Effect of out-of-hospital defibrillation by basic life support providers on cardiac arrest mortality: a metaanalysis

Ann Emerg Med. 1995 May;25(5):642-8. doi: 10.1016/s0196-0644(95)70178-8.


Study objective: Although some studies demonstrate otherwise, we hypothesized that metaanalysis would demonstrate a reduction in the relative risk of mortality when basic life support (BLS) providers can defibrillate out-of-hospital cardiac arrest patients.

Design: Metaanalysis of studies meeting the following criteria: single-tier or two-tier emergency medical service (EMS) system, survival to hospital discharge for patients in ventricular fibrillation, and manual and/or automatic external defibrillators. The alpha error rate was .05.

Results: Seven trials qualified for metaanalysis. Across all trials, the risk of mortality for BLS care with defibrillation versus that without was .915 (P = .0003). Separate subset analyses of single-tier and two-tier EMS systems demonstrated similar results.

Conclusion: BLS defibrillation can reduce the relative risk of death for out-of-hospital cardiac arrest victims in ventricular fibrillation. Weaknesses in individual study designs and regional clustering limit the strength of this metaanalysis and conclusion.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Electric Countershock / instrumentation
  • Electric Countershock / statistics & numerical data*
  • Emergency Medical Services / standards*
  • Heart Arrest / etiology
  • Heart Arrest / mortality*
  • Heart Arrest / therapy*
  • Humans
  • Research Design
  • Risk Factors
  • Survival Analysis
  • Treatment Outcome
  • United States
  • Ventricular Fibrillation / complications