Age and survival after in-hospital cardiopulmonary resuscitation

EDITOR: There are contradicting results regarding the prognostic importance of age after in-hospital cardiopulmonary resuscitation (CPR) [1]. Only few studies have investigated long-term survival of older patients after a cardiac arrest [2]. We aimed to assess age-related immediate and long-term survival after in-hospital CPR. The medical records, including special resuscitation forms, of all 479 patients who underwent in-hospital CPR between 1994 and 1999 were retrospectively analysed. Patients who were resuscitated in the intensive care unit (ICU) or in the emergency department were excluded from the study. Of the remaining patients those with a primary cardiac arrest were identified. Cardiac arrest was defined as the absence of palpable pulses or other evidence of the absence of effective circulation requiring cardiac massage or defibrillation. The resuscitation effort was considered successful if there was a systolic blood pressure (BP) ≥80 mmHg at the end of the resuscitation effort. The resuscitation team of the Weezenlanden hospital consists of physicians from the ICU and the department of cardiology, and specially trained nurses from both wards. Resuscitation forms were reviewed to determine details of the cardiac arrest, patient characteristics data, hospital stay and survival to discharge. In August 2000 the general practitioners (GPs) of the patients discharged from the hospital were contacted to ascertain the patients' longer term outcomes. The collected outcome data were analysed for immediate survival, survival to hospital discharge and 1-yr survival. The population was dichotomized for further analysis at age ≥70 yr and age <70 yr. The χ2-test was used to compare categorical data between survivors and non-survivors. Differences between group means were tested by two-tailed t-test. Fischer's exact test was used if there was an expected cell value of <5. Survival functions were calculated using the Kaplan-Meier product limit method. Mantel-Cox (or log-rank) test was applied to evaluate the differences between survival functions. Statistical significance was defined as a P-value ≤0.05. During the study period, a total of 282 patients fulfilled the criteria of primary in-hospital cardiac arrest. Main reason for exclusion was cardiac-respiratory insufficiency without cardiac arrest. The mean age was 69 ± 12 yr. One hundred and fifty-six patients (55%) were older than 70 yr. It concerned 173 males (61%) and 109 females (39%). Immediate survival was similar for younger and older patients: <70 yr 50.8% (64/126) vs. ≥70 yr 50.0% (78/156), P = 0.89. Survival to hospital discharge was higher in younger patients: <70 yr 31.0% (39/126) vs. ≥70 yr 20.5% (32/156), P = 0.04, as was 1-yr survival: <70 yr 26.2% (33/126) vs. ≥70 yr 15.4% (24/156), P = 0.02. Of the total initial survivors, 71 patients (50%) were discharged alive, and 80% of the discharged patients lived to 1 yr. Thus, the proportion of initial survivors who lived to 1 yr was 40%. Figure 1 shows 1-yr survival of the different age groups. Of the patients who were initially successfully resuscitated, 1-yr survival was significantly better (P = 0.03) in the group <70 yr.Figure 1.: One-year survival of patients <70 yr and ≥70 yr after initial successful resuscitation on a general ward.The immediate outcome of resuscitation in our study is comparable with other reports, in which resuscitation was successful in 40-50% of the patients [3], even when heterogeneous groups of patients are included. Possibly, composition of the study population is less important for the immediate success rate of resuscitation. Several studies show that survival to discharge is age dependent [4]. Particularly patients ≥70 yr had a decreased likelihood of leaving the hospital alive, as was the case in our study. However, others show that age is not predictive of survival [5] or, like Parish and colleagues [1] report that the relationship between age and survival depends on the rhythm at the start of resuscitation. They showed that age was negatively related to survival particularly when the initial rhythm was perfusing or pulseless electrical activity, and was positively related in case of supraventricular tachycardia. The 1-yr survival in the older group of our study showed a less favourable outcome than in the younger group. This is in contradiction with the long-term outcome of the study of Bari and colleagues, which can possibly be explained by the difference in inclusion of intensive care patients, who have a less favourable outcome in all other studies as well. Multiple co-morbidities may be more important in older patients. In a study of resuscitated octogenarians only 11% of the patients could be discharged alive [6]. There are several important limitations to our study. Our primary goal was to identify whether age was an important factor related to outcome. We did not include the relation to several other factors, such as underlying disorders, unwitnessed cardiac arrest, location of cardiac arrest, pre-arrest history, number of direct current shocks and epinephrine doses, which have all been identified by other authors as predictive for survival after in-hospital cardiac resuscitation [7]. In conclusion, our study shows that the immediate outcome in patients ≥70 yr after resuscitation for in-hospital cardiac arrest is similar to that in younger patients, but that the 1-yr survival rate is worse. Patients who were discharged from the hospital had a good survival after 1 yr, with a moderately, but significantly better outcome in the younger group. J. M. Perdok P. J. A. van der Starre J. P. Ottervanger A. R. Y. Jager F. T. F. Snellen W. A. Siemons F. H. Pasma 1Department of Cardiothoracic Anesthesiology and Intensive Care, Weezenlanden Hospital, Isala Clinics, Zwolle, The Netherlands 2Department of Anesthesiology, University Medical Center Groningen, Groningen, The Netherlands 3Department of Anesthesia, Stanford University Medical Center, Stanford, CA, USA 4Department of Cardiology, Weezenlanden Hospital, Isala Klinieken, Zwolle, The Netherlands