Intensive Care M e d i c i n e
Intens. Care med. 5, 49 - 53 (1979)
9 by Springer-Verlag 1979
Editorial
Cardiac Resuscitation Services: Principles and Practice Alan Gilston National Heart Hospital, Westmoreland Street, London W.1, England
"Sudden death from heart attack is the most important medical emergency today" [42]. The combination of the two basic manual techniques of cardiopulmonary resuscitation (CPR), expired air resuscitation and external cardiac massage, is barely twenty years old, but its widespread use has already saved countless lives in patients with "hearts too good to die" [3]. Accidental drowning is second only to road accidents as a cause of sudden death in healthy young people [38], whilst an acute ischemic heart attack [28] is the great killer in older persons, most untreated patients dying before they reach hospital [2]. But in both conditions cardiac arrest is reversible in up to half the cases with immediate CPR, emphasising the important role of public education in the use of "basic life support" techniques [42]. Moreover, the term "unexpected" can hardly be justified in the definition of cardiac arrest nowadays, when so many gravely ill patients in hospital are resuscitated, often successfully. Uncertain in time maybe, but hardly unexpected. The first aim of CPR is to protect the brain with manual techniques (Stage 1 of CPR), and it is here that swift action by the bystanders is vital, and delay lethal. Despite current, and promising, experimental and clinical work on its therapy [41], severe brain damage is inevitable if cerebral blood flow is interrupted for more than three to four minutes at normal body temperature, and delay in initiating resuscitation remains the dominant cause of brain damage from cardiac arrest. Efficient resuscitation usually protects the brain, even though its blood flow and hence its function is greatly impaired [ 19]. Heart action is restored within fifteen minutes in the majority of patients who leave hospital alive after cardiac arrest, "long-term survivors" [ 19]. Various factors play a role in this, and one of the most important is the functional state of the heart before it stops. It is much easier to restore and maintain satisfactory heart action when the myocardium is relatively healthy, and when cardiac arrest is precipitated by a sudden rhythm disturbance [28], "electrical failure" [21]. It is far more difficult when the myocardium is extensively and irreparably damaged, "power failure"J21]. Delay in initiating resus-
citation also affects the results [1,12,31,34], since it not only damages the brain but the myocardium too. "The balance between energy production and energy utilisation is precarious even in the normal myocardial cell" [24] and its oxygen and energy stores are rapidly consumed when coronary blood flow ceases. Ventricular fibrillation, by far the commonest dysrhythmia at the moment of cardiac arrest in adults, [1,37] can accelerate exhaustion of these stores when the heart is diseased [23]. If resuscitation is delayed more than a few minutes, resistant asystole will succeed ventricular fibrillation and the patient is now unlikely to survive [1,15,34,46], for the myocardium is now irreversibly damaged and its cells cannot even generate an electrical signal. Even if heart action is restored, the patient now has a reduced chance of survival [ 14], whereas prompt resuscitation protects the heart. The importance of these various factors is greatly enhanced where the myocardium is in jeopardy even before cardiac arrest, as in ischemic heart disease, for here delay in resuscitation may ensure the death of threatened myocardium and convert electrical failure into power failure. Protracted resuscitation too may be harmful. Ventricular fibrillation interferes with myocardial, and especially subendocardial blood flow, [5,22], and this is aggravated by the low cardiac output and associated low diastolic blood pressure of CPR. Moreover, CPR is often, and in some respects inevitably accompanied by progressive pathophysiological changes [19,36] such as lactic acidosis, hypoxemia, and after major trauma hyperkalemia, and these too can depress the heart and also the brain. But whilst the brain will afterwards gradually recover completely from the ill-effects of protracted resuscitation, the heart must swifty regain satisfactory function whenits actionis restored if the patient is to survive. A good circulation is also vital to the recovery of a brain damaged by delayed resuscitation [18]. It is clear that the best moment for the restoration of heart action is immediately after the onset of cardiac arrest, before these various harmful changes have had time to develop. Immediate countershock for ventricular fibrillation has rightly become the first step in resuscitation in special care Units, and its "blind" use is fully justified 0342-4642/79/0005/0049/$ 01.00
50 if an electrocardiogram is not instantly available, and can do little harm [13]. Certain misconceptions persist in CPR. For various reasons [19] one of the most unfortunate is the easily remmembered, authoritatively recommended and widely taught ABCD sequence [42]. This approach wrongly emphasises the role of artificial ventilation as the first step in CPR, whereas respiratory problems, including respiratory arrest are a far less common, less important cause of cardiac arrest than heart disease, [13,14] except in the gravely ill [6T It is even taught that the operator should pause to observe the effect of several lung inflations before initiating chest compression. Chest thumping is another time-wasting and rarely successful maneuvre. It should be tried only by a physician fully trained in CPR and even then only if the patient is known to have StokesAdams syndrome or is being nursed in a special Unit in the hospital with electrocardiographic and intravascular blood pressure monitoring already established. The brain must be, and can only be protected by the immediate restoration of its circulation, and it is far better to circulate even "black" blood than none at all [19]. In addition, chest compression not only delivers the same energy impulse to the heart as chest thumping, perhaps more, and restores both cerebral and coronary blood flow, but it too may restore heart action with the first few strokes whilst the myocardium is still in an optimal state. Some training programmes emphasise the importance of carotid palpation in the diagnosis of cardiac arrest. But this pulse may not be easily felt even in a normal person, and especially if he is hypotensive or hypothermic, as any experienced anesthesiologist can testify. The femoral pulse is easier, but this too may not be located easily in the obese, and it is unsuitable for a public place. The radial pulse is the best compromise for all but the most experienced operators, and it avoids hesitancy and delay in the diagnosis of cardiac arrest. It is impossible to diagnose brain death with certainty during cardiac resuscitation [19], and widely dilated, fixed pupils, for example, are not reliable evidence. The only reason to abandon resuscitation in the majority of cases is failure to restore and maintain spontaneous heart action (Stage 2 failure of CPR). I have met success after more than three hours, and others have reported a similar experience [7]. Heroic measures lasting many hours in accidental hypothermia, for example, have also proved rewarding [10]. Certainly the decision to stop resuscitation should not be made without reviewing all factors, including the medical status of the patient and all aspects of CPR therapy. The age of the patient is not an important consideration. Once initiated, CPR should be continued for at least one hour. These pathophysiological considerations are highly pertinent to the establishment of a mobile cardiac resuscitation service. But since it is far better to prevent cardiac arrest than treat it, a resuscitation service should be available for any acute, potentially reversible, life-threatening condition, wherever the patient. This is clearly an ideal, and impossible even for technologically advancedcountries.
