title: Effectiveness of bystander cardiopulmonary resuscitation and survival following out-of-hospital cardiac arrest.
abstract: OBJECTIVE
  To examine the independent relationship between effectiveness of bystander cardiopulmonary resuscitation (CPR) and survival following out-of-hospital cardiac arrest.
  
  
  METHODS
  Prospective observational cohort.
  
  
  METHODS
  New York City.
  
  
  METHODS
  A total of 2071 consecutive out-of-hospital cardiac arrests meeting Utstein criteria.
  
  
  METHODS
  Trained prehospital personnel assessed the quality of bystander CPR on arrival at the scene. Satisfactory execution of CPR required performance of both adequate compressions and ventilations in conformity with current American Heart Association guidelines.
  
  
  METHODS
  Adjusted association between CPR effectiveness and survival. Survival 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, interval 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).
  
  
  CONCLUSIONS
  The association between bystander CPR and survival in out-of-hospital cardiac arrest appears to be confounded by CPR quality. Effective CPR is independently associated with a quantitatively and statistically significant improvement in survival.
authors.affiliation: Department of Emergency Medicine, Albert Einstein College of Medicine, Bronx, NY, USA.
authors.forename: E J
authors.initials: EJ
authors.lastname: Gallagher
authors.forename: G
authors.initials: G
authors.lastname: Lombardi
authors.forename: P
authors.initials: P
authors.lastname: Gennis
mesh_terms: D016887:Cardiopulmonary Resuscitation / Q000401:mortality*; D015331:Cohort Studies; D004632:Emergency Medical Services; D006323:Heart Arrest / Q000401:mortality / Q000628:therapy*; D006801:Humans; D016015:Logistic Models; D009519:New York City / Q000453:epidemiology; D011446:Prospective Studies; D015996:Survival Rate; D016896:Treatment Outcome; D000078329:Workforce