi ne - needle aspiration. Lower paratracheal 4 Colored dots represent lymph nodes. Aortic nodes Subaortic (A- P window) 5 Para - aortic (ascending aorta or phrenic) 6 Inferior mediastinal nodes Subcarinal 7 Para - esophageal 8 Pulmonary ligament 9 N1 nodes Hilar 10 |
Interlobar 1 1 Lobar 1 2 Segmental 1 3 Subsegmental 1 4 Adapted from: Naruke T, Suemasu K and Ishikawa S. Lymph node mapping and curability at various levels of metastasis in resected lung cancer. J Thorac Cardiovasc Surg Figure 6.2 Endoscopic ultrasound scope (GIF - UC 240P 1978;76:832 –3 9, with permission. Olympus Corporation). diagnostic modality for sampling mediastinal aden- CT, PET and EBUS- TBNA for diagnosing lung cancer opathy (sensitivity 94% and specifi city 100%) [4] . in mediastinal and hilar lymph nodes was 76.9%, Other studies comparing the sensitivity of PET, CT and 80%, and 92.3%, respectively. The specifi cities EBUS - TBNA for staging of lung cancer showed a were 55.3%, 70.1% and 100%, respectively. The diag- higher yield with EBUS - TBNA [5] . The sensitivity of nostic accuracies were 60.8%, 72.5% and 98% [6] , 60 CHAPTER 6 Endoscopic Ultrasound-Guided Mediastinal Lymph Node Aspiration respectively, for the three modalities. Therefore, Table 6.2 Accessibility of lymph node stations by different modalities EBUS - TBNA has better sensitivity and specifi city than either CT or PET scanning in staging mediastinal Modality Accessible lymph node stations disease in lung cancer. Standard Superior mediastinal, subcarinal mediastinoscopy Stations 1, 2, 3, 4 and 7 References Extended Aortic nodes 1 Kramer H , G roen H JM . Current concepts in the medias- mediastinoscopy Stations 5 and 6 tinal lymph node staging of non - small cell lung cancer. Anterior Aortic nodes Ann. Surg 2003 ; 238 : 180 – 188 . mediastinoscopy * Stations 5 and 6 2 Eloubeidi M A , C erfolio R I , C hen V K , et al. E ndoscopic ultrasound - guided fi ne needle aspiration of mediastinal VATS Superior mediastinal (right), lymph node in patients with suspected lung cancer after subcarinal, and aortic nodes positron emission tomography and computed tomogra- Stations 1, 2R, 3, 4R, 7, 5 and 6 phy scans. A nn Thorac Surg 2005 ; 79 : 263 – 268 . TBNA Superior mediastinal, subcarinal, N1 3 Yasufuku K , Chiyo M , Sekine Y , Chhajed PN , nodes Shibuya K , et al. Real - time endobronchial ultrasound - Stations 1, 2, 3, 4, 7, 10, 11 and 12 guided trans- bronchial needle aspiration of mediastinal and hilar lesions. Chest 2004 ; 126 : 122– 128 . TTNA Superior mediastinal (anterior) 4 Herth FJ , Eberhardt R , Vilmann P , Krasnik M , Ernst A . Stations 1, 2, 3 and 4 Real - time endobronchial ultrasound- guided transbron- EUS - FNA Left lower paratracheal, subaortic, chial needle aspiration for sampling mediastinal lymph inferior mediastinal nodes . Thorax 2006 ; 61 : 795 – 798 . Stations 4L, 7, 8 and 9 5 Yasufuku K Nakajima T , Motoori K , Sekine Y , Shibuya K , et al. Comparison of endobronchial ultrasound, posi- EBUS - TBNA Superior mediastinal, subcarinal and tron emission tomography, and CT for lymph node N1 nodes staging of lung cancer. Chest 2006 ; 130 : 710 – 718 . Stations 1, 2, 3, 4, 7, 10, 11 and 12 6 Mountain C F , D resler C M . Regional lymph node classi- fi cation for lung cancer staging . Chest 1 997 ; 111: * Chamberlain procedure. 1718 – 1723 . 61 7 Qualitative Analysis of Peripheral Pulmonary Lesions Using Endobronchial Ultrasonography logical fi ndings in cases of cystic tumor, calcifi cation, Introduction and pancreatic stones [ 12,13] . Currently there are few published comparative Numerous studies have shown that high frequency, analyses of the internal structure of peripheral pulmo- two - dimensional ultrasonography is a useful tech- nary lesions as visualized by EBUS and the histopatho- nique for evaluating the depth of invasion of gastroin- logical fi ndings, so this section will rely largely on our testinal tumors, detecting lymph node metastasis, and own results. identifying coronary arterial stenosis and thrombosis [1 – 5] . Since 1994, we have engaged in the develop- ment of endobronchial ultrasonography (EBUS) [ 6 – 7] , Correlation between Preoperative including the localization of peripheral pulmonary EBUS Scans and Histopathological lesions during endobronchial brushing and transbron- Examination of Peripheral chial biopsy (TBB). In addition to EBUS localizing a Pulmonary Lesions lesion the analysis of the images can be useful in terms of suggesting the underlying pathology. Concepts of We reviewed the records of patients who underwent the qualitative analysis of the internal structure of diagnostic preoperative EBUS for a peripheral pulmo- peripheral pulmonary lesions as visualized by EBUS nary lesion where a surgical specimen was available have been developed by comparing these fi ndings to be sectioned. The histopathological fi ndings were with the histopathological fi ndings (Figure 7 .1 ). The correlated with the internal structure of the lesions as aim of this study is to improve the criteria for distin- visualized by EBUS. guishing between benign and malignant peripheral Most cases of well- differentiated adenocarcinoma pulmonary tumors. showed preservation of blood vessels within the lesion EBUS uses high- frequency ultrasound (20 MHz) to using EBUS (Video clip 7.1). These lesions had homog- create detailed images of the internal structure of enous internal echoes overall, but some hyperechoic lesions [ 8 – 11] , although it cannot delineate tissues dots (less than 1 mm in size) were also seen, represent- external to the lesion. Endoscopic ultrasonography ing residual air in invaded alveoli. The distribution of has been used to examine the internal structure of the the hyperechoic dots was irregular, as were the pancreas, the results correlating well with histopatho- margins of the lesions. Blood vessels could be seen coursing through the lesions (Figure 7.2 ). In some cases of well- differentiated adenocarci- noma, no blood vessels were visualized. These lesions Endobronchial Ultrasonography, 1st edition. also presented an irregular distribution of hyperechoic By Noriaki Kurimoto, David I. K. Fielding and Ali I. Musani. dots or arcs around the probe and had poorly defi ned Published 2011 by Blackwell Publishing Ltd. borders. 62 CHAPTER 7 Qualitative Analysis of Peripheral Pulmonary Lesions Using Endobronchial Ultrasonography EBUS Histopathological findings Figure 7.1 Qualitative analysis of the internal structure of peripheral pulmonary lesions as visualized by EBUS, comparing these fi ndings with the histopathology fi ndings. Figure 7.2 A representative case of well - differentiated adenocarcinoma. Most cases of well - differentiated adenocarcinoma show preservation of blood vessels within the lesion using EBUS. Blood vessels could be seen coursing through this lesion. In most cases of moderately differentiated adenocar- In one case of moderately differentiated adenocarci- cinoma and squamous cell carcinoma, EBUS images noma, numerous very small hyperechoic echoes showed obstruction of blood vessels within the lesions, were observed within the lesion, their distribution obstruction of bronchi, heterogenous internal echoes, identical to that of the multiple calcifi cations observed and irregular margins (Figure 7.3 , Video clip 7.2). histopathologically (Figure 7 .4 ). In some cases of 63 Endobronchial Ultrasonography Figure 7.3 A representative case of moderately- differentiated adenocarcinoma. In most cases of moderately differentiated adenocarcinoma and squamous cell carcinoma, the EBUS images show obstruction of blood vessels within the lesion, obstruction of bronchi, heterogenous internal echoes, and irregular margins. Figure 7.4 In this case of moderately differentiated adenocarcinoma, numerous very small hyperechoic echoes are observed within the lesion, their distribution identical to the multiple calcifi cations observed histopathologically. 64 CHAPTER 7 Qualitative Analysis of Peripheral Pulmonary Lesions Using Endobronchial Ultrasonography squamous cell carcinoma, numerous anechoic areas of bronchus, resulting in stenosis of the pulmonary artery various sizes were noted, their distribution corre- within the lesion (Figure 7 .7 , Video clip 7.5). In some sponding to areas of necrosis (Figure 7 .5 , Video clip cases of carcinoid, the tumor arises in the bronchial 7.3). Squamous cell carcinoma sometimes showed a wall and grows across the bronchial lumen, resulting circumferential hyperechoic line around the probe in a characteristic snowman - like form, with the neck corresponding to the bronchial wall, caused by tumor located at the cartilaginous part of the bronchus. growth and outward compression of the bronchial Bleeding within the carcinoid appears as mottled adventitia (Figure 7.6 , Video clip 7.4). Most cases of hyperechoic areas on the EBUS image (Figure 7.8 ). poorly differentiated adenocarcinoma on EBUS Homogenous internal echoes are seen in cases of showed heterogenous internal echoes, irregular primary malignant lymphoma of the lung, with an margins, and few patent blood vessels or bronchi. appearance similar to that of pneumonia. Large blood This small nodular small cell carcinoma has directly vessels remain patent within the lesions, indicating invaded the pulmonary artery adjacent to the affected that the lesions are soft. Figure 7.5 In this case of squamous cell carcinoma, numerous anechoic areas of various sizes are seen, their distribution corresponding to areas of necrosis. Figure 7.6 Outward compression of the bronchial adventitia on EBUS image. Squamous cell carcinoma sometimes shows a circumferential hyperechoic line around the probe corresponding to the bronchial wall, caused by tumor growth and outward compression of the Bronchial cartilage bronchial adventitia. 65 Endobronchial Ultrasonography Figure 7.7 This small nodular small cell carcinoma has directly invaded the pulmonary artery adjacent to the affected bronchus, resulting in stenosis of the pulmonary artery within the lesion. Figure 7.8 This carcinoid tumor arises in the bronchial wall and grows across the bronchial lumen, resulting in a characteristic snowman- like form, with the neck located at the cartilaginous part of the bronchus. Bleeding within the carcinoid can be seen as mottled hyperechoic areas in the EBUS images. Anechoic areas with star - shaped margins are visible within the lesion in this case of infl ammatory pseudo- Internal Structure of Lesions Visualized tumor, corresponding to the lumen of the dilated by E BUS by Histological Subtype bronchus (Figure 7.9 ). In contrast to histopathology, EBUS enables visualiza- We found that EBUS can clearly visualize internal tion of the internal structures of peripheral pulmonary structures of peripheral pulmonary lesions, including lesions, such as vessels, bronchioles, bleeding, calcifi ca- vessels, bronchioles, compressed alveolar air within tions, bronchial dilatation, and necrosis (Figure 7.10 ). lesions, calcifi cations, necrosis, and the homogeneity/ 66 CHAPTER 7 Qualitative Analysis of Peripheral Pulmonary Lesions Using Endobronchial Ultrasonography Figure 7.9 A representative case of infl ammatory pseudotumor. Echolucent areas with star- shaped margins are visible within the lesion in this case of infl ammatory pseudotumor, corresponding to the lumen of the dilated bronchus. internal structure of these lesions was analysed, and Calcification Bleeding lesions were typed based on these fi ndings. Bronchiole Lesions were typed based on internal echo pattern (homogenous or heterogenous), vascular patency, Dilatation of Vessel and the morphology of hyperechoic areas (refl ecting bronchus the presence of air and the state of the bronchi) Multiple cysts W/D (Figure 7.11 ). Adenoca Type I : Homogenous Pattern Type I a : Homogenous Pattern with Patent Vessels and Patent Bronchioles (Figure 7.12 , Video clip 7.6) Figure 7.10 Visualization of the internal structure of peripheral The majority of these cases were pneumonia, charac- pulmonary lesions. In contrast to histopathology, using EBUS we terized by exudate - fi lled alveoli. EBUS images of this are able to visualize the internal structure of peripheral type revealed normal blood vessels and bronchi, free pulmonary lesions, including blood vessels, bronchioles, of compression or stenosis, within the lesion. The haemorrhage, calcifi cations, bronchial dilatation, and necrosis. internal echoes were homogenous. There was there- fore little ultrasonic attenuation, and even tissue 15 to heterogeneity of the ultrasonic pattern. Tumor typing 20 mm from the probe could be seen clearly. Because based on the internal structure as visualized by EBUS lesions extend from one lobule to another, the margins can assist in distinguishing between benign and malig- were linear in some areas. nant tumors, and assessment of the degree of differ- entiation. We conducted tumor typing based on the Type I b : Homogenous Pattern with No tumor internal structure as visualized by high resolu- Patent Vessels or Bronchioles (Figure 7.13 ) tion EBUS. No blood vessels were seen within these lesions using We were able to visualize the lesion in 143 out of EBUS. Mottled or linear hyperechoic areas were 168 patients (85.1%) with a peripheral pulmonary scarce. The internal echoes were homogenous. As lesion who underwent EBUS. Of these a defi nitive with Type |
Ia, there was little ultrasonic attenuation, tissue diagnosis was obtained in 124 (73.8%). The and even tissue 15 to 20 mm from the probe could be 67 Endobronchial Ultrasonography Type II; hyperechoic dots Type I; homogenous Type III; heterogenous and linear arcs Patent vessels and Without vessels With hyperechoic Without hyperechoic Without vessels With patent vessels patent bronchioles and bronchioles dots and short lines dots and short lines I a II a III a I b II b III b Figure 7.11 Type classifi cation of peripheral pulmonary lesions. II: hyperechoic dots and linear arcs pattern; Type IIa: hyperechoic Lesions are typed based on internal echo pattern (homogenous dots and linear arcs with no patent vessels; Type IIb: hyperechoic or heterogenous), vascular patency, and the morphology of dots and linear arcs with patent vessels. Type III: heterogenous hyperechoic areas (refl ecting the presence of air and the state of pattern; Type IIIa: heterogenous pattern with hyperechoic dots, the bronchi). Type I: homogeneous pattern; Type Ia: homogenous and short lines; Type IIIb: heterogenous pattern without pattern with patent vessels and patent bronchioles; Type Ib: hyperechoic dots or short lines. homogenous pattern with no patent vessels or bronchioles. Type Type I a; homogenous pattern with patent vessels and patent bronchioles Figure 7.12 EBUS of Type Ia lesion. This EBUS image shows normal blood vessels and bronchi, free of compression or stenosis, within the lesion. The internal echoes are homogenous. 68 CHAPTER 7 Qualitative Analysis of Peripheral Pulmonary Lesions Using Endobronchial Ultrasonography Type I b; homogenous pattern without vessels and bronchioles Figure 7.13 EBUS of Type Ib lesion. In this EBUS image, no patent blood vessels are seen within the lesion. Few mottled or linear hyperechoic areas are visible. The internal echoes are hypoechoic and homogenous. Type II a; hyperechoic dots and linear arcs without vessels Figure 7.14 EBUS of Type IIa lesion. In this EBUS image, no blood vessels could be visualized within the lesions. Hyperechoic dots (less than 1 mm in diameter) or hyperechoic linear arcs (primarily around the probe) were distributed irregularly within the lesions. seen clearly. The Type Ib group mainly included cases larly within the lesions. The presence of residual air of organising pneumonia and tuberculomas. in alveoli is characteristic of well - differentiated adeno- carcinoma, which grows to replace the alveolar epi- Type II : Hyperechoic Dots and Linear thelium. The air remaining in the alveoli hampered Arcs Pattern visualization of blood vessels within the lesions and Type II a : Hyperechoic Dots and Linear obscured the margins of the lesions. Arcs with No Patent Vessels (Figure 7.14 , Video clip 7.7) Type II b : Hyperechoic Dots and Linear Arcs Most cases were well- differentiated adenocarcinoma with Patent Vessels (Figure 7.15 , Video clip 7.8) which had replaced the alveolar epithelium. No blood The majority of cases were well- differentiated adeno- vessels could be visualized within the lesions using carcinoma which had proliferated and replaced the EBUS. Hyperechoic dots or hyperechoic linear arcs alveolar epithelium while preserving the blood vessels (primarily around the probe) were distributed irregu- within the lesion. In the EBUS images, the blood 69 Endobronchial Ultrasonography Type II b; hyperechoic dots and linear arcs with patent vessels Figure 7.15 EBUS of Type IIb lesion. In this EBUS image, blood vessels, almost free of compression or stenosis, are visible within the lesion, and the internal echoes are relatively homogenous. Hyperechoic dots (less than 1 mm in diameter) are distributed irregularly within the lesions, corresponding to the presence of residual air in the alveoli. Type III a; heterogenous pattern with hyperechoic dots, and short lines Figure 7.16 EBUS of Type IIIa lesion. The majority of cases are moderately differentiated adenocarcinomas that grow with a relatively high cell density and form a mass. No blood vessels are seen within the lesion using EBUS. Areas of mottling and linear hyperechoic areas are irregularly distributed within the lesion, corresponding to compressed or stenotic bronchi or alveolar air. vessels showed little or no compression or stenosis Type III : Heterogenous Pattern within the lesion, and the internal echoes were rela- Type I II a : Heterogenous Pattern with tively homogenous. Hyperechoic dots, distributed Hyperechoic Dots, and Short Lines (Figure 7 .16 ) irregularly within the lesions, corresponded to resid- The majority of cases were moderately differentiated ual air in the alveoli, a characteristic of well- adenocarcinoma which had grown with a relatively differentiated adenocarcinoma. The density of cancer high cell density and had formed a mass. No blood cells was higher and the volume of air remaining in vessels were seen within these lesions using EBUS. alveoli was smaller in Type IIb than in Type IIa, well - Areas of mottling and linear hyperechoic areas were differentiated adenocarcinoma. The margins were irregularly distributed within the lesion, correspond- irregular because the lesions grew, without any rela- ing to compressed or stenotic bronchi or alveolar tionship to existing structures. air. The internal echoes were heterogenous, with 70 CHAPTER 7 Qualitative Analysis of Peripheral Pulmonary Lesions Using Endobronchial Ultrasonography markedly attenuated sound wave transmission, so that bronchi and blood vessels can be seen as they only areas about 6 to 8 mm from the probe could be cross peripheral pulmonary lesions. The advantage of visualized clearly. Because the lesions spread in a MRI is that it is less invasive than EBUS, but the random manner, without extension along lung struc- images are of poorer quality because the beating heart tures, the margins of the lesions often were rounded. and breathing introduce motion artefacts. Moderately differentiated squamous cell carcinoma There have been a number of reports of the use of presented numerous anechoic areas corresponding to miniature ultrasound probes for diagnosing peripheral areas of necrosis within the tumor, which is charac- pulmonary lesions. H ü rter et al. [10] reported success- teristic of squamous cell carcinoma. ful visualization of peripheral lung lesions in 19 out of 26 cases, and Goldberg and colleagues [ 11] reported Type III b: Heterogenous Pattern without that EBUS provided unique information that comple- Hyperechoic Dots or Short Lines (Figure 7.17 , mented other diagnostic modalities in 18 out of 25 Video clip 7.9) cases (including six peripheral lesions and 19 hilar The majority of cases were poorly differentiated tumors). adenocarcinoma, which had a high cell density and Hosokawa et al. [ 17] reported that a typical EBUS had formed a mass. The lesions were avascular and pattern of neoplastic disease was: (1) continuous mar- showed scant mottled or linear hyperechoic areas. The ginal echo; (2) rough internal echoes; and (3) no internal echoes were heterogenous. Since the lesions hyperechoic spots representing bronchi, or no longi- extend outward, their margins tend to be roundish. tudinal continuity if present. Kuo et al. [18] assessed We reported 92.0% of Type I lesions were benign, the feasibility of EBUS in differentiating between and 99.0% of Type II and III lesions were malignant. benign and malignant lesions using the following Well -d ifferentiated adenocarcinoma accounted for three characteristic ultrasonic features indicating 88% of Type II lesions, whereas all Type IIIb cases malignancy: continuous margin, absence of a linear- were malignant, including 81.8% poorly differenti- discrete air bronchogram, and heterogenous echo- ated adenocarcinoma. genicity. The negative predictive value for malignancy Some investigators have reported that dynamic of a lesion with none of these three echoic features is magnetic resonance imaging (dynamic MRI) provides 93.7%. The positive predictive value for malignancy information on enhancement patterns of peripheral of a lesion with any two of these three echoic features pulmonary lesions [14,15]. Awaya et al. [ 16] reported is 89.2%. Type III b; heterogenous pattern without hyperechoic dots and short lines Figure 7.17 EBUS of Type IIIb lesion. In this EBUS image, the lesion is avascular, and few mottled or linear hyperechoic areas can be seen. The internal echoes are heterogenous. 71 Endobronchial Ultrasonography We developed our classifi cation system with the aim 4 Rosch T. Endoscopic ultrasonography. Endoscopy of distinguishing between benign and malignant 1992 ; 24 : 144 – 153 lesions, identifying the type of lung carcinoma, and 5 Murata Y , Muroi M , Yoshida M , et al. E ndoscopic ultra- determining the degree of differentiation. sonography in diagnosis of esophageal carcinoma. S urg Although CT and MRI scans have been used for Endsc 1987 ; 1 : 11 – 16 . 6 Kurimoto N , M urayama M , Y oshioka S , et al. A ssessment qualitative diagnosis of peripheral pulmonary lesions, of usefulness of endobronchial ultrasonography in ultrasonograms have the following advantages. The determination of depth of tracheobronchial tumor inva- guide sheath can be used to determine the following: sion . Chest 1999 ; 115 : 1500 – 1506 . 1 Patency of microvasculature within the lesion. 7 Miyazu Y , Miyazawa T , Iwamoto Y , et al. T he role of 2 The distribution of micropneumatosis (small white endoscopic techniques, laser- induced fl uorescence dots) within the lesion. endoscopy, and endobronchial ultrasonography in 3 The existence of anechoic areas corresponding to choice of appropriate therapy for bronchial cancer. necrosis within the lesion. J Bronchol 2000 ; 8 : 10 – 16 . 4 The echo strength within the lesion. 8 H ü rtur Th , Hanrath P . E ndobronchial sonography: fea- In particular, the echo strength within lesions visual- sibility and preliminary results . Thorax 1992 ; 47 : ized by 20 MHz high frequency ultrasonography varies 565 – 567 . 9 Becker H . E ndobronchialer Ultraschall - eine Neue according to factors such as the distribution and Perspektive in der Bronchologie . Ultraschall in Med density of tumor cells, presence of mucous, and inter- 1996 ; 17 : 106 – 112 [in German]. stitial hyperplasia within the lesion. The echo strength 10 H ü rter T h , H anarath P . Endobronchiale Sonographie depends on the extent that ultrasound waves are zur Diagnostik Pulmonaler und Mediastinaler Tumoren . refl ected at interfaces between tissue types. Tumors Dtsch Med Wschr 1990 ; 1899 – 1905 [in German]. with increased cell density, e.g. poorly differentiated 11 Goldberg B , Steiner R , Liu J , et al. U S - assisted bronchos- adenocarcinoma, produce a comparatively weak echo. copy with use of miniature transducer - containing cath- Bronchioloalveolar carcinoma (mucinous type), diffi - eters . Radiology 1994 ; 190 : 233 – 237 . cult to distinguish from pneumonia using CT scan- 12 Yasuda K , Mukai H , Nakajima M , et al. S taging of pan- ning, produces a stronger echo than pneumonia using creatic carcinoma by endoscopic ultrasonography . high frequency ultrasonography at 20 MHz. The Endoscopy 1993 ; 25 : 151 – 155 . 13 Rosch T , Braig C , Gain T , et al. S taging of pancreatic reason for this is unclear, but is suspected to be due and ampullary carcinoma by endoscopic ultrasonogra- to viscous mucous, or to increased refl ection from phy . Gastroenterology 1992 ; 102 : 188 – 199 . neoplastic tissue in the alveolar septa. 14 Kusumoto M , Kono M , Yamasaki K , et al. Pulmonary EBUS provides a new way to visualize the internal nodules: quantitative assessment with contrast - structure of peripheral pulmonary lesions. Classifi cation enhanced MR imaging. Radiology 1995 ; 197 : 232 . of the EBUS images suggests the pathology and 15 Guckel C , Schnabel K , Deimling M , et al. S olitary pul- histology. monary nodules: MR evaluation of enhancement pat- terns with contrast - enhanced dynamic snapshot gradient - echo imaging. Radiology 1996 ; 200 : 681 – 686 . References 16 Awaya H , Matsumoto T , Miura G , et al. E valuation of internal characteristic in small adenocarcinoma by MR 1 Grimm H , Binmolleller KF , Hamper K , et al. imaging . J pn J Radiol 2000; 45 : 47 – 57 . Endosonography for preoperative locolesional staging 17 Hosokawa S , Matsuo K , Watanabe Y , et al. Two cases of esophageal and gastric cancer. E ndoscopy 1993 ; 25 : of nodular lesions in the peripheral lung fi eld, success- 224 – 230 . fully diagnosed by endobronchial ultrasonography 2 Abe S , L ifhtdale C J , B rennan M F |
