- Email: [email protected]
Long-term prognosis after out-of-hospital cardiac arrest
Resuscitation (2007) 72, 214—218
CLINICAL PAPER
Long-term prognosis after out-of-hospital cardiac arrest夽 Tina I. Horsted, Lars S. Rasmussen ∗, Christian S. Meyhoff, Søren L. Nielsen Department of Anaesthesia, Centre of Head and Orthopaedics 4231, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark Received 10 February 2006 ; received in revised form 14 June 2006; accepted 20 June 2006 KEYWORDS Out-of-hospital cardiac arrest; Resuscitation; Quality of life
Summary Objective: In this study we aimed to report survival beyond 6 months, including quality of life, for patients after out-of-hospital cardiac arrest (OHCA) with a physician-based EMS in an urban area. Methods: We collected data related to OHCA prospectively during a 2-year period. Long-term survival was determined by cross-referencing our database with two Danish national registries. Patients older than 18 years who had survived for more than 6 months after OHCA were contacted, and after informed written consent was obtained, an interview was conducted in their home and a questionnaire on quality of life (SF-36) and the mini mental state examination (MMSE) were administered. Results: We had data on 984 cases of OHCA. In 512 cases CPR was attempted and at 6 months, a total of 63 patients were alive corresponding to 12.3% [95% CI: 9.7—15.5%] of all who were treated. Of the 33 patients examined, the median MMSE was 29 (16—30) and two patients, corresponding to 6%, [95% CI: 0.7—20.6%] had an MMSE below 24. Two out of eight aspects of the SF-36 were significantly worse than national norms at the same age, but none of the summary scores differed significantly. Conclusion: Survival beyond 6 months was found in 12.3% OHCA in a physician-based EMS. Summary scores of quality of life were not significantly different from the national norm but 2 out of 8 subscores were lower. Signs of dementia were uncommon as only 6% had an MMSE score below 24. © 2006 Elsevier Ireland Ltd. All rights reserved.
Introduction 夽
A Spanish translated version of the summary of this article appears as Appendix in the final online version at doi:10.1016/j. resuscitation.2006.06.029. ∗ Corresponding author. Tel.: +45 35 45 34 88; fax: +45 35 45 29 50. E-mail address: [email protected] (L.S. Rasmussen).
The chance of survival after out-of-hospital cardiac arrest (OHCA) varies between 2% and 49% but it depends upon co-morbidity, initial ECG-rhythm, bystander cardiopulmonary resuscitation (CPR), and also the emergency medical system (EMS).1—3
0300-9572/$ — see front matter © 2006 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.resuscitation.2006.06.029
Long-term prognosis after out-of-hospital cardiac arrest Initial survival to discharge from hospital, however, may not be considered as the most appropriate way to assess outcome because brain dysfunction may seriously affect quality of life. In addition, mortality is high in the first few months after hospital discharge. It is therefore much more relevant to report outcome after OHCA as late survival, including an assessment of neurological status and quality of life. Previous studies of long-term prognosis and quality of life after OHCA have been associated with important limitations such as inclusion of patients over long periods of time and incomplete follow-up. In this study we aimed to report survival beyond 6 months including quality of life for a well-defined cohort of OHCA victims prospectively recorded in 2 consecutive years for a physician-based EMS in an urban area.
