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Automatic external defibrillation: Bringing it home
Editorials
Automatic ExternalDefibrillation: Bringing it Home “Shock, shock, everybody shock” sounds like a cheer rather than an epi-acronym we use to teach the advanced cardiac life support (ACLS) protocol for ventricular fibrillation (VF) to residents and medical students. We also stress administration of “essence of electricity” during ACLS courses, as well as advise providers “Don’t be late, defibrillate,” “If a flat line rhythm moves, shock it,” “Shock it or lose it,” and “Shock first, ask questions later.” These cute phrases emphasize to students what to us is a firmly held conviction. A defibrillatory shock delivered promptly is the most important intervention for sudden cardiac arrest. Ventricular fibrillation occurs most frequently in sudden cardiac death and is the rhythm most likely to allow for successful resuscitation.’ All other rhythms leave minimal or no chance for resuscitation. This emphasis on early defibrillation, however, in no way detracts from the importance of early cardiopulmonary resuscitation (CPR), whether initiated by basic emergency medical technicians (EMTs), bystanders, or with the assistance of telephone CPR instruction.‘.3 CPR buys time until defibrillatory shocks can be applied.4 The relationship of CPR and defibrillation can be put in allegorical terms. The rescuer (doctor, nurse, paramedic, or EMT) can be considered a medieval knight fighting the dragon of sudden cardiac death. The knight uses his shield of CPR to fend off the dragon, but the shield alone is not enough. Ultimately victory is achieved only when the sword of detibrillation is brought to bear and the dragon slain. The status of prompt defibrillatory shocks as the treatment of choice for ventricular fibrillation is recognized by the American Heart Association in the current ACLS protocol and will be similarly recognized in the 1985 recommendations. The issue is no longer whether defibrillatory shocks should be given first for VF, but rather how to insure that defibrillatory shocks are provided promptly. The means to defibrillate rapidly for out-of-hospital cardiac arrest became possible technologically with the development of direct current (DC) defibrillators in the mid-1960s. Direct current detibrillators do not require line power and can be brought directly to the scene of a cardiac arrest. Paramedic programs, using portable defibrillators, are now widespread in the U.S. and many parts of the world. Unfortunately, the time required to respond (even if less than 10 minutes) and the frequent lack of bystander CPR limit the effectiveness of paramedic pro568
grams. Although precise data do not exist, we estimate that in the United States only 1 to 3% of 300,000 patients with out-of-hospital episodes of VF are successfully resuscitated by paramedics and discharged from hospital. One means to provide defibrillatory shocks faster is for emergency medical technicians to be trained to recognize VF and operate a defibrillator. The concept of emergency medical technican defibrillation (EMT-D) is a proven one. 5-8 Yet, even widespread application of EMT-D, while certain to increase the number of VF survivors, will only modestly improve overall survival. New approaches are needed. To achieve a major decrease in mortality and morbidity from out-of-hospital cardiac arrest, we must get the defibrillator to the patient fast, and paramedic and EMT-D programs are not fast enough. We must have the defibrillator directly at the scene. Sudden cardiac death with VF does not conveniently happen in tire stations. It happens in people’s homes, offices, and factories. The need to have defibrillators on hand was recognized by Friedman in 1972 when he stated, “Possibly every home with a person at risk should have a portable defibrillator next to the television set.“’ There has been much reluctance, with good reason, to train lay persons to use defibrillators. Potential physical injuries, not to mention psychological harm, has kept defibrillators in the hands of emergency medical personnel only. We agree that manual defibrillators necessitating interpretation of rhythm and complex psychomotor skills are too complex for lay persons who may rarely or never use the device. This situation has changed. Automatic defibrillators are now available that can, after attachment, determine the rhythm, charge the capacitor, and automatically deliver a defibrillatory shock.lO-‘Z Two devices have received FDA approval for marketing, and additional companies will soon enter the field. Each new product promises to be technologically more sophisticated and, it is hoped, less expensive. Automatic external defibrillators placed in the homes of high-risk patients and in offices, factories, public places, and remote sites (e.g., ships, oil rigs, resorts, and airplanes) can have a dramatic effect on the rate of sudden cardiac death. Potentially tens of thousands of persons could be saved. The technology of automatic defibrillation is exciting and can indeed allow defibrillatory shocks to be
EDITORIALS
delivered rapidly-so rapidly that for many witnessed cardiac arrests, CPR will not even be necessary. Although it is a new technology, it is only an intermediate technology. The real technological breakthrough will be prevention. Automatic defibrillators for cardiac arrest are analogous to iron lungs for polio. When effective prevention of polio appeared, iron lungs vanished. But until the day of prevention is upon us, intermediate solutions are all that are available. Many questions remain to be answered. What sensitivity and specificity should these devices have? Who are among the “at risk” population? Are they all persons over 50? Are they all VF survivors, all myocardial infarction survivors, or as yet unidentified subsets of infarction patients? What are the psychological risks of such machines? Can we afford the technology? Who will pay for the devices? Cost-effective analyses13 are crucial especially while the technology is in its infancy. Will the sword of defibrillation be in the hands of everyone, or will only a few wield its power? MICKEY S. EISENBERG,MD, PHD RICHARD0. CUMMINS,MD, MPH, MSc University of Washington Seattle
REFERENCES
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4.
