lourrial of Internal Medicine 1991 : 2 2 9 : 331-335
Cause of death in unsuccessful prehospital resuscitation T. SILFVAST From the Prehospital Emergency Care Unit. Helsinki University Central Hospital and Helsinki City Fire Ilepartment. Helsinki, Finland
Abstract. Silfvast T (Prehospital Emergency Care Unit, Helsinki University Central Hospital and Helsinki City Fire Department, Helsinki, Finland). Cause of death in unsuccessful prehospital resuscitation. Journal of Znternirl Medicine 1991 : 229 : 331-335.
During 1987-1988, prehospital resuscitation was unsuccessful in 2 0 4 of 381 patients who suffered a witnessed cardiac arrest due to presumed coronary heart disease in Helsinki. The cause of death was verified by autopsy in 80 (39%) of the 2 0 4 patients. Their cause of death could not be estimated on the basis of previous patient history, and their autopsy diagnoses were then related to the initial cardiac rhythm recorded at the scene. At autopsy, coronary heart disease was considered to have been the cause of death in 78% of the patients with ventricular fibrillation, in 43% of the patients with elettromechanical dissociation (EMD),and in 60% of the patients in asystole. Cardiac tamponade or massive pulmonary embolism was the cause of death in 15 of the 28 patients with EMD who underwent autopsy. These findings support previously noted relationships between some causes of cardiac arrest and the initial cardiac rhythm, and also in prehospital cardiac arrest patients with unsuccessful resuscitation. Keywords: cause of death. prehospital care, resuscitation.
Introduction Information on the cause of cardiac arrest of prehospital patients is derived mainly from successfully resuscitated patients [l,21, whereas fewer data are available on the patients who do not respond to prehospital resuscitation [3, 41. In unsuccessful resuscitation, the cause of death may be estimated on the basis of existing patient documentation, or it may be verified by autopsy. The following study was undertaken to analyse the data for cardiac arrest patients with unsuccessful prehospital resuscitation in Helsinki. It includes all patients who were not successfully resuscitated from a witnessed cardiac arrest due to presumed coronary heart disease during 1987-1988. and the cause of death of the patients who underwent autopsy was studied in relation to the initial cardiac rhythm.
Methods Organization of the emergency medical system
The tiered emergency medical system in Helsinki is Abbreviations: Eh4D = electromechanical dissociation, VF = ventricular fibrillation.
administered by the Fire Department, which responds to approximately 3 1000 urgent calls annually. The 500000 inhabitants of Helsinki are served by ordinary ambulances and one physician staffed emergency care unit. This unit is dispatched together with an ambulance in life-threatening emergencies. The ambulances, based at six Ere stations, are manned by two basic emergency medical technicians. In cardiac arrest, the emergency medical technicians manning the geographically closest ambulance initiate basic life support, while advanced life support could only be initiated upon the arrival of the emergency care unit until 1989, i.e. during the study period. The emergency medical system is activated by the regional alarm centre to which all emergency calls in the city are diverted. A national emergency phone number (000) is in operation. For every patient treated by the emergency care unit, information was recorded on a special form (trip sheet), which contained information on the response t i e for both basic life support and advanced life support, data on the patient's history as obtained at the scene of the emergency, the initial cardiac rhythm and the treatment given. The presumed cause of arrest was also recorded on the trip sheet 33 1
14
IMB 2 2 9
332
T. SILFVAST
No resl;scit (n.54;
I
1
All other arrests ( n 128)
-
Witnessed arrest due to presumed coronary couse ( n = 381 1
resuscitation (n.204)
(i.e., coronary heart disease, obvious non-coronary disease such as trauma, drug overdose). The response time for basic life support was taken to be the time period that elapsed between alerting the emergency medical technicians and their arrival on the scene. The response time for advanced life support was the time that elapsed between alerting the emergency medical technicians and the arrival of the emergency care unit. The initial cardiac rhythm in cardiac arrest was classified as ventricular fibrillation (VF), ventricular tachycardia, asystole or electromechanical dissociation (EMD).The data for three patients with ventricular tachycardia were analysed together with the data for the patients with VF. The cardiac rhythm was determined, using the paddles of the cardioscope, immediately upon arrival of the emergency care unit. After defibrillation of VF, the electrodes of the cardioscope were attached. EMD was defined as any
Fig. I . Patients with prehospital cardiac arrest in Helsinki during the period 1987-1988.