Methods In this prospective study we collected data related to OHCA during a 2-year period from 1 June 2002 to 31 May 2004. We included all emergency calls classified as OHCA where the Mobile Emergency Care Unit (MECU) was dispatched. We excluded cases where obvious signs of death were found. The Ethical Committee in Copenhagen and Frederiksberg County approved the study. Data according to the Utstein criteria were collected by the attending specialist in anaesthesiology at the MECU and recorded on a separate sheet. Hospital records and the death certificates were used in all cases for outcome analysis. The shortterm survival for the period 1 June to 31 May 2003 has been reported by us previously.4 Longterm survival was determined by cross-referencing our database with two Danish national registries using the unique personal identification number, which all Danish inhabitants are assigned. In the National Patient Register and the Central Personal Registry we assessed whether patients were alive. Patients older than 18 years who had survived for more than 6 months after OHCA were contacted, and after informed written consent was obtained, an interview was performed in their home. The same examiner conducted all interviews between 6 and 10 months after OHCA. During a 1 h visit, a self-rating Short-Form-36 (SF-36)5 health survey questionnaire was filled in and the mini mental state examination (MMSE) was also administered as a screening test for dementia. The SF-36 is a standardised, 11-item subjective questionnaire divided in 36 questions concerning physical and psychosocial well-being, satisfaction
215
with family life, job, leisure time, and daily life. The MMSE is a screening test for dementia. It includes an objective rating of the persons’ ability in a six-item test containing orientation, attention, simple arithmetic, recall, and language. Maximum score is 30 and a score below 24 is considered to indicate dementia.
Statistical methods Age and time interval were reported as median with (5—95% percentile). Proportions were reported with [95% confidence interval]. The survival rate was the primary end point. Proportions were compared using Chi-square test, continuous data with Mann—Whitney’s test and we considered P-values less than 0.05 statistically significant. We compared SF-36 with national norms for same age using onesample t-test and these values were reported as mean with S.E.
Study area and population Copenhagen is the capital of Denmark. The city covers 90 km2 with a resident population of 590,000, increased in the daytime by approximately 20%.
The emergency medical services (EMS) Consistent with the European Union, we have a single emergency number, 112, which put the dialler in direct contact with the emergency dispatch centre. In Copenhagen the EMS is two-tiered. The Basic Life Support unit (BLS-unit), equipped with a defibrillator and two BLS-providers, is called out from seven different locations, 24 h a day and 7 days a week. The MECU is an Advanced Life Support (ALS) unit based at the main fire station, which is located in the centre of Copenhagen. The MECU is manned with a specialist in anaesthesiology and a specially trained ALS-provider. In the daytime and during weekend nights two ALS-units are available. The MECU carries various equipment and drugs for ALS, including a defibrillator with an external pacemaker. In case of presumed cardiac arrest, the BLSunit and the MECU are dispatched simultaneously and they operate in a ‘rendez vous’ fashion at the incident location. The protocol for resuscitation is consistent with guidelines from the European Resuscitation Council for advanced cardiac life support. After resuscitation, the patient is transferred to one of the six hospitals in the area of Copenhagen.
216
T.I. Horsted et al.
Results In the period of evaluation the dispatch centre had 18,149 emergency contacts leading to dispatch of the MECU, 1010 were related to OHCA and we had data on 984 cases, 579 men and 405 women. The median age was 71 years (34—91 years) and the aetiology was presumed cardiac in 792 (80.5%) cases and non-cardiac in 192. Non-cardiac causes were trauma, intoxication, drowning, exsanguination, suffocation, suicide, cot death, and cerebral causes. Time from collapse to 112-alarm was not recorded. The median time interval from 112call to arrival of the MECU was 6 min (2—10 min). The location of OHCA was most commonly in the patient’s home (600 patients), nursing home (141 patients) and in the street (86 patients). OHCA was witnessed in 611 (62.1%) and bystander CPR was provided in 167 (17.0%). In 472 cases the anaesthesiologist decided not to initiate CPR or to terminate the ongoing CPR started by the BLS-unit. The reason for not initiating or discontinuing resuscitation was reported in 457 cases and was due to presumed prolonged anoxia (326), terminal cancer (50), advanced age (51), severe trauma (26) and other causes (4). In 197 patients, the BLS unit had initiated CPR that was subsequently discontinued by the anaesthesiol-
ogist and in 22 patients, CPR initiated by bystanders was discontinued. In 512 cases CPR was attempted. The aetiology was cardiac in 433 cases and non-cardiac in 79 cases. The OHCA was witnessed in 402 (78.5%) and bystander CPR was provided in 145 (28.3%) (Table 1). In total 159 patients (31.1%) had return of spontaneous circulation (ROSC) on arrival to the Emergency Department (ED) and in 34, CPR was on-going. Survival beyond 30 days was seen in 67 (13.1%) out of all 512 treated patients. For witnessed cardiac arrest, presumed cardiac aetiology in VF/VT, survival beyond 1 month was 29.4%. At 6 months, 63 patients were alive corresponding to 12.3% [95% CI: 9.7—15.5%] of all treated patients. Age, sex, initial rhythm, witnessed arrest, and bystander CPR were all significant prognostic factors (Table 1). Survival beyond 6 months was seen in 4 out of 34 patients (11.8%) with on-going CPR on admission to ED.