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7.
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9. 10.
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1. Eisenberg MS, Copass MK, Hallstrom A, et al. Management of out-of-hospital cardiac arrest: I. Factors associated with successful resuscitation. Am J Public Health 1979;69:30-36. 2. Carter WB, Eisenberg MS, Hallstrom AP, et al. Development
13.
and implementation of emergency CPR instruction via telephone. Ann Emerg Med 1984;13:695-700. Eisenberg MS, Hallstrom AP, Carter WB, et al. Emergency CPR instruction via telephone. Am J Public Health 1985;75:47-50. Cummins RO, Eisenberg MS, Hallstrom AP, et al. Survival of out-of-hospital cardiac arrest with early initiation of cardiopulmonary resuscitation. Am J Emerg Med 1985;3:114-118. Eisenberg MS, Copass MK, Hallstrom AP, et al. Treatment of out-of-hospital cardiac arrests with rapid defibrillation by emergency medical technicians. N Engl J Med 1980;302:1379-1383. Stults KR, Brown DD, Schug VL, et al. Prehospital defibrillation performed by emergency medical technicians in rural communities. N Engl J Med 1984;310:219-223. Eisenberg MS, Hallstrom AP, Copass MK, et al. Treatment of ventricular fibrillation: Emergency medical technician defibrillation and paramedic services. JAMA 1984; 251:1723-1726. Weaver WD, Copass WK, Bufi D, et al. Improved neurologic recovery and survival after early defibrillation. Circulation 1984;69:943-948, Friedman CK. Introduction to symposium myocardial infarction. Circulation 1972;45:179-188. Cummins RO, Eisenberg M, Bergner L, et al. Sensitivity, accuracy, and safety of an automatic external defibrillator. Lancet 1984;11:318-320. Jaffarao NSV, Heber M, Grainger R, et al. Use of an automated external defibrillator-pacemaker by ambulance staff. Lancet 1982;2:73-75. Weaver WD, Copass MK, Cobb LA, et al. A new compact automatic external defibrillator designed for layperson use (abstract). J Am Coll Cardiol 1985;5:457. Hallstrom A, Eisenberg M, Bergner L. The potential use of automatic defibrillators in the home for management of cardiac arrest. Med Care 1984;22:1083-1087.
