Early clinical prediction of neurological outcome following out of hospital cardiac arrest managed with therapeutic hypothermia

Background: Therapeutic hypothermia (TH) may improve neurological outcome in comatose patients following out of hospital cardiac arrest (OHCA). The reliability of clinical prediction of neurological outcome following TH remains unclear. In particular, there is very limited data on survival and predictors of neurological outcome following TH for OHCA from resource-constrained settings in general and South Asia in specific. Objective: The objective was to identify factors predicting unfavorable neurological outcome at hospital discharge in comatose survivors of OHCA treated with hypothermia. Design: Retrospective chart review. Setting: Urban 200-bed hospital in Chennai, India. Methods: Predictors of unfavorable neurological outcome (cerebral performance category score [3-5]) at hospital discharge were evaluated among patients admitted between January 2006 and December 2012 following OHCA treated with TH. Hypothermia was induced with cold intravenous saline bolus, ice packs and cold-water spray with bedside fan. Predictors of unfavorable neurological outcome were examined through multivariate exact logistic regression analysis. Results: A total of 121 patients were included with 106/121 (87%) experiencing the unfavorable neurological outcome. Independent predictors of unfavorable neurological outcome included: Status myoclonus <24 h (odds ratio [OR] 21.79, 95% confidence interval [CI] 2.89-Infinite), absent brainstem reflexes (OR 50.09, 6.55-Infinite), and motor response worse than flexion on day 3 (OR 99.41, 12.21-Infinite). All 3 variables had 100% specificity and positive predictive value. Conclusion: Status myoclonus within 24 h, absence of brainstem reflexes and motor response worse than flexion on day 3 reliably predict unfavorable neurological outcome in comatose patients with OHCA treated with TH.