Table 1 Demographic data and other details related to survival beyond 6 months for 512 patients treated for out-of-hospital cardiac arrest Number of patients
Survival >6 months
Sex Male Female
339 173
50 (14.7%) 13 (7.5%)
0.02
Age (years) 0—50 51—70 71—90 91
97 198 199 18
14 (14.4%) 35 (17.7%) 14 (7.0%) 0
0.004
Witnessed (N = 509) Yes 402 No 107
55 (13.7%) 7 (6.5%)
0.04
Bystander CPR (N = 510) Yes 145 No 365
31 (21.4%) 31 (8.5%)
<0.0001
Initial rhythm VF/VT 176 Asystole 183 Other 153
50 (28.4%) 4 (2.2%) 9 (5.9%)
<0.0001
P: probability in 2 -test.
P
Figure 1 Flowchart—–from 18,149 emergency contacts to 33 interviews with 6 months survivors.
Long-term prognosis after out-of-hospital cardiac arrest
Figure 2 Quality of life in 33 patients with survival beyond 6 months after out-of-hospital cardiac arrest in comparison with national norm. Mean ± S.E. * Statistically significant difference, P < 0.05.
Follow-up interview and examination was done in 33 patients out of 63 surviving for 6 months or more (Figure 1). Twelve patients refused to participate and eight patients did not respond, in spite of three attempts. Of those refusing follow-up examination, two patients replied that they had returned to normal activity and three patients were living in nursing homes. In the 33 patients examined, the median MMSE was 29 (16—30) and 2 patients, 6% [95% CI: 0.7—20.6%] had an MMSE below 24. Data related to quality of life as assessed by the SF-36 are shown in Figure 2. Two out of eight aspects were significantly worse than national norms at the same age but none of the summary scores were significantly different. One aspect was significantly better (pain).
Discussion We found that 12.3% survived beyond 6 months after OHCA in a physician-based EMS. Follow-up examination was performed in 33 patients out of those 63 survivors. Summary scores of quality of life were not significantly different from the national norm, but 2 out of 8 subscores were lower. Signs of dementia were uncommon as only 6% had a low MMSE score and most patients had an MMSE above 28. The study group included nearly all cases of OHCA during 2 consecutive years and due to the national registry using the unique personal identification number, we were able to assess survival in all patients included. Significant prognostic factors were those already known to be important for
217
early survival (Table 1). In our assessment of functional status, however, an important limitation is that 20 out of 63 survivors either refused or did not respond when we invited them to participate in the follow-up examination. The data on quality of life and MMSE are therefore based on 33 out of 53 adult patients that were alive and living in our country. This is a rather small sample as illustrated by the wide confidence interval for the incidence of dementia. Still, two of the subscores in the SF-36 showed significantly lower values than the national norms. Those were ‘‘role-physical’’ and ‘‘role-emotional’’. The magnitude of the difference is considerable and we expect that even less favourable data would be obtained if all patients could be examined. This is related to the problem that many patients with cognitive deficits are reluctant to undergo examination. It is not easy to compare our findings with other studies because there are important differences in the time of assessment and the method of examination. In one study of more than 3000 cases of OHCA over 4 years, only 35 out of 93 survivors underwent examination 1—2 years after the incident, first of all because 44% had died after discharge from hospital before follow-up. Approximately one-third reported a worse quality of life than