organized electrical rhythm in the heart of less than 100 beats min-' in the absence of a palpable femoral or carotid pulse and lacking heart sounds on auscultation. Electrical rhythms of both narrow and broad complexes were regarded as EMD. because the outcome for the two morphologies appears to be equally poor [4, 51. The arrest was classified as witnessed if it was directly seen or heard. Treatment of cardiac arrest was according to the guidelines issued by the American Heart Association in 1986 [6]. The emergency medical technicians initiated basic life support in every patient in cardiac arrest without postmortem lividity. On arrival of the emergency care unit, the decision to initiate advanced life support (i.e. to resuscitate) or to discontinue basic life support was made. If the physician decided not to initiate advanced life s u p port, the patient was declared dead and taken to the morgue by a different system. Advanced life support
333
UNSUCCESSFUL PREHOSPITAL RESUSCITATION
is not initiated in approximately 5 0 % of cardiac arrest calls in Helsinki. These patients are recorded as dead on the scene, and they are not included in the present study. The patients in whom advanced life support measures are initiated are referred to as patients with attempted resuscitation. If the patient does not regain spontaneous circulation at the site of the event, resuscitation is terminated as unsuccessful and a copy of the trip sheet is left with the patient. The police are notified, and the patient is transported to the forensic department. If an autopsy is not required by law (e.g. suspected suicide, sudden death of a previously healthy individual), the patient's own physician is contacted by the police. If the physician considers the existing patient documentation sufficient to estimate the cause of death, the death certificate is written without an autopsy. However, if the physician considers that the cause of death cannot be estimated on the basis of the patient files, a n autopsy is performed at the forensic department. A copy of the report is sent to the physician of the emergency care unit. During the study period, resuscitation was attempted in 509 of the 1052 prehospital cardiac arrest patients who were seen by the emergency care unit (Fig. 1). The arrest was unwitnessed or due to an obvious non-coronary cause in 128 of the patients with attempted resuscitation, and they were excluded from subsequent analyses. Of the remaining 381 patients who suffered a witnessed arrest due. to presumed coronary heart disease, resuscitation was unsuccessful in 2 0 4 cases. The statistical analysis included the unpaired Student's t-test for parametric data and the Chisquare test for non-parametric data.
the patients without autopsy were VF in 63%, EMD in 2 6 % and asystole in 11 % of the patients. In 4 2 of the 80 patients who underwent autopsy, the initial cardiac rhythm was VF. The mean age of these patients, 53 years, was lower than that of the patients in VF who did not undergo autopsy ( 6 5 years, P c 0.005). At autopsy, coronary heart disease was considered to have caused the arrest in 33 (78%) patients (Table 2). EMD was the initial cardiac rhythm in 28 of the patients who underwent autopsy. There was no difference in mean age between the patients in EMD with and without autopsy (67 and 71 years, respectively). At autopsy, coronary heart disease was considered to have been the cause of death in 1 2 (43%) patients (Table 2). In four of these patients, ruptured myocardium with cardlac tamponade complicating myocardial infarction was the cause of death. Fifteen (54%) patients were found to have a non-coronary cause of death at autopsy. Massive pulmonary embolism was the ctiuse of death in six patients, and cardiac tamponade due to a dissecting aortic aneurysm was the cause of death in five patients (Table 2). Of the patients with cardiac tamponade, two with ruptured myocardium and two with a dissecting aortic aneurysm collapsed without preceding symptoms. Of the remaining patients with this condition, one expressed anferior neck pain and one had chest pain before cardiac arrest. Four of the patients with pulmonary embolism had a short episode of dyspnoea of acute onset prior to collapse. In no instance did the physician at the scene express suspicion of such conditions on the trip sheet, but notes on persistent cyanosis and distended jugular Table 1 . Characteristics of patients with unsuccessful prehospital resuscitation Autopsy not performed
Results An autopsy was performed in 80 (39%) of the 2 0 4 patients with unsuccessful resuscitation, whereas the probable cause of death was estimated without a n autopsy in 1 2 4 patients (Table 1). The mean age (58 years) of the patients who underwent autopsy was lower than that of the patients without autopsy (67 years, P < 0.005). The patients were reached with similar delays for basic and advanced life support. The initial cardiac rhythm was VF in 53%, EMD in 3 5 % and asystole in 1 2 % of the patients who underwent autopsy. The corresponding values for
No. of patients Mean age ( fSD) (years) Sex (M/F)
124 67
* 11
9313 1
Mean response time ( + SE) (min) Basic life support 6 . 2k 0 . 2 11.6 f 0.4 Advanced life support Initial cardiac rhythm (VF/EMD/asystole)
78/32/14
* P c 0.005 compared with patients who VF = ventricular fibrillation, EMD dissociation.