A. Gilston: Cardiac Resuscitation Services The most that can be achieved is the best use of available facilities and whatever more the community can offer. Moreover, the functions, organisation and problems of a mobile resuscitation service crucially depend on whether it is designed for the hospital or for the whole community outside. Whilst its main function inside hospital is restricted to established cardiac arrest, outside hospital the service should cover a far wider field, in particular the prevention of cardiac arrest and the management of all grave emergencies, whatever their cause. But in hospital or outside, the service can only be one link in the chain of an effective policy. Its members cannot, for example, initiate therapy in every case of cardiac arrest, for this vital step must depend on those present, professionals or laymen, when the emergency appears, "the rescuers". In most cases of cardiac arrest, the primary aims of the service are to continue resuscitation efficiently, to restore and maintain satisfactory spontaneous heart action, and to safely transport the patient to a special Unit for aftercare (Stage 3 of CPR), all as swiftly as possible. In other words, the essential feature of an effective cardiac resuscitation programme is the combination of a trained population, ready to act swiftly, with a highly organised service which can respond immediately and efficiently to every call. Whilst public education is largely voluntary, certain sections of the community are necessarily trained in the basic life support techniques. They include, for example, the police, firemen and armed forces, swimming attendants, and Red Cross and similar first aid workers. Some far-sighted countries teach all their school-children CPR as part of their education [26], the logical and socially correct approach to the problem. Many cities have now established a special coronary care rescue service, following the pioneer lead from Belfast [33] which recognised the dominant role of ischemic heart disease in unexpected cardiac arrest and its potential for recovery. But whilst a round-the-clock physician staffed resuscitation service is possible in hospital, it is not always feasible outside because of its heavy manpower requirements in a densely populated city and its cost, although some centres deny the existence of these factors. For these reasons, coronary care ambulances or other suitable vehicles, whilst specially designed and equipped for cardiac emergencies, are now commonly staffed solely by highly qualified lay attendants, "paramedics" [4,8,17,32]. These paramedics are fully trained not only in the basic life support techniques of CPR but also in advanced life support, including the management of the patient with an acute ischemic attack, and the prevention and treatment of dangerous dysrhythmias with drugs and countershock. Some centres now hold their own training courses with a rigorous qualifying examination [4], whilst in the U.S.A. there is now a nationally recognised programme and certificate [45]. From a medico-legal viewpoint, such training must necessarily be acceptable [39,42]. Although coronary patients form the bulk of dangerous emergencies, in many centres the rescue service has now been extended and expanded to deal
A. Gilston: Cardiac Resuscitation Services with any acute grave problem. Such centres provide mobile intensive care units (MICUs) which can handle not only cardiac problems, but major trauma, near-drowning, poisoning and obstetric and psychiatric emergencies, for example [25]. The patients are treated, "stabilized", on site, and transported to hospital only when they are fit to travel. Currently there are moves to establish national, and even international rescue services for major disasters [16]. These are major extensions of the traditional "collection and delivery" role of the ambulance service. The number of coronary care ambulances varies from city to city. The proper number depends not only on the size of the population at risk but on other factors such as the geography of the area, its traffic patterns, the sites of its hospitals and ambulance centres, and most important, the degree the facility is used by laymen and physicians. Many experts believe that not every patient with an acute ischemic heart attack, but without cardiac arrest, needs admission to hospital. Inevitably, the availability of staff and funds will finally determine whether the ambulances required are supplied. The coronary care ambulance must arrive at the scene swiftly. This is not only because of the urgent needs of cardiac resuscitation, but because of the equal importance of preventing cardiac arrest, if this is possible. A quarter of the deaths from ischemic heart attacks occur within fifteen minutes of onset [37], though unfortunately the majority have no warning symptoms [2]. However, the majority also have no significant myocardial damage [2,28], and can be saved with prompt therapy. Different centres have designed their own methods of establishing rapid and effective communication and coordination between the emergency site, the ambulance service and the hospital. Inevitably most rely on the telephone, though emergency lines reduce delay. In many areas the ambulance arrives at the scene within five minutes or less [4,8,35] and delivers the patient to the hospital shortly afterwards, the accompanying physicians or paramedics having meanwhile initiated appropriate therapy. Some centres maintain constant contact between ambulance and hospital by telemetry, with twoway radio communication and transmission of biological signals [25,34,45]. But others feel this is unnecessary provided the hospital is aware of and prepared for the impending arrival of the patient [8]. Experience in a hospital resuscitation service shows that a special alarm is essential, and combined with visual and widely displayed information about the site it can avoid dependance on the hospital telephone system. With rare exceptions, all cases of cardiac arrest outside hospital should be admitted directly and without delay to a special care Unit for the management not only of the underlying condition and the complications of resuscitation, but in case of a further episode [34]. Clearly a hospital has inherent advantages for the establishment of an effective cardiac resuscitation service, which is largely needed for those areas where skilled staff and facilities are not instantly available, in other words everywhere except for the emergency room, the operating