before OHCA. Eleven percent had an MMSE below 25.6 A similar low proportion (50/169) underwent interview 5—68 months after OHCA in another study and quality of life was significantly worse than controls for most variables of the Nottingham Health Profile and the Everyday-Life Questionnaire.7 In a much smaller study, MMSE was below 27 in 6/17 (35%) subjects approximately 2 years after OHCA.8 In another 38 patients surviving OHCA due to ventricular fibrillation, the SF-36 and a memory function questionnaire were distributed after a mean follow-up of 4.9 years. Only one of the subscores (vitality score) were lower than that of the general population but approximately 50% reported memory problems.1 Of 101 survivors examined at a median of 15 months after cardiac arrest in various settings, 90 were interviewed and 17% were classified as cognitively impaired, based on an MMSE of 23 or less.9 Also, quality of life as assessed by Sickness Impact profile, was worse than in elderly control subjects in most subscores.9 One of the most pessimistic studies reported that deficits in at least one cognitive area was found in all survivors after OHCA but only 12 subjects were assessed after a median of 25 months.10 The reported differences in quality of life between controls and survivors of OHCA can be explained in different ways. Patients having OHCA typically suffer from cardiac disease (85% of our
218 patient had OHCA with cardiac aetiology) and it should therefore be questioned if healthy agematched people constitute the most appropriate control population. In stead, it may be relevant to compare survivors of OHCA with cardiac patients. As an example, in a recent study of 1351 patients with myocardial infarction, differences of the same magnitude as in our study were reported between patients and national norms for the SF-36 ‘‘rolephysical’’ and the ‘‘role-emotional’’.5 For the MMSE, it seems that 10—20% of survivors after OHCA have a score compatible with dementia. In the general population, approximately 5% of people aged 70 and over have an MMSE score below 24 and accordingly, in those surviving OHCA beyond 6 months there does not seem to be a major cognitive problem.11—13 On the other hand, dementia cannot be diagnosed on the basis of MMSE alone but more extensive neuropsychological testing was not feasible and it is also a problem that no reliable assessment of baseline performance is possible in OHCA victims. In conclusion, survival beyond 6 months was found in 12.3% OHCA in a physician-based EMS. Summary scores of quality of life were not significantly different from the national norm but 2 out of 8 subscores were lower. Signs of dementia were uncommon as only 6% had an MMSE score below 24.
References 1. Bunch TJ, White RD, Smith GE, et al. Long-term subjective memory function in ventricular fibrillation out-of-hospital cardiac arrest survivors resuscitated by early defibrillation. Resuscitation 2004;60:189—95.
T.I. Horsted et al. 2. Fischer M, Fischer NJ, Schuttler J. One-year survival after out-of-hospital cardiac arrest in Bonn city: outcome report according to the ‘Utstein style’. Resuscitation 1997;33:233—43. 3. Fredriksson M, Herlitz J, Nichol G. Variation in outcome in studies of out-of-hospital cardiac arrest: a review of studies conforming to the Utstein guidelines. Am J Emerg Med 2003;21:276—81. 4. Horsted TI, Rasmussen LS, Lippert FK, Nielsen SL. Outcome of out-of-hospital cardiac arrest—why do physicians withhold resuscitation attempts? Resuscitation 2004;63:287—93. 5. Mortensen OS, Bjorner JB, Oldenburg B, et al. Health-related quality of life one month after throm-bolysis or primary PCI in patients with ST-elevation infarction. A DANAMI-2 substudy. Scand Cardiovasc J 2005;39:206—12. 