. The Japanese experi- (EBUS) . Kokyuu 2004 ; 23 : 57 – 60 . ence with endoscopic ultrasonography in staging 1 8 Kuo C , Lin S , Chen H , et al. Diagnosis of peripheral lung of gastric cancer. G astrointest Endosc 1993 ; 39 : 536 – 541. cancer with three echoic features via endobronchial 3 Murata Y , M uroi M , A kimoto S , et al. Evaluation of ultrasound . Chest 2007 ; 132 : 922 – 929 . ultrasonography for the diagnosis of submucosal tumors of esophagus. S urg Endosc 1988 ; 2 : 51 – 58 . 72 8 EBUS - Guided Peripheral Pulmonary Nodule Biopsy bronchoscope [5] . This allowed ease of biopsy once Introduction the probe had been removed by simply passing forceps and brushes into the location found by the ultrasound The adaptation of ultrasound miniprobes to broncho- miniprobe prior to its removal. Further refi nements scopic diagnosis was an important step forward in have included the use of virtual bronchoscopy to aid bronchoscopy. It grew out of a need for an improved in tracking the bronchial openings which give the best way to biopsy peripheral lung nodules which tradi- access to the lesion [6] . Also, whilst the traditional tionally had been performed just with X- ray guidance means of performing this type of biopsy has been with [1,2] . Ultrasound miniprobes had previously been X - ray fl uoroscopy, with greater experience some used in the large airways; however a fl uid- fi lled authors advocate that fl uoroscopy may not be neces- balloon sheath was required to allow for a probe – sary in performing this technique [7] . Finally, the tissue interface [ 3] . An important understanding in aspect of ultrasound diagnosis by interpretation of the allowing the development of the peripheral lung mini- ultrasound images can be useful to give a qualitative probe was that no balloon sheath was required in the impression of malignancy versus benign disease and, periphery of the lung [4] . This was somewhat counter- in selected situations, may add to the histological intuitive given the air - rated structure of the lung; samples obtained [8,9] . however, there was an excellent ultrasound image obtained when the ultrasound miniprobe was placed bronchoscopically within peripheral lung lesions. Conventional Transbronchial Lung Biopsy Because of the small caliber of the bronchial airways in the periphery, the ultrasound probe was applied There has always been the need to biopsy lesions directly to the lesions and no balloon- sheath fi lled beyond the reach of a bronchoscope and the standard with water was required. It was also noted that when method has been to use X- ray fl uoroscopy with a the probe was in a bronchus surrounded by normal brush or biopsy forceps passed under X- ray guidance air - fi lled lung, there was just artifact image on the into the lesion as seen on X - ray fl uoroscopy. For best ultrasound monitor and therefore it was easy to dis- results, the X - ray fl uoroscopy is usually performed in criminate between normal and abnormal tissue. The two planes and this may be achieved by rotating the next step was the use of a guide sheath – into which fl uoroscopy C arm or altering the patient’ s position the thin caliber miniprobe could be deployed. Both the during the procedure with the bronchoscope in situ. miniprobe and the guide sheath could therefore be For lesions of 3 cm or less, there can be considerable inserted as one into the biopsy channel of the standard misjudgment of the placement of the forceps in respect of the actual lesion. Furthermore, it is not uncommon for small lesions to be totally invisible on X- ray fl uor- oscopy, particularly those close to the diaphragm and Endobronchial Ultrasonography, 1st edition. adjacent to the cardiac borders. High apical lesions By Noriaki Kurimoto, David I. K. Fielding and Ali I. Musani. may also be diffi cult to visualize. Perhaps for these Published 2011 by Blackwell Publishing Ltd. reasons, there is a wide variation in overall sensitivity 73 Endobronchial Ultrasonography Table 8.1 Standard TBLB x studies. Reference Year n Lesion size < 2 cm % Sensitivity Pneumothorax % Bleeding % Popovich 1982 20 75% Fletcher 1982 101 6/21(28%) 36% 5(5%) 4(4%) Stringfi eld 1977 29 1/3(33%) 48% Radke 1976 97 0% 56% Wallace 1982 143 3/65(5%) 19% Hanson 1976 164 57% 7(4%) 15(9%) Shiner 1988 71 0 70% 1(1%) 3 hemoptysis(4%) Torrington 1993 30 9% Chechani 1996 49 6/11(55%) 72% 3(6%) severe, 6/49 moderate (12%) of this method with yield between 18 and 75% made in six of 11, 12 of 21, and 24 of 30 lesions [10 – 12] . Because of the requirement to move the C respectively [2] . Overall, from 49 bronchoscopies, arm of the patient, it can be cumbersome and time lesions which had a positive diagnosis had a mean consuming, and some radiation is always delivered to lesion diameter of 4.55 cm compared to lesions which the patient, and to a much lesser extent into the bron- were negative on biopsy which had a lesion diameter choscopy room. of 3.14 cm. In peripherally placed carcinomas, Shiner A number of studies have looked at the effi cacy of et al. showed that lesions 2– 4 cm in size, 4– 6 cm, and standard transbronchial lung biopsy for peripheral 6 – 8 cm had positive diagnoses made in nine of 13, 10 solitary pulmonary nodules (Table 8 .1 ). These pre - of 15, and two out of three lesions [14] . This series date EBUS guide sheath biopsy, from as early as 1976. excluded data from lesions less than 2 cm in size. One small retrospective study only evaluated a diag- Fletcher ’ s series lesions 2– 4 cm in size had a 40% nostic effi cacy for malignancy which was 9% [ 13] . yield, and those greater than 4 cm had a 63% yield [ 15] . The range of diagnostic effi cacies no doubt was due to Chechani et al. commented that certain pulmonary different combinations of malignant and benign segments of the bronchial tree were diffi cult to visual- disease, variable size and location of the lesions, the ize on fl uoroscopy. This is the common experience of extent to which the lesions were biopsied, incorporat- most bronchoscopists, including when dealing with ing some or all of the techniques of bronchoalveolar the basal segments of the lower lobes and the apical lavage, bronchial brushings, biopsies, and transbron- segments of the upper lobes [ 2] . An interesting chial needle aspiration. comment from Chechani et al. was that “ lesions which Typical sensitivities for lesions of less than or equal had sharp borders on X - ray had a poorer diagnostic to 2 cm in size ranged from 5% up to 55% and most rate (54%) compared to lesions which had fuzzy studies commented that there was a signifi cant reduc- borders (83%) or cavitating (100%) ” . They postulated tion in diagnostic effi cacy below 2 cm in size. Obviously, that the reason for this was that the more sharply small size would mean diffi culty in visualizing the demarcated lesions were not likely to be intra - luminal. lesion on X - ray fl uoroscopy in two planes. In one This included both benign lesions and metastatic study by Chechani, lesions less than 2 cm, less than deposits and with these there was a recommendation 3 cm, and greater than 3 cm had positive diagnoses that the transbronchial needle aspiration approach 74 CHAPTER 8 EBUS-Guided Peripheral Pulmonary Nodule Biopsy should be used in an attempt to cross the bronchial account of the ultrasound characteristics of malignant wall into the lesion. This is mentioned by other authors and benign lesions [5] . This included cases analysed performing endobronchial ultrasound techniques as preoperatively with an ultrasound miniprobe passed discussed below. into the lesion bronchoscopically prior to surgical With respect to pneumothorax rate, where reported, resection. There was close correlation between the the incidence was between 1% and 5% [ 15] . Bleeding ultrasound image and anatomical structures such as complications were not uncommon. In one series by bronchi and small blood vessels within the lesion. As Chechani, three out of 48 patients (6%) had severe discussed below, a detailed scheme of analysis of the bronchial bleeding [2] . In addition to this, moderate internal structures was described and the potential for bleeding was seen in six out 40 cases that had trans- interpretation of ultrasound images in tissue diagnosis bronchial lung biopsies and three of 48 cases that had was raised. Both of these series used the 20 MHz mini- transbronchial brushes. In another series by Blascow probes from Olympus. These were radial probes, either in 169 patients with solitary pulmonary nodules, three UM - 3R or UM- 20 - 26R. patients had bleeding of more than 100 mL after the In 2004, Kurimoto published a series describing the biopsy [16] . Fletcher et al. also reported a 4% inci- addition of the guide sheath, the plastic sheath into dence of severe bleeds. There were no mortalities which the ultrasound miniprobe was passed prior to reported; however the extent of the bleeding is quite insertion down the biopsy channel of the broncho- different from that observed in endobronchial ultra- scope [9] . This was coupled with the introduction of sound as discussed below [ 15] . the thinner 20 MHz radial probe (UM- S20 - 20R). This probe itself had an outer diameter of 1.7 mm and, Method and Equipment combined with the guide sheath, meant that it could History be inserted into a 2 mm working channel of a fi ber- The possible role of ultrasound miniprobes in evaluat- scope. This smaller probe demonstrated its fl exibility ing and biopsying peripheral lung lesions was demon- in terms of accessing the subsegments of the smaller strated by Hurther [17] and Goldberg [ 18] . Both upper lobes which had more acute angles; in the pre- recognized the potential for ultrasound miniprobes in vious studies it had been diffi cult to access these with the lung which had previously been used in other the slightly larger caliber UM - 3R miniprobe. This specialties of gastroenterology and urology. Goldberg study also demonstrated the practical benefi ts of the demonstrated that 15 out of 25 peripheral lung lesions, guide sheath when coupled with the miniprobe with most less than 3 cm in diameter, could be localized virtually nil evidence of bleeding and facilitation of with an ultrasound probe. The characteristics of the multiple biopsies at the same site. solid tumor, blood vessels within the tumor, and air The next step was the addition of pre - procedure artifact within normal lung, were demonstrated. In evaluation of the patient using virtual bronchoscopy that series, there was no guide sheath used and the CT images [6] . By tracking the path that the broncho- biopsy point was simply determined by the position of scope and probe would take out towards the lesion the ultrasound miniprobe within the lesion and with virtual bronchoscopy, it was demonstrated that recorded by fl uoroscopy. Quite correctly, both authors choice of the correct bronchial segment could be foresaw the potential for this method in its simplicity improved. and inherent safety. In 2002, there were two publica- tions which further elucidated the benefi ts of this Equipment technique. Herth, Ernst and Becker demonstrated, in The most commonly used miniprobe for EBUS directed a prospective series of 50 patients, the ability of endo- peripheral nodule biopsy is the 20 - 20R Olympus bronchial ultrasound miniprobe biopsies to yield a Miniprobe, usually the 1.7 mm diameter probe with similar success rate to fl uoroscopic guidance (80% accompanying guide sheath. Prior to inserting this into versus 76%) [2] . This demonstrated fi rst the accurate the guide sheath, it is necessary to calibrate the biopsy localization of the lesions by EBUS, but also the forceps and brush forceps to the length of the plastic advantage that far less radiation exposure would be guide sheath. This allows the forceps to be inserted up required. Also in 2002, Kurimoto published a detailed |
to a pre- marked point when the guide sheath is in situ 75 Endobronchial Ultrasonography in the lesion in the lung. This pre - marked point is sheath in the desired direction. Having obtained an simply made by placing adhesive tape on the proximal improved position in this way, the ultrasound mini- end of the forceps or brush at the point where the probe is re - inserted and moved to the best position distal end is either just protruding from the end of the based on the ultrasound image. plastic sheath in the case of the forceps, or just at the Usually the point at which the ultrasound images tip of the sheath in the case of the brush. Lastly, prior are best can be saved with a fl uoroscopy picture and to commencing the procedure, the ultrasound mini- the C arm kept stationary. If fl uoroscopy is used in this probe is placed inside the sheath and taped with way, it is possible to simply leave the guide sheath in double - ended adhesive tape. This stops the miniprobe place and advance fi rst the brush and then the biopsy slipping back into the sheath as it is passed out from into position. Fluoroscopy can be shown to demon- the end of the bronchoscope into the selected bron- strate the brush and biopsy actually taking the samples, chus. The double - ended tape means that the tape can so that it is clear that each of these have exited from be removed simply once the lesion has been located. the end of the plastic sheath. It is also a further check Now the guide sheath is available with dedicated that the parietal pleura is not being breached by these rubber markers to simplify this preparation. biopsy methods. Some centers do not advocate doing A 2.8 mm biopsy channel bronchoscope is required this to minimize fl uoroscopy exposure, given the for this procedure. It is very important to select the excellent results of the procedure done completely segmental or subsegmental bronchus which is consid- without any form of fl uoroscopy [7,19] . ered to lead most directly to the lesion in question. Having taken the necessary samples, the brush and This is determined by careful scrutiny of the CT scan biopsy forceps are removed in turn and the guide prior to the procedure. The ultrasound miniprobe in sheath is usually left in place for 1 – 2 minutes. This is the guide sheath is passed gently out into this bron- an extremely effective way to tamponade any bleed- chus towards the periphery of the lung until a slight ing from the segmental bronchus simply because the resistance is felt suggesting proximity to the visceral caliber of the sheath is usually equivalent to the caliber pleura, similar to the procedure of a standard trans- of the biopsied bronchus. Then, under bronchoscopic bronchial lung biopsy. It is possible to perform this vision, the guide sheath is carefully and slowly part of the procedure with fl uoroscopy guidance to removed, watching for bleeding in the usual way as prevent the miniprobe being passed out too far. Once one would after completion of a transbronchial lung this slight resistance is felt, the ultrasound probe is biopsy. Following the procedure, X - ray fl uoroscopy turned on by the foot pedal and slowly pulled back as can be used if available to confi rm the absence of an ultrasound pictures are obtained. Once a clear image immediate pneumothorax, and it is usually desirable is obtained, it is usual to pull the ultrasound probe to perform a departmental chest X- ray to exclude back to the proximal extent of the lesion. This is so pneumothorax after an interval of 1 – 2 hours. that biopsy forceps, when passed back down the guide More recent refi nements have included the adop- sheath, are not passed too far beyond the lesion, tion of even smaller miniprobes (1.5 mm diameter rather opening into the middle of the lesion. On occa- with a 1.7 mm bronchoscopic sheath) to go down sions, the lesion in question is only imaged peripher- the biopsy channel (2 mm diameter) of a pediatric ally, as opposed to having the lesion fully surrounding video bronchoscope (4– 4.9 mm) [20] . This has been the miniprobe. In this situation, it is best to pull the shown to further improve access into the smaller sub- miniprobe back and re - advance into an adjacent sub- segments at greater angles. These smaller miniprobes segmental bronchus, preferably done under broncho- use dedicated smaller caliber biopsy forceps and scopic vision. Sometimes only slight adjustment in this brushes. way can greatly improve the ultrasound image. Some centers use a curette passed into the guide sheath to facilitate that purpose. To do this, the ultrasound mini- Clinical Trials probe must be removed from the guide sheath and the curette passed out with angulation of the curette used The advent of endobronchial ultrasound transbron- under fl uoroscopy guidance, in order to turn the guide chial lung biopsy has been an important milestone in 76 CHAPTER 8 EBUS-Guided Peripheral Pulmonary Nodule Biopsy the expansion of bronchoscopic techniques, in some within the lesion. This is, once again, indicative of the of the larger studies performed in various methods ability of ultrasound to locate these very small lesions. of bronchoscopy. These studies are summarized in If fl uoroscopy was not able to localize the lesion, the Table 8.2 . yield was still 74% in terms of positive histology; those The fi rst prospective study was published in 2002 small lesions where fl uoroscopy could detect the by Herth, Ernst and Becker [ 4] . The aim of this study lesion had a 67% positive histology rate. The guide was to determine the added benefi t of using ultra- sheath was left in place for two minutes after the sound compared to standard transbronchial lung biopsies in an attempt to prevent any bleeding after biopsy. Guide sheath was not used in this early study. the biopsies. Careful quantitation of bleeding was The study design was to perform both ultrasound and undertaken in this last study and, in only two patients standard fl uoroscopy- guided transbronchial lung (1%), was there moderate bleeding estimated as biopsy in each patient. The results were excellent with between 30 and 50 mL of blood, which was self - EBUS biopsies providing a tissue diagnosis in 40 limiting and did not affect the patient ’ s oxygenation patients (80%) and showed a signifi cant improvement status. The overall procedure time was not signifi - compared to standard fl uoroscopy biopsies in lesions cantly prolonged by the EBUS guide sheath proce- less than 3 cm in size where the overall diagnostic rate dure. The total procedure time was 9 minutes with the was still 80% compared to 57% for fl uoroscopically mean time of use of ultrasound being only 1 minute, guided biopsies. An important aspect was that the time and the mean time for use of fl uoroscopy also being for the EBUS- guided transbronchial biopsy was close 1 minute. to the time for the procedure performed with fl uoros- Also in 2004 Shirakawa reported 50 cases who had copy, both being approximately 6 minutes each. The EBUS - guided biopsy of a peripheral lung lesion [21] . limitation of this investigation was that whereas the These were compared with 42 controls assessed with methods were applied sequentially in random order, fl uoroscopy only. An important aspect of this study it could not exclude bias in that the location of the was that 78% of patients had their lesion accessed by lesion may have been established by the respective endobronchial ultrasound. This meant that changing fi rst method. That is, if the lesion was localized fi rst position of the patient was not required to assist in with fl uoroscopy, it could have been an aid to the fl uoroscopy. Usually fl uoroscopy should be performed subsequent EBUS - guided biopsy. However, the in two planes to facilitate lesion location and clearly authors did not feel that prior fl uoroscopy enhanced this was obviated in a large percentage of these the ability to locate lesions by EBUS, as three out of patients. Overall, this study showed trends to improve four lesions not found with EBUS were previously diagnosis with the EBUS guide sheath; however they detected by fl uoroscopy. Overall, there was a very did not reach statistical signifi cance. Nonetheless the high localization of lesions by EBUS. overall yields were high with fl uoroscopy alone The next important study was by Kurimoto and refl ecting a better than usual profi ciency with this reported the introduction of the guide sheath associ- standard technique. ated with the miniprobe [ 9] . The overall diagnostic In the same year, a study using a smaller miniprobe yield in this study once again was very high with 77% (20R - 17R, 1.4 mm outer diameter), was used [ 6] . This of procedures obtaining a tissue diagnosis in lesions could also be included in a guide sheath and, impor- which, once again, in general, were quite small. The tantly, could be used with a small caliber 4 mm bron- ultrasound was able to enter the lesion in 87% of choscope. This was because access to the upper lobe cases. The important fi nding in this study was the subsegmental bronchi is often important with these uniform high histology rate across lesion sizes, with types of biopsies. Often lesions are high in the upper lesions less than or equal to 10 mm, having a 76% lobes and acute angulation of the bronchoscope is success rate; lesions 15 – 20 mm in size having a 66% required to access these points. This study demon- success rate; and lesions 20 – 30 mm in size having a strated the ability to localize even very small lesions, 77% success rate. There were 81 lesions less than with lesions < 3 cm in size entered by the EBUS probe. 20 mm in size in this study and standard fl uoroscopy In this study, the diagnostic rate for malignancy was was not able to confi rm whether the forceps were 67%. These authors had prior long experience using 77 Endobronchial Ultrasonography Table 8.2 Prospective clinical studies: E BUS Guide sheath. Author Year R eference Miniprobe Scope Biopsy n ebus comparator comparator n channel calibre Herth 2002 4 20 - 20 1T30/1T40/ 25 standard 25 XT20 TBLBx Kurimoto 2004 9 20 - 20 iT30/1T40/ 150 240R Shirakawa 2004 21 UM3R/ 1T240 R 50 standard 42 UM4R/20 - 20 TBLBx Kikuchi 2004 6 20 - 17 260F/p240/ 2 mm 24 p200 Yang 2004 24 96 standard 122 TBLBx Asahina 2005 20 20 - 17 p 260f/p240 2 mm 29 Paone 2005 22 20 - 20 bf b3/t20 87 standard 119 TBLBx Herth 2006 7 20 - 20 bf t 160 54 Chao 2006 27 20 - 20 p 260f 131 Yamada 2007 23 20 - 17 and p 260 2 mm/ 155 20 - 20 f/1T30/1T260 2.8 mm Fielding 2007 29 20 - 20 1T40 2.8 mm 140 CT FNA 121 Chung 2007 28 20 - 20 p260f 113 Dooms 2007 25 50 Yoshikawa 2007 19 20 - 17 260/p240 2 mm 121 Asano 2009 26 20 - 17 2 mm 32 X - ray fl uoroscopy at their hospital in diagnosing small was removed. They assumed, as did Kurimoto, that peripheral lesions. In the prior 12 months, simply by the wedged guide sheath in the bronchus was tam- using fl uoroscopy alone, for lesions less than 20 mm ponading any bleeding. As with Kurimoto ’ s study, in diameter, fl uoroscopy did not allow the biopsy these authors were adept at using a doubled- hinged forceps to reach the lesion in 35%, and only 13% curette. This was used to facilitate placement of the were able to obtain a tissue diagnosis. The authors catheter in adjacent bronchi if the original pass with commented that the gap between localizing the lesion the ultrasound probe in the sheath was unsuccessful. and obtaining a tissue diagnosis could have been Clearly, using this method does require fl uoroscopy affected by the small size of biopsy |
forceps and brushes and does require some skill and practice. used with this smaller caliber guide sheath. The In 2005, Paone reported a large series of 221 patients authors made qualitative comments that bleeding of who were randomly assigned to either EBUS biopsy any kind was hardly ever seen when the guide sheath or transbronchial biopsy for small peripheral lung 78 CHAPTER 8 EBUS-Guided Peripheral Pulmonary Nodule Biopsy mean Procedure time Lesion Yield Yield Yield Yield < 3 cm Yield < 2 cm Side effects lesion entered malignat benign size mm 33.1 6 minutes EBUS 92% 8 0% 80% minor bleeding time × 2( no guide sheath), px × 1 1 min EBUS 87% 77% 81% 69% moderate > 30 ml 9 mins procedure bleeding× 2 (33/50 78% 71% < 2 cm) 18 mm 79% 5 3% 67% 33% 53% × 1 px 55 – 66% 55% 19 mm 25 mins whole 80% 6 3% exam, time to fi rst ebus imaging 12 mins 9.8 mins including 76% 79% 69% 75% 71% nil instrument set up 22 mm 12.3 mins 89% 7 0% 1 px, 3 self limited including bleeding biopsies 44 mm 63% 21 mm 67% 76% 40%((15 – 30) 29 mm 25 mins for all 66% 63% 70% 2 px bronchoscopy 25 mm 72% 6 8% - see 73% 24% × 1 px, × 5 mild comments bleeding 37 mm 74% 6 2% 31 mm 62% 76%(> 20 mm) 30% 1 px 31 mm 22 mins total 94% 80% lesions [22] . Eighty - seven patients underwent EBUS chial lung biopsy which was highly statistically signifi - and 119 had transbronchial lung biopsy. Overall, there cant. This is even allowing for the fact that many was a 76% diagnostic rate for EBUS compared to 52% centers would probably have diffi culty achieving 31% for standard transbronchial lung biopsy without EBUS. success rate with transbronchial lung biopsy alone. For As with the other studies, a variety of benign and lesions less than 2 cm in size, a similar improvement malignant conditions could be diagnosed. There was was found with 71% sensitivity for EBUS and 23% no difference in the overall success rate for lesions sensitivity for transbronchial lung biopsy. greater than 3 cm in diameter; however the evaluation In 2005, Asahina reported EBUS- guided sheath of patients with lesions less than 3 cm showed a sub- biopsy of peripheral lung lesions assisted by CT virtual stantial benefi t for EBUS- guided biopsy compared to bronchoscopy [ 20] . Prior to the bronchoscopy, a fl y- standard transbronchial lung biopsy. There was a 75% through image of the bronchial tree was created using sensitivity for EBUS compared to 31% for transbron- images reconstructed from helical CT data transferred 79 Endobronchial Ultrasonography to a worksite. Images were clear as far as the fi fth copy in 123 procedures [ 19] . Once the EBUS confi rmed general bronchi; however for more peripheral zones, the lesion, the probe was withdrawn and the guide virtual bronchoscopy images were generated using sheath left in place. Brushings and transbronchial pulmonary arterial branches. As in the study of biopsies were performed by the guide sheath; when Kukuchi, once again a thin caliber 1.4 mm EBUS mini- an EBUS image could not be obtained at that stage, probe was used. The bronchoscope was inserted as the bronchoscopic examination became a standard deeply as possible into the target bronchus under fl uoroscopically guided transbronchial lung biopsy. direct vision as suggested by the correct path from the 62% of lesions were diagnosed by the EBUS method CT virtual bronchoscopy. The miniprobe in the guide without fl uoroscopy. Amongst these lesions, those sheath was then inserted. Standard radiographic fl uor- greater than 20 mm in diameter had a 76% diagnostic oscopy and EBUS imaging were used. Using this rate and this was signifi cantly higher than those with method, EBUS was able to detect 24 of the 30 periph- lesion diameters of less than 20 mm where the histol- eral pulmonary lesions (80%) with an average diam- ogy rate was 30%. Two other interesting aspects for eter of 19 mm. The average time to the fi rst EBUS the proceduralist were fi rst that when the CT could imaging of the lesion including anesthesia of the bron- clearly identify a bronchus leading to the lesion, the chial tree and insertion of the bronchoscope and echo overall yield was 79%. In addition, there was a higher probe into the lesion, was 10 minutes. The average diagnostic yield for solid lesions (67%) compared with time for the fi rst biopsy including the time to the fi rst non - solid lesions (35%). Non - solid lesions such as EBUS imaging and adjustment of the forceps position ground glass opacities often simply surround the small was 12 minutes. Overall, the complete examination peripheral bronchus without either compressing or took 25 minutes. This elegant study demonstrated the invading it. Hence, a transbronchial lung biopsy may capacity of virtual bronchoscopy to assist the proce- have diffi culty actually catching the abnormal tissue duralist in identifying relevant small subsegmental in these cases. The goal of this study was to demon- bronchus into which the guide sheath miniprobe strate the ability of EBUS to perform the biopsy should be passed. The upper lobes can be particularly without the excessive radiation exposure for patients subject to signifi cant anatomical variations and guid- and medical workers that can occur with the use of ance in probe site selection is clearly of benefi t to the fl uoroscopy. This study extended the fi ndings of Herth proceduralist. Even lesions less than 20 mm in diam- et al. who had shown in their earlier study similar eter had a 54% success rate in tissue diagnosis. overall success rates for EBUS and fl uoroscopically In a study reported in 2006, Herth et al. presented guided transbronchial lung biopsies. The authors com- results in 54 patients with solitary pulmonary nodules mented that the previous studies by Kikuchi and that could not be visualized with standard fl uoroscopy Paone had higher diagnostic rates for lesions less than done at the time of bronchoscopy [ 7] . These were very 2 cm in diameter (53% and 71% respectively) because small lesions with an average diameter of 2.2 cm. A there could be fl uoroscopically guided confi rmation of very high percentage of these patients could be local- the peripheral pulmonary lesions in those studies. ized with EBUS (89%) and, overall, there was a tissue Second, fl uoroscopy allows the use of the hinged diagnosis in 70% of these patients. Lesions were dis- curette to facilitate repositioning of the probe. Third, tributed quite evenly throughout the lung and there fl uoroscopic guidance may assist with preventing the was a slightly better tissue diagnosis rate for malig- probe from moving during respiratory movement. nancy compared with benign lesions. The results indi- Overall, therefore, the authors concluded that fl uoro- cate the added benefi t of ultrasound in that if standard scopic guidance was not necessary for lesions more transbronchial lung biopsy is performed and the lesion than 20 mm in diameter, but probably would be cannot either be seen or located, the biopsy site required for lesions smaller than this. With respect to becomes the best estimate of the proceduralist. The lesion location, the authors made some interesting advantage of EBUS clearly is the defi nitive localization qualitative comments. First, the diagnostic yields of of the lesion. peripheral pulmonary lesions in the right middle lobe In 2007, Yoshikawa reported EBUS to guide a trans- and lingular were signifi cantly higher. The access to bronchial lung biopsy without radiographic fl uoros- these lobes is clearly easier than some of the apical 80 CHAPTER 8 EBUS-Guided Peripheral Pulmonary Nodule Biopsy segments of the upper lobes. Others had previously shown lower success rates for biopsies in the right Analysis of Internal Structure of upper lobes [9] . Negotiating the sharp bends of the Peripheral Pulmonary Lesions Using E BUS bronchus in these airways opening with the tip of the EBUS catheter can be quite diffi cult. They also felt that In Kurimoto’ s study of 2002, a detailed analysis of the the guide sheath seemed to move and slip off more ultrasound appearance of peripheral pulmonary easily from the lesion with deep inspiration in lesions lesions when accessed by an EBUS probe was pre- in the lower lobes. With respect to peripheral pulmo- sented [ 5] . This work began in January 1996. The nary lesions which are aerated and non- solid, the overall question, of course, is whether there is a cor- authors recommended that transbronchial needle relation between ultrasound characteristics and fi nal aspiration could be used. histological confi rmation. Initially, 69 patients with In 2007, Yamada reported factors which increased preoperative EBUS images were correlated with his- the yield of small peripheral pulmonary lesions [ 23] . topathological fi ndings of surgical specimens upon As noted from these other studies, there is often a gap surgical resection. This allowed exact correlation with between the access to the lesion as confi rmed by ultra- small intra - lesional bronchi and vessels. Subsequent sound and actually confi rming a tissue diagnosis. The to that, another 124 lesions underwent bronchoscopic fi rst important parameter was the location of the probe biopsy, and EBUS pictures were analysed for their with respect to the lesion. There was clearly an internal structures depending on the fi nal tissue diag- improved diagnostic yield (83%) when the probe was nosis. The ultrasound images appeared to have cor- positioned within the lesion compared to those where relation to the lesion in question primarily on the basis it was positioned adjacent to it (61%) were outside the of how much the underlying pathology destroyed the peripheral pulmonary lesion. These were statistically usual structures in the lung, namely the bronchi, signifi cant results and indicate the need for the practi- alveoli, and blood vessels. The more destructive the tioner, possibly with the use of a curette, to facilitate lesion, such as an aggressive carcinoma, the less were placement of the probe well within the lesion. In this these structures identifi able; conversely, the more study, once again, very small peripheral lesions (85%) benign and less destructive the process, the more iden- were actually entered with the EBUS probe. Lesions of tifi able such structures as bronchi were. The former, between 15 and 20 mm, greater than 20 and less than overall, tend to therefore have a somewhat heterog- 25 mm and greater than 25 and less than 30 mm had enous appearance because of the different echodensi- diagnostic yields of 40%, 74%, 72%, and 81% respec- ties of compressed or distorted structures. The latter tively. Other useful data from this paper were that more benign lesions tend to have a homogenous there was an increasing diagnostic yield approaching appearance because of the maintenance of normal 97% where the fi nal diagnosis was made after fi ve lung tissue architecture to some extent within the biopsies. It would therefore seem that at least fi ve lesion. Residual air within a lesion was refl ected as a biopsies ought to be taken. The importance of the hyperechoic dot as air tends to give such an appear- placement of the probe within the lesion was demon- ance on ultrasound. Blood vessels could often be seen strated in that multivariant analysis showed this to be coursing through lesions, sometimes with diameters the most signifi cant factor in overall diagnostic yield, as small as 0.68 mm when measured histopathologi- even overcoming small lesion size, as small as less than cally. These structures tended to be seen more in 15 mm in diameter. The study also demonstrated the benign less destructive pathological processes. At a lack of any statistical difference between operators in frequency of 20 MHz, the spatial resolution of ultra- the procedure, all of whom had had more than four sound images is approximately 0.38 mm. years experience in bronchoscopy. Other factors in Broad groups of three EBUS images were described. biopsying lesions most effectively would be to place the Type 3 lesions had a heterogenous appearance and the guide sheath at the near end of the lesion as gauged |
