Acta anaesth. scand. 1979, 23, 69-77
Prognosis after Cardiac Arrest Occurring Outside Intensive Care and Coronary Units M. WERNBERG and A. THOMASEN Departments of Anaesthesiology and Clinical Neuropliysiology, University Hospital, Arlius, Denmark
Emergency calls to a total of 1686 patients with verified cardiac arrest in the University Hospital, Arhus, were made in the 8-year period 1969-1977. Among the patients, cardiac arrest occurred outside the hospital in 1347, in the general wards in 240, while it was present on arrival at the emergency room in 99. Resuscitation was attempted in 1172 patients; 181 survived for at least 24 hours, and 72 were discharged alive, including 13 with residual brain damage. The prognosis was best when cardiac arrest occurred in the general wards (13% discharged) and poorest when it occurred outside the hospital (4% discharged). However, in the latter group, the prognosis showed considerable improvement when resuscitation was initiated at once by a doctor or by laymen present at the accident site (16% discharged). As regards the mechanism of cardiac arrest, ventricular fibrillation was found to be a relatively favourable prognostic sign (10% discharged), whereas almost none of the patients with asystole or severe bradycardia survived. The possibility of improving the prognosis of cardiac arrest occurring outside hospital by the establishment of mobile coronary care units and by instructing lay people in the technique of cardiopulmonary resuscitation is discussed.
Received 26' M a y , accepted for publication 173uly 1978
1970, LIBERTHSON et al. 1974, 1 x 0 et~al.~ ~ Sudden cardiac death most often occurs 1974, BRIGGS et al. 1976). outside hospitals. Thus, this is the case in about 60% of all deaths due to acute myoReports from these emergency call systems & PEMBERTONshow that 5-10% of patients in whom cardial infarction (MCNEILLY 1968, HACHFELT 1970). resuscitation was attempted were discharged During the last 15 years, the ambulance alive. As the time from cardiac arrest to the service has therefore been improved accord- initiation of resuscitation is of crucial importing to two main principles: ance to the fate of the patient (ADCEYet al. 1. Specially equipped ambulances manned by a doctor and a nurse have bcen pro& GEDDES1967, LUND vided (PANTRIDGE & SKULBERC 1971, PALM& ELKJER1974). 2 . Ambulances manned by specially trained salvage-corps men and equipped with defibrillators, oscilloscopes, and most often with radiotelemetry have been provided, making it possible to transmit EGGS to the coronary care unit and to talk to the medical officers there (NAGEL et al.
1969, HACHFELT1976, LUND& SKULBERC 1976), many authors have during the last few years argued in favour of teaching lay people the technique of cardiopulmonary resuscitation (ADGEYet al. 1969, PANTRIDCE 1970, R ~ J E L et al. 1974, LUND& SKULBERG 1976, J0RGENSEN 1977), and further improvements in the existing ambulance service are still a much-debated subject ( R ~ J E Let al. 1974, BETENKNING (REPORT)No. 766, 1976, HACHFELT1976, 1977, R ~ J E 1977). L The present paper is a contribution to
70
M. WERNBERG AN13 A. THOMASSEN
this debate, and reports a retrospective study of the final results obtained after emergency calls to 1686 patients with cardiac arrest.
