Abstract 1: The Utility of Therapeutic Hypothermia for Post-Cardiac Arrest Syndrome Patients with an Initial Nonshockable Rhythm
Background: Therapeutic hypothermia (TH) attenuates reperfusion injury in comatose survivors of cardiac arrest with an initial shockable rhythm. The utility of TH in patients with nonshockable initial rhythms has not been widely accepted due to lack of randomized controlled trial data.
Objectives: To determine whether TH improved neurologic outcome and survival in post-arrest patients with initial nonshockable rhythms.
Methods: We identified 522 patients with nonshockable initial rhythms from 16 hospitals in the Penn Alliance for Therapeutic Hypothermia (PATH) registry between 2000-2013. Our dependent variable of interest was good neurologic outcome (determined by Cerebral Performance Category (CPC) score dichotomized into “good” (1-2) and “poor” (3-5)) and survival to hospital discharge. Propensity score matching was used to control for confounding. The patient and arrest characteristics used to estimate the propensity to receive TH were age, sex, location of arrest, witnessed arrest, nonshockable rhythm, and downtime. 405 matched pairs were identified using STATA 12 (College Station, TX) module for propensity score matching. To determine the association between TH and outcome, we created a multivariate logistic model controlling for age, sex, witnessed arrest, and downtime.
Results: Of the 405 propensity score matched patients, the mean age was 63±17 years, 51% were male, and 60% had an initial rhythm of pulseless electrical activity. 17.6% of patients who did not receive TH survived to hospital discharge vs 28.9% of patients who received TH (p=0.007); 13.7% who did not receive TH had a CPC 1-2 at discharge vs 21.4% in patients who received TH (p= 0.043). In adjusted analyses, patients who received TH had better survival (OR 2.09, CI 1.24-3.50, p=0.018) and better neurologic outcome (OR 2.02, CI 1.13-3.62, p=0.005) compared to those that did not receive TH.
Conclusions: Using propensity score matching to create a treatment and control cohort, we found that patients with nonshockable initial rhythms treated with TH had better survival and neurologic outcome at hospital discharge than those who did not receive TH.
- © 2013 by American Heart Association, Inc.