title: Early versus later rhythm analysis in patients with out-of-hospital cardiac arrest.
abstract: BACKGROUND
  In a departure from the previous strategy of immediate defibrillation, the 2005 resuscitation guidelines from the American Heart Association-International Liaison Committee on Resuscitation suggested that emergency medical service (EMS) personnel could provide 2 minutes of cardiopulmonary resuscitation (CPR) before the first analysis of cardiac rhythm. We compared the strategy of a brief period of CPR with early analysis of rhythm with the strategy of a longer period of CPR with delayed analysis of rhythm.
  
  
  METHODS
  We conducted a cluster-randomized trial involving adults with out-of-hospital cardiac arrest at 10 Resuscitation Outcomes Consortium sites in the United States and Canada. Patients in the early-analysis group were assigned to receive 30 to 60 seconds of EMS-administered CPR and those in the later-analysis group were assigned to receive 180 seconds of CPR, before the initial electrocardiographic analysis. The primary outcome was survival to hospital discharge with satisfactory functional status (a modified Rankin scale score of ≤3, on a scale of 0 to 6, with higher scores indicating greater disability).
  
  
  RESULTS
  We included 9933 patients, of whom 5290 were assigned to early analysis of cardiac rhythm and 4643 to later analysis. A total of 273 patients (5.9%) in the later-analysis group and 310 patients (5.9%) in the early-analysis group met the criteria for the primary outcome, with a cluster-adjusted difference of -0.2 percentage points (95% confidence interval, -1.1 to 0.7; P=0.59). Analyses of the data with adjustment for confounding factors, as well as subgroup analyses, also showed no survival benefit for either study group.
  
  
  CONCLUSIONS
  Among patients who had an out-of-hospital cardiac arrest, we found no difference in the outcomes with a brief period, as compared with a longer period, of EMS-administered CPR before the first analysis of cardiac rhythm. (Funded by the National Heart, Lung, and Blood Institute and others; ROC PRIMED ClinicalTrials.gov number, NCT00394706.).
authors: Department of Emergency Medicine and Ottawa Hospital Research Institute, University of Ottawa, Ottawa. istiell@ohri.ca
authors: Ian G
authors: IG
authors: Stiell
authors: Graham
authors: G
authors: Nichol
authors: Brian G
authors: BG
authors: Leroux
authors: Thomas D
authors: TD
authors: Rea
authors: Joseph P
authors: JP
authors: Ornato
authors: Judy
authors: J
authors: Powell
authors: James
authors: J
authors: Christenson
authors: Clifton W
authors: CW
authors: Callaway
authors: Peter J
authors: PJ
authors: Kudenchuk
authors: Tom P
authors: TP
authors: Aufderheide
authors: Ahamed H
authors: AH
authors: Idris
authors: Mohamud R
authors: MR
authors: Daya
authors: Henry E
authors: HE
authors: Wang
authors: Laurie J
authors: LJ
authors: Morrison
authors: Daniel
authors: D
authors: Davis
authors: Douglas
authors: D
authors: Andrusiek
authors: Shannon
authors: S
authors: Stephens
authors: Sheldon
authors: S
authors: Cheskes
authors: Robert H
authors: RH
authors: Schmicker
authors: Ray
authors: R
authors: Fowler
authors: Christian
authors: C
authors: Vaillancourt
authors: David
authors: D
authors: Hostler
authors: Dana
authors: D
authors: Zive
authors: Ronald G
authors: RG
authors: Pirrallo
authors: Gary M
authors: GM
authors: Vilke
authors: George
authors: G
authors: Sopko
authors: Myron
authors: M
authors: Weisfeldt
mesh_terms: D000368:Aged; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D004562:Electrocardiography; D004632:Emergency Medical Services; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D058687:Out-of-Hospital Cardiac Arrest / Q000401:mortality / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome