In-Hospital Defibrillation

This article is my most complete statement of my views on the general problem of delayed in-hospital defibrillation and possible approaches to improve survival. With kind permission from Aspen Publishers, Inc.

Stewart JA. A more effective approach to in-hospital defibrillation. Journal of Cardiovascular Nursing. 1996;10(4):37-46.

A More Effective Approach to In-Hospital Defibrillation

John A. Stewart, RN, MA
Swedish Medical Center
Seattle, WA

Abstract

Survival from in-hospital cardiac arrests is low and has not improved since the 1960s. Increased emphasis on early defibrillation has significantly improved prehospital survival in recent years, but the organization of resuscitation efforts in hospitals has not changed. Nurses throughout the hospital should be trained and authorized to defibrillate on their own initiative, using defibrillators that are already close at hand. The basic procedure is not difficult, and an aggressive protocol using blind defibrillation could further simplify training and maximize survival. Working together, nurses can overcome psychological and emotional barriers to these changes and improve their patients' odds of survival.

The current practice of resuscitation in acute care hospitals has a fundamental weakness-delayed defibrillation-that may be contributing to unnecessary deaths. This article explores some practical and effective ways to address the problem of delayed in-hospital defibrillation, with the ultimate goal of improving survival from cardiac arrests in hospitals.

There have been no significant advances in hospital resuscitation since the acceptance of closed-chest defibrillation in the early 1960s, and survival from cardiac arrests on general units has not improved since then.[1, 2] Survival rates of cardiac arrest patients outside critical care units remain about 15% at best, and survival is consistently lower on general units than in critical care areas.[1, 3, 4] Explanations for this lack of progress usually involve comorbidity [5, 6] and unwitnessed arrests [2, 7] among patients on general units. Until recently, proposals for change focused on identifying patient groups with poor prospects for survival and preventing futile resuscitation attempts by means of "no code" orders [2, 5, 8, 9]-basically a passive response. Investigators have been disinclined to consider the possible contribution of controllable system factors to low survival rates. However, the experiences of hospital nurses argue that a simple change of approach may improve survival.

The General Unit Nurse's Perspective

General unit nurses are in the most difficult position of anyone involved in the resuscitation effort. They are expected to respond immediately to unanticipated crises, unlike the members of the code team, who at least have a little time to collect their wits while in transit to the scene. More importantly, several factors preordain almost certain failure in the general unit nurse's primary designated task of initiating basic cardiopulmonary resuscitation (CPR).

Performing basic CPR has been shown to be difficult for all levels of health care providers, even in nonstressful classroom simulations.[10, 11] Performance in an actual in-hospital cardiac arrest is harder and takes longer. In the emotionally stressful setting of an actual arrest, several preparatory steps must be taken: acquiring a respiratory barrier device, bringing a crash cart with cardiac board to the scene, and placing the cardiac board under the patient (a two-person task). [12, 13] Initiating ventilations and chest compressions requires the coordinated actions of at least two people, because the use of pocket masks and most other barrier devices makes effective one-person CPR almost impossible. Given these obstacles, effective CPR is rarely initiated before the code team arrives. [14, 15] Expecting the general unit nurse to perform an excessively complex and difficult task in an emergency situation may cause a state of "learned helplessness" and increased dependence on the code team. Could general unit nurses instead be given a goal that is more attainable and at the same time much more effective in promoting survival?

The Cardiovascular Nurse's Perspective

Cardiovascular nurses must often respond to cardiac arrests in their own units as well as in their hospital's general units. Every experienced cardiovascular nurse knows that in cases of sudden dysrhythmic arrest in critical care areas, defibrillation is the most important and successful intervention. Nurses on these units use prompt defibrillation almost routinely to restore a patient to prearrest status.[16] Many cardiovascular nurses also participate in electrophysiologic testing, where ventricular fibrillation is routinely induced with confidence that prompt defibrillation will correct it. [17]

Those cardiovascular nurses who serve on in-hospital code teams see a different situation on general nursing units. Multiple shocks often are delivered, and if conversion to a perfusing rhythm occurs, it rarely results in immediate restoration of consciousness. Most of the patients who do regain spontaneous circulation die before leaving the hospital, either in a critical care bed or as a "no code" back on a general unit. Cardiovascular nurses may therefore see a wide variation in defibrillation success depending on location in the hospital. They may also come to see that the most important factor is time, not place-the extra time needed to initiate monitoring and defibrillation in unmonitored arrests on general units.