majority of these were malignant (Table 8.3 ). No by ultrasound. In this way, as the forceps comes out, blood vessels were seen within the lesion by EBUS and it will not over - reach the lesion as it may do if the guide there were irregular mottled and linear areas distrib- sheath is left in the middle of the lesion. uted in the lesion corresponding to the destructive 81 Endobronchial Ultrasonography Table 8.3 Differentiation of peripheral lesions on E BUS images Kurimoto Key features Type 1 Type 2 Type 3 hetrogeneous/homogeneuos H omogeneous Heterogeneous vessels seen Type 1a Type 2b Type 3a bronchi seen Type 1a Type 2b Type 3a hyperechoic points Marked Malignant 99 99 Benign 92 Kurimoto N, Murayama M, Shinchikiro S, Nishisaka T. Analysis of the internal structure of peripheral pulmonary lesions using endobronchial ultrasonography. Chest 2002;122:1887– 1894. Chao Homogenous/heterogenous Hyperechoic dots Concentric circles Continuous margin Malignant 4% 97% 5 4% 2% 22% Benign 41% 59% 7 4% 53% 9% p < 0.001 < .001 0.09 Adapted from Chao TY, Lie CH, Chung YH, et al. Differentiating peripheral pulmonary lesions based on images of endobronchial ultrasonography. Chest 2006;130:1191 – 1197. effects of the tumor compressing bronchi and alveolar some of these lesions did not have blood vessels visu- air. The echoes were therefore heterogenous and rela- alized because of the predominance of the alveolar air tively dense. There was a signifi cant attenuation of the pockets which hampered the visualization of the sound waves by the tumor so that only about 6– 8 mm vessels. In those type 2 lesions where vessels were of the lesion could be seen clearly, whereas tissue identifi able, there was a greater density of adenocar- outside this was seen clearly. Most of these were cinoma cells and presumably this allowed identifi ca- peripheral adenocarcinomas. Some type 3 lesions did tion of vessels because of more solid tissue surround not have any hyperechoic dots or short lines, possibly them as opposed to air pockets. because they were relatively avascular, and remnants Type 1 lesions had the unifying characteristic of of previous structures which caused such features in being homogenous. That is, the internal echoes other type 3 lesions were therefore absent. Therefore, between any visible structures such as vessels or bron- type 3 lesions could be classifi ed as either A or B chioles were homogenous. In some of these cases, the depending on the presence or absence of these hyper- vessels and bronchioles were visible and predomi- echoic dots and short lines. Overall, however, there nantly these included cases of pneumonia where there was always heterogeneity of internal echoes. was a pattern of exudates - fi lled alveoli demonstrate Type 2 lesions had a predominance of hyperechoic on histopathology. Because the pneumonia was not dots and linear arcs and these represented the residual causing any compression or stenosis of bronchi or alveoli (small points of hyperechoic air) and slightly vessels, these were well seen. There was small ultra- compressed bronchi. These lesions could be further sound attenuation because of this type of lesion which subclassifi ed as either A or B depending on whether was not particularly dense and even tissue 15 – 20 mm vessels were not, or were, visualized. The histopatho- from the probe could be seen clearly. Sometimes, logical correlate of these residual alveolar structures where the lesion was up against a fi ssure, the margins was that of well - differentiated adenocarcinomas of the lesion could be seen to be linear. There was one which grow in a lepidic fashion without destroying the case of malignancy amongst this group because the underlying alveolar parenchyma. It was thought that form of metastasis from a pancreatic carcinoma was of 82 CHAPTER 8 EBUS-Guided Peripheral Pulmonary Nodule Biopsy a pneumonic type with respect to the CT scan and bined with concentric circles was included. The third histopathology. Some cases of homogenous type 1 characteristic was hyperechoic dots and here the spots pattern did not have vessels or bronchioles visualized; were generally bigger than normal particles. The dots however the important aspect was that mottled or may have merged several variable sized areas or hyper- linear hyperechoic areas were absent or scant. These echoic linear arcs. The presence of residual air in the included cases of organizing pneumonia and tubercu- lesions or tiny calcifi cations could have been the reason lomas; it did include one case of moderately differenti- for this pattern. Overall, more than half of all the ated squamous cell carcinoma. lesions displayed hyperechoic dots including 54% of Overall, using this classifi cation, there was an neoplastic lesions and 73.5% of non- neoplastic lesions. extremely good correlation between the presence of Therefore, it was thought not to be useful in distin- type 2 or 3 lesions and the presence of malignancy guishing lesions. Finally, the presence of concentric (99%). Furthermore, 21 of 24 type 2 lesions (87.5%) circles was analysed. There was a sense of gradation were well - differentiated adenocarcinomas. All of the from the inner to the outer parts of the lesion. It was type 3 B lesions were malignant. With respect to type thought to represent the effect of the residual intact 1 lesions, 25 (92%) were shown to be benign. architecture of the bronchioles within the lesion. In 2006, Chao et al. reported a similar study [ 27] . About one half of the non- neoplastic lesions had the They developed a classifi cation involving four particu- characteristics of concentric circles and this was only lar aspects of the ultrasound image from 20 consecu- detected in one case of malignancy. This difference was tive patients. In the following 131 patients, this highly statistically signifi cant and the signifi cance was classifi cation scheme was tested. The four points persistent even by the multivaried analysis combined described were: (1) a continuous hyperechoic margin with internal echoes. Note that it was present in only around the lesion; (2) a distinction between homoge- 53% of the benign lesions. Therefore, this classifi cation nous or heterogenous internal echoes; (3) hyperechoic system did not use the pattern of vessels or bronchioles dots in the lesion; and (4) concentric circles along the to type the lesions. In their scheme, there was unanim- echo probe . Points 2 and 3 had been a critical part of ity amongst three reviewers in the vast majority of Kurimoto’ s earlier classifi cation. With respect to the cases. The time taken to perform this analysis was less margin, the thickness of the margin varied among dif- than four minutes. Overall, the authors concluded that ferent parts of the lesion. The margin was basically the presence of concentric circles favored the periph- between the lesion and normal aerated pulmonary eral lung lesion as being benign and that the existence tissues. From 93 patients, only 16 had a continuous of a continuous hyperechoic margin was suspicious for hyperechoic margin fully around the lesion. In 13 of malignancy. The remainder of the fi ndings at this stage 16 cases of these 16 cases (81.3%) there was malig- were therefore regarded as qualitative and perhaps nancy. This did not quite reach statistical signifi cance used in support of further observation in biopsies comparing benign and malignant lesions (p = 0.09). where the histology is benign. With respect to the internal echoes of the lesion, Other authors [ 8] have used image analysis soft- homogenous internal echoes were unanimous in size, ware to determine the presence of underlying hetero- echogenicity and distribution, and the echogenicity geneity or homogeneity of the echoes within an was invariably slightly lower than that in normal lung ultrasound lesion. This would facilitate the kinds of parenchyma. Heterogenous internal echoes displayed distinctions made in both the Kurimoto and Chao a mosaic pattern in imaging particle distribution and classifi cations and has shown to be useful in a prospec- the particles varied in size. The echogenicity of the tive follow- up series. lesions comprised both hyper and hypoechogenicity. Overall, there were 16 subjects from the 93 who had homogenous internal echoes and the majority of these Side Effects and Tolerability (88%) were benign. Ninety- seven percent of neoplas- tic lesions demonstrated heterogenous internal echoes Table 8 .1 highlights the low incidence of side effects and this was statistically different (p < 0.001). This of transbronchial lung biopsy easing into bronchial signifi cance was lost after multivariant analysis com- ultrasound method. Bleeding and pneumothorax are 83 Endobronchial Ultrasonography inherent to transbronchial lung biopsy; however, in biopsy [ 29] . We demonstrated that we had an inci- all of these series, the overall incidence of these was dence of 1% pneumothorax rate from 140 cases of less than 1%. An important observation is that studies EBUS - guided sheath biopsy. This compared to a 28% that did not use a guide sheath had a slightly higher pneumothorax rate and 6% rate of intercostal catheter incidence of minor bleeding; no incidences of severe insertion in 121 retrospectively reviewed cases of CT bleeding were seen. Nonetheless, this can be discon- fi ne needle aspiration. certing for the proceduralist at the time and, as described by a number of authors, the most common scenario was to have absolutely no bleeding of any Conclusions quantity upon removal of the guide sheath and one or two minutes after the last biopsy. A paper by Chung Endobronchial ultrasound- guided sheath peripheral described EBUS guide sheath peripheral mass biopsy biopsy provides a safe, reliable, and technically simple without the use of the guide sheath, using the meas- means of extending the bronchoscopist ’ s capacity to urement of length of the lesion away from the end of obtain tissue diagnosis on small peripheral lung the bronchoscope by fl uoroscopy as the ultrasound lesions. It has an excellent safety profi le, probably probe was removed [28] . The biopsy forceps were safer than standard transbronchial lung biopsy in placed back that same distance out from the end of terms of bleeding, and probably better than usual rates the bronchoscope to take the samples. Normally, for pneumothorax compared to CT- guided fi ne needle when the guide sheath was used, the end of the guide aspiration biopsy. Not only does it allow the accurate sheath itself becomes the marker point to which the localization of very small peripheral pulmonary forceps are passed. There was a signifi cant improve- lesions, it also allows the qualitative characterization ment in the overall diagnostic yield (79% compared of the underlying lesion by way of assessment of the to 57%) in patients where this measurement was ultrasound characteristics of the lesion. In a recent used. An important fi nding from the point of view of recommendation, the American College of Chest side effects was that, from these 158 lesions, there Physicians advocated the use of endobronchial ultra- were fi ve episodes of mild bleeding. Some of the other sound in lesions less than 2 cm in diameter [30] . studies, however, suggest that the guide sheath does In many respects, the biopsy of peripheral lesions have a protective effect in terms of minimizing any larger than this can also be benefi ted by the use of bleeding. With respect to pneumothorax limitation, endobronchial ultrasound particularly in centers not the important aspect is to prevent excessive passage of frequently using standard X - ray fl uoroscopy for the biopsy forceps or brush beyond the tip of the guide such types of biopsy. Because of its safety and simplic- sheath. Most, but not all, operators use X- ray fl uoros- ity, it rapidly allows the bronchoscopist to gain access copy to manage this part of the procedure thereby to the lesion without the need to image in two planes preventing excessive lengths of the biopsy forceps by fl uoroscopy. It also provides safety advantages coming out the end of the guide sheath. Clearly, the over and above the standard transbronchial lung localization of the guide sheath at the proximal end of biopsy technique by way of the benefi ts of the guide the lesion should prevent this happening. In the sheath. author ’ s experience, one case of pneumothorax occurred because the biopsy brush was extended too The Future of EBUS Peripheral Lung Biopsy far. It is an inherent problem of using |
a biopsy brush Presently, there are two aspects in development with that sometimes in taking the specimen, the brush can respect to endobronchial ultrasound. First, there is the be advanced 2 or even 3 cm and thereby breach the ongoing miniaturization of the equipment and the visceral pleura. Special care should be therefore taken greater use of the 1.4 mm diameter EBUS Miniprobe. to prevent over - excessive application of the brush This being combined with a 4 mm diameter broncho- length. In a retrospective series, we demonstrated that scopes has been demonstrated to access very small our incidence of pneumothorax with this technique lesions in two studies from Japanese centers. Better was much less than our current hospital experience biopsy forceps and brushes for use with these smaller with pneumothorax from CT - guided fi ne needle miniprobes and smaller guide sheaths are currently 84 CHAPTER 8 EBUS-Guided Peripheral Pulmonary Nodule Biopsy allowing better diagnostic yields, particularly in very techniques have returned yields of 58– 73%, 58– 77%, small lesions of less than 1– 2 cm in diameter. Such and 63% respectively. Interestingly, there was a miniaturization can afford the bronchoscopist greater diminished lower lobe yield of 29% in the ENB alone access to very small bronchi in somewhat tortuous group and this was thought possibly due to naviga- positions as experienced with bronchoscopes of stand- tional error; navigation in the lower lobes was thought ard caliber. to be more effective by diaphragmatic movement The increasing use of CT virtual bronchoscopy will during breathing. This could have hampered the CT be an important component in the ongoing develop- images acquired in a single breath hold prior to the ment of this technique [ 31] . Many practitioners do not actual procedure, with such planning data being used have the encyclopedic knowledge of small segmental in the navigation process. The overall rate of pneu- bronchi that surgeons have, nor the knowledge held mothorax was 5% in EBUS and 5% in ENB. in some of the Japanese and European centers. Fluoroscopy was not used because earlier data had Therefore, there will probably always be a need for shown that it did not decrease the rate of the iatro- some radiological assistance of practitioners in identi- genic pneumothorax after transbronchial lung biopsy. fying the correct bronchus. The development of sim- Perhaps this was the explanation for the slightly plifi ed user interfaces for virtual bronchoscopy is increased pneumothorax rate. ongoing, and this combined with the use of small caliber miniprobes and bronchoscopes should further increase the user- friendliness of this technique. Tips for Endobronchial Ultrasound - Guided In a recent report from Eberhart et al. EBUS was Transbronchial Lung Biopsy combined with electromagnetic navigation bronchos- copy to determine their relative contribution to biopsy The techniques are not particularly different from of peripheral lung lesions [ 32] . Electromagnetic navi- standard transbronchial lung biopsy and hence the gation bronchoscopy utilizes a system of navigational procedure is accessible to many. Some simple sugges- guidance to the lesion based on specifi c hardware and tions may assist in the uptake of the technique. software interfaces, but importantly uses a steerable 1 CT anatomy: becoming more familiar with the biopsy forceps. This type of forceps has a guide sheath common appearances of the takeoff of each of the ten and is for single patient use. This study was performed subsegmental bronchi on the right and the nine sub- in lesions, once again, very small in diameter, ranging segmental bronchi on the left and their associated fi fth between 25 and 28 mm for the two techniques. In this border branchings is important. It is relatively easy to study, navigation to the lesion was fi rst performed by become familiar with this over one of two months of electromagnetic navigational bronchoscopy (ENB). repeated study of the CTs. Discussion with the radiolo- When the lesion was located, the sensor probe was gist can also be helpful as can scrolling through the withdrawn and the EBUS probe was inserted through digital images on a PC. This allows tracking of the bron- the ENB guide sheath. If the EBUS image confi rmed chial segments out to the corresponding lesion. Having that the sensor was indeed within the target, then the done this, it is necessary to make a shopping list of biopsy was performed. However, if no acceptable bronchial segments into which the guide sheath can be EBUS image was obtained, re- navigation with ENB passed starting from the most likely to the least likely. and subsequent reconfi rmation with EBUS was done. Even the most experienced bronchoscopist will do this. This combined technique had a signifi cantly higher 2 Increased familiarity with the numerical system for diagnostic yield of 88% compared to EBUS alone naming of bronchi as originally described by Boyer (69%) or electromagnetic navigational bronchoscopy and Icheda. This is much more familiar to Japanese alone (59%). The authors felt that ENB enhanced and European readers as opposed to readers in the EBUS by providing real time and subtle navigation UK, United States and Australasia. The numerical through the steering mechanism of the locatable system greatly facilitates an understanding of the guide. They felt that this navigation capability was inter - relationship of the bronchial appearance to marginally better than that afforded by either fl uoros- the CT scan appearance. Clearly, there will be varia- copy, curettes, or virtual bronchoscopy. These three tions but improving one’ s awareness of these and the 85 Endobronchial Ultrasonography 7 Use separate monitors for white light bronchoscopic fi ndings and for ultrasound fi ndings. There is the facility to have a picture display on the monitor, one showing ultrasound and the other showing bron- choscopic fi ndings, or the facility to swap between the two images on one monitor. In the author’ s experience, it is always better to have both showing constantly and simultaneously on two separate monitors. 8 In some patients, there is chronic bronchitis in the End of Transducer large airways and holding the bronchoscope in one the sheath position can occasionally lead to abrasion of the bron- chial wall over a 10 - minute period during which time ultrasound and biopsies are taken. This can lead to some bleeding from the bronchus itself due to this Figure 8.1 Set up of distal end of EBUS minprobe which is abrasion as opposed to from the lung and it is always shown exiting from the guide sheath (left). important to remain aware of the endobronchial situ- ation even though one’ s concentration is on the lesion likely expected bronchial anatomy greatly improves in the periphery of the lung. success rate. 9 Care with transbronchial brushings as mentioned 3 Probe preparation: it is important to have the ultra- above; over- extension of a bronchial brush can occa- sound part of the miniprobe just outside the end of sionally cause breach of the visceral pleura and pneu- the plastic sheath (see Figure 8.1 ). If any part of the mothorax. Lesions which are more centrally placed processor is hampered by the plastic sheath, interfer- should not pose a problem; however those lesions up ence images will appear. Sometimes as the probe is against the visceral pleura particularly in the upper passed out into the peripheral bronchi, compression lobes may have a risk of pneumothorax if the brush from bronchial structures pushes the probe back inside is extended too far. the sheath and such interference patterns can appear. 10 Once the lesion is found, withdraw the guide As such, it is important to ensure that the proximal sheath to the near end of the lesion so that the ultra- end of the probe is fi rmly taped to the guide sheath. sound image is just disappearing. Fix the guide sheath 4 The biopsy forceps and brushes need to have a tape at this point rather than within the lesion as this will mark placed at the proximal end prior to starting the facilitate better biopsy positivity as described above. procedure such that, in particular with the biopsy 11 Interpretation of ultrasound images. This need not forceps, the end corresponds to the point of the EBUS hold the procedure up and is often done following the miniprobe transducer. completion of the procedure. The decision to take 5 Use an assistant. This is important because small the biopsy is made before the procedure begins changes in position of the bronchoscope or the mini- rather than as a result of an interpretation of an image probe can affect biopsy yield and it is often helpful to at the time of the procedure. It is easy to record ultra- have an assistant hold the bronchoscope in place sound images on the hard drive of the ultrasound while the main proceduralist actually takes the processor or to record the whole ultrasound procedure biopsies. on digital video and interrogate still images from that. 6 With the use of an image intensifi er, it is often Such interpretation may be of some assistance in helpful to save the image of the point of the guide prospective evaluation of one ’ s own performance sheath on one screen and have another screen to and demonstrate for audit purposes that the procedur- show the actual live passage of the biopsy forceps. This alist is achieving reasonable diagnostic accuracy results can allow a very accurate positioning of the biopsy by comparing ultrasound image and histology forceps; however this is not essential as keeping the fi ndings. guide sheath in place once the ultrasound confi rms 12 Where a lesion appears to be a small ground glass positioning may be all that is required. opacity and to have an aerated type of appearance, 86 CHAPTER 8 EBUS-Guided Peripheral Pulmonary Nodule Biopsy transbronchial needle aspiration should be added to pulmonary nodules to assess the histology. Chest the biopsy method as described above. This would 2003 ; 124 ( suppl 4 ): 77 . increase the yield in that such lesions tend not to 9 Kurimoto N , M iyazawa T , O kimasa S , et al. Endobronchial invade the bronchus and therefore sampling outside ultrasonography using a guide sheath increases the the bronchus could improve the results; it can be done ability to diagnose peripheral pulmonary lesions endo- scopically . Chest 2004 ; 126 : 959 – 965 . without any increased risk of side effects. 10 Popvich J J r , K vale P A , E ichenhorn M S , et al. Diagnostic 13 Consider a broader range of indications than accuracy of multiple biopsies from fl exible fi beroptic simply small peripheral nodules. For example, patchy bronchoscopy: a comparison of central versus periph- subsegmental pulmonary infi ltrates can be very ame- eral carcinoma. A m Rev Respir Dis 1982 ; 125 : 521 – 523 . nable to EBUS biopsy; standard transbronchial lung 11 Radke JR , C onway WA , E yler WR , et al. Diagnostic biopsies can miss infi ltrative processes which are quite accuracy in peripheral lung lesions: factors predicting patchy such as chronic fungal infections or early cases success with fl exible fi beroptic bronchoscopy . Chest of infl ammatory alveololitis. In the author ’ s experi- 1 976 ; 76 : 176 – 179 . ence, even in these cases, it is possible to completely 12 Schreiber G , M cCrory D C . Performance characteristics miss the pathology in one segmental bronchus, as one of different modalities for diagnosis of suspected lung retreats and passes the probe into a segmental bron- cancer: summary of published evidence. C hest 2003 ; 123 (suppl): 115s – 128s . chus only 1 mm away, only to fi nd the probe com- 13 Torrington K C , K ern J D . The utility of fi beroptic bron- pletely surrounded by pathology. choscopy in the evaluation of the solitary pulmonary nodule . Chest 1993 ; 104 : 1021 – 1024 . 14 Shiner RJ , Rosenman J , Katz I , et al. Bronchoscopic References evaluation of peripheral lung tumors. Thorax 1 988 ; 43 : 887 – 889 . 1 Wallace J M , D eutch A L . F lexible fi beroptic bronchos- 15 Fletcher EC , Levin DC. F lexible fi beroptic bronchoscopy |
