Survival and recovery of consciousness in anoxic-ischemic coma after cardiopulmonary resuscitation

Objective: In patients who remain unconscious after cardiopulmonary resuscitation (CPR) poor outcome may be predicted with several tests. To use these tests, knowledge of a priori chances of poor outcome after varying periods of unconsciousness is needed. This study is aimed at providing such data. Design and patients: Data regarding survival and recovery of consciousness were extracted from registry-based and prospective cohort studies of patients with anoxic-ischemic coma. A survival analysis was done using Kaplan-Meier estimates and 28-day outcomes were calculated for all patients unconscious after 24 h and 72 h, and 5 days, 7 days and 14 days after CPR. Patient characteristics and outcomes in our cohort were compared with those of published patient series. Results: After 28 days, 27% of 172 patients from the two cohort studies were alive and conscious, 9% were still unconscious, and 64% had died. The proportion of patients who regained consciousness decreased from 34% of those unconscious within the first 6 h post-CPR to 13% of those still unconscious after 2 weeks. The proportion surviving in an unconscious state increased from 6% of patients who were unconscious initially to 33% of those still unconscious after 2 weeks. The chance of survival remained unchanged up to 7 days after CPR, irrespective of the duration of unconsciousness. Patient characteristics and outcomes in our cohort were comparable to data available from the literature. Conclusions: The a priori chances of (poor) outcome vary with the duration of unconsciousness after CPR. This study provides data for different time-intervals after CPR.