The Problem Identified

Since its discovery, external defibrillation has been the cornerstone of emergency cardiac care (ECC) and the principal intervention in most successful resuscitations from full cardiac arrest. [18, 19] A large body of out-of-hospital research shows that rapidity of defibrillation is the most important determinant of survival in arrests because of shockable dysrhythmias. Early defibrillation programs can improve survival rates significantly by shortening the time from arrest to defibrillation. [20, 21] Studies suggest that improving the speed of in-hospital defibrillation may produce even better results. [22, 23] Despite this evidence, the current approach to resuscitation practiced in hospitals has inherent delays. Code teams are dispatched from critical care areas to respond to arrests, with most nurses on general units trained only in basic CPR. [12, 24] Most hospital units have a defibrillator, and general nurses usually arrive first for an unmonitored arrest. [25] Consequently, these are the nurses who may defibrillate at the earliest possible time. The American Heart Association (AHA) has acknowledged under-emphasizing defibrillation in relation to basic CPR:

In the last decade, we have under-emphasized the role of prompt defibrillation. CPR should be initiated only when a defibrillator is not immediately available or after initial shocks have failed to restore spontaneous circulation. CPR should never be used as a substitute for definitive care. [16]

Defibrillation frequently does not receive the highest priority, even from code teams responding to arrests on general units. [14, 26] In unmonitored arrests, efforts often are directed to optimizing basic CPR for seconds or minutes after the code team arrives, delaying initial defibrillation further (J.A.S., unpublished observations, 1977-1993). If survival rates are to improve, early action must be directed to defibrillation-the intervention that is clearly most effective in saving lives.

History of the Current Approach

For many years, defibrillation has been known to be effective and very time-dependent. Why is this not reflected in the organization of in-hospital resuscitation? When external defibrillation gained wide acceptance in the I960s, a defibrillator was a large and cumbersome device which had to be moved from the critical care unit to arrests in other areas of the hospital. Trained emergency personnel were usually at the scene of an arrest by the time the defibrillator arrived. During the 1970s and 198Os there was a trend toward greater numbers of more portable defibrillators in hospitals. Currently, a defibrillator on every nursing unit is the norm, [12] and a defibrillator is usually at the scene of an arrest before an authorized user arrives.

The AHA's first advanced cardiac life support (ACLS) guidelines in 1974 reflected practical realities in combining defibrillation with advanced skills because defibrillation required specialized and scarce equipment. The distinction between basic life support (BLS) and ACLS interventions was initially useful in organizing the ECC curriculum, but it has solidified into an abstract model that is too often assumed to have clinical validity. Even with improved defibrillator technology and availability, defibrillation is still considered an "advanced" skill that should be restricted to a select few hospital staff. The historical BLS/ACLS model has not kept up with medical progress.

The BLS/ACLS model classifies all definitive treatments as "advanced." This classification implies that these treatments are equally well supported by clinical studies and constitute an interdependent body of knowledge. However, the historical evolution of ACLS tells a different story. The impetus for ACLS was the discovery of external defibrillation, the first clearly effective treatment for cardiac arrest. Coupled with the new "holding action" technique of external chest compressions, defibrillation promised for the first time the real prospect of bringing patients back from clinical death. One hospital in England started an early defibrillation program in 1970 (still in existence), [27] and at least two hospitals in the United States instituted defibrillation training programs for nurses in the early 1970s. [28, 29] (The U.S. programs were short-lived, possibly because of the ascendance of the AHA's ACLS model.) Enthusiasm soon extended to cases of arrest in which defibrillation was ineffective or not indicated, leading to a proliferation of treatments that were based on personal experience, animal studies, or speculation. The most widely accepted of these treatments were organized into the AHA's ACLS Guidelines, which have become recognized as the standard of care for cardiac arrest. [30] Despite this acceptance, none of these additional ACLS treatments improved survival.