51 suite and the special care Units. The best way of providing this service is to have a designated and easily summoned resuscitation team. The team should consist of at least two physicians, both free to respond immediately to the alarm whilst on duty, day or night, both trained in CPR techniques, and both young'and fit. More senior colleagues are likely to arrive at the scene out of breath, and soon tire from the exertions of chest compression. Ideally one of the team should be an anesthesiologist (or intensivist) already well-trained in pharmacology, airway and respiratory management, arterial and venous cannulation, and the other techniques commonly used in cardiac and respiratory emergencies. A third person, preferably a trained nurse, is a most useful addition. Her duties include the preparation of drugs, keeping a record of the time and various procedures and drugs and assisting the physicians in other important ways. All resuscitation equipment, whether for the hospital or the ambulance must be portable and the electrical devices battery operated. Most hospitals store and transport the equipment on a trolley for convenience, a "crashcart", though there is no general agreement about its design. Ideally, it should be as simple and as small as possible, though with a good working surface, to allow maximum mobility and close access to the patient even when space is limited. There should also be at least one trolley per floor to avoid delay and dependance on elevators. Heavy, elaborate trollies, specially built around large pieces of equipment, with many drawers and cupboards to house every conceivable item, are impractical, their needless expense being aggravated by their being difficult to adapt to new equipment. Resuscitation equipment is also becoming increasingly available in appropriate public places, especially where there is a dense concentration of people. They include sports stadiums, beaches, airports and large factory or office blocks [37]. These "life support stations" may be staffed by skilled laymen or paramedics. The invention of manual, or power-operated devices, some elaborate and costly, to compress the chest and even ventilate the patient during CPR is in some ways unfortunate. Despite their supposed advantages, there is no evidence they are beneficial. Moreover, they can divert attention from the patient and seriously interrupt resuscitation in its early, critical phase. At most, they have a place in protracted resuscitation or during the transport of the patient. They also have a place in research in the very difficult field of the hemodynamics of clinical resuscitation [43,44], since the compression stroke can be precisely regulated [43,44], a feature which is not essential during resuscitation. A Resuscitation Officer should be responsible for the resuscitation service, though his duties will depend on whether the service is for the hospital or outside. His function is not only to organise and direct its work, cooperating where necessary with other experts and organisations, but to arrange training and refresher courses in CPR, regularly check the equipment, maintain adequate records and resolve problems and inadequacies.
52 Is the effort and expense of cardiac resuscitation worthwhile? Survival rates from cardiac arrest depend on various factors, the most important being the state of the myocardium, the nature of the precipitating lesion [35] and the swiftness and efficiency of resuscitation. Age is also important but not crucial [8,19,29]. Some workers have achieved a long-term survival rate of over forty per cent after cardiac arrest in near-drowning [30]. There are inevitably far more reports on long-term survival in ischemic heart disease [ 1,2,4,9,11 ]. They range from about thirteen per cent up to more than sixty per cent, a figure which refutes the suggested maximum possible success rate of twenty per cent [40]. A minority of experts remain unconvinced of the value of a mobile coronary care service [20], but their views may not bear critical analysis [11]. Recent advances in coronary vascular surgery and circulatory support devices have not only changed the outlook in ischernic heart disease but have dramatically improved the prognosis even for cardiogenic shock and other grave complications, further justifying an aggressive approach to resuscitation. A cardiac resuscitation service clearly cannot be called into action every time a heart stops, for not only is death sooner or later inevitable for everyone, but in hospital, for example, many of the patients have a terminal illness. We now recognise the need to moderate our enthusiasm for all types of resuscitation, including intensive therapy, with the patient's (and his relatives') right to "death with dignity". This ethical dilemma is greater for the layman than for a physician, who can make a proper decision. Fortunately the dilemma is more apparent than real since a layman does not often face such a problem. But one of the main hazards of widespread resuscitation may be an increase in the number of survivors with permanent brain damage from delayed or unskilled resuscitation. For this reason, most trained people carefully avoid starting CPR when cardiac arrest has already been present for at least some minutes, though near-drowning is a most difficult problem in this context, especially if the victim is cold. Reports of brain damage following CPR vary. In most series it has not been a major problem, though one report described brain damage in forty per cent of the survivors, in some cases severe [27]. The great majority of long-term survivors can resume normal life and return to their previous work. But have we now reached a stage, already feared by some, where no one may die without attempted resuscitation by a trained bystander? Another disc to add to the blood-group, kidney-donor, corneadonor, heart-donor chain, "not to be resuscitated"?