Autopsy performed
80
58+15* 56/24
6.4f0.3 12.3 k 0 . 6 42/28/10
were not autopsied.
= electromechanical
14-2
334
T. SILFVAST
Table 2. Autopsy diagnoses of patients with unsuccessful
prehospital resuscitation
No. of patients Age
(*SD) (years)
Diagnosis (n) Coronary heart disease Non-coronary heart disease Other non-coronary disease Pulmonary embolism Dissecting aortic aneurysm with cardiac tamponade Ruptured abdominal aortic aneurysm lntracerebral haemorrhrage Intoxication Other causest
Ventricular fibrillation
Electromechanical dissociation Asystole
42
28
10
53k12
67k16
53k16
33
12.
5
3
1
1
-
6
2
-
5
-
-
2
-
-
-
1
1
-
1
5
2
-
Includes four patients with ruptured myocardium and cardiac tamponade complicating myocardial infarction. t Includes sepsis, pneumonia and epilepsy.
veins were made for four of these patients. The patients' previous history, as obtained at the scene, did not provide any clues as to the cause of arrest of the patients. Ten of the patients who underwent autopsy had asystole as initial cardiac rhythm (Table 2). The mean age of these patients was 53 years, and that of the patients in asystole without autopsy was 6 4 years (NS). Coronary heart disease was considered to have been the cause of arrest in five of the 10 patients who underwent autopsy, and five patients had a non-coronary cause of arrest (Table 2).
Discussion Most of the available data on the cause of cardiac arrest in prehospital patients deal with successfully resuscitated patients [2, 7, 81. Several reports have also included hospitalized patients [l,3, 91, whose cause of arrest may be assumed to be different from that of patients who suddenly collapse outside hospital. Patients successfully resuscitated from VF frequently suffer from coronary heart disease [10121, whereas autopsy findings in hospitalized cardiac
arrest patients with EMD have shown this rhythm also to be associated with non-coronary conditions such as pulmonary embolism or cardiac tamponade [3]. The cause of arrest of prehospital patients who are not successfully resuscitated has not been extensively studied [4]. It must be borne in mind that the present study partly consists of selected patients in that an autopsy was performed on those subjects whose cause of death, as judged by the patient's own physician, could not be estimated. This probably explains the finding that the patients who underwent autopsy were younger than the patients whose cause of death was estimated without an autopsy. On the other hand, the proportion of patients with VF, EMD and asystole was similar for the patients with and without autopsy. This implies that the patients were not selected for autopsy on the basis of the initial cardiac rhythm. Coronary heart disease was considered to have been the cause of death in 78% of the patients who underwent autopsy after unsuccessful resuscitation from VF. This figure is consistent with those reported for patients successfully resuscitated from this rhythm [lo-121. The finding that 68% of the patients who were not successfully resuscitated from EMD at autopsy displayed a complication of coronary heart disease or a non-coronary cause of death despite presumed coronary heart disease was surprising. It suggests that the poor primary success of resuscitation of patients with EMD [l,131 could be explained by a fatal underlying cause of arrest in many patients. The majority of these autopsy diagnoses were cardiovascular emergencies described as causing EMD [14], but little is known about the proportion of these cases in patients for whom prehospital resuscitation was unsuccessful. Some indices may be available to the rescuer (e.g. persistent central cyanosis) and thus help us to understand why the patient does not respond to resuscitation. In this study, some clinical signs were recorded on the trip sheet, but they did not appear to be interpreted. Because of the very poor prognosis for the patient with prehospital cardiac arrest due to pulmonary embolism or cardiac tamponade. the identification of these conditions would prove valuable, particularly when limited prehospital advanced life support resources must be distributed simultaneously to different locations. The patients in asystole showed a similar trend with regard to non-coronary autopsy findings, despite presumed coronary heart disease, although