The major change in out-of-hospital treatment of cardiac arrest in recent years has been a rediscovery of the central importance of defibrillation. This insight, however, has not extended to the in-hospital setting. One reason may be simple inertia in the absence of clear evidence that a problem exists. [14] The paucity of good data is understandable, given the unexpected and stressful nature of in-hospital codes. Accurate information about these events is difficult to obtain, particularly with regard to critical time intervals. [31]

Although discussion of the problem of delayed in-hospital defibrillation has barely begun in professional literature, a few authors have acknowledged it, closely following with the assertion that the advent of automated external defibrillators (AEDs) has made it possible to improve the situation. [12, 32] The AHA recently recognized the problem in the Textbook of Advanced Cardiac Life Support, simultaneously promoting AEDs as the remedy. [19] Other positions advocated in the Textbook of Advanced Cardiac Life Support, such as integration of AED training into BLS courses and prohibiting shocks for apparent asystole, also can be seen as providing support for use of AEDs by hospitals. This promotion by the AHA of AED technology for in-hospital use is questionable on the basis of present evidence. The Textbook states that AEDs, in contrast to manual defibrillators, require only "brief, convenient training sessions and minimal continuing education." [19, p 4-10] However, the sole reference cited to support this statement is a comparison of brief and extended training programs that both used manual defibrillators. [33] The purported training advantage of AEDs over manual defibrillators has not been verified in a meaningful side-by-side comparison, and published research indicates that AEDs are not essential to a successful in-hospital early defibrillation program. [27, 34]

However, reluctance to shock has been a significant problem in EMT-defibrillation programs,[35] and the same can be expected with in-hospital programs. AEDs may be most useful in hospitals as "training wheels" to give nurses new to early defibrillation programs an additional measure of confidence that defibrillation is indicated. This role for AEDs would require devices with a fast and easy mechanism for overriding the AED decision algorithm, so that the devices could be used by more confident operators without concern about delays and possible lockouts resulting from automatic rhythm analysis. Overly aggressive defibrillation, unlike reluctance to shock, has not been a significant problem with nonphysician operators. [21]

The Principal Objection Answered

The problem of delayed defibrillation in hospitals results more from tradition and culture than from rational analysis. The main reason offered for restricting defibrillation to physicians and specialty-area nurses is "the perceived need to ensure correct identification of the rhythm." [36, p35] The principal basis of this perceived need is concern for patient safety. This argument is open to challenge on two levels.

Ease of identifying ventricular fibrillation

First, objections based on the need for positive rhythm identification assume that training general unit nurses to recognize ventricular fibrillation (VF) is not feasible. The typical length of manual defibrillation courses for emergency medical technicians (1O-16 hours) appears to support the contention that such training for hospital nurses is impractical. [37, 38] However, those courses cover rhythm analysis skills that are irrelevant to the basic problem of recognizing VF. Identifying VF requires simple discrimination between order and chaos. The chief difficulties are distinguishing VF from asystole and monitor artifact-tasks that have nothing to do with rhythm analysis per se. Studies suggest that properly focused initial training in defibrillation, including positive identification of VF, can be much shorter than present EMT courses. [33, 39]

Importance of sensitivity over specificity

Diagnostic criteria for rhythm identification before shocking a pulseless patient are a compromise between sensitivity (detecting a condition when it is present) and specificity (ruling out a condition that is not present). With defibrillation, delaying or omitting appropriate shocks (sensitivity errors) has much greater clinical significance than countershocks given to patients in non-VF cardiac arrest (specificity errors). [40]

The most recent ACLS Guidelines for the first time state that shocks in cases of true asystole may be harmful and recommend that they be "strongly discouraged." [41, p 2220] However, the hypothesized mechanism of harm is not well supported by the references cited and has no demonstrated clinical relevance [42]; elsewhere the Guidelines state that survival in these cases is very low despite treatment. One retrospective study failed to find a decrease in survival from shocking asystole despite a determined search using nine statistical tests. [43] For pulseless electrical activity (PEA) the story is the same: no evidence of clinical harm from defibrillation, with negligible survival in any case. [44]

Because sensitivity errors are so much more important clinically than specificity errors, it follows that requiring positive identification of a shockable dysrhythmia before shocking a pulseless patient may be detrimental to survival. De-emphasizing specificity would raise the probability that shocks would occasionally be given to patients not in VF or VT. Such shocks have traditionally been considered treatment errors, but these "errors" have no apparent adverse effect on clinical outcomes.