MATERIAL AND METHODS Since 1956, a special mobile emergency service has been in operation in Arhus. It was established by the Department of Anaesthesiology in co-operation with the local ambulance station, which serves a population of nearly 250,000 in an urban district. The mediral emergency team ronsists of an anaesthetist and a nurse, who are equipped with a portable cardioscope, a DCdefibrillator and the appropriate drugs, infusion fluids and intubation sets needed for resuscitation. Emergency calls are made in cases of threatened or impaired vital funrtions. During an 8-year period, about 40% of the emergency patients had cardiac arrest on the arrival of the ambulance crew. The medical emergency team can be called to cases of cardiac arrest both inside and outside the hospital. When a cardiac arrest occurs outside the hospital, two ambulances start simultaneously. One goes directly to the patient and the other goes to the hospital, where it picks up the medical emergency team and takes them to the accident site. T h e two rescuers in the first ambulance start external cardiac compression and artificial vcntilation immediately they reach the patient, usually only a few minutes after the emergency call. When the anaesthetist arrives, he takes over the treatment and decides whether further attempts at resusritation are to be abandoned because the period of anoxia has been too long. If he stops the rescuers without himself performing any active treatment of the patient, we have termed it “no resuscitation” in the following sections. When a cardiac arrest occurs in a general ward, outside the intensive rare and coronary units, the emergency team can be called. Resuscitation is usually started immediately by any staff members present. The hospital has 1419 beds, and the greatest distance is about 800 metres, so that the emergency team can be on the spot at latest 5 minutes after a call. Finally, the emergency team is sent for if a patient with cardiac arrest arrives at the emergency room by an ordinary ambulance, in which only one rescuer is available for resuscitation during the journey. Because of the radio communication between the ambulance and hospital, the anaesthetist and nurse arrive in the emergency room before the patient. All resuscitated patienls are admitted to the intensive care unit for continued treatment. Our study includes all patients who in the period from 1 April, 1969 to 31 March, 1977 had cardiac arrest on the arrival of the emergency team. In all rases, the arrest was verified clinically, and usually
also electrocardiographically, by thr anaesthetist. Children nnder 16 years and patients with primary cerebral disease, traumatic injuries or poisoning were excluded. In all cases the following were recorded: the sex and age of thc patient; the primary electrocardiographic rhythm; where the cardiac arrest occurred; and when and by whom resuscitation was started. Primary resuscitation was considered to bc successful if the patient survived for more than 24 hours. The patient was followed during the hospital stay, and residual brain damage, if any, was recorded. In patients who died a t once, the cause of cardiac arrest could usually be disclosed by the clinical history or autopsy findings. In patients who were admitted to hospital, the diagnosis was also based on the course of their illness and the results of laboratory investigations, including serial ECGs, the latter being evaluated in collaboration with a cardiologist. The prognostic significance of the site of the occurrence of cardiac arrest, and of cardiac rhythm, diagnosis and resuscitation initiated by those present were all assessed.
RESULTS The series included a total of 1686 patients, who consisted of 1248 men and 438 women aged from 16 to 93 years. The sex and age distributions are shown in Figure 1. I n 1347 cases, cardiac arrest occurred outside the hospital, in 240 it occurred in general wards, while 99 patients arrived at the emergency room with cardiac arrest. The frequency of resuscitation and survival in relation to the site of cardiac arrest appears from Table 1. In addition, it shows the frequency of residual brain damage and the number of patients who on the arrival of the emergency team had unquestionable signs of death (i.e. rigor or livor mortis). Note that the prognosis is much better in cases of cardiac arrest in the general wards than outside the hospital, while the prognosis for patients taken to the emergency room with cardiac arrest lies in between these two. The fact that a n immediate attempt at resuscitation is of great prognostic significance can be seen from Table 2. I n a total of 81 cases, people present started resuscitation outside the hospital before the arrival of the first ambulance. I n 45 cases, this was done by a physician, and in the remaining 36
PROGNOSIS AFTER CARDIAC ARREST
71
males
0
females
450
400
350
ul
u
.Qj300 u
m
a LH
0 Li
;250
5 200
150
100
50
4 10-19
20-29
age in y e a r s
Fig. 1.
Sex
and age distribution.
cases by laymen. Efficient resuscitation includes both external cardiac compression and artificial ventilation. I t is called inefficient when only one of these measures was performed. The relation between primary electrocardiographic rhythm and prognosis is shown in Table 3. I n cases of “no monitor-
1
ing”, the diagnosis of cardiac arrest was based only on clinical observations, which especially occurred in the early years. I t can be seen that ventricular fibrillation had by far the best prognosis, while almost none of the patients survived asystole or severe bradycardia. Table 4 shows the electrocardiographic
72
M. WERNBERC AND A . THOMASSEN
w o o 0 w3 - N
11 2
PROGNOSIS A F T E R CARDIAC ARREST
73
Table 2 Efficiency of resuscitation startcd by people at the site compared with resuscitation delayed until the arrival of the ambulance crew. Patients with rigor or livor mortis are excluded from this table. ~~
~~
Sitrvivcd 24 hours Resuscitation startcd by
Total
x
No.
People at site Efirient Inefficient Ambulance C I C W
"/,
No.