UNSUCCESSFUL PREHOSPITAL RESUSCITATION
335
the number of patients was small. Asystole as the initial electrocardiographic recording in cardiac arrest is often the result of lengthy delays before the patient is reached: as the delay increases, asystole as the terminal ‘rhythm ’ will become more frequent. In patients who are reached within minutes after witnessed cardiac arrest, as in the present study, asystole is probably a primary event. In some patients it reflects a non-coronary cause of arrest, partly explaining the poor prognosis noted for these patients as well [2, 151. Depending on the emergency medical system, the prehospital cardiac arrest patient who does not respond to resuscitation may not present at the hospital at all, and the cause of arrest may remain unknown to the parties involved. Discrepancies between the clinical and autopsy diagnoses of hospitalized patients have shown that assessment of the cause of death based on patient history is unreliable [16, 171. One would expect this to be true in prehospital patients as well. In an autopsy study of 100 adults who died suddenly outside hospital apparently without unnatural cause or manner, Lundberg and Voigt [18] found that 51 of the patients had a non-coronary cause of death. For example, pulmonary embolism, a condition which has also been shown to be frequently underdiagnosed in hospitalized patients [19, 201, was the cause of death in eight of their patients. In this study, 38 % of the patients who underwent autopsy died from noncoronary causes, a Ending consistent with that of Lundberg and Voigt. The vast majority of coronary causes of death shown at autopsy among the patients in VF, and the high proportion of non-coronary causes among the patients in EMD. suggests that there is also a relationship between the initial cardiac rhythm and the cause of arrest in many prehospital patients who do not respond to resuscitation. Particularly when the initial cardiac rhythm has been EMD, it seems possible that some non-coronary causes are missed when the cause of death is estimated solely on the basis of existing patient files. In these patients, the autopsy may provide a means of learning more about sudden prehospital death.
20
References
Received 29 December 1989, accepted 27 September 1990.
1 Mgren E. Kelsey S. Sutton K. Safar P and The Brain
Resuscitation Clinical Trial I Study Group. The presenting ECC
2
3
4
5
6
7
8
9
10
1
2
3
14
15
16 17
18
19
pattern in survivors of cardiac arrest and its relation to the subsequent long-term survival. Actn Anaesthesiol Scand 1989 : 33: 265-71. Myerburg R. Conde C. Sung R et al. Clinical, electrophysiologic and hemodynamic profile of patients resuscitated from prehospital cardiac arrest. Am 1 Med 1980: 68: 568-76. Pirolo 1. Hutchins G. Moore W. Electromechanical dissocI iation : pathologic explanations in 50 patients. H U ~ Pathol 1985: 16: 485-7. lseri L. Humphrey S. Siner E. Prehospital brady-asystolic cardiac arrest. Ann Intern Med 1978: 88: 741-5. Weaver D. Cobb L. Hallstrom A, Copass MK. Ray R. Emery M. Fahrenbruch C. Considerations for improving survival from out-of-hospital cardiac arrest. Ann Emerg Med 1986; 15: 1181-6. American Heart Association. Standards and guidelines for cardiopulmonary resuscitation and emergency cardiac care. 1 Am Med Assoc 1986: 255: 2841-3044. Stueven H. Aufderheide T. Wake 11. Mateer J. Electromechanical dissociation : six years prehospital experience. Resuscitation 1989; 17: 173-82. Sutton-Tyrrell K. Abramson NS. Safar P et al. Predictors of electromechanical dissociation during cardiac arrest. Ann Emerg Med 1988; 17: 572-5. Vincent J , Thijs L. Weil M. Michaels S. Silverberg, A. Clinical and experimental studies on electromechanical