copy and percutaneous lung aspiration for evaluating and fl uoroscopically guided transbronchial biopsy in the solitary pulmonary nodule . Chest 1982 ; 81 : management of solitary pulmonary nodules. West J 665 – 671 . Med 1982 ; 135 : 477 – 483 . 2 Chechani V . Bronchoscopic diagnosis of solitary pulmo- 16 Blasco LH , Hernandez IMS , Garrido VV , et al. S afety of nary nodules and lung masses in the absence of endo- transbronchial biopsy in outpatients. C hest 1991 ; 99 : bronchial abnormality. C hest 1996 ; 109 : 620 – 625 . 562 – 565 . 3 Becker H D , H erth F . Endobronchial ultrasound of the 17 H ü rtur T , H anrath P . Endobronchial sonography: feasi- airways and mediastinum . In Bolliger C T , M athur P N , bility and preliminary results. T horax 1 992 ; 47 : eds. Interventional Bronchoscopy. Basel : K arger , 565 – 567 . 2000 : 80 – 93 . 18 Goldberg B , Steiner R , Liu J , et al. U S - assisted bronchos- 4 Herth F , Ernst A , Becker H D . E ndobronchial ultrasound copy with use of miniature transducer - containing cath- (EBUS) guided transbronchial lung biopsy (TBBX) in eters . Radiology 1 994 ; 190 : 233 – 237 . solitary pulmonary nodules and peripheral lesions . Eur 19 Yoshikawa M , Sukoh N , Yamazaki K . D iagnostic value Respir J 2002 ; 20 : 972 – 975 . of endobronchial ultasonography with a guide sheath 5 Kurimoto N , M urayama M , S hinchikiro S , N ishisaka T . for peripheral pulmonary lesions without X - ray fl uor- Analysis of the internal structure of peripheral pulmo- oscopy . Chest 2007 ; 131 : 1788 – 1793 . nary lesions using endobronchial ultrasonography . 20 Asahina H , Y amazaki K , O nodera Y , et al. T ransbronchial Chest 2002 ; 122 : 1887 – 1894 . biopsy using endobronchial ultrasonography with a 6 Kikuchi E , Y amazaki K , S ukoh N , et al. 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F actors related 28 Chung Y H , L ie C H , C hao T Y , et al. Endobronchial ulta- to diagnostic yield of transbronchial biopsy using endo- sonography with distance for peripheral pulmonary bronchial ultrasonography with a guide sheath in small lesions . R esp Med 2007 ; 101 : 738 – 745 . peripheral pulmonary lesions . Chest 2007 ; 132 : 603 – 608 . 29 Fielding D I , R obinson P J , K urimoto N . Biopsy site 24 Yang MC , Liu WT , Wang CH , et al. Diagnostic value of selection for endobronchial ultrasound guide- sheath endobronchial ultrasound guided transbronchial lung transbronchial biopsy of peripheral lung lesions. Intern biopsy in peripheral lung cancers . J Formos Med Assoc Med J 2008 ;3 8 : 77 – 84 . 2004 ; 103 : 124 – 129 . 30 Rivera MP , Mehta AC . I nitial diagnosis of lung cancer: 25 Dooms CA , Verbeken EK, Becker HD, et al. E ndobronchial ACCP evidence - based clinical practice guidelines, 2nd ultrasonography in bronchoscopic occult pulmonary edn . 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The probe is connected to an Endoscopic Introduction Ultrasound System (EU - M30, EU - M2000; Olympus). Guide sheaths are now available commercially under Bronchial brushing cytology and transbronchial biopsy the name of The Guide Sheath Kit (Olympus). (TBB) are used to diagnose peripheral pulmonary lesions (PPLs). Fluoroscopy is required in most cases to direct the operator to site of interest, although it is EBUS - GS Procedure often diffi cult to confi rm whether the biopsy forceps have reached the lesion. Since 1994, we have been For preparation of equipment for EBUS - GS, see able to delineate PPLs through the introduction of a Chapter 3 , p . 28 , Video clip 3.3. miniature ultrasonic probe into a peripheral bronchus For actual EBUS - GS techniques, see Chapter 3 , [1] , but this has involved withdrawing the probe after pp. 28 – 30 , Figure 3 .6 , and Video clip 3.4. the ultrasound image has been obtained, then intro- EBUS - GS procedures and images will be described ducing a brush or biopsy forceps, and obtaining the using a representative case. tissue or brushing sample. This method has made it diffi cult to be sure that the tissue or brushing sample Representative Case (Video Clip 9.1, has been accurately taken from the site of the lesion, Figure 9.1 ) however. To increase the reliability of sample collec- This 74- year - old man had a 10 × 8 mm nodular lesion tion from PPLs, we devised a technique using EBUS in segment B5a of the right lung. Bronchoscopy was with a guide sheath (EBUS - GS). performed to establish the diagnosis. A miniature probe covered by a guide sheath was introduced into the B5a bronchus of the right lung, and pulled back Equipment to obtain EBUS images. EBUS revealed heterogenous internal echoes in a lesion with an irregular margin Between 1996 and the commencement of EBUS- GS that contained almost no vessels or bronchi. These in 1999, we used a 20 MHz, mechanical- radial type fi ndings were suggestive of a solid tumor with a high miniature ultrasonic probe (UM- BS20 - 20R; Olympus cell density. The guide sheath was left at the site of Optical Co., Ltd, Tokyo, Japan) with an outer diameter the lesion identifi ed by EBUS, and the probe was with- of 1.7 mm. Since 2000, we have used a 20 MHz, drawn. A bronchial brush and biopsy forceps were mechanical - radial type thin ultrasonic probe (UM - introduced into the bronchus. Cytology of the bron- BS20 - 17R; Olympus) with an outer diameter of chial brushings revealed adenocarcinoma, and trans- 1.4 mm (see Chapter 3 , Figure 3 .5 , Procedure for bronchial biopsy (TBB) confi rmed the diagnosis of poorly differentiated adenocarcinoma. We previously reported the overall yield of EBUS Endobronchial Ultrasonography, 1st edition. using a thick guide sheath (EBUS- thick GS) to be By Noriaki Kurimoto, David I. K. Fielding and Ali I. Musani. 77% (116/150), and the diagnostic yield of EBUS- Published 2011 by Blackwell Publishing Ltd. GS in malignant and benign lesions as 81% (82/101) 89 Endobronchial Ultrasonography 8 × 8mm Figure 9.1 Poorly differentiated adenocarcinoma in the left vessels or bronchi within the lesion. Bottom left: a miniature lingular segment. Top left: the lesion is diffi cult to identify on probe covered by the guide sheath introduced into the left B5a this plain chest radiograph. Top center: chest CT revealed a bronchus. Bottom center: guide sheath (arrow) left at the site of 10 × 8 mm nodular lesion in left segment B5a. Top right: The the lesion. Bottom right: bronchial biopsy forceps introduced EBUS image revealed echogenic internal echoes with almost no into the lesion. and 73% (35/49), respectively [ 2] . Lesions in which 69%), and > 20 ≤ 30 mm (33/43, 77%) were similar. In the probe was advanced to within the lesion, as other words, for lesions ≤ 30 mm, size did not affect the determined from the EBUS image, had a signifi cantly diagnostic yield using EBUS - GS, and the yield was not higher diagnostic yield (105/121, 87%) than when decreased for lesions ≤ 10 mm. It was impossible to the probe was adjacent to the lesion on the EBUS confi rm fl uoroscopically that biopsy forceps had image (8/19, 42%). The diagnostic yield using TBB reached the lesion in 54 out of 81 lesions ≤ 20 mm in for lesions in which the probe was located within size. The diagnostic yield in these lesions was 74% the lesion (85/104, 82%) was signifi cantly higher (40/54), similar to the yield when it was possible to than when the probe was adjacent to the lesion determine fl uoroscopically that the forceps had (1/15, 7%). reached the lesion (18/27, 67%). The diagnostic yield using EBUS- GS for lesions The diagnostic yield was affected by the location of defi ned as a mass ( > 30 mm; 24/26, 92%) was signifi - the lesion. Positive yield rates were as follows: right cantly higher than that for lesions defi ned as nodules upper lobe apical segment (8/13, 64%), right upper ( ≤ 30 mm; 92/124, 74%). The diagnostic yields using lobe posterior segment (8/12, 67%), left upper apical EBUS - GS for lesions ≤ 10 mm (16/21, 76%), > 10 and posterior segment (6/15, 40%), upper lobe anterior ≤ 15 mm (19/25, 76%), > 15 and ≤ 20 mm (24/35, segment (34/42, 81%), lingula (5/7, 71%), right 90 CHAPTER 9 Diagnosis of Peripheral Pulmonary Lesions middle lobe (14/14, 100%), lower lobe superior bronchi. The yield from the lower lobe basal segments segment (12/19, 63%), and lower lobe basal segment was satisfactory (22/27, 81%). EBUS - GS is therefore (22/27, 81%). The yield from the left upper apical superior to fl uoroscopy for localising lesions in the posterior segment (6/15, 40%) was signifi cantly lower lower lobe basal segments. than that from other locations. One advantage of EBUS - GS lies in the repeatability Moderate bleeding was seen in two (1%) out of 150 of access to the bronchial lesion for sampling. Without patients. Patients required bronchial intubation. There a guide sheath, it can be diffi cult at times to be certain were no deaths, pneumothoraces, or other clinically that forceps are being inserted into the same bronchial signifi cant morbidities. branch for a second biopsy. Further, the bronchial EBUS - GS increases the reliability of specimen col- mucosa becomes edematous after several attempts at lection via bronchoscopy. Reported bronchoscopic manipulation, making it diffi cult to introduce the diagnostic yields for PPLs ≤ 2 cm in size vary from 5 to forceps into the bronchus. 28% [3 – 14] . |
Radlke et al. [ 6] reported a positive yield Another advantage of EBUS- GS lies in its ability to of 6/21 (28%), Stringfi eld et al. [ 7] reported a positive protect against bleeding into the bronchus proximal to yield in 4/15 (27%), Fletcher et al. reported a positive the biopsy site. Although massive hemorrhage into the yield in 4/32 (12.5%), and Wallance et al. [ 8] reported bronchus following TBB is infrequent ( < 2%) [14,15] , a positive yield in 3/65 (5%). The diagnostic yield in excessive bleeding may require wedging the tip of the this study was far superior to the earlier studies, and bronchoscope to obtain hemostasis. If bleeding occurs similar to the overall yield, even when the lesion was during EBUS - GS, blood drains through the sheath, undetectable fl uoroscopically. When a fl uoroscopically because the outer surface of the sheath is snug against undetectable lesion is in contact with the probe intro- the internal surface of the bronchus. duced into the bronchus, the lesion can be visualized The fi nal advantage of EBUS- GS is the ability to using EBUS. EBUS - GS is particularly useful for lesions obtain short - axis bronchial views of PPLs. Several ≤ 20 mm that are undetectable using fl uoroscopy. investigators have reported successful use of miniature EBUS - GS is most successful when the probe can be probes [1,2] . placed within the lesion. The yield of TBB when the Yoshikawa [16] evaluated the feasibility and effi - probe was adjacent to the lesion was very low (1/15, cacy of TBB and bronchial brushing using EBUS- GS 7%). This suggests that lesions visualized as adjacent as a guide for diagnosing PPLs without radiographic to the probe may only be in contact with the outer fl uoroscopy. Seventy - six of 123 PPLs (61.8%) were surface of the affected bronchus, and therefore sam- diagnosed by EBUS - GS guidance without fl uoroscopy. pling is unlikely to be diagnostic. In this circumstance, The diagnostic yield for PPLs > 20 mm in diameter the operator should attempt to delineate the lesion via (75.6%) was signifi cantly higher than that for those another bronchus. ≤ 20 mm in diameter. PPLs located in the middle lobe Chechani [ 13] reported fl uoroscopic localization is and the lingular segment had signifi cantly higher diag- most diffi cult when the lesion is small ( < 2 cm) and nostic yields. Multivariate analysis revealed that the located in the lower lobe basal segment or the upper diameter and location of the PPL were independent lobe apical segment. The diagnostic yield for lesions in predictors of diagnostic sensitivity by EBUS- GS - guided these two segments (58%) was lower than yields from bronchoscopy. all other locations (83%). Fletcher et al. [ 5] reported Further studies are needed to determine the diag- that the worst diagnostic yields were from the lower nostic yield of transbronchial needle aspiration under lobe basal (2/7, 28%) and superior segments (5/19, EBUS - GS guidance, and the usefulness of using a 26%). In our EBUS - GS study [ 2] , the worst diagnostic curette via the guide sheath. yields were noted for left upper lobe apical posterior segment lesions (6/15, 40%) (p = 0.003, χ 2 ) when compared with yield from all other locations (103/135, Changes in E BUS - GS Techniques 76%). The reason for the lower diagnostic yield in the left upper lobe apical posterior segment is thought to When we began EBUS- GS in 1996, we used large bore be due to diffi culty introducing a probe into the B1+ 2 guide sheaths with an outer diameter of 2.5 mm, but 91 Endobronchial Ultrasonography for almost all PPLs we now insert a narrow bore guide bronchial brachytherapy. Asano et al. [19 – 21] devel- sheaths with an outer diameter of 2.0 mm down the oped a bronchoscope insertion guidance system that working channel of a bronchoscope with an outer produces virtual images by extracting the bronchi by diameter of 4.0 mm. Large bore guide sheaths are used automatic threshold adjustment, and searching for the only in cases where relatively large specimens are bronchial route to the determined target. They used required. The use of bronchoscopes with an outer this system in combination with a thin bronchoscope diameter of 4.0 mm allows us to select fourth and fi fth and EBUS - GS. This system automatically produced order bronchi (two or three branchings more periph- virtual images to fi fth order bronchi on average. EBUS eral than the standard bronchoscopes around 6 mm in visualized 93.8% of cases successfully, providing a outer diameter). tissue diagnosis in 84.4%. Using this bronchoscope insertion guidance system, virtual images can be How to Identify the Drainage Bronchus readily produced, successfully guiding the broncho- Leading to the Target Lesion (Representative scope to the target. This method shows promise as a Case: Video Clips 9.2 – 9.8) routine part of PPL biopsy techniques (representative case: Video clips 9.6, 9.7 and 9.8). Identifi cation of the Bronchial Branch Using CT Imaging Tips for E BUS - GS On the CT scan we identify the bronchus entering the lesion, and follow the bronchial branches towards the Use of Signal Attenuation Caused by the hilum. Guide Sheath (See Chapter 3 , Figure 3 .7 and From this bronchial route, we identify the bronchial Video Clips 9.9 and 9.10) branch, its bronchial segment and subsegment, the This is a method of accurately placing the guide sheath branching directions (laterally, mediastinally, etc.), within a PPL. Once a peripheral lesion has been delin- and what are the adjacent subsegments. eated using EBUS, at the point the lesion appears at We determine the name of the branch from the CT its largest and clearest, without disturbing the guide scan, mentally transform this into the bronchoscopic sheath the assistant should withdraw the ultrasonic fi ndings in our head, and delineate the bronchial probe 1 mm at a time until the probe transducer enters branch that we should approach. the guide sheath. When the transducer completely For example, if the candidate bronchus is the right enters the guide sheath, the ultrasonic pulse will be B6c bronchus, and the B6c lesion is next to region of refl ected by the guide sheath, and the ultrasound segment B6b on the CT, at bronchoscopy we should image will suddenly become darker. If the site of this introduce the ultrasonic probe, into the bronchus phenomenon is within the lesion, the guide sheath branches of the right B6c bronchus which are closest will be placed precisely within the peripheral pulmo- to the B6b bronchi. nary lesion. Identifi cation of the Bronchial Branch Moving the Probe from Adjacent to the Using Navigation Systems Lesion to within the Lesion on the In recent years, two methods of navigation for PPLs Ultrasonic Image (See Chapter 3 , Figure 3 .8 have been developed. The electromagnetic navigation and Video Clip 9.11) system is a localization device that assists in placing When we use the bronchoscopic image to select the endobronchial equipment in the desired areas of the subsegmental bronchus into which to introduce the lung. This system uses low- frequency electromagnetic probe to delineate a lesion using EBUS, the probe is waves, which are emitted from an electromagnetic sometimes placed adjacent to the lesion. In that case, board placed under the bronchoscopy table mattress the probe should be introduced into another subseg- [17] . Harms et al. [18] introduced in a technical mental bronchus in an attempt to place the probe note a new approach to the treatment of inoperable within the lesion. When the probe has been introduced peripheral lung tumors combining an electromagnetic into the lesion, the guide sheath can be left in the navigation system and EBUS with 3 - D - planned endo- lesion, giving a 90% diagnostic yield. 92 CHAPTER 9 Diagnosis of Peripheral Pulmonary Lesions When a Lesion Can Be Identifi ed device will advance them down the drainage bron- Fluoroscopically, but Cannot Be Delineated chus. As the guiding device is advanced in this direc- Using EBUS (See Chapter 3 , Figure 3 .9 and tion the guide sheath will follow, allowing accurate Video Clip 9.12) placement of the guide sheath within the peripheral When a lesion cannot be delineated using EBUS, the pulmonary lesion. The guiding device is then removed, ultrasonic probe should be removed without moving the ultrasonic probe is reintroduced, and the lesion the guide sheath, and guide forceps introduced can be delineated. into the guide sheath until their tips protrude. The tip of the guiding device is bent in the direction of the When the Bronchus Leading to the Target lesion, and the forceps are then withdrawn slowly, Lesion Is Stenosed at the Entry to the looking for a point at which they move slightly towards Lesion (Figure 9.2 ) the lesion. A bronchus leading to the lesion branches If the ultrasonic probe is introduced as far as the entry off from this point, and the tip of the guiding device to the lesion, sometimes only part of the lesion can be have entered this branch, and advancing the guiding delineated using EBUS, and the probe cannot be Figure 9.2 When the bronchus leading to the target lesion is bronchus at the tumor entrance. The probe should be stenosed at the entry to the lesion. If the ultrasonic probe is withdrawn, and a curette introduced, allowing dilatation of introduced as far as the entry to the lesion, sometimes only part the stenosed bronchus. The probe can now be introduced as of the lesion can be delineated using EBUS, and the probe far as the interior of the lesion, allowing biopsy and other cannot be pushed any further. This is due to stenosis of the procedures. 93 Endobronchial Ultrasonography Figure 9.3 Management of post- biopsy hemorrhage. When hemorrhaging occurs following brushing or biopsy via the guide sheath, the blood usually passes back into the guide sheath rather than into the airway. This is because the outer surface of the guide sheath is snug against the bronchial lumen. If we wait around 2 min before withdrawing the guide sheath, in almost all cases it can be withdrawn without any further hemorrhage. We have experiencing a case of a large intrapulmonary hemorrhage, but thanks to the guide sheath no further treatment was necessary and only a small amount of blood escaped into the airway. pushed any further. This is due to stenosis of the multiple biopsies from the same site, protects against bronchus at the tumor entrance. The probe should be bleeding into the proximal bronchus from the biopsy withdrawn, and a curette introduced, allowing dilata- site, and can delineate the inner structure of PPLs. tion of the stenosed bronchus. The probe can now be introduced as far as the interior of the lesion, allowing biopsy and other procedures. References Management of Post - Biopsy Hemorrhage 1 Kurimoto N , M urayama M , Y oshioka S , et al. Analysis of the internal structure of peripheral pulmonary lesions (Figure 9.3 ) using endobronchial ultrasonography. C hest 2002 ; 122 : When hemorrhaging occurs following brushing or 1877 – 1894 . biopsy via the guide sheath, the blood usually passes 2 Kurimoto N , Miyazawa T , Okimasa S , et al. Endobronchial back into the guide sheath rather than into the airway. ultrasonography using a guide sheath increases the This is because the outer surface of the guide ability to diagnose peripheral pulmonary lesions endo- sheath is snug against the bronchial lumen. If we wait scopically . Chest 2004 : 126 ; 959 – 965 . around 2 min before withdrawing the guide sheath, in 3 Mori K , Y anase N , K aneko M , et al. Diagnosis of periph- almost all cases it can be withdrawn without any eral lung cancer in cases of tumors 2 cm or less in size. further hemorrhage. We have experiencing a case of Chest 1989 ; 95 : 304 – 308 . a large intrapulmonary hemorrhage, but thanks to 4 Popvich J J r , K vale P A , E ichenhorn M S , et al. D iagnostic accuracy of multiple biopsies from fl exible fi beroptic the guide sheath no |
further treatment was necessary bronchoscopy – a comparison of central versus periph- and only a small amount of blood escaped into the eral carcinoma. A m Rev Respir Dis 1982 ; 125 : 521 – 523 . airway. 5 Fletcher EC , Levin DC . F lexible fi beroptic bronchoscopy and fl uoroscopically guided transbronchial biopsy in management of solitary pulmonary nodules. W est J Conclusion Med 1982 ; 135 : 477 – 483 . 6 Stringfi eld J T , M rkowitz D J , B entz R R , et al. The effect EBUS - GS permits more accurate collection of samples of tumor size and location on diagnosis by fi beroptic from PPLs than other methods. This method facilitates bronchoscopy . Chest 1977 ; 72 : 474 – 476 . 94 CHAPTER 9 Diagnosis of Peripheral Pulmonary Lesions 7 Radke J R , C onway W A , E yler W R , et al. Diagnostic 15 Ahmad M , L ivingston D R , G olish J A , et al. T he safety accuracy in peripheral lung lesions: Factors predicting of outpatient transbronchial biopsy. Chest 1986 ; 90 : 403 . success with fl exible fi beroptic bronchoscopy . C hest 16 Yoshikawa M , S ukoh N , Y amazaki K , et al. D iagnostic 1976 ; 76 : 176 – 179 . Value of Endobronchial Ultrasonography with a Guide 8 Wallace JM , D eutch AL . F lexible fi beroptic bronchos- Sheath for Peripheral Pulmonary Lesions Without X - Ray copy and percutaneous lung aspiration for evaluating the Fluoroscopy . Chest 2007 ; 131 : 1788 – 1793 . solitary pulmonary nodule. C hest 1 982 ; 81 : 665 – 671 . 17 Schwarz Y , M ehta AC , E rnst A , et al. Electromagnetic 9 Hadson RR , Zavala DC , Rhodes ML , et al. T ransbronchial navigation during fl exible bronchoscopy . R espiration biopsy via fl exible fi beroptic bronchoscope; results in 2003 ; 70 : 516 – 522 . 164 patients. A m Rev Respir Dis 1976 ; 114 : 67 – 72 . 18 Harms W , K rempien R , G rehn C , et al. Electromagnetically 10 Kvale P A , B ode F R , K ini S . Diagnostic accuracy in lung navigated brachytherapy as a new treatment option for cancer; comparison of techniques used in association peripheral pulmonary tumors. S trahlenther Onkol with fl exible fi beroptic bronchoscopy . Chest 1976 ; 69 : 2006 ; 182 ; 108 – 111 . 752 – 757 . 19 Asano F , M atsuno Y , M atsushita T , et al. T ransbronchial 11 Shiner RJ , Rosenman J , Katz I , et al. B ronchoscopic diagnosis of a pulmonary peripheral small lesion using evaluation of peripheral lung tumors. Thorax 1 988 ; an ultrathin bronchoscope with virtual bronchoscopic 43 : 887 – 889 . navigation . J Bronchol 2002 ; 9 : 108 – 111 . 12 Torrington KC , Kern JD . The utility of fi beroptic bron- 20 Asano F , M atsuno Y , S hinagawa N , et al. A virtual choscopy in the evaluation of the solitary pulmonary bronchoscopic navigation system for pulmonary periph- nodule . Chest 1993 ; 104 : 1021 – 1024 . eral lesions . Chest 2006 ; 130 : 559 – 566 . 13 Chechani V . Bronchoscopic diagnosis of solitary pulmo- 21 Asano F , Matsuno Y , Tsuzuku A , et al. D iagnosis of nary nodules and lung masses in the absence of endo- pulmonary peripheral lesions using a bronchoscope bronchial abnormality. C hest 1996 ; 109 : 620 – 625 . insertion guidance system combined with endobron- 1 4 Blasco LH , Hernandez IMS , Garrido VV , et al. S afety of chial ultrasonography with a guide sheath. L ung Cancer transbronchial biopsy in outpatients. C hest 1991 ; 99 : 562 . 2008 ; 60 : 366 – 373 . 95 10 Endobronchial Ultrasonographic Analysis of Airway Wall Integrity and Tumor Involvement tion. First, there was a need to analyse the laminar Introduction structure of the tracheal and bronchial wall. There are several reports by H ü rter et al. [ 2] , Baba et al. [ 3] , The clinical application of intralumenal ultrasonogra- Becker [4] , and Kurimoto et al. [ 1] on the bronchial phy using a miniature ultrasonic probe began with laminar structure as delineated by high - frequency intravascular ultrasonography. A number of reports ultrasonography. H ü rter [2] stated that the bronchial have been published concerning the use of endoscopic laminar structure is trilaminar, comprising an inner ultrasonography of the gastrointestinal tract for echodense layer and an intermediate echolucent zone delineation of the structure of the esophageal, stomach of nearly the same diameter. Baba [3] reported that and bowel walls, and determination of the depth of the intrapulmonary bronchi have six layers: 1st + 2nd tumor invasion. CT scanning has been the mainstay layers (epithelium, lamina propria, and submucosa), of tracheobronchial diagnostic imaging for invasive 3rd + 4th layers (cartilage), and 5th + 6th layers disease of the airways. CT scanning can recognize the (adventitia). The extrapulmonary bronchi were also tracheobronchial wall as the structure between the seen as having six layers, with cartilaginous and mem- lumen and the peritracheobronchial tissue, but branous portions similar to the intrapulmonary detailed evaluation of the tracheobronchial wall, only bronchi: 1st + 2nd layers (epithelium, lamina propria, 1 or 2 mm thick, requires an imaging modality with and submucosa), 3rd + 4th layers (longitudinal muscle higher resolution such as high frequency ultrasonic layer) and 5th + 6th layers (adventitia or loose con- tomography. Since 1994, we have performed endo- nective tissue. Becker [ 4] stated that the tracheobron- bronchial ultrasonography (EBUS) with a thin ultra- chial wall comprises seven layers, and the supporting sonic probe inserted through the working channel of wall, composed of cartilage and connective tissue a fl exible bronchoscope. When we commenced EBUS, which could not be distinguished, provides a triple we found that the presence of cartilage gives the tra- layer ultrasonographic image of low internal intensity cheobronchial wall a laminar structure [1] . and a strong echo at the internal and external surface of the cartilage and the adjacent structures on both Laminar Structure of the Tracheobronchial sides – the mucosa and submucosa on the inside and Wall the adventitia on the outside – each showing a ultra- With EBUS, we can visualize the laminar structure sonographic double layer with a strong echo at the of the tracheobronchial wall. The depth of tumor inva- surface and an echopoor underlying structure. sion into the tracheobronchial wall is a most impor- Based on the premise that knowledge of the differ- tant determinant of the choice of therapy, specifi cally ent anatomic layers of the bronchial walls and their bronchoscopic laser tumor ablation vs. surgical resec- ultrasonographic correlations is the basis for interpret- ing ultrasound images, we performed a needle- puncture experiment [1] (Figure 10.1 ). We fastened a Endobronchial Ultrasonography, 1st edition. resected specimen of bronchial wall to a rubber board By Noriaki Kurimoto, David I. K. Fielding and Ali I. Musani. with two 23 G needles. We inserted a 29 G needle into Published 2011 by Blackwell Publishing Ltd. the cut end and immersed the assembly in water. We 96 CHAPTER 10 Endobronchial Ultrasonographic Analysis of Airway Wall Integrity and Tumor Involvement Water A hole created 23G by the needle 23G needle Bronchial wall Scanning plane Probe Outermost 23C hypo.layer 29G needle 29G Rubber Rubber Slab slab Figure 10.1 Diagram of the needle - puncture experiment. A resected specimen bronchial wall was fastened to a rubber slab with two 23 G needles. A 29 G needle was inserted into the various layers from the cut end, and advanced so that it passed between the two 23 G needles. We scanned the specimen to obtain an image that included the two 23 G needles with the 29 G needle showing as a dot- like hyperechoic spot. For histopathological evaluation in the ultrasonic scanning plane, a cut was made to include the path of both 23 G needles. The hyperechoic spot of the 29 G needle on the ultrasonogram and the needle hole in the histopathological fi nding were compared to determine which layers in the tissue specimen corresponded to the ultrasonographic layers. Figure 10.2 Representative example of the needle- puncture experiment. In this specimen in which the dot - like hyperechoic scanned the plane, including both 23 G needles, com- spot produced by the needle (black arrow) was observed in the paring the hyperechoic spot of the 29 G needle with center of the outermost hypoechoic layer (white arrow) of a the hole in the pathological sample. segmental bronchus, the histopathological fi ndings were of a In Figure 1 0.2, we can see a representative speci- hole in the cartilage (black arrow), indicating that the outermost men. The dot- like hyperechoic spot from the 29 G hypoechoic layer was the cartilage. needle can be seen in the center of the outermost hypoechoic layer on the ultrasonogram of this seg- mental bronchus, where the histopathological fi nding was of a hole in the bronchial cartilage. This confi rms the marginal echo on the outer aspect of the bronchial that the outermost hypoechoic layer of the segmental cartilage. In the membranous portion, the 1st layer bronchus is the cartilage layer. (hyperechoic) is a marginal echo, the 2nd layer (hyp- Conducting this experiment on 45 specimens oechoic) represents submucosal tissue, and the 3rd yielded the following results. layer (hyperechoic) is the adventitia (Figure 10.3 ). Using a 20 MHz probe, the cartilaginous portion of A point to be borne in mind when identifying the both extrapulmonary and intrapulmonary bronchi are laminar structure of the wall ultrasonically is that mar- visualized as fi ve layers. The 1st layer (hyperechoic) is ginal echoes [5] (hyperechoic bands produced by a marginal echo, the 2nd layer (hypoechoic) repre- many reverberations) occur wherever there is an sents submucosal tissue, the 3rd layer (hyperechoic) interface between tissue types. Aibe [5] reported that is the marginal echo on the inner aspect of the bron- marginal echoes include transitional tissue, and that chial cartilage, the 4th layer (hypoechoic) represents they are high linear echoes that extend distally in the bronchial cartilage, and the 5th layer (hyperechoic) is direction of propagation of the ultrasound waves. 97 Endobronchial Ultrasonography 543 21 1 2 3 1 2 3 4 5 Figure 10.3 Bronchial wall layers delineated by endobronchial layer (hyperechoic) is a marginal echo, the second layer ultrasonography. Extrapulmonary bronchus (left): The (hypoechoic) represents smooth muscle, and the third layer cartilaginous portion of the trachea and the extrapulmonary (hyperechoic) is the adventitia. Intrapulmonary bronchus (right): bronchi is visualized as fi ve layers, and the membranous portion The intrapulmonary bronchi are visualized as fi ve layers. The 1st as three layers. The 1st layer (hyperechoic) is a marginal echo, layer (hyperechoic) is a marginal echo, the 2nd layer the 2nd layer (hypoechoic) represents smooth muscle, the 3rd (hypoechoic) represents submucosal tissue, the third layer layer (hyperechoic) is the marginal echo on the inner side of the (hyperechoic) is the marginal echo on the inner side of the bronchial cartilage, the 4th layer (hypoechoic) represents bronchial cartilage, the fourth layer (hypoechoic) represents bronchial cartilage, and the 5th layer (hyperechoic) is the bronchial cartilage, and the fi fth layer (hyperechoic) is the marginal echo on the outer side of the cartilage. In the marginal echo on the outer side of the cartilage. membranous portion of the extrapulmonary bronchi, the fi rst Marginal echoes, visualized as hyperechoic, are of the depth of invasion was the same for 23 cases observed between the lumen and the mucosal epithe- (95.8%), and different in one case (4.2%). In the case lium, between the submucosa and cartilage, and of disagreement between the EBUS and histopatho- between cartilage and the adventitia (Figure 10.4 ). logical fi ndings, lymphocytic infi ltration protruded We also compared EBUS images of resected lung between cartilages was mistakenly interpreted as cancer specimens with the histopathological fi ndings tumor invasion. to assess the |
