Outcome of non-traumatic out-of-hospital cardiac arrest in the elderly

Background: Because of changes in lifestyle and the advancement of medical science, human life expectancy in Taiwan is longer than it used to be. Since 1993, we have had an "aging population", i.e., the proportion of the elderly population is greater than 7% of the general population and is increasing over time. However, to our knowledge, no study of the outcomes of out-of-hospital cardiac arrest (OHCA) in the elderly has been performed in Taiwan. This study was, therefore, undertaken to identify both the outcomes of these occurrences and the factors that influenced them. Methods: This was a retrospective study. The characteristics of 299 nontraumatic OHCA patients (elderly/adult ratio, 198:101), who received cardiopulmonary resuscitation upon arrival at the emergency department (ED) between January 1, 2005 and December 31, 2005 were reviewed. The group was split between "elderly patients" aged 65 or over and "adult patients" aged 18 to 64. The outcome measurements included return of spontaneous circulation (ROSC) at the ED, survival to hospital admission, and survival to hospital discharge with full neurologic function. Results: The overall survival rate of patients was 7.4%. Of the 198 elderly patients, 85 (42.9%) had ROSC, 50 (25.3%) survived to admission and 12 (6.1%) survived to hospital discharge. In comparison, of the 101 adult patients, 32 (31.7%) had ROSC, 21 (20.8%) survived to admission and 10 (9.9%) survived to hospital discharge. The differences in outcomes between the two groups were not statistically significant. In the subgroup of patients who had ROSC at the ED, the adult group had a higher rate of survival to hospital discharge than the elderly (31.3% vs. 14.1%; p=0.035); but in multivariate analysis, only the initial ventricular fibrillation/ventricular tachycardia rhythm predicted survival rate (odds ratio, 7.912; p=0.007). The factor that predicted ROSC was witnessed arrest. Factors that predicted hospital discharge included witnessed arrest and shorter duration of resuscitation in the ED. Post-resuscitation neurologic outcomes of the survivors showed no significant difference between the two groups. Conclusion: It is rational and necessary to aggressively resuscitate in cases of cardiac arrest among the elderly, because their age did not significantly decrease their survival rate or worsen their post-resuscitation neurologic outcomes, compared with non-elderly patients. All the elderly survivors studied were witnessed arrest cases, with return of circulation within 20 minutes at the ED.