6. Hsu JW, Madsen CD, Callaham ML. Quality-of-life and formal functional testing of survivors of out-of-hospital cardiac arrest correlates poorly with traditional neurologic outcome scales. Ann Emerg Med 1996;28:597—605. 7. Saner H, Borner RE, Kummer-Bangerter A, Schuppel R, von Planta M. Quality of life in long-term survivors of out-ofhospital cardiac arrest. Resuscitation 2002;53:7—13. 8. Sunnerhagen KS, Johansson O, Herlitz J, Grimby G. Life after cardiac arrest; a retrospective study. Resuscitation 1996;31:135—40. 9. de Vos R, de Haes HC, Koster RW, de Haan RJ. Quality of survival after cardiopulmonary resuscitation. Arch Intern Med 1999;159:249—54. 10. Pusswald G, Fertl E, Faltl M, Auff E. Neurological rehabilitation of severely disabled cardiac arrest survivors. Part II. Life situation of patients and families after treatment. Resuscitation 2000;47:241—8. 11. Espino DV, Lichtenstein MJ, Palmer RF, Hazuda HP. Ethnic differences in mini-mental state exami-nation (MMSE) scores: where you live makes a difference. J Am Geriatr Soc 2001;49:538—48. 12. Hansson L, Lithell H, Skoog I, et al. Study on cognition and prognosis in the elderly (SCOPE): base-line characteristics. Blood Press 2000;9:146—51. 13. Grigoletto F, Zappala G, Anderson DW, Lebowitz BD. Norms for the mini-mental state examination in a healthy population. Neurology 1999;53:315—20.
CLINICAL PAPER
Long-term prognosis after out-of-hospital cardiac arrest夽 Tina I. Horsted, Lars S. Rasmussen ∗, Christian S. Meyhoff, Søren L. Nielsen Department of Anaesthesia, Centre of Head and Orthopaedics 4231, Copenhagen University Hospital, Rigshospitalet, DK-2100 Copenhagen, Denmark Received 10 February 2006 ; received in revised form 14 June 2006; accepted 20 June 2006 KEYWORDS Out-of-hospital cardiac arrest; Resuscitation; Quality of life
Summary Objective: In this study we aimed to report survival beyond 6 months, including quality of life, for patients after out-of-hospital cardiac arrest (OHCA) with a physician-based EMS in an urban area. Methods: We collected data related to OHCA prospectively during a 2-year period. Long-term survival was determined by cross-referencing our database with two Danish national registries. Patients older than 18 years who had survived for more than 6 months after OHCA were contacted, and after informed written consent was obtained, an interview was conducted in their home and a questionnaire on quality of life (SF-36) and the mini mental state examination (MMSE) were administered. Results: We had data on 984 cases of OHCA. In 512 cases CPR was attempted and at 6 months, a total of 63 patients were alive corresponding to 12.3% [95% CI: 9.7—15.5%] of all who were treated. Of the 33 patients examined, the median MMSE was 29 (16—30) and two patients, corresponding to 6%, [95% CI: 0.7—20.6%] had an MMSE below 24. Two out of eight aspects of the SF-36 were significantly worse than national norms at the same age, but none of the summary scores differed significantly. Conclusion: Survival beyond 6 months was found in 12.3% OHCA in a physician-based EMS. Summary scores of quality of life were not significantly different from the national norm but 2 out of 8 subscores were lower. Signs of dementia were uncommon as only 6% had an MMSE score below 24. © 2006 Elsevier Ireland Ltd. All rights reserved.
Introduction 夽
A Spanish translated version of the summary of this article appears as Appendix in the final online version at doi:10.1016/j. resuscitation.2006.06.029. ∗ Corresponding author. Tel.: +45 35 45 34 88; fax: +45 35 45 29 50. E-mail address: [email protected] (L.S. Rasmussen).