References 1. Adgey, A. A. Nelson, P. G. et al.: Management of ventricular fibrillation outside hospital. Lancet 1, 1169 (1969) 2. Baum, R. S., Alvarez, H, Cobb, L. A.: Survival after resuscitation from out of hospital ventricutar fibrillation. Circulation 50, 1231 (1974)
A. Gilston: Cardiac Resuscitation Services 3. Beck, C. S., Leighinger, D. S.: Hearts too good to die our problem. Ohio State Med. J. 56, 1221 (1960) 4. Briggs, R. S. Brown, P. M. et at.: The Brighton resuscitation ambulance: a continuing experiment in pre-hospital care by ambulance staff. Br. Med. J. 2, 1161 (1976) 5. Buckberg, G. D., Hottenrott, C. E.: Ventricular fibrillation: its effect on myocardial flow, distribution and performance. Ann. Thorac. Surg. 20, 76 (1975) 6. Camarata, S. J., Well, M. H. et al.: Cardiac arrest in the critically ill. I. A. Study of predisposing causes in 132 patients. Circulation 44, 688 (1971) 7. Cleveland, J. C.: Complete recovery after cardiac arrest for three hours. New Engl. J. Med. 284,334 (1971) 8. Cobb, L. A., Baum, R. S. et al.: Resuscitation from out of hospital ventricular fibrillation: 4 years follow up. Circulation 51, (Suppl. 3)p. 223 (1975) 9. Conley, M. J., MeNeer, J. F. et al.: Cardiac arrest complicating acute myocardial infarction; predictability mad prognosis. Am. J. CardioL 39, 7 (1977) 10. Coughlin, F.: Heart-warming procedure. New Engl. J. Med. 288, 326 (1973) 11. Crampton, R. S., Aldrich, R. F. et al.: Reduction of prehospital ambulance and community coronary death rates by the community wide cardiac care system. Am. J. Med. 58, 151 (1975) 12. Crampton, R. S., Aldrich, R. F. et al.: Pre-hospital cardiopulmonary resuscitation in acute myocardial infarction. New Engl. J. Med. 286, 1320 (1972) 13. Cranefield, P. F.: Ventricular fibrillation. New. Engl. J. Med. 289, 732 (1973) 14. Editorial: Cardiorespiratory resuscitation: status report. New Engl. J. Med. 286, 1000 (1972) 15. Editorial: Pre-hospital ventricular defibrillation. Lancet 2, 1361 (1974) 16. Frey, R.: The Club of Mainz for improved world wide emergency and critical care medicine systems and disaster preparedness. Crit. Care Med. 6,390 (1978) 17. Gearty, G. F., Hickey, N., et al.: Pre-hospital coronary care service. Br. Med. J. 3, 33 (1971) 18. Gilston, A.: Techniques and complications in cardiac surgery. In: Recent advances in anaesthesia and analgesia, 13th Ed., Hewer, C. L., Atkinson, R. S.(eds.).London and Edinburgh: Churchill-Livingstone 1979 19. Gilston, A., Resnekov, L.: Cardiorespiratory resuscitation. London: Heinemann Medical Books 1971 20. Hampton, J. R., Nicholas, S. C.: Randomised trial of a mobile coronary care unit for emergency calls. Br. Med. J. 1, 1118 (1978) 21. Hellerstein, H. K., Turell, D. J.: The mode of death in coronary artery disease: an electrocardiographic and clinicophathological correlation. In: Sudden cardiac death. Surawicz, B. Pellegrino,E. D. (eds.).New York: Grune and Stratton, 1964 22. Hoffmann, J. I. E., Buckberg, G. D.: Pathophysiology of subendocardial ischemia. Br. Med. J. 1, 76 (1975) 23. Hottenrott, C. E., Towers, B. et al.: The hazards of ventricular fibrillation in hypertrophied ventricles during cardiopulmonary bypass. J. Thorac. Cardiovasc. Surg. 66, 742 (1973) 24. Katz, A.: A new inotropic agent: its promise and a caution. New. Engl. J. Med. 299, 1409 (1978) 25. Lambrew, C. T.: Mobile intensive care. I. Primary transport In: Recent advances in intensive therapy. Ledingham, I. McA. (ed.). London and Edinburgh: Churchill-Livingstone 1977 26. Lind, B.: Teaching resuscitation in primary schools. Der Anaesthesist 22,464 (1973) 27. Lithbertson, R. R., Nagel, E. L. et al.: Pre-hospital ventricular fibrillation: prognosis and follow-up course. New Engl. J. Med. 291,317 (1974) 28. Lovegrove, T., Thompson, P.: The role of acute myocardial infarction in sudden death: a statistician's nightmare. Am. Heart J. 96,711 (1978)
A. Gilston: Cardiac Resuscitation Services 29. Lemire, J. G., Johnson, A. L.: Is cardiac resuscitation worthwhile? A decade of experience. New Engl. J. Med. 286, 970 (1972) 30. Lund, I., Skulberg, A.: Resuscitation of cardiac arrest outside hospital: experiences with a mobile intensive care unit in Oslo. Acta. Anaesthesiol. Scand. 53, 13 (1973) 31. Lund, I., Skulberg, A.: Cardiopulmonary resuscitation by lay people. Lancet 2, 702 (1976) 32. Mackintosh, A. F., Crabb, M. E. et al.: The Brighton resuscitation ambulance: review of 40 consecutive survivors of out-of-hospital cardiac arrest. Br. Med. J. 1, 1115 (1978) 33. Pantridge, J. F., Geddes, J. S.: A mobile Intensive Care Unit in the management of myocardial infarction. Lancet 2, 271 (1967) 34. Pantridge, J.F., Adgey, A.A.J.: The pre-hospital phase of acute myocardial infarction. In: Textbook of coronary care. Meltzer, L.E., Dunning, A.J. (eds.). Amsterdam: Excerpta Medica 1972 35. Peatfield, I.: Towards more selective resuscitation. Am. Heart J. 96,698 (1978) 36. Rackwitz, V. R., Jahrmarker, H. et al.: Pathogenese und therapie der azidose bei reanimation. Intensivmedizin 12, 1 (1975) 37. Report of a Joint Working Party at the Royal College of Physicians of London and the British Cardiac Society, J. Roy. Coil. Phys. 10, 5 (1975) 38. Report of a Subcommittee of the Standing Advisory Committee: Uses and Dangers of Oxygen Therapy 1969. (Her Majesty's Stationery Office, Edinburgh)
