title: Increasing use of cardiopulmonary resuscitation during out-of-hospital ventricular fibrillation arrest: survival implications of guideline changes.
abstract: BACKGROUND
  The most recent resuscitation guidelines have sought to improve the interface between defibrillation and cardiopulmonary resuscitation; the survival impact of these changes is unknown, however. A year before issuance of the most recent guidelines, we implemented protocol changes that provided a single shock without rhythm reanalysis, stacked shocks, or postdefibrillation pulse check, and extended the period of cardiopulmonary resuscitation from 1 to 2 minutes. We hypothesized that survival would be better with the new protocol.
  
  
  RESULTS
  The present study took place in a community with a 2-tiered emergency medical services response and an established system of cardiac arrest surveillance, training, and review. The investigation was a cohort study of persons who had bystander-witnessed out-of-hospital ventricular fibrillation arrest because of heart disease, comparing a prospectively defined intervention group (January 1, 2005, to January 31, 2006) with a historical control group that was treated according to previous guidelines of rhythm reanalysis, stacked shocks, and postdefibrillation pulse checks (January 1, 2002, to December 31, 2004). The primary outcome was survival to hospital discharge. The proportion of treated arrests that met inclusion criteria was similar for intervention and control periods (15.4% [134/869] versus 16.6% [374/2255]). Survival to hospital discharge was significantly greater during the intervention period compared with the control period (46% [61/134] versus 33% [122/374], P=0.008) and corresponded to a decrease in the interval from shock to start of chest compressions (28 versus 7 seconds). Adjustment for covariates did not alter the survival association.
  
  
  CONCLUSIONS
  These results suggest the new resuscitation guidelines will alter the interface between defibrillation and cardiopulmonary resuscitation and in turn may improve outcomes.
authors.affiliation: Department of Medicine, University of Washington, Seattle, WA, USA. rea123@u.washington.edu
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Rea
authors.forename: Michael
authors.initials: M
authors.lastname: Helbock
authors.forename: Stephen
authors.initials: S
authors.lastname: Perry
authors.forename: Michele
authors.initials: M
authors.lastname: Garcia
authors.forename: Don
authors.initials: D
authors.lastname: Cloyd
authors.forename: Linda
authors.initials: L
authors.lastname: Becker
authors.forename: Mickey
authors.initials: M
authors.lastname: Eisenberg
mesh_terms: D000368:Aged; D016887:Cardiopulmonary Resuscitation / Q000379:methods / Q000592:standards*; D015331:Cohort Studies; D004496:Education, Continuing; D004632:Emergency Medical Services / Q000458:organization & administration; D004634:Emergency Medical Technicians / Q000193:education / Q000706:statistics & numerical data; D005260:Female; D006323:Heart Arrest / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010045:Outpatients; D016019:Survival Analysis; D017741:Survivors; D014693:Ventricular Fibrillation / Q000401:mortality / Q000628:therapy*; D014861:Washington