Physician Education in Emergency and Critical-care Medicine: A Continuum? Critical care medicine (CCM), as interpreted by its a confounding fathers, l-5 should be considered tinuum-from pre-hospital emergency care, through in-hospital emergency department therapy, ultimately culminating in management of the patient in the operating room and/or intensive care unit (ICU). In the United States, emergency physicians have now established a firm foothold in the first two of these three phases, whereas CCM physicians have, in most hospitals, limited their responsibilities to the ICU.6 Because truly critically ill patients constitute only a small proportion of the total number of.patients evaluated and treated in an emergency department, ex-
pertise in the long-term management of critically ill patients is not a natural outgrowth of specialty training in emergency medicine. Although in small hospitals the emergency physician (frequently the only physician present in such hospitals overnight) is often called upon to diagnose and treat critically ill ICU patients, his, role in the treatment of these patients in larger teaching hospitals has been minimal. For emergency medicine residency graduates (EMRG’s) seeking additional expertise in the management of critical illness, several questions arise: How does one obtain additional training in CCM? Is emergency medicine the best, or even an acceptable, foundation for specializa569
Automatic ExternalDefibrillation: Bringing it Home “Shock, shock, everybody shock” sounds like a cheer rather than an epi-acronym we use to teach the advanced cardiac life support (ACLS) protocol for ventricular fibrillation (VF) to residents and medical students. We also stress administration of “essence of electricity” during ACLS courses, as well as advise providers “Don’t be late, defibrillate,” “If a flat line rhythm moves, shock it,” “Shock it or lose it,” and “Shock first, ask questions later.” These cute phrases emphasize to students what to us is a firmly held conviction. A defibrillatory shock delivered promptly is the most important intervention for sudden cardiac arrest. Ventricular fibrillation occurs most frequently in sudden cardiac death and is the rhythm most likely to allow for successful resuscitation.’ All other rhythms leave minimal or no chance for resuscitation. This emphasis on early defibrillation, however, in no way detracts from the importance of early cardiopulmonary resuscitation (CPR), whether initiated by basic emergency medical technicians (EMTs), bystanders, or with the assistance of telephone CPR instruction.‘.3 CPR buys time until defibrillatory shocks can be applied.4 The relationship of CPR and defibrillation can be put in allegorical terms. The rescuer (doctor, nurse, paramedic, or EMT) can be considered a medieval knight fighting the dragon of sudden cardiac death. The knight uses his shield of CPR to fend off the dragon, but the shield alone is not enough. Ultimately victory is achieved only when the sword of detibrillation is brought to bear and the dragon slain. The status of prompt defibrillatory shocks as the treatment of choice for ventricular fibrillation is recognized by the American Heart Association in the current ACLS protocol and will be similarly recognized in the 1985 recommendations. The issue is no longer whether defibrillatory shocks should be given first for VF, but rather how to insure that defibrillatory shocks are provided promptly. The means to defibrillate rapidly for out-of-hospital cardiac arrest became possible technologically with the development of direct current (DC) defibrillators in the mid-1960s. Direct current detibrillators do not require line power and can be brought directly to the scene of a cardiac arrest. Paramedic programs, using portable defibrillators, are now widespread in the U.S. and many parts of the world. Unfortunately, the time required to respond (even if less than 10 minutes) and the frequent lack of bystander CPR limit the effectiveness of paramedic pro568
grams. Although precise data do not exist, we estimate that in the United States only 1 to 3% of 300,000 patients with out-of-hospital episodes of VF are successfully resuscitated by paramedics and discharged from hospital. One means to provide defibrillatory shocks faster is for emergency medical technicians to be trained to recognize VF and operate a defibrillator. The concept of emergency medical technican defibrillation (EMT-D) is a proven one. 5-8 Yet, even widespread application of EMT-D, while certain to increase the number of VF survivors, will only modestly improve overall survival. New approaches are needed. To achieve a major decrease in mortality and morbidity from out-of-hospital cardiac arrest, we must get the defibrillator to the patient fast, and paramedic and EMT-D programs are not fast enough. We must have the defibrillator directly at the scene. Sudden cardiac death with VF does not conveniently happen in tire stations. It happens in people’s homes, offices, and factories. The need to have defibrillators on hand was recognized by Friedman in 1972 when he stated, “Possibly every home with a person at risk should have a portable defibrillator next to the television set.“’ There has been much reluctance, with good reason, to train lay persons to use defibrillators. Potential physical injuries, not to mention psychological harm, has kept defibrillators in the hands of emergency medical personnel only. We agree that manual defibrillators necessitating interpretation of rhythm and complex psychomotor skills are too complex for lay persons who may rarely or never use the device. This situation has changed. Automatic defibrillators are now available that can, after attachment, determine the rhythm, charge the capacitor, and automatically deliver a defibrillatory shock.lO-‘Z Two devices have received FDA approval for marketing, and additional companies will soon enter the field. Each new product promises to be technologically more sophisticated and, it is hoped, less expensive. Automatic external defibrillators placed in the homes of high-risk patients and in offices, factories, public places, and remote sites (e.g., ships, oil rigs, resorts, and airplanes) can have a dramatic effect on the rate of sudden cardiac death. Potentially tens of thousands of persons could be saved. The technology of automatic defibrillation is exciting and can indeed allow defibrillatory shocks to be
EDITORIALS
delivered rapidly-so rapidly that for many witnessed cardiac arrests, CPR will not even be necessary. Although it is a new technology, it is only an intermediate technology. The real technological breakthrough will be prevention. Automatic defibrillators for cardiac arrest are analogous to iron lungs for polio. When effective prevention of polio appeared, iron lungs vanished. But until the day of prevention is upon us, intermediate solutions are all that are available. Many questions remain to be answered. What sensitivity and specificity should these devices have? Who are among the “at risk” population? Are they all persons over 50? Are they all VF survivors, all myocardial infarction survivors, or as yet unidentified subsets of infarction patients? What are the psychological risks of such machines? Can we afford the technology? Who will pay for the devices? Cost-effective analyses13 are crucial especially while the technology is in its infancy. Will the sword of defibrillation be in the hands of everyone, or will only a few wield its power? MICKEY S. EISENBERG,MD, PHD RICHARD0. CUMMINS,MD, MPH, MSc University of Washington Seattle
REFERENCES
3.