53 39. Rose, L. B., Press, C.: Cardiac defribillation by ambulance attendants. J. Am. Med. Assoc. 219, 63 (1972) 40. Simon, A. B., Alonzo, H. A.: Sudden death in non-hospitalised cardiac patients. An epidemiologic study with implications for intervention techniques. Arch. Int. Med. 132, 163 (1973) 41. Special Symposium: Brain resuscitation. Crit. Care Med. 6, 4 (1978) 42. Standards for Cardiopulmonary Resuscitation (CPR) and Emergency Cardiac Care (ECC). J. Am. Med. Assoc. 227, 833 (1974) 43. Taylor, G. J., Tucker, W. M. et al.: Prolonged compression during cardiopulmonary resuscitation in man. New Engl. J. Med. 296, 1515 (1977) 44. Vaagenes, P., Lund, I. et al.: On the technique of external cardiac compression. Crit Care Med. 6,176 (1978) 45. White, R. D., O'Donovan, T. P. B.: Pre-hospital life-support systems in traumatic and cardiac emergencies. Anaesth. Analg. Curt. Res. 53,734 (1974) 46. Wildsmith, J. A. W., Dennyson, W. G., Myers, K. W.: Results of resuscitation following cardiac arrest. Br. J. Anesth. 44, 716 (1972) Dr. Alan Gilston Consultant Anaesthetist National Heart Hospital Westmoreland Street London W. 1 England
Intens. Care med. 5, 49 - 53 (1979)
9 by Springer-Verlag 1979
Editorial
Cardiac Resuscitation Services: Principles and Practice Alan Gilston National Heart Hospital, Westmoreland Street, London W.1, England
"Sudden death from heart attack is the most important medical emergency today" [42]. The combination of the two basic manual techniques of cardiopulmonary resuscitation (CPR), expired air resuscitation and external cardiac massage, is barely twenty years old, but its widespread use has already saved countless lives in patients with "hearts too good to die" [3]. Accidental drowning is second only to road accidents as a cause of sudden death in healthy young people [38], whilst an acute ischemic heart attack [28] is the great killer in older persons, most untreated patients dying before they reach hospital [2]. But in both conditions cardiac arrest is reversible in up to half the cases with immediate CPR, emphasising the important role of public education in the use of "basic life support" techniques [42]. Moreover, the term "unexpected" can hardly be justified in the definition of cardiac arrest nowadays, when so many gravely ill patients in hospital are resuscitated, often successfully. Uncertain in time maybe, but hardly unexpected. The first aim of CPR is to protect the brain with manual techniques (Stage 1 of CPR), and it is here that swift action by the bystanders is vital, and delay lethal. Despite current, and promising, experimental and clinical work on its therapy [41], severe brain damage is inevitable if cerebral blood flow is interrupted for more than three to four minutes at normal body temperature, and delay in initiating resuscitation remains the dominant cause of brain damage from cardiac arrest. Efficient resuscitation usually protects the brain, even though its blood flow and hence its function is greatly impaired [ 19]. Heart action is restored within fifteen minutes in the majority of patients who leave hospital alive after cardiac arrest, "long-term survivors" [ 19]. Various factors play a role in this, and one of the most important is the functional state of the heart before it stops. It is much easier to restore and maintain satisfactory heart action when the myocardium is relatively healthy, and when cardiac arrest is precipitated by a sudden rhythm disturbance [28], "electrical failure" [21]. It is far more difficult when the myocardium is extensively and irreparably damaged, "power failure"J21]. Delay in initiating resus-
citation also affects the results [1,12,31,34], since it not only damages the brain but the myocardium too. "The balance between energy production and energy utilisation is precarious even in the normal myocardial cell" [24] and its oxygen and energy stores are rapidly consumed when coronary blood flow ceases. Ventricular fibrillation, by far the commonest dysrhythmia at the moment of cardiac arrest in adults, [1,37] can accelerate exhaustion of these stores when the heart is diseased [23]. If resuscitation is delayed more than a few minutes, resistant asystole will succeed ventricular fibrillation and the patient is now unlikely to survive [1,15,34,46], for the myocardium is now irreversibly damaged and its cells cannot even generate an electrical