accuracy of EBUS in determining the Recently, we have encountered some cases with depth of tumor invasion [ 1] . We compared ultrasono- seven layers in the cartilage portion of the trachea and graphic measurements of the depth of tumor invasion the right and left main bronchi. An adenoid - cystic in specimens resected from 24 patients with lung carcinoma of the trachea was seen to have seven cancer with the histopathological fi ndings. Two repre- layers using a 20 MHz probe. Compared histopatho- sentative examples of squamous cell carcinoma arising logical fi ndings and the EBUS images, the 5th and 7th in the right intermediate trunk are shown in Figure hyperechoic layers were the marginal echoes at the 10.5 . The left hand picture shows a tumor in contact outer surface of the bronchial cartilage and collagen with the inner surface of the bronchial cartilage, at the fi bers outside the loose connective tissue, respectively. boundary between the membranous and cartilaginous The 6th hypoechoic layer corresponded to thick loose portions. The right hand picture of a tumor adjacent connective tissue outside the cartilage (Figure 10.6 ). to the inner surface of the smooth muscle of the mem- If the loose connective tissue outside the cartilage is branous portion shows a tumor in contact with the relatively thin, the 5th hyperechoic layer becomes second layer on the EBUS image. Comparison of the attached to the 7th hyperechoic layer, so they are EBUS images with the histopathological fi ndings in 24 visualized as one layer. We believe that in general patients with lung cancer showed that measurements the cartilaginous portion is visualized as fi ve layers, 98 CHAPTER 10 Endobronchial Ultrasonographic Analysis of Airway Wall Integrity and Tumor Involvement 5th 3rd 1st 4th 2nd Marginal Marginal Marginal echo echo echo Figure 10.4 Comparison of ultrasonographic and submucosa. The marginal echo of the 3rd layer appears to histopathological layers of the bronchial wall. Marginal echoes extend from the inner margin of the bronchial cartilage to the include the transitional tissue, and are highly linear echoes that middle of the cartilage, and the marginal echo of the 5th extend distally in the direction of propagation of the ultrasound hyperechoic layer extends from the outer margin of the waves. The marginal echo (1st layer) extends from the inner bronchial cartilage to the adventitia. margin of the mucosal epithelium to the inner part of the Figure 10.5 Comparison of ultrasonographic and confi rming the ultrasonic determination of the depth of tumor histopathological fi ndings. Left: representative example of invasion. Right: representative example of invasion as far as submucosal invasion. This lesion is in contact with the inner side smooth muscle of membranous portion. This lesion is in contact of the hyperechoic third layer (inner marginal echo of cartilage: with the inner side of the hypoechoic second layer, which white arrow), and tumor in contact with the inner surface corresponds to smooth muscle (black arrow), and this was (white arrow) of the cartilage was observed histopathologically, confi rmed on histopathological examination. 99 Endobronchial Ultrasonography Figure 10.6 Seven tracheal layers demonstrated using EBUS. Left: This adenoid -c ystic carcinoma of the trachea had seven layers visualized using EBUS. Right: Comparison of the histopathological fi ndings and EBUS image showed that the 6th hypoechoic layer corresponds to thick loose connective tissue outside the cartilage, and the 7th hyperechoic layer corresponds to collagen fi bers outside the loose connective tissue. Lobar and segmental sub-segmental sub-sub-segmental bronchus bronchus bronchus Figure 10.7 Bronchial cartilage of lobar, segmental, subsegmental, and sub - subsegmental bronchi. Bronchial cartilage is visualized in fi ve layers of the segmental bronchi in these resected specimens. It is rather diffi cult to point out the bronchial cartilage beyond intact segmental 2mm bronchus. and the cartilaginous portion of the trachea and right frequency ultrasonography include marginal echoes and left main bronchi sometimes shows seven layers. (boundary echoes). Marginal echoes are the artefacts To which bronchial generation can the bronchial that high frequency ultrasound waves produce at tissue cartilage be visualized? The bronchial cartilage is boundaries, such as the cartilage surface. A shallow visualized as fi ve layers in a resected specimen of a carcinoma in situ will therefore be hidden behind the segmental bronchus. It is rather diffi cult to detect the 1st hyperechoic layer (marginal echo). Using the bronchial cartilage beyond an intact segmental bron- laminar structures of the bronchial wall, the depth of chus (Figure 1 0.7 ). However, it is easy to detect the tumor invasion of the tracheobronchial wall is classi- bronchial cartilage if a tumor invades beyond the fi ed into fi ve categories: epithelium (superfi cial subepi- bronchial cartilage, that is to say bronchial cartilage is thelium), subepithelium, cartilage, adventitia, and present within the tumor (Figure 10.8 ). beyond the adventitia (Figure 1 0.9 , Video clip 10.1). Once again we should make clear that the laminar In the next step, in order to determine the ability of structures of the bronchial wall as visualized by high EBUS to delineate the depth of tumor invasion, we 100 CHAPTER 10 Endobronchial Ultrasonographic Analysis of Airway Wall Integrity and Tumor Involvement Figure 10.8 Squamous cell carcinoma (left B3 bronchus). Left: fi ndings also show this lesion to have invaded beyond the A polypoid lesion obstructing the left B3 bronchus is shown at bronchial cartilage to protrude at 12 o’ clock (arrow), confi rming bronchoscopy. Right upper: Ultrasonography shows this lesion to the ultrasonographic determination of the depth of tumor have invaded beyond the bronchial cartilage to protrude at 12 invasion. Hematoxylin and eosin: original magnifi cation × 10. o ’ clock beyond the adventitia. Right lower: The histopathological Determination of depth of tumor invasion by EBUS Epithelium Beyond Submucosa Cartilage Adventitia submucosa adventitia Figure 10.9 Depth determination using EBUS. Using the laminar structures of the bronchial wall, the depth of tumor invasion of tracheobronchial wall is classifi ed into fi ve categories: epithelium (superfi cial subepithelium), subepithelium, cartilage, adventitia, and beyond the adventitia. 101 Endobronchial Ultrasonography Figure 10.10 Typical carcinoid in the right upper bronchus. Left upper: Chest CT scanning shows a tumor located in the right upper bronchus. Left lower: Ultrasonography shows that the tumor has invaded beyond the bronchial cartilage (arrow), compressing the fi fth layer (adventitia). Right upper: The bronchoscopic fi ndings show this tumor obstructing the right upper bronchus. Right lower: Histopathologically, tumor has invaded beyond the bronchial cartilage (arrow) to compress and invade the adventitia. The histopathological fi ndings confi rm the ultrasonographic determination of the depth of tumor invasion. Hematoxylin and eosin: original magnifi cation × 10. compared preoperative EBUS fi ndings in tracheobron- shown to have invaded beyond the bronchial carti- chial tumors with the histopathological fi ndings in lage, compressing the fi fth layer (corresponding to the surgically resected lungs subjected to complete sec- adventitia, Figure 10.10 ). Histopathologically, the tioning. Histopathological examination of 42 speci- tumor compressed and invaded the adventitia. Again, mens showed the depth of tumor invasion as the histopathological fi ndings confi rmed the ultra- carcinoma in situ (epithelium) in fi ve cases, submu- sonographic determination of the depth of tumor cosal (subepithelium) in 7, bronchial cartilage in 1, invasion. adventitial in 5, and extramural (beyond the adventi- On the other hand, one misdiagnosed case was a tia) in 24. The depth of tumor invasion according to squamous cell carcinoma that histopathologically preoperative ultrasonography agreed with the his- compressed and invaded the adventitia, while ultra- topathologic fi ndings in 35 out of 42 cases (83%). The sonography showed a hypoechoic area extending accuracy of EBUS according to histological depth was beyond the adventitia (Figure 1 0.11 ). Another misdi- 0% (0/5) for carcinoma in situ, 86% (6/7) for submu- agnosed case was a squamous cell carcinoma that his- cosal, 100% (1/1) for cartilage, 80% (4/5) for adven- topathologically invaded the submucosa while titia, and 100% (24/24) for extramural lesions. ultrasonography showed a hypoechoic area extending The fi ndings in two representative cases where from the mucosa to the adventitia. While this lesion EBUS determination of the depth of tumor invasion was diagnosed by EBUS as invading the adventitia, the agreed with the histopathologic fi ndings are given hypoechoic region extending between the cartilage below. rings to the adventitia was histopathologically shown A squamous cell carcinoma was located at B3 on the to represent lymphocytic infi ltration that caused over- left. Ultrasonography showed this lesion to invade estimation of the depth of invasion by EBUS (Figure beyond the bronchial cartilage, protruding at 12 10.12 ). The other fi ve misdiagnosed cases were squa- o ’ clock; thus the ultrasonically determined depth of mous cell carcinomas that histopathologically invaded tumor invasion was extramural (Figure 1 0.8 ). The his- only the mucosa (carcinoma in situ), in three of which topathological fi ndings confi rmed this determination. ultrasonography showed fi ve layers with normal In the second case, a typical carcinoid tumor involv- appearance (Figure 10.13 ). The remaining two ing the right upper bronchus was ultrasonographically cases were carcinomas in situ where ultrasonography 102 CHAPTER 10 Endobronchial Ultrasonographic Analysis of Airway Wall Integrity and Tumor Involvement Figure 10.11 Squamous cell carcinoma in the right upper invaded beyond the adventitia. Right lower: Histopathologically, bronchus. Left upper: Chest CT scanning shows a tumor located the tumor does not extend beyond the adventitia. The depth of in the right upper bronchus. Left lower: The bronchoscopic tumor invasion has therefore been overestimated. Hematoxylin fi ndings locate this tumor in the right upper bronchus and B3. and eosin: original magnifi cation × 10. Right upper: Ultrasonographically, the tumor appears to have Figure 10.12 Squamous cell carcinoma in the right B2 bronchus. Left: The bronchoscopic fi ndings locate this tumor in the right upper bronchus and B2. Right upper: Ultrasonography shows a hypoechoic area extending from the epithelium to the adventitia, indicating tumor invasion of the adventitia. Right lower: Histopathologically, this tumor invades the submucosa. The hypoechoic region extending from between the cartilages to the adventitia corresponds to lymphocytic infi ltration. The depth of tumor invasion has been overestimated. Hematoxylin and eosin: original magnifi cation × 10. 103 Endobronchial Ultrasonography Figure 10.13 Squamous cell carcinoma (left B6 bronchus). Left: The bronchoscopic fi ndings are of a dull appearance of the surface at the left B6 bifurcation. Right upper: Ultrasonography demonstrates fi ve normal - appearing layers. Right lower: Histopathologically, this tumor was observed to involve the mucosa (carcinoma in situ). The marginal echo (1st layer) extends from the luminal margin of the mucosa to the superfi cial portion of the submucosa. Carcinoma in situ thus occupies the intact- appearing fi rst layer (hyperechoic, marginal echo) as seen with a 20 MHz probe. showed a hypoechoic area extending from the epithe- ultrasonography (EUS) for oesophageal cancer was lium to the adventitia. This was diagnosed by EBUS as not able to distinguish either fi brotic change resulting tumor invasion of the adventitia, while histopatho- from esophagitis or lymphoid hyperplasia adjoining a logically most of the hypoechoic region corresponded tumor from tumor invasion. Arima et al. [6] similarly to lymphocytic infi ltration and prominent bronchial noted that changes in the tissues around a tumor such glands, leading to overestimation of the depth of as hyperplasia of lymphoid follicles, cellular infi ltra- tumor invasion (Figure 1 0.14 ). tion, and fi brosis of tumor invasion, were often mis- Unlike other diagnostic imaging methods, EBUS interpreted as tumor. Kikuchi et al. [ 8] attributed using a 20 MHz probe allows visualization of the depth misdiagnosis of the depth of invasion of colorectal of tumor invasion of the tracheobronchial wall. When cancers using EUS to attenuation of ultrasound waves the tumor has invaded beyond the bronchial cartilage, related to tumor thickness, as well as diffi culty in dif- this modality clearly shows the bronchial cartilage ferentiating between cancer invasion and lymphocytic within the tumor. infi ltration, lymphoid follicles, or submucosal fi brosis. The most important point in determination of the Menzel and Domschke [ 9] also reported that ultra- depth of tracheobronchial tumor invasion using EBUS sonographic overstaging of oesophageal cancers might is examination of the third and fourth layers, corre- involve misinterpretation of submucosal infl amma- sponding to the bronchial cartilage. An important tion. In four lesions (three carcinomas in situ, one limitation of |
preoperative EBUS in determination of submucosally invading carcinoma) we also overesti- the depth of tumor invasion is diffi culty distinguishing mated the depth of tumor invasion because of lym- lymphocytic infi ltration from tumor invasion (Figure phocytic infi ltration and bronchial glands in the 10.15 ). As ultrasonography visualizes tissues accord- submucosa, and between bronchial cartilage and ing to the speed of propagation of ultrasound waves, adventitia. In recent years, we have begun to use a it would appear that the speed of ultrasound waves 30 MHz probe to obtain higher resolution images of from the 20 MHz probe passing through invasive the superfi cial layers, and a convex probe to provide cancer is similar to that through lymphocytic infi l- longitudinal images of the tracheobronchial wall. trates and hypertrophied bronchial glands. Arima et Comparison of the ultrasonographic and histopatho- al. [6] and Kawano et al. [7] reported that endoscopic logic fi ndings in this study indicated that the depth of 104 CHAPTER 10 Endobronchial Ultrasonographic Analysis of Airway Wall Integrity and Tumor Involvement Figure 10.14 Squamous cell carcinoma (right B2 bronchus). Left upper: Bronchoscopic fi ndings show the right B2 to be near normal. Left lower: Ultrasonographically, the bronchial wall is thickened. A hypoechoic area extending from the epithelium to the adventitia suggests tumor invasion of the adventitia. Right: Histopathologically, this tumor is confi ned to the mucosa (carcinoma in situ). Most of the hypoechoic region corresponds to lymphocytic infi ltration and hypertrophied bronchial glands, causing overestimation of the depth of tumor invasion. Hematoxylin and eosin: original magnifi cation × 10. Figure 10.15 Lymphocytic infi ltration of the bronchus. A squamous cell carcinoma located in right B8. EBUS showed a submucosal hypoechoic area connected to the area resembling rabbit ears (arrow). This tumor was assessed as invading the adventitia. Histopathologically the tumor extends to the submucosa. Limitations of preoperative EBUS in determination of the depth of tumor invasion include diffi culty in distinguishing lymphocytic infi ltration from tumor invasion. 105 Endobronchial Ultrasonography tumor invasion of the bronchial wall can be accurately assigned by EBUS to one of fi ve levels: EP (epithelium, or minimal invasion of subepithelium), SE (subepithe- Extra- cartilagenous lium), C (cartilage), A (adventitia), and Ai (invasion beyond the adventitia). When the bronchus at the site of the lesion still shows fi ve layers, the depth of inva- 5th sion would be EP. When the lesion extends from the 4th 1st layer (hyperechoic marginal echo) to the 2nd layer 3rd Cartilage (hypoechoic, submucosa), while the third layer (hyperechoic marginal echo from the inner aspect of the cartilage) can be clearly delineated, the depth of Intra- invasion is SE. When the lesion extends from the 1st cartilagenous layer to the 4th layer, but the 5th layer (hyperechoic marginal echo at the outer aspect of the cartilage) can Figure 10.16 Intracartilaginous or extracartilaginous. be clearly delineated, the depth of invasion is C. When Tracheobronchial tumors are diagnosed as intracartilaginous or the lesion extends from the 1st layer to the 5th layer, extracartilaginous using EBUS. but the 5th layer is intact, the depth of invasion is A. Finally, when wedge- shaped interruptions are seen in layers 3, 4, and 5, the depth of invasion is Ai. An ultrasonographic depth of invasion of EP or SE allows EBUS for Infl ammatory Diseases of selection of local endobronchial therapy. the Tracheobronchial Tree We performed EBUS for the evaluation infl ammatory Photodynamic Therapy with EBUS diseases of the tracheobronchial wall, including tuber- In bronchoscopic treatment of localized lesions, avoid- culosis, relapsing polychondritis, chronic infl amma- ing tissue destruction beyond the cartilage layer is tion following tracheotomy, Wegener ’ s granulomatosis, important for success and safety [ 10 – 12]. Miyazu [ 12] and ulcerative colitis. The greatest benefi t of EBUS for reported that determination of the depth of tumor infl ammatory diseases of the tracheobronchial wall is invasion using EBUS, rather than simply measuring the ability to visualize and assess the bronchial lesion size and height, improves the chances of success cartilage. of photodynamic therapy (PDT). Eighteen patients In Figure 10.17 , we can see that in this patient with with biopsy- proven squamous cell carcinomas, consid- relapsing polychondritis, EBUS revealed thickening of ered to be appropriate candidates for PDT by conven- the tracheobronchial cartilage, containing calcifi ca- tional bronchoscopy under high- resolution computed tions, and an intact membranous portion (Figure tomography (HR - CT) control, were enrolled. Nine 10.17 ). EBUS, with its superior tissue analysis ability, lesions were diagnosed as intracartilaginous using allows us to discern the laminar structure of the mem- EBUS (Figure 10.16) , and subsequently underwent branous portion as well. In chronic infl ammatory con- PDT. Long- term complete remission has been achieved ditions such as post - tracheotomy infl ammation, in these patients, with a median follow - up term follow- Wegener ’ s granulomatosis and ulcerative colitis, the ing PDT of 32 months. infl ammatory process involves the entire circumfer- The remaining nine lesions were diagnosed as ext- ence of the trachea, and thickening of both the carti- racartilaginous using EBUS, and were considered can- laginous and membranous portions of the tracheal didates for other therapies such as surgical resection, and main bronchial walls can be seen on the EBUS chemotherapy, and radiotherapy, although two were images. This allows us to distinguish these conditions not detectable using HR - CT, three were superfi cial, from relapsing polychondritis, in which the membra- and fi ve were ≤ 1 cm in diameter at bronchoscopy. The nous portion is spared (Figure 1 0.18 ). depth of tumor invasion estimated by EBUS was con- Another advantage of EBUS in cases of bronchoma- fi rmed by histopathological fi ndings in six specimens lacia due to infl ammatory diseases of the tracheo- after surgical resection. bronchial wall is that the diameter of the infl ated 106 CHAPTER 10 Endobronchial Ultrasonographic Analysis of Airway Wall Integrity and Tumor Involvement Figure 10.17 Relapsing polychondritis. In this case of relapsing polychondritis, EBUS revealed thickening of the tracheobronchial cartilage, containing calcifi cations, and an intact membranous portion. Cartilage Figure 10.18 Chronic infl ammation. In chronic infl ammatory conditions such as post - tracheotomy infl ammation, Wegener ’ s granulomatosis and ulcerative colitis, thickening of both the cartilaginous and membranous portions can be seen on the EBUS images, allowing us to distinguish these conditions from relapsing polychondritis. bronchus can be measured using the infl ated balloon the bronchial cartilage has been destroyed, a stent probe. should be inserted to maintain the patency of the Iwamoto et al. [ 13] reported the usefulness of EBUS affected bronchus. in the management of airway stenosis due to tracheo- bronchial tuberculosis. Prior to interventions for Measurement of Airway Diameters airway stenosis caused by tracheobronchial tuberculo- When performing interventions for airway stenosis, sis, EBUS was performed to evaluate whether the such as stent placement, it is important to accurately bronchial cartilages were destroyed or intact. When measure the internal diameters of the normal bronchus 107 Endobronchial Ultrasonography proximal and distal to the lesion, and of the lesion itself. when there is a discontinuity of this interface echo. This will aid in the selection of the optimum diameter This is particularly useful in determining whether stent, and the best size balloon for balloon dilatation. there is tracheal invasion by a thyroid cancer, or direct Similarly, when laser ablation is to be performed, Using invasion of the left main bronchus by oesophageal EBUS we measure the distance between the luminal cancer. Herth et al. [ 15] investigated whether EBUS surface of the lesion to the inner surface of the bron- can reliably differentiate between airway infi ltration chial cartilage, so the laser depth of penetration can and compression by tumor. The ability of chest CT and be set. EBUS to distinguish between compression and infi l- I conducted an experiment to evaluate the accuracy tration was measured against the histological results. of measurements using EBUS. I measured the inner They found that EBUS is a highly accurate diagnostic diameter of a syringe using EBUS, comparing these tool, and superior to chest CT in evaluating the ques- fi ndings with the actual diameter. The syringe tion of airway involvement by central intrathoracic diameter as measured using EBUS was 0.1 mm greater tumors. than the actual diameter. When performing EBUS for central lesions in the clinical setting, a balloon sheath 30 MHz Versus 20 MHz is necessary to exclude air over the target lesion. Shaw Radial probes operating at 20 MHz have been used et al. [ 14] evaluated whether infl ation of a fl uid- fi lled since EBUS fi rst began, and now 30 MHz radial probes balloon sheath over the transducer infl uenced i n vitro are available. As the ultrasound frequency increases, measurements. In vivo comparison of EBUS with high the resolution is higher but the depth of penetration resolution computed tomography scanning (HRCT), decreases (Figure 10.19 ). Radial probes operating at statistical analysis of measurements of airway internal 30 MHz show more differentiated 2nd and 4th layers diameter and wall thickness with and without the than 20 MHz radial probes. At 30 MHz, the submucosal balloon sheath showed agreement between EBUS and tissue is more echo intense, and the cartilage more HRCT. We believe that the accuracy of measurements hypoechoic. Nakamura et al. [16] compared 20 MHz using EBUS is acceptable. and 30 MHz probes using a plot profi le derived from CT scanning is also used to measure the internal the image analysis software NIH Image. A normal diameters of the normal bronchus proximal and distal bronchial wall image consists of fi ve layers, and the to the lesion, and of the lesion itself. Measurements plot profi le shows a W - shape curve. The differences in using EBUS are necessary in the following cases: (1) mean echo intensity between the 3rd and 4th layers, when tracheobronchomalacia is present; (2) when a and the 2nd and 4th layers, were found to be signifi - build -u p of secretions or sputum is present distal to the cantly greater with the 30 MHz probe than with the stenosis; and (3) when CT scanning cannot be per- 20 MHz probe. The 30 MHz probe was found to be formed, e.g. the patient is unable to hold their breath. more useful than the 20 MHz probe in delineating the In cases of tracheobronchomalacia, as typifi ed by laminar structures of the bronchial wall. relapsing polychondritis, the tracheobronchial lumen In the future, higher probe frequencies, electrical is narrowed during both the inspiratory and expiratory scanning, and linear probes will allow higher resolu- phases. Accurate measurement of the inner diameter tion EBUS images of the tracheobronchial wall. We with the lumen expanded is necessary, a requirement believe that both cross- sectional and longitudinal met by EBUS with the balloon fi lled with fl uid. images are necessary for accurate diagnosis of the depth of tracheobronchial wall invasion. Diagnosis of Invasion of the Bronchial Tree from Outside The tracheobronchial laminar structure delineated by Conclusions EBUS using high frequency ultrasonic waves is made up of interface echoes generated at the interfaces 1 EBUS using a high - frequency ultrasonic probe between the submucosa and cartilage, and cartilage allows visualization of the depth of invasion of tra- and serosa. Diagnosis of direct invasion of the tracheo- cheobronchial tumors, not possible with other diag- bronchial wall from outside can therefore be made nostic imaging methods. 108 CHAPTER 10 Endobronchial Ultrasonographic Analysis of Airway Wall Integrity and Tumor Involvement 20MHz 30MHz Figure 10.19 30 MHz vs. 20 MHz. The differences in the mean echo intensity between the 3rd and 4th layers, and the 2nd and 4th layers were found to be signifi cantly greater with the 30 MHz probe than with the 20 MHz probe. 2 Preoperative EBUS using a 20 MHz probe clearly 4 Becker H . E ndobronchialer Ultraschall – eine Neue visualizes bronchial cartilage within the tumor when Perspektive in der Bronchologie. Ultraschall In Med the adventitia has been invaded. 1996 ; 17 : 106 – 112 [in German]. 3 Some problems persist with EBUS using a 20 MHz 5 Aibe T . A study on the structure of layers of the gas- probe for the determination of the depth of tumor trointestinal wall |