~~
~~
81 54 27 1560
4.1
18
95.1
14 4 163
~
Discharged alive ___No. % ~~~
22.2 25.9 14.8 10.4
13 11 2 59
16.0 20.4 7.4 3.8
'I'able 3 Mechanism of cardiac arrest related to outconic. Survived 24 hours Cardiac rhythm No monitoring Ventricular fibrillation Asystole Severe bradycardia Complete heart block
Total
No.
445 452 705 72 I2
45 114 15 3 4
10.0 25.2 2.1 4.2 33.3
Discharged alive ___No. 23 45 3 0 1
5.2 10.0 0.4 0.0 8.3
Table 4 Electrocardiographic diagnosis related to sitc of cardiac arrest. ~~
~
Cardiac rhythm
~~~
Outside hospital
General wards
Emergency
326 345 59 1 44 5
59 80 75 20 6
24 27 39 8 I
No monitoring Ventricular fibrillation Asystole Severe bradycardia Complete heart block
rhythm in relation to the site of cardiac arrest. I t should be noted that asystole was the typical arrhythmia recorded outside hospital, while ventricular fibrillation was found most often in general wards. The frequency of autopsy, diagnoses and the prognostic significance of the latter are wen from Table 5. I n cases of sudden death of uncertain cause, the clinical history most often suggested a cardial genesis, and surprisingly often, there had been prodromes
room
for several hours. As autopsy was not performed in this group of patients, the diagnosis could not be definitely confirmed. The average age of the patients who were discharged alive (64 years) did not differ significantly from the average age of the patient group as a whole (65 years). DISCUSSION AND COMMENTS For resuscitation to bc successful, it is of
74
M. WERNBERG AN11 A. THOMASSEN
Table 5 Cause of cardiac arrest rda t ed to outcomr. Survived 24 hours Diagnoses Acute myocardial infarction Artrriosclerotic heart disease without infarction Non-coronary heart disease Pulmonary embolism Acute asphyxia Other diagnoses Sudden death of uriccrtain cause
Total
'Total
No autopsy
Discharged alive
Autopsy
No.
x,
No.
:'
Prognosis after Cardiac Arrest Occurring Outside Intensive Care and Coronary Units M. WERNBERG and A. THOMASEN Departments of Anaesthesiology and Clinical Neuropliysiology, University Hospital, Arlius, Denmark
Emergency calls to a total of 1686 patients with verified cardiac arrest in the University Hospital, Arhus, were made in the 8-year period 1969-1977. Among the patients, cardiac arrest occurred outside the hospital in 1347, in the general wards in 240, while it was present on arrival at the emergency room in 99. Resuscitation was attempted in 1172 patients; 181 survived for at least 24 hours, and 72 were discharged alive, including 13 with residual brain damage. The prognosis was best when cardiac arrest occurred in the general wards (13% discharged) and poorest when it occurred outside the hospital (4% discharged). However, in the latter group, the prognosis showed considerable improvement when resuscitation was initiated at once by a doctor or by laymen present at the accident site (16% discharged). As regards the mechanism of cardiac arrest, ventricular fibrillation was found to be a relatively favourable prognostic sign (10% discharged), whereas almost none of the patients with asystole or severe bradycardia survived. The possibility of improving the prognosis of cardiac arrest occurring outside hospital by the establishment of mobile coronary care units and by instructing lay people in the technique of cardiopulmonary resuscitation is discussed.
Received 26' M a y , accepted for publication 173uly 1978
1970, LIBERTHSON et al. 1974, 1 x 0 et~al.~ ~ Sudden cardiac death most often occurs 1974, BRIGGS et al. 1976). outside hospitals. Thus, this is the case in about 60% of all deaths due to acute myoReports from these emergency call systems & PEMBERTONshow that 5-10% of patients in whom cardial infarction (MCNEILLY 1968, HACHFELT 1970). resuscitation was attempted were discharged During the last 15 years, the ambulance alive. As the time from cardiac arrest to the service has therefore been improved accord- initiation of resuscitation is of crucial importing to two main principles: ance to the fate of the patient (ADCEYet al. 1. Specially equipped ambulances manned by a doctor and a nurse have bcen pro& GEDDES1967, LUND vided (PANTRIDGE & SKULBERC 1971, PALM& ELKJER1974). 2 . Ambulances manned by specially trained salvage-corps men and equipped with defibrillators, oscilloscopes, and most often with radiotelemetry have been provided, making it possible to transmit EGGS to the coronary care unit and to talk to the medical officers there (NAGEL et al.