signal. Even if heart action is restored, the patient now has a reduced chance of survival [ 14], whereas prompt resuscitation protects the heart. The importance of these various factors is greatly enhanced where the myocardium is in jeopardy even before cardiac arrest, as in ischemic heart disease, for here delay in resuscitation may ensure the death of threatened myocardium and convert electrical failure into power failure. Protracted resuscitation too may be harmful. Ventricular fibrillation interferes with myocardial, and especially subendocardial blood flow, [5,22], and this is aggravated by the low cardiac output and associated low diastolic blood pressure of CPR. Moreover, CPR is often, and in some respects inevitably accompanied by progressive pathophysiological changes [19,36] such as lactic acidosis, hypoxemia, and after major trauma hyperkalemia, and these too can depress the heart and also the brain. But whilst the brain will afterwards gradually recover completely from the ill-effects of protracted resuscitation, the heart must swifty regain satisfactory function whenits actionis restored if the patient is to survive. A good circulation is also vital to the recovery of a brain damaged by delayed resuscitation [18]. It is clear that the best moment for the restoration of heart action is immediately after the onset of cardiac arrest, before these various harmful changes have had time to develop. Immediate countershock for ventricular fibrillation has rightly become the first step in resuscitation in special care Units, and its "blind" use is fully justified 0342-4642/79/0005/0049/$ 01.00
50 if an electrocardiogram is not instantly available, and can do little harm [13]. Certain misconceptions persist in CPR. For various reasons [19] one of the most unfortunate is the easily remmembered, authoritatively recommended and widely taught ABCD sequence [42]. This approach wrongly emphasises the role of artificial ventilation as the first step in CPR, whereas respiratory problems, including respiratory arrest are a far less common, less important cause of cardiac arrest than heart disease, [13,14] except in the gravely ill [6T It is even taught that the operator should pause to observe the effect of several lung inflations before initiating chest compression. Chest thumping is another time-wasting and rarely successful maneuvre. It should be tried only by a physician fully trained in CPR and even then only if the patient is known to have StokesAdams syndrome or is being nursed in a special Unit in the hospital with electrocardiographic and intravascular blood pressure monitoring already established. The brain must be, and can only be protected by the immediate restoration of its circulation, and it is far better to circulate even "black" blood than none at all [19]. In addition, chest compression not only delivers the same energy impulse to the heart as chest thumping, perhaps more, and restores both cerebral and coronary blood flow, but it too may restore heart action with the first few strokes whilst the myocardium is still in an optimal state. Some training programmes emphasise the importance of carotid palpation in the diagnosis of cardiac arrest. But this pulse may not be easily felt even in a normal person, and especially if he is hypotensive or hypothermic, as any experienced anesthesiologist can testify. The femoral pulse is easier, but this too may not be located easily in the obese, and it is unsuitable for a public place. The radial pulse is the best compromise for all but the most experienced operators, and it avoids hesitancy and delay in the diagnosis of cardiac arrest. It is impossible to diagnose brain death with certainty during cardiac resuscitation [19], and widely dilated, fixed pupils, for example, are not reliable evidence. The only reason to abandon resuscitation in the majority of cases is failure to restore and maintain spontaneous heart action (Stage 2 failure of CPR). I have met success after more than three hours, and others have reported a similar experience [7]. Heroic measures lasting many hours in accidental hypothermia, for example, have also proved rewarding [10]. Certainly the decision to stop resuscitation should not be made without reviewing all factors, including the medical status of the patient and all aspects of CPR therapy. The age of the patient is not an important consideration. Once initiated, CPR should be continued for at least one hour. These pathophysiological considerations are highly pertinent to the establishment of a mobile cardiac resuscitation service. But since it is far better to prevent cardiac arrest than treat it, a resuscitation service should be available for any acute, potentially reversible, life-threatening condition, wherever the patient. This is clearly an ideal, and impossible even for technologically advancedcountries.