Recommendations

Maximizing survival rates requires an aggressive defibrillation policy, including a training approach that would predispose nurses to shock pulseless patients at the earliest possible moment, without excessive concern with definitive rhythm identification. Such a policy could be expected to simplify training and eliminate incorrectly withheld shocks, which would speed defibrillation and save lives.

Blind defibrillation

"Blind" defibrillation-shocking pulseless patients when a monitor is unavailable or without reference to the monitor pattern-has a number of clinical precedents. It was done routinely before monitors were integrated into defibrillators [45] and has been advocated to simplify and expand training or to hasten defibrillation. [46-48] Identification of VF, whether by a human caregiver or an AED, delays defibrillation for at least a few seconds. If artifact confuses the picture, the delay may significantly decrease the probability of success. The ACLS guidelines and Textbook offer little guidance about dealing with persistent monitor artifact or a defective monitor. How long should a rescuer try to troubleshoot artifact before shocking? What if the monitor is broken but the defibrillator works?

Consider the hypothetical case of a lone caregiver faced with an arrested patient, with a monitor and defibrillator available. Assume that the caregiver can place the paddles correctly and press the charge and shock buttons but is ignorant about monitor patterns. What should the caregiver do? Despite the AHA's current emphasis on early defibrillation, the ACLS guidelines appear to favor withholding the shock because the rhythm cannot be identified. However, if a functioning cardiac monitor is not available, the guidelines say a caregiver should defibrillate without identifying the rhythm. The contradiction is evident.

Blind defibrillation could produce quicker initial shocks in cases involving monitor artifact or "occult" VF [49] and might facilitate faster performance by experienced operators by removing delays for rhythm identification. Blind defibrillation may be helpful in getting first-timers past the obstacle of giving their first shock to a human being: with blind shocks, the action would depend only on the skill of pulse detection.

The appropriate sequence of actions after the initial shock is problematic if caregivers are trained only in blind defibrillation. If blind defibrillation proves helpful in encouraging quick initial shocks, it might be combined with required rhythm confirmation on subsequent shocks. In any case, providing even one early shock should improve a patient's chances of survival. [50, 51]

What if cardiac arrest is misdiagnosed? The most credible objection to a policy of blind defibrillation is the specter of a patient not in cardiac arrest dying from an inappropriate shock. For a death of this type to occur, an arrest must be misdiagnosed, a shock must be given and must cause VF, and a follow-up shock must be delayed or omitted. No cases have been reported in the literature in some 30 years of external defibrillation, although harmless inappropriate shocks have been documented.

Health professionals may have more trouble with carotid pulse checks than has been recognized in the past, [52] but general unit nurses are unlikely to misdiagnose a cardiac arrest. Accidental hypothermia, a significant factor in prehospital misdiagnosis of arrest, [53] is not a problem in hospitals, and general unit nurses usually have a baseline mental image of the patient to aid them in assessing emergent conditions. Requiring positive identification of a shockable dysrhythmia would provide an indirect secondary check against overtreatment of a missed pulse but would not prevent the more likely problem with pulse checks-delay of shocks because of hesitance in identifying pulselessness. [54]

The question of accurate carotid pulse checks has broader significance, particularly with regard to basic CPR training. Why use it to urge caution in defibrillation without addressing the much larger potential for harm from inappropriate basic CPR? The ill effects of basic CPR are better established than harm from defibrillation, [55, 56] yet the AHA has promoted widespread CPR training for many years. Problems with pulse assessment should be handled by providing better training in this skill at all levels of emergency cardiac care. To quote a common ECC injunction: "Treat the patient, not the monitor."

But what if a nurse does miss a pulse and shocks a patient with a perfusing rhythm? The probability of an unsynchronized shock precipitating VF has been calculated at 2% [57] and clinical reports suggest it may be almost zero at the energy levels used for defibrillation. [58, 59] If a shock did induce VF, a prompt second shock probably would correct it.

VF as the default diagnosis

A more conservative alternative to blind defibrillation is a policy favoring VF as the default diagnosis. With this approach, shocks would be given unless a slow, organized rhythm was seen. This would provide additional protection against the remote possibility of shocking a patient with a pulse but would still be more aggressive (and probably more effective) than an approach requiring positive rhythm identification. Delays because of artifact and "occult" VF would be prevented, and training would not be much more than with blind defibrillation.

