title: Time-dependent effectiveness of chest compression-only and conventional cardiopulmonary resuscitation for out-of-hospital cardiac arrest of cardiac origin.
abstract: BACKGROUND
  Little is known about the effect of the type of bystander-initiated cardiopulmonary resuscitation (CPR) for prolonged out-of-hospital cardiac arrest (OHCA).
  
  
  OBJECTIVE
  To evaluate the time-dependent effectiveness of chest compression-only and conventional CPR with rescue breathing for witnessed adult OHCA of cardiac origin.
  
  
  METHODS
  A nationwide, prospective, population-based, observational study of the whole population of Japan included consecutive OHCA patients with emergency responder resuscitation attempts from 1 January 2005 to 31 December 2007. Multiple logistic regression analysis was performed to assess the contribution of the bystander-initiated CPR technique to favourable neurological outcomes.
  
  
  RESULTS
  Among 55014 bystander-witnessed OHCA of cardiac origin, 12165 (22.1%) received chest compression-only CPR and 10851 (19.7%) received conventional CPR. For short-duration OHCA (0-15min after collapse), compression-only CPR had a higher rate of survival with favourable neurological outcome than no CPR (6.4% vs. 3.8%; adjusted odds ratio (OR), 1.55; 95% confidence interval (CI), 1.38-1.74), and conventional CPR showed similar effectiveness (7.1% vs. 3.8%; adjusted OR, 1.78; 95% CI, 1.58-2.01). For the long-duration arrests (>15min), conventional CPR showed a significantly higher rate of survival with favourable neurological outcome than both no CPR (2.0% vs. 0.7%; adjusted OR, 1.93; 95% CI, 1.27-2.93) and compression-only CPR (2.0% vs. 1.3%; adjusted OR, 1.56; 95% CI, 1.02-2.44).
  
  
  CONCLUSIONS
  For prolonged OHCA of cardiac origin, conventional CPR with rescue breathing provided incremental benefit compared with either no CPR or compression-only CPR, but the absolute survival was low regardless of type of CPR.
authors.affiliation: Kyoto University Health Service, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Tetsuhisa
authors.initials: T
authors.lastname: Kitamura
authors.forename: Taku
authors.initials: T
authors.lastname: Iwami
authors.forename: Takashi
authors.initials: T
authors.lastname: Kawamura
authors.forename: Ken
authors.initials: K
authors.lastname: Nagao
authors.forename: Hideharu
authors.initials: H
authors.lastname: Tanaka
authors.forename: Robert A
authors.initials: RA
authors.lastname: Berg
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hiraide
mesh_terms: D000368:Aged; D004632:Emergency Medical Services / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006336:Heart Massage / Q000379:methods*; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D058687:Out-of-Hospital Cardiac Arrest / Q000209:etiology / Q000401:mortality / Q000628:therapy*; D011159:Population Surveillance; D011446:Prospective Studies; D012042:Registries; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D016896:Treatment Outcome