dissociation. Circulation 198 1 : 64: 1 8-2 7. Myerburg RJ. Kessler KM. Estes D et a/. Long-term survival after prehospital cardiac arrest: analysis of outcome during an 8-year study. Circulation 1984: 70: 5 3 8 4 6 . Baum RS. Alvarez 111 H. Cobb LA. Survival after resuscitation from out-of-hospital ventricular fibrillation. Circulation 19 74 : 50: 1231-5. Liberthson RR. Nagel EI. Hirschnian JC. Nussenfeld SR. Prehospital ventricular fibrillation. f’rognosis and follow-up course. N EirglI Med 1974: 291 : 31 7-21. Einarson 0.Jakobson F. Sigurdsson C. Advanced cardiac life support in the prehospital setting: the Reykjavik experience. Intern Med 1989: 225: 129-35. Friedman H. Diagnostic considerations in electromechanical dissociation (editorial). Am 1 Cnrdiol 1976: 38: 268-9. Eitel DR. Walton SL. Guerci AD, Hess DR. Sabulski NK. Out-ofhospital cardiac arrest: ii six-year experience in a suburbanrural system. Ann Emerg Med 1988: 17: 808-12. Britton M. Diagnostic errors discovered at autopsy. Acta Med S c a d 1974: 196: 203-10. Kircher T. Nelson J , Burdo H. The autopsy as a measure of accuracy of the death certificate. N Engl 1 Med 1985 : 3 13 : 1263-9. Lundberg GD. Voigt CE. Reliability of a presumptive diagnosis in sudden unexpected death in adults. The case for the autopsy. 1 Am Med Assoc 1979: 242: 2328-30. Battle RM. Pathak D. Humble CG el al. Factors influencing discrepancies between premortem and postmortem diagnoses. 1 Am Med Assoc 1987: 258: 3 3 9 4 4 . Coldman L. Sayson R. Robbins S. Cohn LH. Bettmann M. Weisberg M. The value of the autopsy in three medical eras. N E n g l ] Med 1983: 308: 1000-5.
Correspondence: Tom Silfvast. MD. lsokaari 32 E. 00200 Helsinki, Finland.
Cause of death in unsuccessful prehospital resuscitation T. SILFVAST From the Prehospital Emergency Care Unit. Helsinki University Central Hospital and Helsinki City Fire Ilepartment. Helsinki, Finland
Abstract. Silfvast T (Prehospital Emergency Care Unit, Helsinki University Central Hospital and Helsinki City Fire Department, Helsinki, Finland). Cause of death in unsuccessful prehospital resuscitation. Journal of Znternirl Medicine 1991 : 229 : 331-335.
During 1987-1988, prehospital resuscitation was unsuccessful in 2 0 4 of 381 patients who suffered a witnessed cardiac arrest due to presumed coronary heart disease in Helsinki. The cause of death was verified by autopsy in 80 (39%) of the 2 0 4 patients. Their cause of death could not be estimated on the basis of previous patient history, and their autopsy diagnoses were then related to the initial cardiac rhythm recorded at the scene. At autopsy, coronary heart disease was considered to have been the cause of death in 78% of the patients with ventricular fibrillation, in 43% of the patients with elettromechanical dissociation (EMD),and in 60% of the patients in asystole. Cardiac tamponade or massive pulmonary embolism was the cause of death in 15 of the 28 patients with EMD who underwent autopsy. These findings support previously noted relationships between some causes of cardiac arrest and the initial cardiac rhythm, and also in prehospital cardiac arrest patients with unsuccessful resuscitation. Keywords: cause of death. prehospital care, resuscitation.
Introduction Information on the cause of cardiac arrest of prehospital patients is derived mainly from successfully resuscitated patients [l,21, whereas fewer data are available on the patients who do not respond to prehospital resuscitation [3, 41. In unsuccessful resuscitation, the cause of death may be estimated on the basis of existing patient documentation, or it may be verified by autopsy. The following study was undertaken to analyse the data for cardiac arrest patients with unsuccessful prehospital resuscitation in Helsinki. It includes all patients who were not successfully resuscitated from a witnessed cardiac arrest due to presumed coronary heart disease during 1987-1988. and the cause of death of the patients who underwent autopsy was studied in relation to the initial cardiac rhythm.
