Predicting survival from out-of-hospital cardiac arrest.

OBJECTIVE: To determine the effect of a return of spontaneous circulation (RO SC) on survival to hospital discharge as compared to other established predictors of survival.

METHODS: A retrospective case review of all out-of-hospital primary cardiac arrests from 01 January, 1992 to 31 December 1994 was conducted. The relative values of age, race, gender, presenting cardiac rhythm, witnessed event, initiation of CPR by bystanders, response time intervals, and return of spontaneous circulation (ROSC) in an Utstein-template database were tested as predictors of survival of patients who had suffered a cardiac arrest in the out-of-hospital setting. The ROSC was defined as return of spontaneous circulation prior to and present upon arrival at the emergency department. Predictors were evaluated for statistical significance using a logistic regression analysis (p < 0.05). Odds ratios (OR) and 95% confidence intervals (CI) with positive and negative predictive values (PPV, NPV) were calculated.

RESULTS: Of 832 patients with primary cardiac arrest, 153 (18.4%) had ROSC and 67 (8.1%) survived to hospital discharge. Comparing survivors to nonsurvivors, the mean values for age were 64 to 67 years, with 59.7% to 36.1% being witnessed, 35.8% to 23.9% having bystander CPR initiated, 88.1% to 48.4% having ventricular fibrillation (V-fib) and 82.1% to 64.0% having ROSC. An initial electrocardiographic rhythm of V-fib (p = 0.009; OR = 2.2; CI = 1.2-3.9), and ROSC (p < 0.0001; OR = 5.2; CI = 3.6-7.5) are statistically significant predictors of survival to hospital discharge. The PPV was 13.8% for V-fib and 35.9% for ROSC, and the NPV was 98.0% for V-fib and 98.2% for ROSC.

CONCLUSION: Presenting V-fib and out-of-hospital ROSC are significant predictors of survival from cardiac arrest. Failure to obtain ROSC in the out-of-hospital setting strongly suggests consideration for terminating resuscitation efforts.