1969, HACHFELT1976, LUND& SKULBERC 1976), many authors have during the last few years argued in favour of teaching lay people the technique of cardiopulmonary resuscitation (ADGEYet al. 1969, PANTRIDCE 1970, R ~ J E L et al. 1974, LUND& SKULBERG 1976, J0RGENSEN 1977), and further improvements in the existing ambulance service are still a much-debated subject ( R ~ J E Let al. 1974, BETENKNING (REPORT)No. 766, 1976, HACHFELT1976, 1977, R ~ J E 1977). L The present paper is a contribution to
70
M. WERNBERG AN13 A. THOMASSEN
this debate, and reports a retrospective study of the final results obtained after emergency calls to 1686 patients with cardiac arrest.
MATERIAL AND METHODS Since 1956, a special mobile emergency service has been in operation in Arhus. It was established by the Department of Anaesthesiology in co-operation with the local ambulance station, which serves a population of nearly 250,000 in an urban district. The mediral emergency team ronsists of an anaesthetist and a nurse, who are equipped with a portable cardioscope, a DCdefibrillator and the appropriate drugs, infusion fluids and intubation sets needed for resuscitation. Emergency calls are made in cases of threatened or impaired vital funrtions. During an 8-year period, about 40% of the emergency patients had cardiac arrest on the arrival of the ambulance crew. The medical emergency team can be called to cases of cardiac arrest both inside and outside the hospital. When a cardiac arrest occurs outside the hospital, two ambulances start simultaneously. One goes directly to the patient and the other goes to the hospital, where it picks up the medical emergency team and takes them to the accident site. T h e two rescuers in the first ambulance start external cardiac compression and artificial vcntilation immediately they reach the patient, usually only a few minutes after the emergency call. When the anaesthetist arrives, he takes over the treatment and decides whether further attempts at resusritation are to be abandoned because the period of anoxia has been too long. If he stops the rescuers without himself performing any active treatment of the patient, we have termed it “no resuscitation” in the following sections. When a cardiac arrest occurs in a general ward, outside the intensive rare and coronary units, the emergency team can be called. Resuscitation is usually started immediately by any staff members present. The hospital has 1419 beds, and the greatest distance is about 800 metres, so that the emergency team can be on the spot at latest 5 minutes after a call. Finally, the emergency team is sent for if a patient with cardiac arrest arrives at the emergency room by an ordinary ambulance, in which only one rescuer is available for resuscitation during the journey. Because of the radio communication between the ambulance and hospital, the anaesthetist and nurse arrive in the emergency room before the patient. All resuscitated patienls are admitted to the intensive care unit for continued treatment. Our study includes all patients who in the period from 1 April, 1969 to 31 March, 1977 had cardiac arrest on the arrival of the emergency team. In all rases, the arrest was verified clinically, and usually
also electrocardiographically, by thr anaesthetist. Children nnder 16 years and patients with primary cerebral disease, traumatic injuries or poisoning were excluded. In all cases the following were recorded: the sex and age of thc patient; the primary electrocardiographic rhythm; where the cardiac arrest occurred; and when and by whom resuscitation was started. Primary resuscitation was considered to bc successful if the patient survived for more than 24 hours. The patient was followed during the hospital stay, and residual brain damage, if any, was recorded. In patients who died a t once, the cause of cardiac arrest could usually be disclosed by the clinical history or autopsy findings. In patients who were admitted to hospital, the diagnosis was also based on the course of their illness and the results of laboratory investigations, including serial ECGs, the latter being evaluated in collaboration with a cardiologist. The prognostic significance of the site of the occurrence of cardiac arrest, and of cardiac rhythm, diagnosis and resuscitation initiated by those present were all assessed.