4.
5.
6.
7.
8.
9. 10.
11.
12.
1. Eisenberg MS, Copass MK, Hallstrom A, et al. Management of out-of-hospital cardiac arrest: I. Factors associated with successful resuscitation. Am J Public Health 1979;69:30-36. 2. Carter WB, Eisenberg MS, Hallstrom AP, et al. Development
13.
and implementation of emergency CPR instruction via telephone. Ann Emerg Med 1984;13:695-700. Eisenberg MS, Hallstrom AP, Carter WB, et al. Emergency CPR instruction via telephone. Am J Public Health 1985;75:47-50. Cummins RO, Eisenberg MS, Hallstrom AP, et al. Survival of out-of-hospital cardiac arrest with early initiation of cardiopulmonary resuscitation. Am J Emerg Med 1985;3:114-118. Eisenberg MS, Copass MK, Hallstrom AP, et al. Treatment of out-of-hospital cardiac arrests with rapid defibrillation by emergency medical technicians. N Engl J Med 1980;302:1379-1383. Stults KR, Brown DD, Schug VL, et al. Prehospital defibrillation performed by emergency medical technicians in rural communities. N Engl J Med 1984;310:219-223. Eisenberg MS, Hallstrom AP, Copass MK, et al. Treatment of ventricular fibrillation: Emergency medical technician defibrillation and paramedic services. JAMA 1984; 251:1723-1726. Weaver WD, Copass WK, Bufi D, et al. Improved neurologic recovery and survival after early defibrillation. Circulation 1984;69:943-948, Friedman CK. Introduction to symposium myocardial infarction. Circulation 1972;45:179-188. Cummins RO, Eisenberg M, Bergner L, et al. Sensitivity, accuracy, and safety of an automatic external defibrillator. Lancet 1984;11:318-320. Jaffarao NSV, Heber M, Grainger R, et al. Use of an automated external defibrillator-pacemaker by ambulance staff. Lancet 1982;2:73-75. Weaver WD, Copass MK, Cobb LA, et al. A new compact automatic external defibrillator designed for layperson use (abstract). J Am Coll Cardiol 1985;5:457. Hallstrom A, Eisenberg M, Bergner L. The potential use of automatic defibrillators in the home for management of cardiac arrest. Med Care 1984;22:1083-1087.
Physician Education in Emergency and Critical-care Medicine: A Continuum? Critical care medicine (CCM), as interpreted by its a confounding fathers, l-5 should be considered tinuum-from pre-hospital emergency care, through in-hospital emergency department therapy, ultimately culminating in management of the patient in the operating room and/or intensive care unit (ICU). In the United States, emergency physicians have now established a firm foothold in the first two of these three phases, whereas CCM physicians have, in most hospitals, limited their responsibilities to the ICU.6 Because truly critically ill patients constitute only a small proportion of the total number of.patients evaluated and treated in an emergency department, ex-
pertise in the long-term management of critically ill patients is not a natural outgrowth of specialty training in emergency medicine. Although in small hospitals the emergency physician (frequently the only physician present in such hospitals overnight) is often called upon to diagnose and treat critically ill ICU patients, his, role in the treatment of these patients in larger teaching hospitals has been minimal. For emergency medicine residency graduates (EMRG’s) seeking additional expertise in the management of critical illness, several questions arise: How does one obtain additional training in CCM? Is emergency medicine the best, or even an acceptable, foundation for specializa569