The chance of survival after out-of-hospital cardiac arrest (OHCA) varies between 2% and 49% but it depends upon co-morbidity, initial ECG-rhythm, bystander cardiopulmonary resuscitation (CPR), and also the emergency medical system (EMS).1—3
0300-9572/$ — see front matter © 2006 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.resuscitation.2006.06.029
Long-term prognosis after out-of-hospital cardiac arrest Initial survival to discharge from hospital, however, may not be considered as the most appropriate way to assess outcome because brain dysfunction may seriously affect quality of life. In addition, mortality is high in the first few months after hospital discharge. It is therefore much more relevant to report outcome after OHCA as late survival, including an assessment of neurological status and quality of life. Previous studies of long-term prognosis and quality of life after OHCA have been associated with important limitations such as inclusion of patients over long periods of time and incomplete follow-up. In this study we aimed to report survival beyond 6 months including quality of life for a well-defined cohort of OHCA victims prospectively recorded in 2 consecutive years for a physician-based EMS in an urban area.
Methods In this prospective study we collected data related to OHCA during a 2-year period from 1 June 2002 to 31 May 2004. We included all emergency calls classified as OHCA where the Mobile Emergency Care Unit (MECU) was dispatched. We excluded cases where obvious signs of death were found. The Ethical Committee in Copenhagen and Frederiksberg County approved the study. Data according to the Utstein criteria were collected by the attending specialist in anaesthesiology at the MECU and recorded on a separate sheet. Hospital records and the death certificates were used in all cases for outcome analysis. The shortterm survival for the period 1 June to 31 May 2003 has been reported by us previously.4 Longterm survival was determined by cross-referencing our database with two Danish national registries using the unique personal identification number, which all Danish inhabitants are assigned. In the National Patient Register and the Central Personal Registry we assessed whether patients were alive. Patients older than 18 years who had survived for more than 6 months after OHCA were contacted, and after informed written consent was obtained, an interview was performed in their home. The same examiner conducted all interviews between 6 and 10 months after OHCA. During a 1 h visit, a self-rating Short-Form-36 (SF-36)5 health survey questionnaire was filled in and the mini mental state examination (MMSE) was also administered as a screening test for dementia. The SF-36 is a standardised, 11-item subjective questionnaire divided in 36 questions concerning physical and psychosocial well-being, satisfaction
215
with family life, job, leisure time, and daily life. The MMSE is a screening test for dementia. It includes an objective rating of the persons’ ability in a six-item test containing orientation, attention, simple arithmetic, recall, and language. Maximum score is 30 and a score below 24 is considered to indicate dementia.
Statistical methods Age and time interval were reported as median with (5—95% percentile). Proportions were reported with [95% confidence interval]. The survival rate was the primary end point. Proportions were compared using Chi-square test, continuous data with Mann—Whitney’s test and we considered P-values less than 0.05 statistically significant. We compared SF-36 with national norms for same age using onesample t-test and these values were reported as mean with S.E.
Study area and population Copenhagen is the capital of Denmark. The city covers 90 km2 with a resident population of 590,000, increased in the daytime by approximately 20%.
The emergency medical services (EMS) Consistent with the European Union, we have a single emergency number, 112, which put the dialler in direct contact with the emergency dispatch centre. In Copenhagen the EMS is two-tiered. The Basic Life Support unit (BLS-unit), equipped with a defibrillator and two BLS-providers, is called out from seven different locations, 24 h a day and 7 days a week. The MECU is an Advanced Life Support (ALS) unit based at the main fire station, which is located in the centre of Copenhagen. The MECU is manned with a specialist in anaesthesiology and a specially trained ALS-provider. In the daytime and during weekend nights two ALS-units are available. The MECU carries various equipment and drugs for ALS, including a defibrillator with an external pacemaker. In case of presumed cardiac arrest, the BLSunit and the MECU are dispatched simultaneously and they operate in a ‘rendez vous’ fashion at the incident location. The protocol for resuscitation is consistent with guidelines from the European Resuscitation Council for advanced cardiac life support. After resuscitation, the patient is transferred to one of the six hospitals in the area of Copenhagen.
216
T.I. Horsted et al.