What Cardiovascular Nurses Can Do

Within the next few years early defibrillation will be a prominent topic in hospital care, just as it is now in the out-of-hospital setting, and nurses will be facing the issue, both individually and collectively. What can cardiovascular nurses do to make change in this area? Nurses who serve on code committees or in administrative positions can work for changes in hospital policy. The more difficult long-term challenge, however, is to change attitudes.

Defibrillation has been performed by paramedics and critical care nurses under "standing orders," and this convention could be extended to general unit nurses. This change will require general nurses to assume primary responsibility for defibrillation, and physicians and critical care nurses will have to give up control of defibrillation. This kind of change is hard when a routine treatment is involved; with defibrillation the obstacles may be greater. Defibrillation is a potent treatment modality, and it inspires fear and wonder.

Defibrillation is the occasional subject of clinical tales involving someone who sustained a bad shock and "almost died," but after 30 years of shocks given in all sorts of circumstances, there are no published reports of caregivers or bystanders sustaining fatal or debilitating injuries from defibrillator accidents. There is a small risk to in-hospital caregivers of an accidental shock resulting in temporary peripheral neuropathy, [60, 61] but the risk is trivial compared with the potential benefit for the patient.

Doing anything in a code is emotionally difficult, but defibrillation is no more difficult than other tasks floor nurses are expected to perform in codes. The basic procedure of defibrillation is both easy and safe, even when used with a policy of blind defibrillation. This basic realization may be difficult to accept, given the strong association of lifesaving treatments with specialized knowledge and advanced training. Cardiovascular nurses can play a key role in delivering the message.

Cardiovascular nurses with defibrillation experience can dispel these misconceptions and retain some "ownership" of future early defibrillation programs by acting as mentors and role models to their colleagues on the floors. After basic fears and misconceptions about the procedure are dispelled, it still will be a large step for floor nurses to go from a minor role in the resuscitation effort to shouldering major responsibility for their patients' survival. But it will be worth the effort. If nurses can take united action for early in-hospital defibrillation, many lives may be saved in the future.

REFERENCES

1. McGrath PB. In-house cardiopulmonary resuscitation-after a quarter of a century. Ann Emerg Med. 1987;11:1,365-1,368.

2. Dans PE,Nevin KL, Seidman CE, McArthur JC. Inhospital CPR 25 years later: why has survival decreased? South Med J. 1985;78:1,174-1,178.

3. Tunstall-Pedoe H, Bailey L, Chamberlain DA, Marsden AK, Ward ME. Zideman DA. Survey of 3765 cardiopulmonary resuscitations in British hospitals (the BRESUS study: methods and overall results. BMJ. 1992;304:1,347-1,351.

4. Lazzam C, McCans JL. Predictors of survival of in-hospital cardiac arrest. Can J Cardiol. 1991:7(3):113-116.

5. Bedell SA, Delbanco EF, Cook EF, Epstein FH. Survival after cardiopulmonary resuscitation in the hospital. N EngI J Med. 1983;309:569-576.

6. Hershey CO, Fisher L. Why outcome of cardiopulmonary resuscitation in general wards is poor. Lancet. 1982:i:31-34.

7. Grauer K, Cavallaro D. ACLS-A comprehensive review. St. Louis, Mo: Mosby Lifeline; 1993.

8. Schwenzer KJ, Smith WA, Durbin CG. Selective application of cardiopulmonary resuscitation improves survival rates. Anesth Analg. 1993;76:478-4844.

9. O'Keefe S, Ebell MR. Prediction of failure to survive following in-hospital cardiopulmonary resuscitation: comparison of two predictive instruments. Resuscitation. 1994:28(1):21-25.

10. Berden HJ, Hendrick JM, van Doornen JP, Willems FF, Pijls NH, Knape JT. A comparison of resuscitation skills of qualified nurses and ambulance nurses in The Netherlands. Heart Lung. 1993;22(6):509-515.

11. Flesche C, Neruda B, Breuer S, Tarnow J. Basic cardiopulmonary resuscitation skills: a comparison of ambulance staff and medical students in Germany. Resuscitation. 1994;28(October):S25 Abstract.

12. Kaye W, Mancini ME, Giuliano KK, et al. Strengthening the in-hospital chain of survival with rapid defibrillation by first responders using automated external defibrillators: training and retention issues. Ann Emerg Med. 1995;25(2):163-168.

