title: Efficacy of bystander CPR: intervention by lay people and by health care professionals.
abstract: BACKGROUND
  Early cardiopulmonary resuscitation (CPR) by bystanders prior to the arrival of the rescue team has been shown to be associated with increased survival after out-of-hospital cardiac arrest. The aim of this survey was to evaluate the impact on survival of no bystander CPR, lay bystander CPR and professional bystander CPR.
  
  
  METHODS
  Patients suffering an out-of-hospital cardiac arrest in Sweden between 1990 and 2002 who were given CPR and were not witnessed by the ambulance crew were included.
  
  
  RESULTS
  In all, 29,711 patients were included, 36% of whom received bystander CPR prior to the arrival of the rescue team. Among the latter, 72% received CPR from lay people and 28% from professionals. Survival to 1 month was 2.2% among those who received no bystander CPR, 4.9% among those who received bystander CPR from lay people (p<0.0001) and 9.2% among those who received bystander CPR from professionals (p<0.0001 compared with bystander CPR by lay people). In a multivariate analysis, lay bystander CPR was associated with improved survival compared to no bystander CPR (OR: 2.04; 95% CI: 1.72-2.42), and professional bystander CPR was associated with improved survival compared to lay bystander CPR (OR: 1.37; 95% CI: 1.12-1.67).
  
  
  CONCLUSIONS
  Among patients suffering an out-of-hospital cardiac arrest, bystander CPR by lay persons (excluding health care professionals) is associated with an increased chance of survival. Furthermore, there is a distinction between lay persons and health care providers; survival is higher when the latter perform bystander CPR. However, these results may not be explained by differences in the quality of CPR.
authors.affiliation: Division of Cardiology, Sahlgrenska University Hospital, SE-413 45 Göteborg, Sweden. johan.herlitz@hjl.gu.se
authors.forename: Johan
authors.initials: J
authors.lastname: Herlitz
authors.forename: Leif
authors.initials: L
authors.lastname: Svensson
authors.forename: Stig
authors.initials: S
authors.lastname: Holmberg
authors.forename: Karl-Axel
authors.initials: KA
authors.lastname: Angquist
authors.forename: Marie
authors.initials: M
authors.lastname: Young
mesh_terms: D017677:Age Distribution; D000368:Aged; D016887:Cardiopulmonary Resuscitation / Q000706:statistics & numerical data*; D004632:Emergency Medical Services / Q000706:statistics & numerical data*; D005260:Female; D006323:Heart Arrest / Q000401:mortality* / Q000628:therapy*; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D016017:Odds Ratio; D010043:Outcome and Process Assessment, Health Care; D017678:Sex Distribution; D016019:Survival Analysis; D013548:Sweden / Q000453:epidemiology