Methods Organization of the emergency medical system
The tiered emergency medical system in Helsinki is Abbreviations: Eh4D = electromechanical dissociation, VF = ventricular fibrillation.
administered by the Fire Department, which responds to approximately 3 1000 urgent calls annually. The 500000 inhabitants of Helsinki are served by ordinary ambulances and one physician staffed emergency care unit. This unit is dispatched together with an ambulance in life-threatening emergencies. The ambulances, based at six Ere stations, are manned by two basic emergency medical technicians. In cardiac arrest, the emergency medical technicians manning the geographically closest ambulance initiate basic life support, while advanced life support could only be initiated upon the arrival of the emergency care unit until 1989, i.e. during the study period. The emergency medical system is activated by the regional alarm centre to which all emergency calls in the city are diverted. A national emergency phone number (000) is in operation. For every patient treated by the emergency care unit, information was recorded on a special form (trip sheet), which contained information on the response t i e for both basic life support and advanced life support, data on the patient's history as obtained at the scene of the emergency, the initial cardiac rhythm and the treatment given. The presumed cause of arrest was also recorded on the trip sheet 33 1
14
IMB 2 2 9
332
T. SILFVAST
No resl;scit (n.54;
I
1
All other arrests ( n 128)
-
Witnessed arrest due to presumed coronary couse ( n = 381 1
resuscitation (n.204)
(i.e., coronary heart disease, obvious non-coronary disease such as trauma, drug overdose). The response time for basic life support was taken to be the time period that elapsed between alerting the emergency medical technicians and their arrival on the scene. The response time for advanced life support was the time that elapsed between alerting the emergency medical technicians and the arrival of the emergency care unit. The initial cardiac rhythm in cardiac arrest was classified as ventricular fibrillation (VF), ventricular tachycardia, asystole or electromechanical dissociation (EMD).The data for three patients with ventricular tachycardia were analysed together with the data for the patients with VF. The cardiac rhythm was determined, using the paddles of the cardioscope, immediately upon arrival of the emergency care unit. After defibrillation of VF, the electrodes of the cardioscope were attached. EMD was defined as any
Fig. I . Patients with prehospital cardiac arrest in Helsinki during the period 1987-1988.
organized electrical rhythm in the heart of less than 100 beats min-' in the absence of a palpable femoral or carotid pulse and lacking heart sounds on auscultation. Electrical rhythms of both narrow and broad complexes were regarded as EMD. because the outcome for the two morphologies appears to be equally poor [4, 51. The arrest was classified as witnessed if it was directly seen or heard. Treatment of cardiac arrest was according to the guidelines issued by the American Heart Association in 1986 [6]. The emergency medical technicians initiated basic life support in every patient in cardiac arrest without postmortem lividity. On arrival of the emergency care unit, the decision to initiate advanced life support (i.e. to resuscitate) or to discontinue basic life support was made. If the physician decided not to initiate advanced life s u p port, the patient was declared dead and taken to the morgue by a different system. Advanced life support
333
UNSUCCESSFUL PREHOSPITAL RESUSCITATION
is not initiated in approximately 5 0 % of cardiac arrest calls in Helsinki. These patients are recorded as dead on the scene, and they are not included in the present study. The patients in whom advanced life support measures are initiated are referred to as patients with attempted resuscitation. If the patient does not regain spontaneous circulation at the site of the event, resuscitation is terminated as unsuccessful and a copy of the trip sheet is left with the patient. The police are notified, and the patient is transported to the forensic department. If an autopsy is not required by law (e.g. suspected suicide, sudden death of a previously healthy individual), the patient's own physician is contacted by the police. If the physician considers the existing patient documentation sufficient to estimate the cause of death, the death certificate is written without an autopsy. However, if the physician considers that the cause of death cannot be estimated on the basis of the patient files, a n autopsy is performed at the forensic department. A copy of the report is sent to the physician of the emergency care unit. During the study period, resuscitation was attempted in 509 of the 1052 prehospital cardiac arrest patients who were seen by the emergency care unit (Fig. 1). The arrest was unwitnessed or due to an obvious non-coronary cause in 128 of the patients with attempted resuscitation, and they were excluded from subsequent analyses. Of the remaining 381 patients who suffered a witnessed arrest due. to presumed coronary heart disease, resuscitation was unsuccessful in 2 0 4 cases. The statistical analysis included the unpaired Student's t-test for parametric data and the Chisquare test for non-parametric data.