13. Brown J, Latimer-Heeter M, Marinelli A, Rex E, Reynolds L. The first 3 minutes: code preparation for the staff nurse. Orthop Nurs. 1995;14(3):35-40.

14. Sullivan MJJ, Guyatt GH. Simulated cardiac arrests for monitoring quality of in- hospital resuscitation. Lancet. 1986;ii:618-620.

15. Brenner BE, Kauffman J. Response to cardiac arrests in a hospital setting: Delays in ventilation. Circulation. 1995;92(8,S1):i-761 Abstract.

16. American Heart Association. Textbook of Advanced Cardiac Life Support, 2nd Ed. Dallas. American Heart Association; 1987.

17. Josephson ME. Clinical Cardiac Electrophysiology: Techniques and Interpretations. Philadelphia, Pa: Lea & Febiger; 1993.

18. Cummins RO, Eisenberg MS, Hallstrom AP, Litwin PE. Survival of out-of-hospital cardiac arrest with early initiation of cardiopulmonary resuscitation. Am J Emerg Med. 1985;3:1I4-118.

19. American Heart Association. Textbook of Advanced Cardiac Life Support. 2nd Ed. Dallas: American Heart Association; 1994.

20. Eisenberg MS, Copass MK, Hallstrom AP, Blake B, Bergner L., Short FA, Cobb LA. Treatment of out-of-hospital cardiac arrests with rapid defibrillation by emergency medical technicians. N Engl J Med. 1980;302:1,379-1,383.

21. Eisenberg MS, Horwood BT, Cummins RO, Reynolds-Haertle R, Hearne TR. Cardiac arrest and resuscitation: a tale of 29 cities. Ann Emerg Med. 1990;19:179-186.

22. Eisenberg MS, Cummins RO, Litwin PE, Hallstrom AP. Out-of-hospital cardiac arrest: significance of symptoms in patients collapsing before and after arrival of paramedics. Am J Emerg Med. 1986;4(2):II6-120.

23. Aufderheide T. Pacemakers and electrical therapy during advanced cardiac life support. Respir Care. 1994;40(4):364-379.

24.Wright D, Bannister J, Mackintosh AF. How quickly is defibrillation performed in coronary care and other medical wards? Br Heart J. 1990;64:P57. Abstract.

25. Bernard WN, Turudorf H, Cottrell JE, Vea F, Basak A. Impact of cardiopulmonary resuscitation training on resuscitation. Crit Care Med. 1979;7:257-262.

26. Buechler D. Code blue evaluation. Nurs Manage. 1982;13(5):25-28.

27. MacKintosh AF, Crabb ME, Brennan H, Williams J, Chamberlain DA. Hospital resuscitation from ventricular fibrillation in Brighton. Br Med J. 1979;1:511-513.

28. Adelhardt D, Rigney J, Grace WJ. Every nurse's station is a life-support station. Heart Lung. 1973;2(6):832-833. Editorial.

29. Hopewell WS. Defibrillation by nurses. N Engl J Med. 1973;289(26):1,424. Letter.

30. Pepe PE, Abramson NS, Brown CG. ACLS-Does it really work? Ann Emerg Med. 1994;23:1,037-1,041.

31. Wright D, Bannister J, Mackintosh AF. Automatic recording and timing ofdefibrillation on general wards by day and night. Eur Heart J. 1994;15:631-636.

32. de Bono DP. Resuscitation-time for a re-think? Q J Med. 1991;81:959-960.

33. Bradley K, Sokolow AE, Wright KJ. A comparison of an innovative four-hour FMT-D course with a "standard" ten-hour course. Ann Emerg Med. 1988;17:813-819.

34. Stewart AJ, Martin DL. Knowledge and attitude of nurses on medical wards to defibrillation. J Royal Coll Phys Lond. 1994;28(5):399-401.

35. Cummins RO, Eisenberg MS, Graves JR, Austin D, Damon S. EMT-defibrillation, III: achieving medical control. J Emerg Med Serv. 1985;10(3):48-53.

36. McKee DR, Wynne G, Evans TR. Student nurses can defibrillate within 90 seconds: an evaluation of a training programme for third year student nurses in the use of an automatic external defibrillator. Resuscitation. 1994;27(1):35-37.

