EFFECTIVENESS OF BYSTANDER CARDIOPULMONARY-RESUSCITATION AND SURVIVALFOLLOWING OUT-OF-HOSPITAL CARDIAC-ARREST

Objective.-To examine the independent relationship between effectivene ss of bystander cardiopulmonary resuscitation (CPR) and survival follo wing out-of-hospital cardiac arrest. Design.-Prospective observational cohort. Setting.-New York City. Participants.-A total of 2071 consecu tive out-of-hospital cardiac arrests meeting Utstein criteria. Interve ntion.-Trained prehospital personnel assessed the quality of bystander CPR on arrival at the scene. Satisfactory execution of CPR required p erformance of both adequate compressions and ventilations in conformit y with current American Heart Association guidelines. Main Outcome Mea sure.-Adjusted association between CPR effectiveness and survival. Sur vival was defined as discharge from hospital to home. Results.-Outcome was determined on all members of the inception cohort-none were lost to follow-up. When the association between bystander CPR and survival was adjusted for effectiveness of CPR in the parent data set (N=2071), only effective CPR was retained in the logistic model (adjusted odds ratio [OR]=5.7; 95% confidence interval [CI], 2.7 to 12.2; P<.001). Of the subset of 662 individuals (32%) who received bystander CPR, 305 ( 46%) had it performed effectively. Of these, 4.6% (14/305) survived vs 1.4% (5/357) of those with ineffective CPR (OR=3.4; 95% CI, 1.1 to 12 .1; P<.02). After adjustment for witness status, initial rhythm, inter val from collapse to CPR, and interval from collapse to advanced life support, effective CPR remained independently associated with improved survival (adjusted OR=3.9; 95% CI, 1.1 to 14.0; P<.04). Conclusion.-T he association between bystander CPR and survival in out-of-hospital c ardiac arrest appears to be confounded by CPR quality. Effective CPR i s independently associated with a quantitatively and statistically sig nificant improvement in survival.