the patients without autopsy were VF in 63%, EMD in 2 6 % and asystole in 11 % of the patients. In 4 2 of the 80 patients who underwent autopsy, the initial cardiac rhythm was VF. The mean age of these patients, 53 years, was lower than that of the patients in VF who did not undergo autopsy ( 6 5 years, P c 0.005). At autopsy, coronary heart disease was considered to have caused the arrest in 33 (78%) patients (Table 2). EMD was the initial cardiac rhythm in 28 of the patients who underwent autopsy. There was no difference in mean age between the patients in EMD with and without autopsy (67 and 71 years, respectively). At autopsy, coronary heart disease was considered to have been the cause of death in 1 2 (43%) patients (Table 2). In four of these patients, ruptured myocardium with cardlac tamponade complicating myocardial infarction was the cause of death. Fifteen (54%) patients were found to have a non-coronary cause of death at autopsy. Massive pulmonary embolism was the ctiuse of death in six patients, and cardiac tamponade due to a dissecting aortic aneurysm was the cause of death in five patients (Table 2). Of the patients with cardiac tamponade, two with ruptured myocardium and two with a dissecting aortic aneurysm collapsed without preceding symptoms. Of the remaining patients with this condition, one expressed anferior neck pain and one had chest pain before cardiac arrest. Four of the patients with pulmonary embolism had a short episode of dyspnoea of acute onset prior to collapse. In no instance did the physician at the scene express suspicion of such conditions on the trip sheet, but notes on persistent cyanosis and distended jugular Table 1 . Characteristics of patients with unsuccessful prehospital resuscitation Autopsy not performed
Results An autopsy was performed in 80 (39%) of the 2 0 4 patients with unsuccessful resuscitation, whereas the probable cause of death was estimated without a n autopsy in 1 2 4 patients (Table 1). The mean age (58 years) of the patients who underwent autopsy was lower than that of the patients without autopsy (67 years, P < 0.005). The patients were reached with similar delays for basic and advanced life support. The initial cardiac rhythm was VF in 53%, EMD in 3 5 % and asystole in 1 2 % of the patients who underwent autopsy. The corresponding values for
No. of patients Mean age ( fSD) (years) Sex (M/F)
124 67
* 11
9313 1
Mean response time ( + SE) (min) Basic life support 6 . 2k 0 . 2 11.6 f 0.4 Advanced life support Initial cardiac rhythm (VF/EMD/asystole)
78/32/14
* P c 0.005 compared with patients who VF = ventricular fibrillation, EMD dissociation.
Autopsy performed
80
58+15* 56/24
6.4f0.3 12.3 k 0 . 6 42/28/10
were not autopsied.
= electromechanical
14-2
334
T. SILFVAST
Table 2. Autopsy diagnoses of patients with unsuccessful
prehospital resuscitation
No. of patients Age
(*SD) (years)
Diagnosis (n) Coronary heart disease Non-coronary heart disease Other non-coronary disease Pulmonary embolism Dissecting aortic aneurysm with cardiac tamponade Ruptured abdominal aortic aneurysm lntracerebral haemorrhrage Intoxication Other causest
Ventricular fibrillation
Electromechanical dissociation Asystole
42
28
10
53k12
67k16
53k16
33
12.
5
3
1
1
-
6
2
-
5
-
-
2
-
-
-
1
1
-
1
5
2
-
Includes four patients with ruptured myocardium and cardiac tamponade complicating myocardial infarction. t Includes sepsis, pneumonia and epilepsy.
veins were made for four of these patients. The patients' previous history, as obtained at the scene, did not provide any clues as to the cause of arrest of the patients. Ten of the patients who underwent autopsy had asystole as initial cardiac rhythm (Table 2). The mean age of these patients was 53 years, and that of the patients in asystole without autopsy was 6 4 years (NS). Coronary heart disease was considered to have been the cause of arrest in five of the 10 patients who underwent autopsy, and five patients had a non-coronary cause of arrest (Table 2).