RESULTS The series included a total of 1686 patients, who consisted of 1248 men and 438 women aged from 16 to 93 years. The sex and age distributions are shown in Figure 1. I n 1347 cases, cardiac arrest occurred outside the hospital, in 240 it occurred in general wards, while 99 patients arrived at the emergency room with cardiac arrest. The frequency of resuscitation and survival in relation to the site of cardiac arrest appears from Table 1. In addition, it shows the frequency of residual brain damage and the number of patients who on the arrival of the emergency team had unquestionable signs of death (i.e. rigor or livor mortis). Note that the prognosis is much better in cases of cardiac arrest in the general wards than outside the hospital, while the prognosis for patients taken to the emergency room with cardiac arrest lies in between these two. The fact that a n immediate attempt at resuscitation is of great prognostic significance can be seen from Table 2. I n a total of 81 cases, people present started resuscitation outside the hospital before the arrival of the first ambulance. I n 45 cases, this was done by a physician, and in the remaining 36
PROGNOSIS AFTER CARDIAC ARREST
71
males
0
females
450
400
350
ul
u
.Qj300 u
m
a LH
0 Li
;250
5 200
150
100
50
4 10-19
20-29
age in y e a r s
Fig. 1.
Sex
and age distribution.
cases by laymen. Efficient resuscitation includes both external cardiac compression and artificial ventilation. I t is called inefficient when only one of these measures was performed. The relation between primary electrocardiographic rhythm and prognosis is shown in Table 3. I n cases of “no monitor-
1
ing”, the diagnosis of cardiac arrest was based only on clinical observations, which especially occurred in the early years. I t can be seen that ventricular fibrillation had by far the best prognosis, while almost none of the patients survived asystole or severe bradycardia. Table 4 shows the electrocardiographic
72
M. WERNBERC AND A . THOMASSEN
w o o 0 w3 - N
11 2
PROGNOSIS A F T E R CARDIAC ARREST
73
Table 2 Efficiency of resuscitation startcd by people at the site compared with resuscitation delayed until the arrival of the ambulance crew. Patients with rigor or livor mortis are excluded from this table. ~~
~~
Sitrvivcd 24 hours Resuscitation startcd by
Total
x
No.
People at site Efirient Inefficient Ambulance C I C W
"/,
No.
~~
~~
81 54 27 1560
4.1
18
95.1
14 4 163
~
Discharged alive ___No. % ~~~
22.2 25.9 14.8 10.4
13 11 2 59
16.0 20.4 7.4 3.8
'I'able 3 Mechanism of cardiac arrest related to outconic. Survived 24 hours Cardiac rhythm No monitoring Ventricular fibrillation Asystole Severe bradycardia Complete heart block
Total
No.
445 452 705 72 I2
45 114 15 3 4
10.0 25.2 2.1 4.2 33.3
Discharged alive ___No. 23 45 3 0 1
5.2 10.0 0.4 0.0 8.3
Table 4 Electrocardiographic diagnosis related to sitc of cardiac arrest. ~~
~
Cardiac rhythm
~~~
Outside hospital
General wards
Emergency
326 345 59 1 44 5
59 80 75 20 6
24 27 39 8 I
No monitoring Ventricular fibrillation Asystole Severe bradycardia Complete heart block
rhythm in relation to the site of cardiac arrest. I t should be noted that asystole was the typical arrhythmia recorded outside hospital, while ventricular fibrillation was found most often in general wards. The frequency of autopsy, diagnoses and the prognostic significance of the latter are wen from Table 5. I n cases of sudden death of uncertain cause, the clinical history most often suggested a cardial genesis, and surprisingly often, there had been prodromes
room
for several hours. As autopsy was not performed in this group of patients, the diagnosis could not be definitely confirmed. The average age of the patients who were discharged alive (64 years) did not differ significantly from the average age of the patient group as a whole (65 years). DISCUSSION AND COMMENTS For resuscitation to bc successful, it is of
74
M. WERNBERG AN11 A. THOMASSEN
Table 5 Cause of cardiac arrest rda t ed to outcomr. Survived 24 hours Diagnoses Acute myocardial infarction Artrriosclerotic heart disease without infarction Non-coronary heart disease Pulmonary embolism Acute asphyxia Other diagnoses Sudden death of uriccrtain cause
Total
'Total
No autopsy
Discharged alive
Autopsy
No.
x,
No.
:'