Results In the period of evaluation the dispatch centre had 18,149 emergency contacts leading to dispatch of the MECU, 1010 were related to OHCA and we had data on 984 cases, 579 men and 405 women. The median age was 71 years (34—91 years) and the aetiology was presumed cardiac in 792 (80.5%) cases and non-cardiac in 192. Non-cardiac causes were trauma, intoxication, drowning, exsanguination, suffocation, suicide, cot death, and cerebral causes. Time from collapse to 112-alarm was not recorded. The median time interval from 112call to arrival of the MECU was 6 min (2—10 min). The location of OHCA was most commonly in the patient’s home (600 patients), nursing home (141 patients) and in the street (86 patients). OHCA was witnessed in 611 (62.1%) and bystander CPR was provided in 167 (17.0%). In 472 cases the anaesthesiologist decided not to initiate CPR or to terminate the ongoing CPR started by the BLS-unit. The reason for not initiating or discontinuing resuscitation was reported in 457 cases and was due to presumed prolonged anoxia (326), terminal cancer (50), advanced age (51), severe trauma (26) and other causes (4). In 197 patients, the BLS unit had initiated CPR that was subsequently discontinued by the anaesthesiol-
ogist and in 22 patients, CPR initiated by bystanders was discontinued. In 512 cases CPR was attempted. The aetiology was cardiac in 433 cases and non-cardiac in 79 cases. The OHCA was witnessed in 402 (78.5%) and bystander CPR was provided in 145 (28.3%) (Table 1). In total 159 patients (31.1%) had return of spontaneous circulation (ROSC) on arrival to the Emergency Department (ED) and in 34, CPR was on-going. Survival beyond 30 days was seen in 67 (13.1%) out of all 512 treated patients. For witnessed cardiac arrest, presumed cardiac aetiology in VF/VT, survival beyond 1 month was 29.4%. At 6 months, 63 patients were alive corresponding to 12.3% [95% CI: 9.7—15.5%] of all treated patients. Age, sex, initial rhythm, witnessed arrest, and bystander CPR were all significant prognostic factors (Table 1). Survival beyond 6 months was seen in 4 out of 34 patients (11.8%) with on-going CPR on admission to ED.
Table 1 Demographic data and other details related to survival beyond 6 months for 512 patients treated for out-of-hospital cardiac arrest Number of patients
Survival >6 months
Sex Male Female
339 173
50 (14.7%) 13 (7.5%)
0.02
Age (years) 0—50 51—70 71—90 91
97 198 199 18
14 (14.4%) 35 (17.7%) 14 (7.0%) 0
0.004
Witnessed (N = 509) Yes 402 No 107
55 (13.7%) 7 (6.5%)
0.04
Bystander CPR (N = 510) Yes 145 No 365
31 (21.4%) 31 (8.5%)
<0.0001
Initial rhythm VF/VT 176 Asystole 183 Other 153
50 (28.4%) 4 (2.2%) 9 (5.9%)
<0.0001
P: probability in 2 -test.
P
Figure 1 Flowchart—–from 18,149 emergency contacts to 33 interviews with 6 months survivors.
Long-term prognosis after out-of-hospital cardiac arrest
Figure 2 Quality of life in 33 patients with survival beyond 6 months after out-of-hospital cardiac arrest in comparison with national norm. Mean ± S.E. * Statistically significant difference, P < 0.05.
Follow-up interview and examination was done in 33 patients out of 63 surviving for 6 months or more (Figure 1). Twelve patients refused to participate and eight patients did not respond, in spite of three attempts. Of those refusing follow-up examination, two patients replied that they had returned to normal activity and three patients were living in nursing homes. In the 33 patients examined, the median MMSE was 29 (16—30) and 2 patients, 6% [95% CI: 0.7—20.6%] had an MMSE below 24. Data related to quality of life as assessed by the SF-36 are shown in Figure 2. Two out of eight aspects were significantly worse than national norms at the same age but none of the summary scores were significantly different. One aspect was significantly better (pain).
