Hypoxic ischemic brain injury following in hospital cardiac arrest - lessons from autopsy

Hypoxic ischemic brain injury (HIBI) is the most decisive factor in determining the outcome following a cardiac arrest. After an arrest, neuronal death may be early or delayed. The aim of our study is to determine the prevalence and predictors of HIBI on autopsy following an in hospital cardiac arrest. We retrospectively reviewed the medical records of patients who sustained an in hospital cardiorespiratory arrest and underwent autopsy following in hospital mortality at our tertiary care medical center from January 2004-June 2012. These patients were identified from the autopsy registry maintained by the Department of Pathology and were classified into two groups based on the presence or absence of HIBI on autopsy. We compared the baseline demographics, risk factors, total duration of cardiopulmonary resuscitation, number of resuscitative events and survival time between both groups. Multivariate logistic regression analysis was performed to identify predictors of hypoxic ischemic injury following cardiac arrest. Out of 71 patients identified during this study period, 21% had evidence of HIBI on autopsy. On univariate analysis, predictors of HIBI were prolonged hospital stay, prolonged survival time following an arrest and a slight increased trend following multiple resuscitative events. On multivariate analysis, prolonged survival time was the only significant predictor of HIBI. Similar to other prognostication cardiac arrest studies, there were minimal predictors of early neuronal injury even on autopsy.