visualized by means of the ultrasonic endoscope. The structure of layers of the esophageal invasion, particularly its inability to visualize carci- wall and the colonic wall. G astroenterol Endosc noma in situ and diffi culty in distinguishing tumor 1984 ; 26 : 1465 – 1473 . invasion from lymphocytic infi ltration and hypertro- 6 Arima M , T ada M . Endosonographic assessment of phied bronchial glands. the depth of tumor invasion by superfi cial esophageal cancer, using a high- frequency miniature US probe: diffi culties in interpretation and misleading factors. Stomach and Intestine (Tokyo) 2004 ; 39 : 901 – 913 . References 7 Kawano T , N agai Y , I noue H , et al. E ndoscopic ultrasonography for patients with esophageal cancer . 1 Kurimoto N , Murayama M , Yoshioka S , Nishisaka T , Stomach and Intestine (Tokyo) 2001 ; 36 : 307 – 314 . Inai K , D ohi K . Assessment of the usefulness of endo- 8 Kikuchi Y , Tsuda S , Yurioka M , et al. D iagnosis of bronchial ultrasonography in tracheobronchial depth the depth infi ltration in colorectal cancer- diagnosis and diagnosis . Chest 1999 ; 115 : 1500 – 1506 . issues of the depth of infi ltration investigated by endo- 2 H ü rter T , H anarath P . E ndobronchiale Sonographie scopic ultrasonography (EUS) . Stomach and Intestine zur Diagnostik Pulmonaler und Mediastinaler Tumoren . 2001 ; 36 : 392 – 402 . Dtsch Med Wschr 1990 ; 105(50) : 1899 – 1905 [in German]. 9 Menzel J , D omschke W . Gastrointestinal miniprobe 3 Baba M , Sekine Y , S uzuki M , et al. Correlation between sonography: the current status. A m J Gastroenterol endobronchial ultrasonography (EBUS) images and his- 2000 ; 95 : 605 – 616 . tological fi ndings in normal and tumor invaded bron- 10 Konaka C , Okunaka T , Kato H . C ombined use of photody- chial wall. L ung Cancer 2002 ; 35 : 65 – 71 . namic therapy . Ann Thorac Cardiovasc Surg 1 995 ; 1 : 55– 59 . 109 Endobronchial Ultrasonography 11 Okunaka T , K ato H , K onaka C , et al. P hotodynamic 14 Shaw T J , W akely S L , P eebles C R , et al. E ndobronchial therapy for multiple primary bronchogenic carcinoma . ultrasound to assess airway wall thickening: validation Cancer 1991 ; 68 : 253 – 258 . in vitro and i n vivo . E ur Respir J 2004 ; 23 : 813 – 817 . 12 Miyazu Y , M iyazawa T , K urimoto N , et al. E ndobronchial 15 Herth F J , E rnst A , S chulz M , et al. Endobronchial ultra- ultrasonography in the assessment of centrally located sound reliably differentiates between airway infi ltration early - stage lung cancer before photodynamic therapy . and compression by tumor. C hest 2003 ; 123 : 458 – 462 . Am J Respir Crit Care Med 2002 ; 165 : 832 – 837 . 16 Nakamura Y , Endo C , Sato M , et al. A new technique 13 Iwamoto Y , M iyazawa T , K urimoto N , et al. Interventional for endobronchial ultrasonography and comparison of bronchoscopy in the management of airway stenosis two ultrasonic probes. Analysis with a plot profi le of the due to tracheobronchial tuberculosis. C hest 2004 ; 126 : image analysis software NIH Image. Chest 2004 ; 1344 – 1352 . 126 : 192 – 197 . 110 11 EBUS in Interventional Bronchoscopy assessment for the degree of external compression Introduction versus true invasion are described, particularly with reference to surgical decision making in lesions adja- Some of the earliest applications of EBUS were in cent to the trachea. These techniques have not been interventional bronchoscopy techniques [1] . These evaluated in multicenter studies; however, in the techniques continue to be used in selected centers, description of these techniques, a better understand- particularly where there is a high throughput of large ing of the benefi ts of ultrasound can be obtained. airway obstructive lesions. The largest series and greatest variety of applications of EBUS has been described by Becker and Herth in Heidelberg [ 2] .To a Technique large extent, this refl ects the huge experience of these authors with rigid bronchoscopy and management of In contrast to the miniprobe used for peripheral lesions obstructing large airway lesions. It also refl ects their a saline fi lled balloon is required to obtain EBUS pioneering role of the use of EBUS in these different images in the large airways (Olympus XMAJ - 643R). clinical situations. The techniques predominantly use The probe (XUM - BS20 - 26R) is passed through the the 360 ° radial probe. In this situation EBUS attempts biopsy channel (2.8 mm or greater) of a bronchoscope to carefully scrutinize the layers of the bronchial wall and placed next to the wall at the site for evaluation. and determine whether these layers are invaded either The balloon is slowly infl ated until by bronchoscopic from the inside by endobronchial tumors or from the evaluation, it is seen to fi ll the bronchus. The EBUS outside. Conventional bronchoscopic inspection of the image of the bronchial wall is most detailed where bronchial mucosa can only give a superfi cial impres- there is approximately 1 cm distance from the probe sion of the underlying pathology. EBUS enhances the (inside the balloon) to the wall; however structures at bronchoscopists ’ evaluation particularly with refer- a depth of 4 cm from the bronchus can be visualized ence to tumor staging of both early and advanced [3] . To view the wall over a length it is usual to place tumors. EBUS provides unique information and a the balloon distally fi rst and infl ate at that point number of different studies have been shown greater then gently pull back along the wall of the bronchus sensitivity than any other diagnostic modality particu- as imaging occurs. Becker et al. report that, in terms larly in comparison with CT or MRI [ 2] . of the technique of applying the balloon ultrasound The early studies as discussed in previous chapters probe, the balloon is fi lled until there is close relating to depth diagnosis of small endobronchial contact with the bronchial wall. Clearly, this can mean lesions are a case in point. In this chapter, large airway obstruction of one or other of the main bronchi; however, in terms of ventilating the patient, this is rarely a problem. Sometimes there is complete occlusion even of the trachea; however even this Endobronchial Ultrasonography, 1st edition. can be well - tolerated for short periods under By Noriaki Kurimoto, David I. K. Fielding and Ali I. Musani. suffi cient sedation and with careful preoxygenation. Published 2011 by Blackwell Publishing Ltd. Although it is very uncommon to require it, it is safe 111 Endobronchial Ultrasonography for the patient to undergo 3 or 4 minutes of apnea carcinomas and adenocarcinomas of the lung. On CT for the investigation of mediastinal structures in this scans in these patients, 81 patients (77%) were way [4] . reported to have tumor invasion of the airway while The method is well - suited for studying compressed 24 patients (23%) were considered to have extrinsic airways in that distal access is easily achieved by tumor compression of the airway. In contrast, when passing the uninfl ated balloon probe through the EBUS was performed, it was considered that 49 region of bronchial stricture or tumor, then gently patients (47%) had large airway tumor invasion and infl ating until the balloon image on the monitor shows 56 patients (53%) had tumor compression. On the some “ molding” by the bronchial wall. surgical resected specimens, 55 patients (52%) had The mucosa on the inner surface immediately adja- tumor invasion and tumor compression was seen in cent to the balloon shows a very bright echo. Next to 50 patients (48%). Therefore, all patients that did this, the submucosa is comparatively hypoechoic. have tumor invasion as proved by surgical resection There is a strong echo of the endochondrium and had been diagnosed by EBUS. EBUS had six false- perichondrium (hyperechoic) and this can sometimes negative examinations for tumor invasion within the reduce the visualization of the outside layers (support- trachea. Comparing EBUS and chest CT for infi ltration ing connective tissue and adventitia). Vessels can be by a central tumor of the tracheobronchial tree, accu- seen by both their pulsations and by their low internal racies were 94% and 51%, sensitivity 89% and 75%, echoes and constant reference to anatomical diagrams and specifi city 100% and 28% respectively. The cor- assist the proceduralist in becoming familiar with this relation between EBUS classifi cation and the surgical 360 ° image. Lymph nodes tend to be more hypere- classifi cation of airway involvement was very high at choic than blood vessels. Adjacent to the left main 0.89 (p < 0.01). Importantly, this was a simple safe bronchus, the important structures are the pulmonary technique and only took 3.5 minutes on average to trunk and left and right main pulmonary arteries as perform. EBUS therefore had been demonstrated as well as the ascending aorta and aortic arch. Posteriorly, an effective unique means of anatomically staging a it is easy to see the multilayered structure of the patient. Where there were six false- negative results esophagus. In orienting the radial probe, artifacts from from the EBUS alone, that is, infi ltration was present bronchial openings can also be helpful, for example, on surgery but not detected by EBUS, it was thought the apical segment bronchus. Important structures on due to poor contact of the probe with the wall because the right main bronchus are the pulmonary trunk and of the large tracheal diameter. It was felt to represent right pulmonary artery, and adjacent the lower trachea an accurate means of staging; however the clinical the vena cava and aortic root. The azygous vein crosses relevance in terms of changes in surgical management at the level of the right tracheobronchial angle. remains to be determined by long - term studies. A similar study was reported by Wakamatsu in 2006 [6] , however, the subjects had primary tumors of the Studies of Tracheal Compression Versus esophagus and thyroid. The study aimed to compare Tracheal Wall Invasion the utility of EBUS to assess this invasion as compared to the standard diagnostic techniques of CT and MRI. In 2003, Herth et al. reported on the ability of EBUS The fi ndings of bronchoscopy with EBUS regarding to reliably differentiate between airway infi ltration direct invasion of the airway lumen were used to and compression by tumor [5] . These tumors were determine indications for surgical exploration or defi ned as a mass next to the trachea or within the resection. That is, EBUS was used to change manage- tracheobronchial angles. From 131 patients referred ment and where invasion was evident, those with for evaluation, there were obvious factors which pre- direct invasion underwent chemoradiotherapy. Fifty- cluded them from subsequent surgery. These included four patients were included and from CT, MRI and visible tumor growth into the trachea, contralateral EBUS, invasion was suspected in 29, 28 and 25 endobronchial tumor, N3 node positivity and meta- patients respectively. It is important to note that the static disease. This left 105 patients who did undergo fi nal diagnosis was an intact trachea or bronchial surgery. The majority of these were squamous cell adventitia in 26 patients and invasion in 28 patients, 112 CHAPTER 11 EBUS in Interventional Bronchoscopy but that the invasion was not always proven by sound layers roughly corresponding to the mucosa, surgery. Nonetheless, the sensitivity and specifi city of submucosa, cartilage and adventitia as described in CT, MRI and EBUS for invasion were 59 and 56%; 75 previous chapters. The software determined the differ- and 73%; and 92 and 83% respectively. With respect ences in the mean echo intensity particularly between to the surgically treated patients, the accuracy of EBUS the third and fourth layers and second and fourth was signifi cantly different from that of CT |
and MRI. A layers as a means of plotting the extent of involve- total of 37 patients underwent surgery and direct inva- ment. From 10 normal bronchi and 10 patients with sion was seen in 11 and intact trachea was seen in 26. lung cancer, the ultrasound images were analysed for EBUS correctly identifi ed direct invasion in 10 of these the intensity of ultrasound in each of the fi ve layers. 11 patients (91%), compared to 5 (45%) and 6 (55%) There were fi ve peaks and troughs demonstrable. in CT and MRI respectively. In the intact trachea, Given the greater resolution of the 30 MHz probe com- EBUS correctly identifi ed this in 22 of 26 patients pared to the 20 MHz probe, there were greater differ- (85%) compared to 15 (60%) and 17 (68%) in CT and ences between the peaks and troughs of the echo MRI respectively. The success of this study relates to intensity comparing the two probes. Importantly, the careful inspection of the adventitial layer seen by using the package to digitize the ultrasound image, a radial probe ultrasound. Importantly, the adventitia normal w - shaped curve of the ultrasound intensities was too thin to identify on MRI scan whereas the wall was demonstrated; however, when there was a tumor of the trachea was approximately 2 mm thick by MRI infi ltration, this typical w- shaped curve was absent with two layers, an inner layer corresponding to the with a fl at ultrasound intensity through all of the mucous membrane and submucosa, and an outer fi ve layers where previously there had been peaks layer of cartilage and adventitia. EBUS, on the other and troughs. There was a statistically signifi cant supe- hand, revealed good resolution and imaging of the riority of the 30 MHz probe in this type of imaging. outer most layer of the trachea and bronchial wall as Higher frequency ultrasound allows higher resolution reported by Shirakawa [ 7] . It was common for ultra- of the structures but less in terms of depth of tissue sound depth of diagnosis to go out to 1.5 to 2 cm penetration. allowing good visualization of the total bronchial wall thickness as well as lymph nodes and vessels. In this study, a fi ve- layered system for classifying the tracheal Relapsing Polychondritis with wall was used. When the outermost hyperechoic layer Tracheobronchial Malacia of the trachea was indistinguishable, a diagnosis of tracheobronchial invasion by the tumor was made. This condition is well described in Japan and provides The membranous portion of the extrapulmonary a fascinating insight into the potential applications of bronchi has three layers on EBUS. Esophageal cancer radial probe endobronchial ultrasound. Miyazawa et al. is located in the membranous portion of the trachea [9,10] have demonstrated the qualitative aspects of and the outer hyperechoic layer in this region is the ultrasound interpretation which were important in adventitia. At this point, an interruption of the third supporting a diagnosis of this problem. In a case series layer indicates invasion of the membranous portion. in 2003, a patient who had presented requiring emer- In general, where the cartilage layer was infi ltrated by gency tracheotomy fi ve years previously presented the tumor on EBUS, tumor invasion could be seen with breathlessness and at bronchoscopy there was easily; however, it was considered diffi cult for those malacia of the tracheobronchial tree with collapse of not experienced in the interpretation of the image to the trachea on expiration [ 10] . There was diffuse thick- be confi dent of the invasion of the adventitia. ening of the tracheobronchial wall with severely nar- Some authors such as Nakamura [ 8] have used rowed lumen on CT images. EBUS showed thickening 30 MHz probe to improve the resolution of images for of the bronchial wall due to submucosal edema and the this indication. In 2004, Nakamura described an image cartilage layer appeared ill- defi ned and absent in places. analysis software package to determine the depth of This was present in the trachea and in both main invasion of a tumor through the tracheobronchial bronchi. Biopsy of the tracheal cartilage showed degen- wall. The study confi rmed the presence of fi ve ultra- eration with fi brous changes and infl ammatory cell 113 Endobronchial Ultrasonography infi ltrate. In another case, the hyperechoic third and the evaluation of the airway wall proximal to sites of fi fth layers of the bronchial wall were indistinct on obvious obstruction in patients prior to stenting at the ultrasound and the hypoechoic fourth layer was mark- area of the obstruction [ 9,12] . It was possible to iden- edly swollen indicating cartilage degeneration. In that tify areas of cartilaginous malacia by the tumor on case, biopsy of the tracheal cartilage confi rmed chronic EBUS even though this was not obvious by standard chondritis with infl ammatory cell infi ltrate. Normally, bronchoscopic inspection. In these patients, there there would be more clear images of the third and fi fth tended to be a proximal migration of the large airway hyperechoic layer if the cartilage was intact. Therefore, choke point after the stenting of the original site. there were two patterns of cartilage damage identifi ed Secondary stenting at these subsequent migrated by EBUS, namely fragmentation and edema. These choke points resulted in signifi cant improvement in could be used to distinguish patients with relapsing peak fl ows over the initial stenting and supported the polychondritis from other patients who had tracheo- weakened airway wall. The use of EBUS was therefore bronchial malacia and tracheomegaly who would have able to demonstrate the cause of this choke point intact tracheobronchial cartilages by EBUS. migration. In particular, absence of supporting carti- lage on EBUS images due to external tumor damage was an important cause of this choke point migration. Endobronchial Stenting This type of identifi cation of tracheal or major bron- chial wall is not possible by CT scan. The dynamic changes in airway diameter in patients Herth et al. report that the utility of EBUS in stent with either severe tracheobronchial malacia or malig- placement [ 13] . An important attribute of EBUS is nant airway compression can make it diffi cult to detection of mucosal disease proximal to an area of determine what size stent will be required. CT and obvious tumor involvement and hence the placement MRI are limited because of the static nature of images. of longer tracheobronchial stents to include these EBUS gives a real time image and simply by infl ating involved areas and overcome this problem. In 235 the water- fi lled balloon and measuring the size of the cases of stent placement, EBUS assisted in stent place- balloon on the ultrasound monitor when the probe is ment parameters in 121 cases (51%). In addition to comfortably infl ated, accurate sizing of the stent the identifi cation of submucosal disease, extrinsic required can be obtained. In the report of Miyazu with tumor application to the tracheal wall was a reason to relapsing polychondritis, both patients were stented use a longer stent. using prior EBUS measurement which was particu- larly useful given the complete collapse of the airway and the diffi culty of judging diameter [9] . Iwamoto et Brachytherapy al. reported in 2004 the utility of the EBUS images to demonstrate tracheobronchial wall changes in evalu- EBUS can be used to confi rm staging prior to endo- ating airway stenosis from tracheobronchial tubercu- bronchial brachytherapy. In Herth et al.’ s series of 134 losis [ 11] . In a series of 30 patients, EBUS was patients with endobronchial carcinoma, EBUS revealed performed in four patients and demonstrated the 69 (51%) cases which required some form of changed destruction of the bronchial cartilage or the thickening management [ 13] . In cases where brachytherapy was of the bronchial wall. One of these patients had local to be used for curative treatment of early carcinoma, interruption of the tracheal cartilages demonstrated by 28% had local disease extension or lymph node ultrasound and this gave qualitative information sup- metastasis which escaped all other imaging methods. porting the use of an endobronchial stent. In two of Very small lesions can demonstrate quite signifi cant the four cases, the demonstration of absence or inter- invasion through the tracheobronchial wall (through ruption of tracheal cartilage supported the decision to the cartilage and adventitia) despite relatively minor performed endobronchial stenting. mucosal changes and hence require some other form Similar qualitative information with respect to of therapy, namely, surgery or external beam radio- mural involvement can be obtained for stent evalua- therapy. This was described in detail in the series of tion in patients with lung cancer. Miyazawa reported photodynamic therapy by Miyazu and Kurimoto [ 14] . 114 CHAPTER 11 EBUS in Interventional Bronchoscopy parathyroid function. Also because of a large blood Thermal Applications vessel next to the cyst, it was not possible to aspirate via an external CT- guided technique and therefore the Herth et al. reported the use of EBUS in the perform- EBUS - TBNA was performed. This was done under ance of thermal applications such as laser and argon local anesthetic with mild conscious sedation using plasma coagulation for endobronchial obstructing 2 mg midazolam. The EBUS image would be of the tumors [13] . This use of EBUS in patients having homogenous low echo mass with multiple septae mechanical tumor destruction changed management inside the cyst. 80 mL of fl uid was removed after punc- in 123 of 346 patients (36%). The signifi cant way that ture of the cyst by the needle. Repeated punctures it achieved this was to demonstrate the proximity of were used to allow the overall aspiration to be per- the area being treated to the tumor and external large formed because of septation of the lesion. There was blood vessels. Debridement with laser or APC was immediate relief of dyspnea. stopped when EBUS demonstrated close relationships We have reported the use of convex probe EBUS in with blood vessels. No patient undergoing EBUS- the identifi cation of pericardial recesses which mimic guided tumor destruction demonstrated severe bleed- paratracheal lymph nodes [16] . Characteristic EBUS ing or fi stula formation. Images could demonstrate images show hypodensity and complete loss of any tumors growing through the wall of the bronchus in vascularity adjacent to the trachea in the typical right close proximity to the pulmonary arteries on the ante- lower paratracheal node position (4R) in between the rior wall of the obstructed bronchus. On the left side, azygous vein and the lower part of the superior vena it was easy to demonstrate proximity to the descend- cava. If necessary, cyst fluid can be aspirated for diag- ing aorta. In these cases, the ultrasound images nosis, followed by antibiotics. obtained by placing the miniprobe in the main bron- Shaw et al. reported an interesting application of chus adjacent to the tumor sometimes required only EBUS, namely the accurate measurement of airway small infl ation volumes of the balloon, given the direct wall thickness with the aim of using this to demon- application of the tumor to the probe. The authors strate changes in patients receiving treatment for commented that they used this method in all cases of airways diseases such as asthma [ 17] . In their study of total airway obstruction before and during thermal an animal model of 24 cartilaginous airways, the tumor destruction. ultrasound and actual airway diameter and wall thick- ness were calculated. Subsequent to that, 12 control- led subjects underwent both EBUS imaging of the Miscellaneous Applications posterior basal bronchus of the right lower lobe and this was compared to the airway wall thickness as Nakajima reported the use of EBUS- guided transbron- demonstrated by high resolution CT scanning. In the chial needle aspiration to treat central airway stenosis animal in vitro studies in 24 airways, there was a from a mediastinal cyst [15] . Whereas such an applica- mean internal diameter of 4.3 mm and wall thickness tion had been reported for non - EBUS guided trans- of 1.4 mm without balloon infl ation and 4.2 and bronchial needle aspiration previously, the real time 1.5 mm respectively after infl ation. Signifi cant agree- imaging afforded a means of providing great control ment was |