A. Gilston: Cardiac Resuscitation Services The most that can be achieved is the best use of available facilities and whatever more the community can offer. Moreover, the functions, organisation and problems of a mobile resuscitation service crucially depend on whether it is designed for the hospital or for the whole community outside. Whilst its main function inside hospital is restricted to established cardiac arrest, outside hospital the service should cover a far wider field, in particular the prevention of cardiac arrest and the management of all grave emergencies, whatever their cause. But in hospital or outside, the service can only be one link in the chain of an effective policy. Its members cannot, for example, initiate therapy in every case of cardiac arrest, for this vital step must depend on those present, professionals or laymen, when the emergency appears, "the rescuers". In most cases of cardiac arrest, the primary aims of the service are to continue resuscitation efficiently, to restore and maintain satisfactory spontaneous heart action, and to safely transport the patient to a special Unit for aftercare (Stage 3 of CPR), all as swiftly as possible. In other words, the essential feature of an effective cardiac resuscitation programme is the combination of a trained population, ready to act swiftly, with a highly organised service which can respond immediately and efficiently to every call. Whilst public education is largely voluntary, certain sections of the community are necessarily trained in the basic life support techniques. They include, for example, the police, firemen and armed forces, swimming attendants, and Red Cross and similar first aid workers. Some far-sighted countries teach all their school-children CPR as part of their education [26], the logical and socially correct approach to the problem. Many cities have now established a special coronary care rescue service, following the pioneer lead from Belfast [33] which recognised the dominant role of ischemic heart disease in unexpected cardiac arrest and its potential for recovery. But whilst a round-the-clock physician staffed resuscitation service is possible in hospital, it is not always feasible outside because of its heavy manpower requirements in a densely populated city and its cost, although some centres deny the existence of these factors. For these reasons, coronary care ambulances or other suitable vehicles, whilst specially designed and equipped for cardiac emergencies, are now commonly staffed solely by highly qualified lay attendants, "paramedics" [4,8,17,32]. These paramedics are fully trained not only in the basic life support techniques of CPR but also in advanced life support, including the management of the patient with an acute ischemic attack, and the prevention and treatment of dangerous dysrhythmias with drugs and countershock. Some centres now hold their own training courses with a rigorous qualifying examination [4], whilst in the U.S.A. there is now a nationally recognised programme and certificate [45]. From a medico-legal viewpoint, such training must necessarily be acceptable [39,42]. Although coronary patients form the bulk of dangerous emergencies, in many centres the rescue service has now been extended and expanded to deal
A. Gilston: Cardiac Resuscitation Services with any acute grave problem. Such centres provide mobile intensive care units (MICUs) which can handle not only cardiac problems, but major trauma, near-drowning, poisoning and obstetric and psychiatric emergencies, for example [25]. The patients are treated, "stabilized", on site, and transported to hospital only when they are fit to travel. Currently there are moves to establish national, and even international rescue services for major disasters [16]. These are major extensions of the traditional "collection and delivery" role of the ambulance service. The number of coronary care ambulances varies from city to city. The proper number depends not only on the size of the population at risk but on other factors such as the geography of the area, its traffic patterns, the sites of its hospitals and ambulance centres, and most important, the degree the facility is used by laymen and physicians. Many experts believe that not every patient with an acute ischemic heart attack, but without cardiac arrest, needs admission to hospital. Inevitably, the availability of staff and funds will finally determine whether the ambulances required are supplied. The coronary care ambulance must arrive at the scene swiftly. This is not only because of the urgent needs of cardiac resuscitation, but because of the equal importance of preventing cardiac arrest, if this is possible. A quarter of the deaths from ischemic heart attacks occur within fifteen minutes of onset [37], though unfortunately the majority have no warning symptoms [2]. However, the majority also have no significant myocardial damage [2,28], and can be saved with prompt therapy. Different centres have designed their own methods of establishing rapid and effective communication and coordination between the emergency site, the ambulance service and the hospital. Inevitably most rely on the telephone, though emergency lines reduce delay. In many areas the ambulance arrives at the scene within five minutes or less [4,8,35] and delivers the patient to the hospital shortly afterwards, the accompanying physicians or paramedics having meanwhile initiated appropriate therapy. Some centres maintain constant contact between ambulance and hospital by telemetry, with twoway radio communication and transmission of biological signals [25,34,45]. But others feel this is unnecessary provided the hospital is aware of and prepared for the impending arrival of the patient [8]. Experience in a hospital resuscitation service shows that a special alarm is essential, and combined with visual and widely displayed information about the site it can avoid dependance on the hospital telephone system. With rare exceptions, all cases of cardiac arrest outside hospital should be admitted directly and without delay to a special care Unit for the management not only of the underlying condition and the complications of resuscitation, but in case of a further episode [34]. Clearly a hospital has inherent advantages for the establishment of an effective cardiac resuscitation service, which is largely needed for those areas where skilled staff and facilities are not instantly available, in other words everywhere except for the emergency room, the operating