37. Stults KR, Brown DD, Kerber RE. Efficacy of an automated external defibrillator in the management of out-of-hospital cardiac arrest: validation of the diagnostic algorithm and initial clinical experience in a rural environment. Circulation. 1986;73:701-709.

38. ECRI. Early defibrillation and the role of automated external defibrillators. Health Devices. 1995;24(8-9):300-302.

39. Stewart JA. Defibrillation training for general unit nurses. J Emerg Nurs. 1992;18:519-524.

40. Newman M. To focus on the forest: recognizing the value of early defibrillation despite isolated failures. J Emerg Med Serv.1994;19(5):15-20.

41. Emergency Cardiac Care Committee and Subcommittees, American Heart Association. Guidelines for cardiopulmonary resuscitation and emergency cardiac care, Part III: Adult advanced cardiac life support. JAMA. 1992;268:2,199-2,241.

42. Stewart JA. Questions remain about shocking asystole. Am J Emerg Med. Letter [in press for May 1996 issue].

43. Martin DR, Gavin T, Bianco J, et al. Initial countershock in the treatment of asystole. Resuscitation. 1993;26(1):63-68.

44. Paradis N, Martin G, Goetting M, Rivers E, Feingold M, Nowak R. Aortic pressure during human cardiac arrest: identification of pseudo-electromechanical dissociation. Chest. 1992;101:123-128.

45. Kern KB, Ewy GA. Clinical defibrillation: optimal transthoracic and open-chest techniques. In Tacker WA Jr. Defibrillation of the Heart: ICDS, AEDS, and Manual. St. Louis, Mo: Mosby-Year Book; 1994.

46. Trimble C. Blind defibrillation by basic EMTs. J Am Coll Emerg Phys. 1979;5:543-544.

47. Grace WJ, Kennedy RJ, Nolte CT. Blind defibrillation. Am J Cardiol. 1974;34:115.

48. Hauswald M. Defibrillation in the field: should EMTs interpret rhythms? Am J Emerg Med. 1986;4(3):274-275.

49. Cummins RO, Austin D. The frequency of "occult" ventricular fibrillation masquerading as a flat line in prehospital cardiac arrest. Ann Emerg Med. 1988;17(8):813-817.

50. Hargarten KM, Stueven HA, Waite EM, et al. Prehospital experience with defibrillation of coarse ventricular fibrillation: a ten-year review. Ann Emerg Med. 1990;19(2):157-162.

51. Pionkowski RS, Thompson EM. Gruchow HW, Aprahamian C, Darin JC. Resuscitation time in ventricular fibrillation-a prognostic indicator. Ann Emerg Med. 1983;12:733-738.

52. Flesche CW, Breuer S, Mandel LP, Breivik H, Tarnow J. The ability of health professionals to check the carotid pulse. Circulation. 1994;90(4 pt2):I-288. Abstract.

53. Steinman AM. Cardiopulmonary resuscitation and hypothermia. Circulation. 1985:74(6 pt2):IV 29-32.

54. Stewart JA. Evaluation of a defibrillation training program far noncritical care nurses. Dallas, Tex: Southwestern Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center at Dallas; 1989.

55. Nagel EI, Fine EG, Krischner JP. Complications of CPR. Crit Care Med. 1983;9:424.

56. Sommers MS. Potential for injury: trauma after cardiopulmonary resuscitation. Heart Lung. 1991;20:287-293.

57. Peleska B. Cardiac arrhythmias following condensed discharges and their dependence upon strength of current and phase of the cardiac cycle. Cir Res. 1963;13:21.

58. Kreus KE, Salokannel SJ, Waris EK. Nonsynchronised and synchronised direct-current countershock in cardiac arrhythmias. Lancet. 1966;ii:405-407.

59. Layman TE. Electrical cardioversion resulting in death from synchronization failure. Am J Cardiol. 1995;75:551. Letter.

60. Gibbs W, Eisenberg M, Damon SK. Dangers of defibrillation: Injuries to emergency personnel during patient resuscitation. Am J Emerg Med. 1990;8(2):101-104.

61. Cummins RO, Chesemore K, White RD. Defibrillator failures: causes of problems and recommendations for improvement. Defibrillator Working Group. JAMA. 1990:264:1,019-1,025.

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