seen between the two approaches of actual during this delicate procedure. The cyst was compress- measurement and ultrasound (intra- class coeffi cient ing the membranous portion of the trachea with 0.97 (p < 0.001) and for wall thickness 0.88 airway narrowing and arose from the upper mediasti- (p < 0.001). For the in vitro human airways studies, num. The dimensions were 65 × 57 × 49 mm. The there was a mean internal diameter of 4.9 mm and patient has previously had a left thyroid lobectomy for wall thickness of 1.3 mm using EBUS and these were a goiter and previously had had a diagnostic aspirate measured to be 5.2 mm and 1.2 mm respectively by performed confi rming serous fl uid without any malig- HRCT. Using gland and Altman plots to compare nant cells. There was progressive dyspnea due to measurements without balloon infl ation on the airway the increasing size of this cyst and surgical resection parameters, the mean difference was close to 0 and was not possible due to the risk of loss of thyroid and there was no obvious relationship between the meas- 115 Endobronchial Ultrasonography urement error and the airway parameter. There were area of the second layer of the autologous airways, the no obvious differences when the measurements were relative area of the second layer of the autologous made by different observers. The important aspect of airways was statistically signifi cantly smaller in the this study was the implication that studies done in this rejection group (p = 0.04); however there was no dif- way would not require the radiation exposure of high ference in the absolute values between the two groups. resolution CT scanning. Importantly, the balloon With respect to infection, there was a statistically sig- sheath did not cause any increase in the airway diam- nifi cant difference between the groups in the relative eter or alter the airway wall measurements. area of layer two in the autologous part of the airway Irani et al. reported the use of quantitative assess- (p = 0.02). There were some problems in interpreting ment of the bronchial mural structures in lung trans- data, given that full histologic examination of the plant recipients using EBUS [ 18] . The objective was to central airway walls in vivo is not possible and, there- determine whether EBUS analysis could allow the fore, comparison between the EBUS and true macro- detection of airway anastomosis, infection or rejec- scopic fi ndings could not be done. Overall, it was tion. There were 10 lung transplant recipients and found to be a safe procedure and the multilayered EBUS images were obtained from proximal to the structure of the allogeneic and autologous wall was anastomosis and distal to the anastomosis. Two well - imaged and was felt to represent a possible future hundred images were obtained for qualitative assess- means for surveillance of lung transplant recipients ment. The important fi nding was that the relative although further study was required. thickness of the second layer (hyperechoic submu- cosal tissue) of the transplanted airway was signifi - cantly smaller in patients with graft rejection (p = 0.04) References compared to patients without rejection. Conversely, this was signifi cantly larger in patients with graft 1 Becker H D . Endobronchial Ultrasound – Expensive Toy infection. An ultrasound miniprobe UMBS 20- 26R or Useful Tool? Proc 8th World Congress for Bronchology Olympus was used with a balloon sheath. The Olympus and 8th World Congress for Bronchoesophagology, BUM30 processor and MH240 driving unit were used. Munich 1994, abstr No 237 . After digital recording, the fi lm was screened for at 2 Becker H D , H erth F . Endobronchial ultrasound of the least fi ve representative slides from each autologous airways and the mediastinum In: Bolliger C T , M athur and allogeneic bronchial portion. The slides which PN , eds. P rogress in Respiratory Research, Vol. 30. showed the most obvious and well- defi ned lamina Interventional Bronchoscopy. S. Karger, Basel - Freiburg , 2000 : 80 – 93 . structure were selected by a blinded investigator. 3 Becker H D. T he role of endobronchial ultrasound These fi les were saved in tagged image fi le format and (EBUS) in diagnosis and treatment of centrally located the image was measured using AnalySIS software; soft early lung cancer. In Hirsh FR , Bunn PA , Kato H , imaging system; (Munster Germany). The image size Mulshine JL , eds. T extbook of Prevention and Detection was calibrated and then the largest possible sector of Early Lung Cancer . L ondon : T aylor & Francis , starting at the center of the bronchus containing car- 2005 : 168 – 175 . tilage was defi ned. Then, the absolute values of 4 Frietsch T , Becker HD , Bulzebruck H , Wiedemann K . the thickness of each layer and the relative value of Capnometry for rigid bronchoscopy and high frequency the area of each layer were measured. Because of the jet ventilation compared to arterial pCO 2 . Acta anatomic inconsistency of the diameter of the carti- Anaesthesiol Scand 2000 ; 44 : 391 – 397 . lage, the relative values of the other four layers were 5 Herth , FJ , Ernst , A , Schulz , M , et al. Endobronchial ultrasound reliably differentiates between airway infi l- also calculated after exclusion of the area of the carti- tration and compression by tumor. Chest 2003 ; 123 : lage. As expected, there was a statistically signifi cant 458 – 462 . correlation found for layer three, that is, the inner 6 Wakamatsu T , Tsushima K , Yasuo M , Yamazaki Y , hyperechoic marginal echo of the cartilage between Yoshikawa S , Koide N , et al. U sefulness of preoperative the autologous and allogeneic airways, given that endobronchial ultrasound for airway invasion around there was no change in the cartilage expected due to the trachea: oesophageal cancer and thyroid cancer . either infection or rejection. Conversely, the relative Respiration 2006 ; 73 : 651 – 657 . 116 CHAPTER 11 EBUS in Interventional Bronchoscopy 7 Shirakawa T , Tanaka F , Becker HD : L ayer structure of 13 Herth F , Becker HD , LoCicero J , Ernst A . Endobronchial the central airways viewed using endobronchial ultra- ultrasound in therapeutic bronchoscopy. Eur Respir J sonography (EBUS). In Yoshimura H , Kida A , Arai T , 2002 ; 20 : 118 – 121 . Niimi S , Kaneko M , Kitahara S , eds. B ronchology and 14 Miyazu Y , Miyazawa T , Kurimoto N , Iwamoto Y , Kanoh Bronchoesophagology . S tate of the Art. Amsterdam , K , Kohno N. Endobronchial ultrasonography in the Elsevier , 2001 : 921 – 923 . assessment of centrally located early - stage lung cancer 8 Nakamura Y , E ndo C , S ato M , S akurada A , W atanabe before photodynamic therapy. A m J Respir Crit Care S , S akata R , et al. New technique for endobronchial Med 2001 ; 165 : 832 – 837 . ultrasonography and comparison of two ultrasonic 15 Nakajima T , Y asufuku K , S hibuya K , F ujisawa T . probes: analysis with a plot profi le of the image analysis Endobronchial ultrasound guided transbronchial needle software NIH image. Chest 2004 ; 126 : 192 –1 97 . aspiration for the treatment of central airway stenosis 9 Miyazawa T , Miyazu Y , Iwamoto Y , Ishida A , Kanoh K , caused by a mediastinal cyst . Eur J Cardiothoracic Surg Sumiyoshi H , Doi M , Kurimoto N . S tenting of the 2007 ; 32 : 538 – 540 . fl ow limiting segment in tracheobronchial stenosis 16 Fielding D , Hundloe J , Windsor M , Plit M , Haverick A , due to lung cancer. Am J Crit Care Med 2 004 ; 169 : Pearson R . H igh riding pericardial recess; fi ndings on 1096 – 1102 . EBUS TBNA. J Bronchol 2008 ; 15 : 182 – 184 . 10 Miyazu Y , Miyazawa T , Kurimoto N. , Iwamoto Y , Ishida 17 Shaw TJ , W akely SL , P eebles CR , M ehta RL , T urner JM , A , K anoh K , K ohno N . Endobronchial ultrasonography Wilson SJ , Howarth PH . E ndobronchial ultrasound to in the diagnosis and treatment of relapsing polychon- assess airway wall thickening: validation in vitro and in dritis with tracheobronchial malacia . Chest 2 003 ; 124 : vivo . E ur Repir J 2004 ; 23 : 813 – 817 . 2393 – 2395 . 18 Irani S , Hess T , Hofer M , Gaspert A , Bachmann L , Russi 11 Iwamoto Y , M iyazawa T , K urimoto N , M iyazu Y , I shida E , B oehler A . E ndobronchial ultrasonography for A , Matsuo K , Watanabe Y . I nterventional bronchoscopy the quantitative assessment of bronchial mural struc- in the management of airway stenosis due to tracheo- tures in lung transplant recipients . Chest 2 006 ; 129 : bronchial tuberculosis. C hest 2004 ; 126 : 1344 – 1352 . 349 – 355 . 12 Miyazawa T , Yamakido M , Ikeda S , et al. Implantation of Ultrafl ex nitinol stents in malignant tracheobronchial stenoses . Chest 2000 ; 118 : 959 – 965 . 117 12 Future Directions for Endobronchial Ultrasonography quency of 7.5 MHz, identifi cation of cartilage is just Evaluation of the Depth of Invasion of possible, but delineation of the layer structure is dif- Tracheobronchial Tumors fi cult. Once higher frequencies of 20 or 30 MHz are achieved, the bronchial wall will be much more clearly Endotracheal therapies are indicated for tracheobron- delineated, allowing considerable progress. chial tumors that have not invaded as far as the tra- cheobronchial cartilage, in other words are confi ned to the mucosa or submucosal tissue. Endobronchial EBUS -G uided Transbronchial Needle ultrasonography (EBUS) is presently the most useful Aspiration (E BUS - TBNA ) method of determining the depth of tumor invasion. Tissue resolution improves as the frequency of the B mode images obtained using a convex probe remain ultrasonic transducer increases, providing clear and poor in quality, so we await improvements in ultra- detailed ultrasonic images. Ultrasonic probes are pres- sonographic equipment that will provide better quality ently available at two frequencies, 20 and 30 MHz, but ultrasonic images. The main advantage of using in the future we anticipate the development of even convex probes is the ability to utilize Doppler mode, higher frequency probes. Radial probes now in use are at present only power Doppler, although in the near mechanical radial probes, meaning that images are future the introduction of pulse Doppler is expected obtained by physically rotating the probe through to allow Fast Fourier Transform (FFT) analysis of 360 ° . The development of electronic scanning will bloodfl ow. provide even better images, giving a 360° profi le It is diffi cult to retrieve large tissue samples using without having to move the probe. EBUS - TBNA, but this problem may come close to Radial scanning provides a two- dimensional image, resolution with the development of larger needles. but we can now obtain three - dimensional images by There are limitations to the size of the endoscope withdrawing the probe at a constant speed while scan- working channel, however, that are diffi cult to recon- ning. Large balloons required to make this method cile with the need for larger diameter needles. more practical do not exist at present, but we antici- pate that they will become available in the future. Expectations are also high for evaluation of the Peripheral Pulmonary Lesions depth of invasion of tracheobronchial tumors using bronchial long axial cross - section images obtained At present, we use a 4 mm diameter endoscope with with convex probes. At present, due to the low fre- a 2 mm working channel, through which we pass a guide sheath and ultrasonic probe, 2 mm in outer diameter, into the bronchial tree. In the |
future, we hope to pass even narrower bronchoscopes into Endobronchial Ultrasonography, 1st edition. ever more peripheral bronchi, detecting early lesions By Noriaki Kurimoto, David I. K. Fielding and Ali I. Musani. using narrower gauge guide sheaths and ultrasonic Published 2011 by Blackwell Publishing Ltd. probes. 118 CHAPTER 12 Future Directions for Endobronchial Ultrasonography Cytology and tissue biopsies are presently taken through textbooks such as this one, and through inter- under fl uoroscopic control, but we would like to be net sites such as “ The Essential Bronchoscopist © ” able to watch the real - time EBUS image as we take (h ttp://www.essential- b ronchoscopy.org/intro_en. specimens. asp ). Keeping up with the latest developments in EBUS through sources such as these can provide the basis of self - learning activities. Hands - on training in Training in E BUS EBUS is also available in Japan and other countries. A number of bronchoscopists have participated in train- Continuous education in EBUS techniques is essential ing programs under the aegis of the Japan Society for for bronchoscopists wishing to improve their results. Respiratory Endoscopy, upgrading their skills in Ongoing education in bronchology is presently avail- EBUS - TBNA and other EBUS techniques. able for medical practitioners throughout the world 119 13 Case Reports on EBUS represented lymphocytic infi ltration, passing Introduction through the cartilage layer and showing exactly the same morphology as seen on EBUS (arrows). A case of overestimation of the depth of tumor pen- EBUS was unable to differentiate between tumor etration using EBUS – comparison of EBUS images invasion and lymphocytic infi ltration, although very and histopathological fi ndings (Figure 1 ). similar looking images are obtained with EBUS as with Upper right: In this EBUS image of the resected low magnifi cation light microscopy. specimen, an open V - shaped hypoechoic area can be The fi rst patient on whom I ever performed EBUS seen continuous with the tumor and extending in 1994 was this case of overestimation of the depth beyond the cartilage layer (arrows). of tumor penetration. I recall how I struggled for 2 Lower right: Histopathological examination (low hours to obtain the above image from the resected magnifi cation) revealed that the depth of invasion is specimen immersed in water. I consider myself lucky from the bronchial lumen only to the submucosal to have learned such a useful lesson so early, and I am layer, and not as far as the cartilage. The open V - shaped grateful to the cooperation of the pathologist who hypoechoic area extending beyond the cartilage layer sliced up the entire specimen for me. Figure 1 Endobronchial Ultrasonography, 1st edition. By Noriaki Kurimoto, David I. K. Fielding and Ali I. Musani. Published 2011 by Blackwell Publishing Ltd. 120 CHAPTER 13 Case Reports Preoperative EUS fi ndings (Figures 2 , 3) : We used Case 1 an UM - 3R ultrasonic probe. The target lesion was delineated as a hypoechoic mass extending from 3 Squamous cell carcinoma in the right basal bronchus o ’ clock to 9 o ’ clock, containing triangular and island - (cartilage islands seen within the tumor). shaped areas of cartilage (arrows: high, low, high Moderately differentiated squamous cell carcinoma in echo areas). This tumor was thereby shown to have the right basal bronchus. invaded past the bronchial cartilage layer, beyond the adventitia. Presenting Complaint: Hemoptysis Histopathological examination (low magnifi cation, History: Presented to previous doctor with hemoptysis, Figures 2 , 3 ): This is a squamous cell carcinoma with abnormal opacity seen on plain chest radiograph. CT a defi nite tendency towards keratinisation, forming scanning and bronchoscopy revealed a nodular lesion invasive nests if large and small irregular sheets as in the right basal bronchus. A class V squamous cell it proliferates. These specimens, sliced in the same carcinoma was diagnosed from the endobronchial plane as the EBUS images, show cartilage fragments brushing cytology. The patient underwent right lower (arrows) of the same shape and in the same position lobectomy + R 2 a: t1n0m0, stage IA. as in the EBUS images (arrows: high, low, high echo Macroscopic examination of the resected specimen areas). (Figure 1 ): A nodular invasive squamous cell carci- Bronchial cartilage fragments within tumors are noma can be seen in the right basal bronchus distal to delineated as high, low, high echo areas (3rd, 4th and the B 6 bifurcation. 5th layers in the needle - puncture experiment). Figure 1 Figure 2 Figure 3 121 Endobronchial Ultrasonography seen to invade the membranous portion of the inter- Case 2 mediate bronchus. Bronchoscopic fi ndings (Figure 2 ): The target Squamous cell carcinoma in the right S 6 region (car- lesion is compressing the right intermediate bron- tilage detected within the tumor). chus from behind, and breaking through the mucosa. Moderately differentiated squamous cell carcinoma in Preoperative EBUS fi ndings (Figure 3 ): We used the right S 6 region. an UM - 3R ultrasonic probe + balloon. The right 35 × 30 × 30 mm. pulmonary artery can be seen anterior to the right intermediate bronchus. The target lesion, extending from 3 o’ clock to 9 o ’ clock, has invaded from outside Presenting Complaint: Cough the bronchial wall, past the bronchial cartilage layer History: Presented to previous doctor with cough, (arrow: high, low, high echo area) as far as the abnormal opacity seen on plain chest radiograph. CT submucosa. scanning and bronchoscopy revealed a nodular lesion Histopathological examination (low magnifi cation, in the right B6 directly invading the intermediate Figure 4 ): This specimen, sliced in the same plane as bronchus. A class V squamous cell carcinoma was the EBUS image, shows a cartilage fragment (arrow) diagnosed from the endobronchial brushing cytology. of the same shape and in the same position as in the The patient underwent right lower and middle lobec- EBUS image (arrow: high, low, high echo area). tomy + R2 a: t2n0m0, stage IB. Bronchial cartilage fragments within tumors are delin- CT scan chest (Figure 1 ): A nodular mass largest eated as high, low, high echo areas (3rd, 4th and 5th diameter 35 mm arising in the right B6 bronchus is layers in the needle - puncture experiment). Figure 1 Figure 3 Figure 2 Figure 4 122 CHAPTER 13 Case Reports bronchi, intimately associated with the pulmonary Case 3 artery. Bronchoscopic fi ndings (Figure 2 ): A white- coated Squamous cell carcinoma in the right B8 bronchus polypoid lesion is seen occluding the right B 8 (tumor invading beyond cartilage and adjacent to bronchus. the pulmonary arteries). EBUS fi ndings: We used an UM - 3R ultrasonic probe. Moderately differentiated squamous cell carcinoma in The probe was passed down what was thought to be the right B8 bronchus. the right B 8 b bronchus, readily passing the target lesion, which was shown to be attached in the direction of the bifurcation (Figure 3 ). Passing the probe down what Presenting Complaint: Class V on was thought to be the right B8 a bronchus, it came up Sputum Cytology against the target lesion, and the hypoechoic tumor History: During follow- up for heart disease, sputum was delineated. The target lesion was compressing the cytology in this heavy smoker was class V. Bronchoscopy adjacent pulmonary artery, and had invaded past the revealed a polypoid lesion occluding the right B 8 bronchial cartilage layer (arrow: high, low, high echo bronchus. area) and beyond the bronchial wall (Figure 4 ). CT scan chest (Figure 1 ): A nodular mass can be seen Bronchial cartilage fragments within tumors are just distal to the bifurcation of the right B8 a and B 8 b delineated as high, low, high echo areas (3rd, 4th and 5th layers in the needle - puncture experiment). Figure 1 Figure 2 Figure 3 Figure 4 123 Endobronchial Ultrasonography Bronchoscopic fi ndings (Figure 1 ): Erosions can be Case 4 seen extending from the left main bronchus to the left lower bronchus. Squamous cell carcinoma in the left main and lower CT scan chest (Figure 2 ): Thickening of the medias- bronchi (irregularly shaped cartilage seen within tinal aspect of the left main bronchus can be seen. the tumor). Preoperative EBUS fi ndings (Figure 3 ): We used an Squamous cell carcinoma in the left main and lower UM - 3R ultrasonic probe + balloon. The target lesion bronchi. was delineated as a hypoechoic mass extending from 4 o ’ clock to 9 o’ clock, extending from the bron- Presenting Complaint: Hemoptysis chial lumen through the cartilage layer (arrows: high, History: Presented to previous doctor with hemoptysis, low, high echo areas) beyond the adventitia. The car- abnormal opacity seen on plain chest radiograph. CT tilage has been deformed, becoming convex to the scanning and bronchoscopy revealed thickening of the lumen. left main bronchus. A class V squamous cell carcinoma Bronchial cartilage fragments within tumors are was diagnosed from the endobronchial brushing delineated as high, low, high echo areas (3rd, 4th and cytology. 5th layers in the needle - puncture experiment). Figure 1 Figure 2 Figure 3 124 CHAPTER 13 Case Reports narrowed from this point until the left B 3 bronchus, Case 5 with erythema and erosions of the mucosa. EBUS fi ndings (Figure 3 ): We used an UM- 3R ultra- Squamous cell carcinoma in the left B 3 bronchus sonic probe + balloon. The balloon was infl ated at the (invasion beyond the bronchial wall, beyond the origin of the left B3 bronchus to allow scanning. The 5th layer (hyperechoic) can be seen). target lesion was delineated as a hypoechoic mass Squamous cell carcinoma in the left upper B3 extending from 5 o’ clock to 10 o’ clock, containing a bronchus. hyperechoic line (arrow), representing the marginal echo at the outer margin of the cartilage (5th layer). The adventitia cannot be identifi ed outside this hyper- Presenting Complaint: E Result from echoic line, indicating extramural invasion. (If we Sputum Cytology at Routine Health Check follow the hyperechoic line around to the 11 o’ clock History: Bronchoscopy revealed erythema and thick- to 2 o’ clock arc, outside it we can see two small blood ening of the left upper B 3 bronchus. EBUS was vessels (bronchial arteries) 2 – 3 mm in diameter.) performed to assist selection of treatment modality, Histopathological examination (low magnifi cation, (photodynamic therapy) PDT or surgery. Figure 4 ): This squamous cell carcinoma has passed CT scan chest (Figure 1 ): No abnormality seen on between the bronchial cartilages, invading beyond the CT scanning, in particular at the bifurcation of the left bronchial wall. B3 and B1 + 2 bronchi. Bronchial cartilage fragments within tumors are Bronchoscopic fi ndings (Figure 2 ): Here we can see delineated as high, low, high echo areas (3rd, 4th and the origin of the left upper bronchus. The lumen is 5th layers in the needle - puncture experiment). Figure 1 Figure 2 Figure 3 Figure 4 125 Endobronchial Ultrasonography EBUS fi ndings (Figures 2 , 3 ): We used an UM - 4R Case 6 ultrasonic probe, introducing it into the right B5 bron- chus, which was completely occluded by the target Squamous cell carcinoma in the right middle bron- lesion. The tumor extended from the bronchial lumen chus (irregularly shaped cartilage seen within the through the hyperechoic cartilage layer and invaded tumor). beyond the adventitia (arrow). Moderately differentiated squamous cell carcinoma in the right middle bronchus. Points of Advice When evaluating the depth of tumor invasion, the Presenting Complaint: Abnormal Opacity following points need to be elucidated: (1) At what Seen on Plain Chest Radiograph angle is the tumor to be found? (2) What is the length History: Abnormal opacity seen on plain chest of the lesion? (3) Where is its deepest extent? (4) radiograph by previous doctor. CT scanning and bron- Where is the bronchial cartilage, the outermost hyp- choscopy revealed nodular lesion in the right middle oechoic layer? (5) Can the adventitia be delineated bronchus. A class V squamous cell carcinoma was diag- around the entire circumference? and (6) What has nosed from the endobronchial brushing cytology. happened to the peribronchial vasculature? CT scan chest (Figure 1 ): A mass can be seen in the right middle bronchus at the bifurcation of the right B4 and B 5 bronchi. Figure 1 Figure 2 Figure |
3 126 CHAPTER 13 Case Reports Bronchoscopic fi ndings (Figure 1 ): A polypoid lesion Case 7 obstructs the left B3 bronchus. Preoperative EBUS fi ndings (Figure 2 ): We used an Squamous cell carcinoma in the left B 3 bronchus UM - 3R ultrasonic probe + balloon. Cartilage can be (observation of the 5th layer shows invasion beyond clearly seen within the polypoid lesion (black arrow). the bronchial wall in one area). This hypoechoic mass extends from the bronchial Squamous cell carcinoma in the left B3 bronchus. lumen to beyond the cartilage. The 5th layer can be discerned almost around the entire circumference, Presenting Complaint: Class III Sputum although the hypoechoic mass does protrude beyond Cytology During Follow - Up for Pulmonary the bronchial wall in one area (red arrow), indicating Emphysema extramural invasion. History: During follow - up for pulmonary emphysema, Histopathological examination (low magnifi cation, sputum cytology yielded a class III result. Bronchoscopy Figures 3 , 4) : In this slice that corresponds to the plane revealed an intraepithelial cancer involving the bifur- of the EBUS image, we see a cartilage fragment (black cation of the left upper and lingual bronchi and the arrow) of the same shape and in the same position as origin of the left upper bronchus. PDT was performed in the EBUS images (arrows: high, low, high echo for this tumor. Follow - up bronchoscopy 4 weeks later areas), with hypoechoic cancer cells beyond it. In one revealed a polypoid lesion at the origin of the left B3 area tumor invades beyond the adventitia into the bronchus. Biopsy showed this to be a moderately dif- lung parenchyma (red arrow), corresponding to the ferentiated squamous cell carcinoma, for which the hypoechoic area on the EBUS image. patient underwent surgery. We compared the preop- When the hypoechoic area continues beyond the erative EBUS images and the histopathological fi nd- bronchial cartilage, observation of the 5th hyperechoic ings for this polypoid lesion arising from the origin of layer (including the adventitia) will help distinguish the left B 3 bronchus. between intramural disease and extramural invasion. Figure 1 Figure 2 Figure 3 Figure 4 127 Endobronchial Ultrasonography Preoperative EBUS fi ndings (Figure 4 ): We used an Case 8 UM - 3R ultrasonic probe + balloon. Cartilage can be clearly seen within the polypoid lesion (arrow), and a Squamous cell carcinoma in the right upper bronchus hypoechoic area extends from the bronchial lumen to (observation of the 5th layer the key to determina- beyond the cartilage. The hyperechoic 5th layer tion of the depth of tumor invasion = adventitia). (including the adventitia) is continuous with the outer Moderately differentiated squamous cell carcinoma in edge of the hypoechoic area inferiorly (arrow). This the right upper lobe B3 bronchus. was interpreted as the tumor compressing the adven- titia, and the depth of tumor invasion was assessed as Presenting Complaint: “ Positive ” Result from “ to the adventitia” . Sputum Cytology at Routine Health Check Histopathological examination (low magnifi cation, History: A t routine health check, sputum cytology Figure 5 ): This specimen of the origin of the right yielded an E result. CT scanning and bronchoscopy upper lobe bronchus, sliced in the same plane as the revealed a polypoid lesion in the right upper lobe B3 EBUS image, shows a cartilage fragment (arrow) of bronchus. A class V squamous cell carcinoma was the same shape and in the same position as in the diagnosed from the endobronchial brushing cytology. EBUS image (arrow: high, low, high echo area). The patient underwent right upper lobectomy + R 2 a. Tumor has invaded beyond the cartilage, correspond- Bronchoscopic fi ndings (Figures 1 , 2) : A polypoid ing to the hypoechoic area, pressing up against the mass, lacking a mucosal surface, extends from the adventitia, but not extending beyond it. right upper lobe bronchus to the right B3 bronchus. When the hypoechoic area continues beyond Squamous cell carcinoma was strongly suspected. the bronchial cartilage, observation of the 5th hyper- CT scan chest (Figure 3 ): A nodular mass is present echoic layer (including the adventitia) will help dis- in the bronchial wall, extending from the right upper tinguish between intramural disease and extramural lobe bronchus to the right B 3 bronchus. invasion. Figure 2 Figure 3 Figure 1 Figure 4 Figure 5 128 CHAPTER 13 Case Reports Bronchoscopic fi ndings (Figure 2 ): A fl at polypoid Case 9 mass extends from the origin of the right B6 bronchus to the right lower lobe and intermediate bronchi. A Squamous cell carcinoma in the right intermediate superfi cial spreading squamous cell carcinoma with no bronchus (hyperechoic line corresponds to submu- mucosal cover was strongly suspected. cosal collagen fi bers, depth of tumor invasion = car- Preoperative EBUS fi ndings (Figure 3 ): We used an tilage layer). UM - 3R ultrasonic probe + balloon. Thickening of the Moderately differentiated squamous cell carcinoma in bronchial wall extends from 1 o ’ clock to 11 o’ clock, the right intermediate bronchus nearly circumferential. The tumor has invaded deep enough to contain cartilage between 2 o ’ clock and 3 Presenting Complaint: Cough o ’ clock (arrow: high, low, high echo area), but does History: Presented to previous doctor with cough, not compress the adventitia, and the depth of tumor abnormal opacity seen on plain chest radiograph and invasion was assessed as “ to the cartilage layer ” . CT scan. CT scanning and bronchoscopy revealed a Histopathological examination (low magnifi cation, nodular lesion in the right B6 bronchus, continuous Figure 4 ): This lesion is a squamous cell carcinoma with thickening of the membranous portion of the forming villous projections into the lumen. This speci- right intermediate bronchus. A class V squamous cell men, sliced in the same plane as the EBUS image, carcinoma was diagnosed from the endobronchial show a cartilage fragment (arrow) of the same shape brushing cytology. The patient underwent right lower and in the same position as in the EBUS image (arrow: and middle lobectomy + R 2 a: t2n0m0, stage IB. We high, low, high echo area). Tumor infi ltrates between compared the preoperative EBUS images and the his- cartilages, giving a depth of tumor invasion to the topathological fi ndings for this tumor. cartilage layer. CT scan chest (Figure 1 ): We can see thickening of Hyperechoic lines can be seen in the thickened the membranous portion of the right intermediate bronchial wall (arrow at 5 o ’ clock), corresponding to bronchus, but cannot discern the bronchial wall hyperplastic collagen fi bers (arrow) within the squa- structure. mous cell carcinoma forming villous projections. Figure 1 Figure 2 Figure 3 Figure 4 129 Endobronchial Ultrasonography and B 3 bronchi (arrow). Biopsy showed poorly dif- Case 10 ferentiated squamous cell carcinoma. CT scan chest (Figure 2 ): No abnormality can be Squamous cell carcinoma in the left upper segmental seen at the bifurcation of the left B 1 + 2 and B3 bronchi. bronchus (cartilage compressed by tumor, depth of EBUS fi ndings (Figures 3 , 4 ): We used an UM - 3R tumor invasion = submucosa). ultrasonic probe + balloon. The tumor is delineated as Poorly differentiated squamous cell carcinoma at the a polypoid lesion at 6 o ’ clock. The leading edge of the bifurcation of the left B 1 + 2 and B 3 bronchi. tumor compresses the cartilage (high, low, high echo area), making it convex to the outside. The depth of Presenting Complaint: Polypoid Lesion tumor invasion was assessed as “ to the submucosa ” . Detected at Bronchoscopy Complete remission was achieved with PDT. History: Polypoid lesion at the bronchial spur between In this case of a lesion near a bronchial spur, we had the left B 1 + 2 and B 3 bronchi detected at bronchoscopy diffi culty obtaining a usable images due to the ten- by previous doctor for assessment of interstitial pneu- dency of the balloon to slip past. We blew up the monitis. Biopsy confi rmed squamous cell carcinoma. balloon so that it completely occluded the bifurcation, Bronchoscopic fi ndings (Figure 1 ): A polypoid lesion and achieved a good image by moving the probe back can be seen at the bronchial spur between the left B1 + 2 and forth. Figure 1 Figure 2 Figure 3 Figure 4 130 CHAPTER 13 Case Reports Bronchoscopic fi ndings (Figures 1 , 2) : An erythema- Case 11 tous polypoid lesion can be seen at the origin of the left B6 bronchus (arrow, at 1 o’ clock near the spur with the Squamous cell carcinoma at the origin of the left B 6 basal bronchus). bronchus (cartilage loss detected using EBUS, depth CT scan chest (Figure 3 ): No abnormality can be of tumor invasion = adventitia). seen at the origin of the left B 6 bronchus. Squamous cell carcinoma at the origin of the left B6 EBUS fi ndings (Figure 4 ): We used an UM- 3R ultra- bronchus. sonic probe + balloon. The tumor is delineated as a hypoechoic lesion between 10 o ’ clock and 2 o ’ clock. Presenting Complaint: E Result from Cartilage (red arrow, high, low, high echo area) can Sputum Cytology At Routine Health Check be clearly seen at the periphery of the polypoid lesion. History: This patient underwent left partial upper The submucosal layer of the lesion is thickened (the lobectomy 3 years previously for squamous cell carci- tumor itself). The cartilage tapers and disappears at 12 noma. At follow - up the previous year, an area of ery- o ’ clock, with only the adventitia preserved (yellow thema on the upper wall of the origin of the left B 6 arrow). The depth of tumor invasion was assessed as bronchus was diagnosed as early squamous cell carci- “ to the adventitia” . noma. Although complete remission was achieved with When cartilage visible at the periphery of a PDT, a biopsy of the same site (arrow) approximately 1 lesion trappers and disappears within the lesion, the year later yielded squamous cell carcinoma. EBUS was tumor is assessed as invading beyond the cartilage performed to evaluate the depth of tumor invasion. layer. Figure 2 Figure 1 Figure 3 Figure 4 131 Endobronchial Ultrasonography It appeared to be submucosal in origin, and biopsy Case 12 yielded a diagnosis of adenoid cystic carcinoma. Preoperative EBUS fi ndings (Figures 2 , 4) : We used Adenoid cystic carcinoma of the trachea (important an UM- 3R ultrasonic probe. The target lesion is deline- fi nding of tumor invasion between cartilage rings, ated as a hypoechoic lesion between 7 o ’ clock and 11 depth of tumor invasion = adventitia). o ’ clock. At the cartilaginous portion (Figure 2 ), the Adenoid cystic carcinoma of the trachea. hypoechoic layer corresponding to the tracheal ring (arrow, 4th layer) is preserved, and the lesion can be Presenting Complaint: Cough seen in contact with the marginal echo on the inner History: Presented with cough, polypoid lesion of the side of the tracheal cartilage (3rd layer). Tumor can be trachea on CT scan chest. seen protruding between tracheal rings, adjacent to Reversed CT scan chest (Figure 1 ): For comparison the hyperechoic layer corresponding to the adventitia with the EBUS images, we reversed the image so it (arrow). From the above, the target lesion has invaded appears that we are looking down from above. past the line between neighboring tracheal rings, up Endoscopic examinations and treatments are, of course, to but not beyond the adventitia, so the depth of conducted looking down from above. A polypoid lesion tumor invasion was assessed as “ to the adventitia” . can be seen arising form the left tracheal wall. In the extrapulmonary tracheobronchial tree with Bronchoscopic fi ndings (Figure 3 ): A polypoid lesion cartilage rings, the depth of tumor invasion must be can be seen on the left tracheal wall, protruding assessed in both the cartilaginous portion and in the through the mucosa with a white stripe on its apex. membranous portion between cartilage rings. Figure 1 Figure 2 Figure 3 Figure 4 132 CHAPTER 13 Case Reports not be determined whether the right middle lobe Case 13 bronchial wall was thickened. Bronchoscopic fi ndings (Figures 3, 4 ): Erythema of Squamous cell |