Discussion Most of the available data on the cause of cardiac arrest in prehospital patients deal with successfully resuscitated patients [2, 7, 81. Several reports have also included hospitalized patients [l,3, 91, whose cause of arrest may be assumed to be different from that of patients who suddenly collapse outside hospital. Patients successfully resuscitated from VF frequently suffer from coronary heart disease [10121, whereas autopsy findings in hospitalized cardiac
arrest patients with EMD have shown this rhythm also to be associated with non-coronary conditions such as pulmonary embolism or cardiac tamponade [3]. The cause of arrest of prehospital patients who are not successfully resuscitated has not been extensively studied [4]. It must be borne in mind that the present study partly consists of selected patients in that an autopsy was performed on those subjects whose cause of death, as judged by the patient's own physician, could not be estimated. This probably explains the finding that the patients who underwent autopsy were younger than the patients whose cause of death was estimated without an autopsy. On the other hand, the proportion of patients with VF, EMD and asystole was similar for the patients with and without autopsy. This implies that the patients were not selected for autopsy on the basis of the initial cardiac rhythm. Coronary heart disease was considered to have been the cause of death in 78% of the patients who underwent autopsy after unsuccessful resuscitation from VF. This figure is consistent with those reported for patients successfully resuscitated from this rhythm [lo-121. The finding that 68% of the patients who were not successfully resuscitated from EMD at autopsy displayed a complication of coronary heart disease or a non-coronary cause of death despite presumed coronary heart disease was surprising. It suggests that the poor primary success of resuscitation of patients with EMD [l,131 could be explained by a fatal underlying cause of arrest in many patients. The majority of these autopsy diagnoses were cardiovascular emergencies described as causing EMD [14], but little is known about the proportion of these cases in patients for whom prehospital resuscitation was unsuccessful. Some indices may be available to the rescuer (e.g. persistent central cyanosis) and thus help us to understand why the patient does not respond to resuscitation. In this study, some clinical signs were recorded on the trip sheet, but they did not appear to be interpreted. Because of the very poor prognosis for the patient with prehospital cardiac arrest due to pulmonary embolism or cardiac tamponade. the identification of these conditions would prove valuable, particularly when limited prehospital advanced life support resources must be distributed simultaneously to different locations. The patients in asystole showed a similar trend with regard to non-coronary autopsy findings, despite presumed coronary heart disease, although
UNSUCCESSFUL PREHOSPITAL RESUSCITATION
335
the number of patients was small. Asystole as the initial electrocardiographic recording in cardiac arrest is often the result of lengthy delays before the patient is reached: as the delay increases, asystole as the terminal ‘rhythm ’ will become more frequent. In patients who are reached within minutes after witnessed cardiac arrest, as in the present study, asystole is probably a primary event. In some patients it reflects a non-coronary cause of arrest, partly explaining the poor prognosis noted for these patients as well [2, 151. Depending on the emergency medical system, the prehospital cardiac arrest patient who does not respond to resuscitation may not present at the hospital at all, and the cause of arrest may remain unknown to the parties involved. Discrepancies between the clinical and autopsy diagnoses of hospitalized patients have shown that assessment of the cause of death based on patient history is unreliable [16, 171. One would expect this to be true in prehospital patients as well. In an autopsy study of 100 adults who died suddenly outside hospital apparently without unnatural cause or manner, Lundberg and Voigt [18] found that 51 of the patients had a non-coronary cause of death. For example, pulmonary embolism, a condition which has also been shown to be frequently underdiagnosed in hospitalized patients [19, 201, was the cause of death in eight of their patients. In this study, 38 % of the patients who underwent autopsy died from noncoronary causes, a Ending consistent with that of Lundberg and Voigt. The vast majority of coronary causes of death shown at autopsy among the patients in VF, and the high proportion of non-coronary causes among the patients in EMD. suggests that there is also a relationship between the initial cardiac rhythm and the cause of arrest in many prehospital patients who do not respond to resuscitation. Particularly when the initial cardiac rhythm has been EMD, it seems possible that some non-coronary causes are missed when the cause of death is estimated solely on the basis of existing patient files. In these patients, the autopsy may provide a means of learning more about sudden prehospital death.
20
References
Received 29 December 1989, accepted 27 September 1990.
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Correspondence: Tom Silfvast. MD. lsokaari 32 E. 00200 Helsinki, Finland.
