Predicting Survival for Out-of-Hospital Cardiac Arrests
Purpose: To determine the effect of a return of spontaneous circulation (ROSC) on survival to hospital discharge as compared to other established survival predictors.
Methods: A retrospective case review of all adult out-of-hospital primary cardiac arrests from 1/1/92 to 12/31/94. Survival predictors of age, race, gender, presenting cardiac rhythm, witnessed event, bystander CPR, response intervals, and ROSC were examined from an Utstein template database. Return of spontaneous circulation was denied as ROSC prior to and present on emergency department arrival. Predictors were evaluated for statistical significance using a logistic regression analysis (p <0.05). Odds ratios (OR) and 99% confidence intervals (CI) with positive and negative predictive values (PPV, NPV) were presented.
Results: Of 832 primary cardiac arrest cases, 153 (18.4%) had ROSC as defined and 67 (8.1%) survived to hospital discharge. In comparing survivors to nonsurvivors, the mean age was 64 to 67 years, with 59.7% to 36.1% being witnessed, 35.8% to 23.9% having bystander CPR, 88.1% to 48.4% having ventricular fibrillation (V-fib) and 82.1% to 64.0% having ROSC. Logistic regression analysis revealed V-fib and ROSC to be significant (p = 0.009 [OR 2.2, CI 1.2-3.9]; p <0.0001 [OR 5.2, CI 3.6-7.5], respectively). Positive predictive values were 13.8% V-fib and 35.9% ROSC. Negative predictive values were 98.0% V-fib, and 98.2% ROSC.
Conclusion: Presenting V-fib and out-of-hospital ROSC are significant predictors of cardiac arrest survival. Failure to obtain ROSC in the out-of-hospital setting strongly suggests consideration for terminating resuscitation efforts.