carcinoma of the right lower lobe the bronchial mucosa and narrowing of the lumen (thickening of the right intermediate bronchial sub- extended from the right intermediate bronchus as far mucosa (2nd layer) due to tumor invasion). as could be seen down the lower lobe bronchus. A Squamous cell carcinoma at the origin of the right polypoid lesion was seen at the origin of the right lower lobe bronchus. lower lobe bronchus. EBUS fi ndings: Although the right main bronchial Presenting Complaint: Exertional Dyspnea wall was normal, thickening of the right intermediate History: Presented to previous doctor with exertional bronchus is seen from the bifurcation with right upper dyspnea, abnormal opacity seen on plain chest lobe bronchus distally, strongly suggestive of tumor radiograph. invasion (Figure 5 ). Having passed the probe as far as CT scan chest (Figures 1, 2 ): A cavity - containing the B 8 bronchus, we see destruction of cartilage within tumor was seen at the origin of the right lower lobe the tumor (arrow), representing extramural invasion bronchus. Stenosis of the right intermediate bronchus from the right lower lobe tumor (Figure 6 ). was seen on 1 cm slice CT scanning, although it could Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 133 Endobronchial Ultrasonography the thickened wall of the esophagus was seen to Case 14 compress the left main bronchus from behind. Bronchoscopic fi ndings (Figure 2 ): External com- Esophageal carcinoma (EBUS to determine if the pression of the dorsal aspect of the membranous tumor had invaded the membranous portion of the portion is seen from the left main bronchus to the left main bronchus). left lower lobe bronchus. No abnormality of the Squamous cell carcinoma of the esophagus. mucosa of the membranous portion is seen. Preoperative EBUS fi ndings (Figures 3 , 4) : We used Presenting Complaint: Diffi culty Swallowing an UM- 3R ultrasonic probe + balloon. The esophageal History: Presented to previous doctor with diffi culty carcinoma is delineated as a hypoechoic lesion from 4 swallowing, esophageal stricture at 25 cm from the o ’ clock to 8 o’ clock. No abnormality is seen in the incisors. Biopsy yielded the diagnosis of squamous cell laminar structure of the membranous portion of the carcinoma. EBUS was performed to determine if the left main bronchus, so we concluded that there was tumor had invaded the membranous portion of the no tumor invasion. At operation, it was confi rmed left main bronchus. that the esophageal carcinoma had not invaded the CT scan chest (Figure 1 ): In the slice showing the membranous portion. bifurcation of the left upper and lower lobe bronchi, Figure 1 Figure 2 Figure 3 Figure 4 134 CHAPTER 13 Case Reports CT scan chest (Figure 1 ): We could see enlargement Case 15 of the #10 lymph node is seen, and suspected meta- static squamous cell carcinoma. We could not deter- A metastatic peribronchial lymph node that directly mine whether the #10 lymph node invaded the right invaded the right intermediate bronchial wall. intermediate bronchus. Invasion of the right intermediate bronchial wall by #10 Bronchoscopic fi ndings (Figure 2 ): External com- metastatic lymph node (squamous cell carcinoma). pression of the dorsal aspect of the membranous portion is seen from the left main bronchus to the left Presenting Complaint: Feeling of Things lower lobe bronchus. No abnormality of the mucosa Getting Stuck in the Throat of the membranous portion is seen. History: Abnormal opacity seen in the left upper lobe Preoperative EBUS fi ndings (Figures 3 , 4) : We used on plain chest radiograph. Bronchoscopy revealed an UM- 3R ultrasonic probe + balloon. The target squamous cell carcinomas in two positions, in the left lesion is delineated as a hypoechoic lesion from 8 B3 bronchus and the origin of the right intermediate o ’ clock to 10 o ’ clock. Looking at the site of the poly- bronchus. EBUS was performed to determine if the poid lesion, we see the #10 lymph node invades past latter lesion was the result of invasion by the #10 the cartilage (arrow, high, low, high echo area) as far metastatic lymph node. as the submucosa. Figure 1 Figure 2 Figure 3 Figure 4 135 Endobronchial Ultrasonography Bronchoscopic fi ndings: A submucosal (breaking Case 16 through the mucosa) polypoid lesion was seen pro- truding in to the dorsal aspect of the membranous Small cell carcinoma (metastatic right #11i lymph node portion of the right middle lobe bronchus (Figure 2 ). directly invaded the right middle lobe bronchus). EBUS fi ndings: We positioned an UM- 3R ultrasonic probe directly against the polypoid lesion in the mem- Presenting Complaint: Abnormal Opacity branous portion of the right middle lobe bronchus. Seen on Plain Chest Radiograph at The intramural submucosal polypoid lesion was het- Routine Health Check erogenous but relatively highly echogenic, with loss History: Referred in May 1997 after an abnormal of cartilage within (Figure 3 ). The relatively highly opacity was seen on plain chest radiography at a routine echogenic submucosal polypoid lesion was continuous health check. with the extramural enlarged lymph node (Figure 4 ). CT scan chest (Figure 1 ): A subpleural 1.8 × 1.7 cm This was considered to be small cell carcinoma primary tumor is located at the right S8a region. that had metastasised to the right #11i lymph node, Enlargement of the #12l, #11i, #7 and #3 lymph nodes and then invaded the right middle lobe bronchus led to staging as cT1N2M0, stage IIIA. directly. Figure 1 Figure 2 Figure 3 Figure 4 136 CHAPTER 13 Case Reports chus to the bifurcation of the left upper and lower lobe Case 17 bronchi. Metastatic breast cancer was diagnosed from the endobronchial brushing cytology. Breast cancer (V - shaped bronchial cartilage fragment CT scan chest (Figure 2 ): An enlarged left #11 lymph caused by metastatic left #11 lymph node compress- node was seen to compress the bifurcation of the left ing the bronchial wall from outside). upper and lower lobe bronchi. Left #11 metastatic lymph node (breast cancer). EBUS fi ndings (Figure 3 ): We introduced an UM - 3R ultrasonic probe + balloon into the left B6 bronchus. Presenting Complaint: Abnormal Opacity on The target lesion is delineated as a circumferential CT Scan Chest at Follow- Up after Surgery hypoechoic lesion. The left #11 lymph node is enlarged, for Breast Cancer and directly invades bronchial wall submucosal History: Referred after abnormal opacity seen on layer. Observation of a deformed section of bronchial follow- up CT scan chest 2 years after surgery for breast cartilage allows us to determine whether it is cancer. compressed by proliferating extramural tumor or Bronchoscopic fi ndings (Figure 1 ): Erythema and compressed by proliferating tumor on the mucosal erosions were seen extending from the left main bron- side. Figure 2 Figure 1 Figure 3 137 Endobronchial Ultrasonography EBUS fi ndings: We used an UM - 3R ultrasonic probe. Case 18 The laminar structure of the bronchial wall was diffi cult to visualize in this case because the tumor was located Mucoepidermoid carcinoma arising from the origin of in the right intermediate bronchus obstructing the right the right lower lobe bronchus (diffi cult evaluation lower lobe bronchus, thereby attenuating the ultra- of the depth of tumor invasion). sound pulse before it reached the bronchial wall Mucoepidermoid carcinoma at the origin of the right (Figures 3 , 4 , 5) . This tumor in fact arose from the lower lobe bronchus. bronchial spur between B7 and B1 0 bronchi, invading the right intermediate bronchus from outside. An ane- Presenting Complaint: Abnormal Opacity choic region within the tumor was thought to represent Seen on Plain Chest Radiograph During an area of necrosis (red arrow, Figure 3 ). An extramu- Hospital Admission ral area of different echodensity to the intrabronchial History: Transferred after right lower lobe atelectasis tumor (red arrow, Figure 4 ) was though to correspond seen by previous doctor in plain chest radiograph to the atelectasis. during hospital admission. In cases such as this where a tumor obstructs a large CT scan chest (Figure 1 ): A tumor can be seen bronchus, attenuation of the ultrasound waves makes almost completely obstructing the lumen at the origin it diffi cult to visualize the laminar structure of the of the right intermediate bronchus. bronchial wall, or evaluate the depth of tumor Bronchoscopic fi ndings (Figure 2 ): A pale tumor can invasion. be seen obstructing the right intermediate bronchus. Biopsy showed mucoepidermoid carcinoma. Figure 2 Figure 1 Figure 3 Figure 4 Figure 5 138 CHAPTER 13 Case Reports The patient underwent right lower lobectomy + R 2 a: Case 19 t2n0m0, stage IB. CT scan chest: A mass can be seen in the right lower Comparison of EBUS fi ndings of right #11i lymph lobe S1 0 region (Figure 1 ). Although it measures less node with intraperative fi ndings. than 1 cm on its minor axis, the right #11i lymph node Poorly differentiated squamous cell carcinoma of the can be identifi ed (Figure 2 ). right lower lobe. Preoperative EBUS fi ndings (Figure 3 ): We used an UM - 3R ultrasonic probe + balloon, infl ating the balloon in the right lower lobe bronchus. The pulmo- Presenting Complaint: Abnormal Opacity nary artery (PA) 7 - 10 can be seen between 12 o’ clock Seen on Plain Chest Radiography at a and 3 o’ clock, and to its left the right #11i lymph node Routine Health Check (arrow), measuring 11.9 × 10.4 mm. History: Abnormal opacity seen on plain chest radiog- Intraoperative fi ndings (Figure 4 ): The lower part of raphy at a routine health check. CT scanning and this photograph is the caudal direction. Somewhat bronchoscopy revealed a poorly differentiated squa- distally placed outside the right middle lobe bronchus, mous cell carcinoma in the right lower lobe S1 0 region. we can see the #11i lymph node, next to PA 7- 10, in A class V squamous cell carcinoma was diagnosed agreement with the EBUS fi ndings. The #11i lymph from the endobronchial brushing cytology. node was negative for metastasis. Figure 1 Figure 2 Figure 3 Figure 4 139 Endobronchial Ultrasonography CT scan chest: Although it measures less than 1 cm Case 20 on its minor axis, the right #10 lymph node can be identifi ed (Figure 1 ). Right #10 lymph node and bronchial artery identifi ed Preoperative EBUS fi ndings (Figures 2 , 3) : We used using EBUS. an UM- 3R ultrasonic probe + balloon, infl ating the Poorly differentiated squamous cell carcinoma of the balloon in the right intermediate bronchus. The pul- right lower lobe. monary artery can be seen at 12 o’ clock. The right #10 lymph node can be seen at 9 o’ clock, measuring Presenting Complaint: Abnormal Opacity 8.4 × 6.4 mm, triangular in shape. Two blood vessels on CT Scan Chest Following Surgery for are delineated running anterior to this lymph node Colorectal Cancer (arrow), and a blood vessel running parallel to the History: Abnormal opacity seen on follow- up CT scan bronchus can be seen in the vicinity. chest 4 years after surgery for rectal cancer. CT scan- Intraoperative fi ndings (Figure 4 ): The lower part ning and bronchoscopy revealed a poorly differenti- of this photograph is the caudal direction. The #10 ated squamous cell carcinoma in the right lower lobe lymph node can be seen attached to the right inter- S 6 region. A class V squamous cell carcinoma was mediate bronchus. This bronchial artery (arrow) diagnosed from the endobronchial brushing cytology. seen intraperatively corresponds to the vessel seen The patient underwent right lower lobectomy + R 2 a: using EBUS. The #10 lymph node was negative for t1n0m0, stage IA. metastasis. Figure 1 Figure 2 Figure 3 Figure 4 140 CHAPTER 13 Case Reports responded to oral antimicrobial therapy, with no abnor- Case 21 mality on follow- up radiography 2 months later. CT scan chest (Figure 1 ): A nodular opacity 18 mm Subpleural organizing pneumonia (blood vessels in greatest diameter, containing an air bronchogram, delineated within the lesion). can be seen at the right S9 b region. Organizing pneumonia in the right S 9 b region. EBUS fi ndings (Figure 2 ): This lesion has a clearly delineated |
border, and patent blood vessels can be seen Presenting Complaint: Cough in several places. Hyperechoic points running alongside History: Presented to previous doctor with cough, blood vessels represent patent bronchioles (arrow). abnormal opacity seen on plain chest radiograph. CT Findings of patent blood vessels distributed scanning and bronchoscopy confi rmed an opacity in the regularly throughout the lesion are characteristic right S9 b region. Transbronchial lung biopsy (TBLB) of soft lesions such as pneumonia or organizing yielded the diagnosis of organizing pneumonia. Patient pneumonia. Figure 1 Figure 2 141 Endobronchial Ultrasonography CT scan chest (Figure 2 ): A round nodular opacity Case 22 50 mm in greatest diameter can be seen in the left S1 0 c region. Organizing pneumonia (regularly distributed patent EBUS fi ndings (Figure 3 ): Although we were unable blood vessels). to defi ne the boundaries of this lesion due to its size, Left S1 0 organizing pneumonia. blood vessels remained patent (arrow) throughout the lesion. No hyperechoic air - containing dots are seen, Presenting Complaint: Fever, Cough differentiating this lesion from a highly differentiated History: Presented to previous doctor with fever and adenocarcinoma. cough, abnormal opacity seen on plain chest radio- Findings of patent blood vessels distributed regu- graph. CT scanning and bronchoscopy confi rmed an larly throughout the lesion, and no hyperechoic air- opacity in the left S 10 c region. TBLB yielded the diag- containing dots, are characteristic of pneumonia or nosis of organizing pneumonia. organizing pneumonia. Fluoroscopy at the time of EBUS (Figure 1 ): The UM - 3R probe has passed down the bronchoscope instrument channel into the left B10c bronchus. Figure 1 Figure 2 Figure 3 142 CHAPTER 13 Case Reports CT scan chest (Figure 1 ): A thin elongated nodular Case 23 opacity 30 mm in greatest diameter can be seen in the left S1 + 2 a region. Tuberculoma (homogenous echo pattern with no EBUS fi ndings (Figure 2 ): This thin elongated lesion patent vessels or bronchioles). has a clearly delineated border. No blood vessels can Tuberculoma in the left S1 + 2 a region. be seen within the lesion, and the internal echoes are homogeneous with no hyperechoic points. Presenting Complaint: Abnormal Opacity Seen on Plain Chest Radiograph at Points of Advice Routine Health Check The EBUS fi ndings for tuberculomas are varied, History: Abnormal opacity seen on plain chest radio- including the following possibilities: (1) no patent graph at company health check 3 months earlier. blood vessels, no hyperechoic points and homogene- Tuberculosis was diagnosed on the basis of a Gaffky ous internal echoes; (2) microcalcifi cations; and (3) rating 1 from bronchial washings obtained at bron- patent blood vessels and bronchioles as with choscopy. Near resolution of the radiographic changes pneumonia. was achieved with antituberculosis therapy. Figure 1 Figure 2 143 Endobronchial Ultrasonography ographic changes was achieved with 2 months anti- Case 24 microbial therapy. CT scan chest (Figure 1 ): A nodular opacity 30 mm Cryptococcosis (regular distribution of blood vessels in greatest diameter can be seen at the right S6 and bronchioles throughout the lesion). region, with associated pleural indentation and air Cryptococcosis in the right S 6 region. bronchogram. EBUS fi ndings (Figure 2 ): This lesion has a clearly delineated border, linear in places. Patent blood vessels Presenting Complaint: Abnormal Opacity can be seen throughout the lesion, accompanied by Seen on Plain Chest Radiograph at Routine hyperechoic points corresponding to patent bronchi- Health Check oles. The internal echoes are homogenous. History: Abnormal opacity seen on plain chest radio- Findings of patent blood vessels distributed regularly graph at company health check 1 month earlier. throughout the lesion, hyperechoic corresponding to Cryptococcosis was diagnosed on the basis of TBLB patent bronchioles, and homogeneous internal echoes, obtained at bronchoscopy. Near resolution of the radi- are characteristic of infl ammatory conditions. Figure 1 Figure 2 144 CHAPTER 13 Case Reports TBLB yielded the diagnosis of organizing pneumonia. Case 25 Near resolution of the radiographic changes was con- fi rmed 1 month later without treatment. Organizing pneumonia (lesion with star - shaped CT scan chest (Figure 1 ): A nodular opacity 15 mm border). in greatest diameter can be seen at the right S4 a Organizing pneumonia in the right S 4 a region. region. EBUS fi ndings (Figure 2 ): This lesion has a clearly Presenting Complaint: Abnormal Opacity delineated border, linear in places, forming a star- Seen on Plain Chest Radiograph at Routine shape centred on the bronchus. Health Check An irregular star - shaped pattern centred on a bron- History: Abnormal opacity seen on plain chest radio- chus is characteristic of a peribronchial infl ammatory graph at municipal health check 1 month earlier. condition such as organizing pneumonia. Figure 1 Figure 2 145 Endobronchial Ultrasonography CT scan chest (Figure 1 ): A nodular opacity 25 mm Case 26 in greatest diameter can be seen at the left S4 region, with an infi ltrative pattern distally. Organizing pneumonia (lesion with star - shaped EBUS fi ndings (Figure 2 ): This round lesion has a border). clearly delineated border, and contains a star - shaped Infl ammatory pseudotumor in the right S 4 region. anechoic area. Histopathological examination (Figure 3 ): A fl uid collection within the lesion, corresponding to the star- Presenting Complaint: Fever shaped anechoic area seen using EBUS, is the dilated History: Presented to previous doctor with fever of 1 bronchial lumen itself. month ’ s duration, referred with abnormal opacity An irregular star - shaped anechoic area seen on seen on plain chest radiograph. Investigations EBUS sometimes corresponds to dilatation of a bron- including bronchoscopy TBLB failed to yield a defi ni- chus. We have also experienced some cases where an tive diagnosis. Due to persistent pyrexia and enlarge- anechoic area corresponded to a necrotic area within ment of the lesion, the patient underwent left a squamous cell carcinoma. lingulectomy. Figure 1 Figure 2 Figure 3 146 CHAPTER 13 Case Reports CT scan chest (Figure 1 ): A localized ground - glass Case 27 opacity of largest diameter 17 mm, with increased density centrally, can be seen in the left S9 a region. Well -d ifferentiated adenocarcinoma containing air Preoperative EBUS fi ndings (Figure 2 ): The target and blood vessels. lesion was rounded with well - defi ned margins. It con- Well -d ifferentiated adenocarcinoma (papillary type, tains a ribbon - like hypoechoic structure, thought to Noguchi C 17 mm) of the left S9 region. be a blood vessel (arrow). Multiple hyperechoic points are scattered irregularly throughout the lesion. Presenting Complaint: Abnormal Opacity Histopathological examination (low magnifi cation, Seen on Chest CT Scan Figure 3 ): The target lesion is a well - differentiated History: Ground -g lass opacity detected in the left adenocarcinoma (papillary type, Noguchi C) of the left lower lobe on CT scan chest at the time of surgery for S 9 bronchus, with central fi brosis, and growing out esophageal cancer. Priority was given to the surgery, replacing the alveolar mucosa. In this specimen, sliced as the esophageal cancer was advanced, and the in the same plane as the EBUS image, we can see a abnormal opacity was observed with CT scanning. The bronchial artery, 0.7 mm in diameter, passing through left lower lobe ground - glass opacity had increased in the lesion corresponding to the ribbon- like hypoechoic size from 15 mm to 17 mm after 1 year, so the patient structure in the EBUS image (arrow). The hyperechoic then underwent left lower lobectomy + R 1 : sT1N0M0, points in the EBUS image correspond to alveolar air, P0, D0, E0, PM0: c - stage IA. trapped within the tumor as it invades the alveoli. Figure 1 Figure 2 Figure 3 147 Endobronchial Ultrasonography ular. It contains a ribbon - like hypoechoic structure, Case 28 thought to be a blood vessel passing through the lesion (arrow). Multiple hyperechoic points are scattered Well -d ifferentiated adenocarcinoma (blood vessels irregularly throughout the lesion. and hyperechoic points distributed irregularly Histopathological examination (low magnifi ca- through the lesion). tion): The target lesion is a well - differentiated Well -d ifferentiated adenocarcinoma (papillary type) adenocarcinoma (papillary type). In this specimen, of the right S1 region. sliced in the same plane as the EBUS image, we can see a bronchial artery, 0.65 mm in diameter, corre- Presenting Complaint: Abnormal Opacity sponding to the ribbon - like hypoechoic structure in Seen on Plain Chest Radiograph the EBUS image (Figure 2 , arrow). The hyperechoic History: Nodular opacity detected in the right upper points in the EBUS image correspond to alveolar air, lobe on plain chest radiograph at company health trapped within the tumor as it invades the alveoli check. The patient underwent right upper lobec- (Figure 3 , arrow). tomy + R 2 a: sT1N0M0, P0, D0, E0, PM0: c - stage IA. Hyperechoic lines and points are also seen in EBUS We compared the preoperative EBUS images and the images of infl ammatory conditions, but they are regu- histopathological fi ndings. larly distributed in infl ammatory conditions, and tend CT scan chest (Figure 1 ): A nodular opacity of to be irregularly distributed in neoplastic lesions. largest diameter 20 mm, with a central air broncho- When a patent blood vessel is seen passing through a gram, can be seen in the right S1 region. tumor in the EBUS image, this indicates that the Preoperative EBUS fi ndings (Figures 2 , 3) : The tumor is relatively soft, and suggests it is likely to be margins of the target lesion are well - defi ned but irreg- well - differentiated. Figure 1 Figure 2 Figure 3 148 CHAPTER 13 Case Reports CT scan chest (Figure 1 ): A nodular opacity of Case 29 largest diameter 18 mm can be seen in the left S5 region, associated with pleural indentation. Well -d ifferentiated adenocarcinoma with indistinct Preoperative EBUS fi ndings (Figure 2 ): The margins margins. of the target lesion are indistinct. Multiple hypere- Well -d ifferentiated adenocarcinoma (papillary type) choic points are scattered irregularly throughout the of the left S5 region. lesion. 19 × 18 × 18 mm. Histopathological examination (low magnifi cation, Figure 3 ): The target lesion is a well - differentiated Presenting Complaint: Abnormal Opacity adenocarcinoma (papillary type) with central fi brosis. Seen on Plain Chest Radiograph The hyperechoic points in the EBUS image correspond History: Nodular opacity detected in the left middle to alveolar air, trapped within the tumor as it invades lungfi eld on plain chest radiograph at company health the alveoli. check. The patient underwent left upper lobec- The reason the margins of this tumor were indistinct tomy + R 2 a: sT1N0M0, P0, D0, E0, PM0: s - stage IA. We is because it invades by replacing alveolar mucosa, compared the preoperative EBUS images and the his- trapping alveolar air as it spreads peripherally. topathological fi ndings. Figure 1 Figure 2 Figure 3 149 Endobronchial Ultrasonography E0, PM0: s - stage IA. We compared the preoperative Case 30 EBUS images and the histopathological fi ndings. Plain chest radiograph, CT scan chest (Figures 1 , 2) : Moderately differentiated adenocarcinoma (with A nodular opacity of largest diameter 15 mm can be indistinct margins and hyperechoic points distrib- seen at the boundary of the left S 3 a and b regions, uted irregularly through the lesion). some areas containing air. Moderately differentiated adenocarcinoma of the left Preoperative EBUS fi ndings (Figures 3 , 4) : The S3 a region. margins of the target lesion are well - defi ned but irreg- 1.5 × 1.5 × 1.0 cm. ular. Multiple hyperechoic lines and points are scat- tered irregularly throughout the lesion. Histopathological examination (low magnifi cation, Presenting Complaint: Abnormal Opacity Figure 5 ): The target lesion is a moderately differenti- Seen on Plain Chest Radiograph at ated adenocarcinoma (papillary type) with central Municipal Health Check fi brosis, invades by replacing alveolar mucosa as it History: Abnormal opacity seen on plain chest radio- spreads peripherally. graph at company health check. TBLB yielded the The hyperechoic lines and points in the EBUS image diagnosis of adenocarcinoma, and the patient under- correspond to air trapped inside bronchioles and went left upper lobectomy + R 2 a: sT1N0M0, P0, D0, alveoli within the tumor. Figure 1 Figure 2 Figure |