Predicting survival after out-of-hospital cardiac arrest: role of the Utstein data elements

Abstract

Study objective: Survival after out-of-hospital cardiac arrest depends on the links in the chain of survival. The Utstein elements are designed to assess these links and provide the basis for comparing outcomes within and across communities. We assess whether these measures sufficiently predict survival and explain outcome differences.

Methods: We used an observational, prospective data collection, case-series of adult persons with nontraumatic out-of-hospital cardiac arrest from December 1, 2005, through March 1, 2007, from the multisite, population-based Resuscitation Outcomes Consortium Epistry-Cardiac Arrest. We used logistic regression, receiver operating curves, and measures of variance to estimate the extent to which the Utstein elements predicted survival to hospital discharge and explained outcome variability overall and between 7 Resuscitation Outcomes Consortium sites. Analyses were conducted for all emergency medical services-treated cardiac arrests and for the subset of bystander-witnessed patient arrests because of presumed cardiac cause presenting with ventricular fibrillation or ventricular tachycardia.

Results: Survival was 7.8% overall (n=833/10,681) and varied from 4.6% to 14.7% across Resuscitation Outcomes Consortium sites. Among bystander-witnessed ventricular fibrillation or ventricular tachycardia, survival was 22.1% overall (n=323/1459) and varied from 12.5% to 41.0% across sites. The Utstein elements collectively predicted 72% of survival variability among all arrests and 40% of survival variability among bystander-witnessed ventricular fibrillation. The Utstein elements accounted for 43.6% of the between-site survival difference among all arrests and 22.3% of the between-site difference among the bystander-witnessed ventricular fibrillation subset.

Conclusion: The Utstein elements predict survival but account for only a modest portion of outcome variability overall and between Resuscitation Outcomes Consortium sites. The results underscore the need for ongoing investigation to better understand characteristics that influence cardiac arrest survival.