Discussion We found that 12.3% survived beyond 6 months after OHCA in a physician-based EMS. Follow-up examination was performed in 33 patients out of those 63 survivors. Summary scores of quality of life were not significantly different from the national norm, but 2 out of 8 subscores were lower. Signs of dementia were uncommon as only 6% had a low MMSE score and most patients had an MMSE above 28. The study group included nearly all cases of OHCA during 2 consecutive years and due to the national registry using the unique personal identification number, we were able to assess survival in all patients included. Significant prognostic factors were those already known to be important for
217
early survival (Table 1). In our assessment of functional status, however, an important limitation is that 20 out of 63 survivors either refused or did not respond when we invited them to participate in the follow-up examination. The data on quality of life and MMSE are therefore based on 33 out of 53 adult patients that were alive and living in our country. This is a rather small sample as illustrated by the wide confidence interval for the incidence of dementia. Still, two of the subscores in the SF-36 showed significantly lower values than the national norms. Those were ‘‘role-physical’’ and ‘‘role-emotional’’. The magnitude of the difference is considerable and we expect that even less favourable data would be obtained if all patients could be examined. This is related to the problem that many patients with cognitive deficits are reluctant to undergo examination. It is not easy to compare our findings with other studies because there are important differences in the time of assessment and the method of examination. In one study of more than 3000 cases of OHCA over 4 years, only 35 out of 93 survivors underwent examination 1—2 years after the incident, first of all because 44% had died after discharge from hospital before follow-up. Approximately one-third reported a worse quality of life than before OHCA. Eleven percent had an MMSE below 25.6 A similar low proportion (50/169) underwent interview 5—68 months after OHCA in another study and quality of life was significantly worse than controls for most variables of the Nottingham Health Profile and the Everyday-Life Questionnaire.7 In a much smaller study, MMSE was below 27 in 6/17 (35%) subjects approximately 2 years after OHCA.8 In another 38 patients surviving OHCA due to ventricular fibrillation, the SF-36 and a memory function questionnaire were distributed after a mean follow-up of 4.9 years. Only one of the subscores (vitality score) were lower than that of the general population but approximately 50% reported memory problems.1 Of 101 survivors examined at a median of 15 months after cardiac arrest in various settings, 90 were interviewed and 17% were classified as cognitively impaired, based on an MMSE of 23 or less.9 Also, quality of life as assessed by Sickness Impact profile, was worse than in elderly control subjects in most subscores.9 One of the most pessimistic studies reported that deficits in at least one cognitive area was found in all survivors after OHCA but only 12 subjects were assessed after a median of 25 months.10 The reported differences in quality of life between controls and survivors of OHCA can be explained in different ways. Patients having OHCA typically suffer from cardiac disease (85% of our
218 patient had OHCA with cardiac aetiology) and it should therefore be questioned if healthy agematched people constitute the most appropriate control population. In stead, it may be relevant to compare survivors of OHCA with cardiac patients. As an example, in a recent study of 1351 patients with myocardial infarction, differences of the same magnitude as in our study were reported between patients and national norms for the SF-36 ‘‘rolephysical’’ and the ‘‘role-emotional’’.5 For the MMSE, it seems that 10—20% of survivors after OHCA have a score compatible with dementia. In the general population, approximately 5% of people aged 70 and over have an MMSE score below 24 and accordingly, in those surviving OHCA beyond 6 months there does not seem to be a major cognitive problem.11—13 On the other hand, dementia cannot be diagnosed on the basis of MMSE alone but more extensive neuropsychological testing was not feasible and it is also a problem that no reliable assessment of baseline performance is possible in OHCA victims. In conclusion, survival beyond 6 months was found in 12.3% OHCA in a physician-based EMS. Summary scores of quality of life were not significantly different from the national norm but 2 out of 8 subscores were lower. Signs of dementia were uncommon as only 6% had an MMSE score below 24.
References 1. Bunch TJ, White RD, Smith GE, et al. Long-term subjective memory function in ventricular fibrillation out-of-hospital cardiac arrest survivors resuscitated by early defibrillation. Resuscitation 2004;60:189—95.
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