51 suite and the special care Units. The best way of providing this service is to have a designated and easily summoned resuscitation team. The team should consist of at least two physicians, both free to respond immediately to the alarm whilst on duty, day or night, both trained in CPR techniques, and both young'and fit. More senior colleagues are likely to arrive at the scene out of breath, and soon tire from the exertions of chest compression. Ideally one of the team should be an anesthesiologist (or intensivist) already well-trained in pharmacology, airway and respiratory management, arterial and venous cannulation, and the other techniques commonly used in cardiac and respiratory emergencies. A third person, preferably a trained nurse, is a most useful addition. Her duties include the preparation of drugs, keeping a record of the time and various procedures and drugs and assisting the physicians in other important ways. All resuscitation equipment, whether for the hospital or the ambulance must be portable and the electrical devices battery operated. Most hospitals store and transport the equipment on a trolley for convenience, a "crashcart", though there is no general agreement about its design. Ideally, it should be as simple and as small as possible, though with a good working surface, to allow maximum mobility and close access to the patient even when space is limited. There should also be at least one trolley per floor to avoid delay and dependance on elevators. Heavy, elaborate trollies, specially built around large pieces of equipment, with many drawers and cupboards to house every conceivable item, are impractical, their needless expense being aggravated by their being difficult to adapt to new equipment. Resuscitation equipment is also becoming increasingly available in appropriate public places, especially where there is a dense concentration of people. They include sports stadiums, beaches, airports and large factory or office blocks [37]. These "life support stations" may be staffed by skilled laymen or paramedics. The invention of manual, or power-operated devices, some elaborate and costly, to compress the chest and even ventilate the patient during CPR is in some ways unfortunate. Despite their supposed advantages, there is no evidence they are beneficial. Moreover, they can divert attention from the patient and seriously interrupt resuscitation in its early, critical phase. At most, they have a place in protracted resuscitation or during the transport of the patient. They also have a place in research in the very difficult field of the hemodynamics of clinical resuscitation [43,44], since the compression stroke can be precisely regulated [43,44], a feature which is not essential during resuscitation. A Resuscitation Officer should be responsible for the resuscitation service, though his duties will depend on whether the service is for the hospital or outside. His function is not only to organise and direct its work, cooperating where necessary with other experts and organisations, but to arrange training and refresher courses in CPR, regularly check the equipment, maintain adequate records and resolve problems and inadequacies.
52 Is the effort and expense of cardiac resuscitation worthwhile? Survival rates from cardiac arrest depend on various factors, the most important being the state of the myocardium, the nature of the precipitating lesion [35] and the swiftness and efficiency of resuscitation. Age is also important but not crucial [8,19,29]. Some workers have achieved a long-term survival rate of over forty per cent after cardiac arrest in near-drowning [30]. There are inevitably far more reports on long-term survival in ischemic heart disease [ 1,2,4,9,11 ]. They range from about thirteen per cent up to more than sixty per cent, a figure which refutes the suggested maximum possible success rate of twenty per cent [40]. A minority of experts remain unconvinced of the value of a mobile coronary care service [20], but their views may not bear critical analysis [11]. Recent advances in coronary vascular surgery and circulatory support devices have not only changed the outlook in ischernic heart disease but have dramatically improved the prognosis even for cardiogenic shock and other grave complications, further justifying an aggressive approach to resuscitation. A cardiac resuscitation service clearly cannot be called into action every time a heart stops, for not only is death sooner or later inevitable for everyone, but in hospital, for example, many of the patients have a terminal illness. We now recognise the need to moderate our enthusiasm for all types of resuscitation, including intensive therapy, with the patient's (and his relatives') right to "death with dignity". This ethical dilemma is greater for the layman than for a physician, who can make a proper decision. Fortunately the dilemma is more apparent than real since a layman does not often face such a problem. But one of the main hazards of widespread resuscitation may be an increase in the number of survivors with permanent brain damage from delayed or unskilled resuscitation. For this reason, most trained people carefully avoid starting CPR when cardiac arrest has already been present for at least some minutes, though near-drowning is a most difficult problem in this context, especially if the victim is cold. Reports of brain damage following CPR vary. In most series it has not been a major problem, though one report described brain damage in forty per cent of the survivors, in some cases severe [27]. The great majority of long-term survivors can resume normal life and return to their previous work. But have we now reached a stage, already feared by some, where no one may die without attempted resuscitation by a trained bystander? Another disc to add to the blood-group, kidney-donor, corneadonor, heart-donor chain, "not to be resuscitated"?
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53 39. Rose, L. B., Press, C.: Cardiac defribillation by ambulance attendants. J. Am. Med. Assoc. 219, 63 (1972) 40. Simon, A. B., Alonzo, H. A.: Sudden death in non-hospitalised cardiac patients. An epidemiologic study with implications for intervention techniques. Arch. Int. Med. 132, 163 (1973) 41. Special Symposium: Brain resuscitation. Crit. Care Med. 6, 4 (1978) 42. Standards for Cardiopulmonary Resuscitation (CPR) and Emergency Cardiac Care (ECC). J. Am. Med. Assoc. 227, 833 (1974) 43. Taylor, G. J., Tucker, W. M. et al.: Prolonged compression during cardiopulmonary resuscitation in man. New Engl. J. Med. 296, 1515 (1977) 44. Vaagenes, P., Lund, I. et al.: On the technique of external cardiac compression. Crit Care Med. 6,176 (1978) 45. White, R. D., O'Donovan, T. P. B.: Pre-hospital life-support systems in traumatic and cardiac emergencies. Anaesth. Analg. Curt. Res. 53,734 (1974) 46. Wildsmith, J. A. W., Dennyson, W. G., Myers, K. W.: Results of resuscitation following cardiac arrest. Br. J. Anesth. 44, 716 (1972) Dr. Alan Gilston Consultant Anaesthetist National Heart Hospital Westmoreland Street London W. 1 England
