title: Defibrillation time intervals and outcomes of cardiac arrest in hospital: retrospective cohort study from Get With The Guidelines-Resuscitation registry.
abstract: OBJECTIVE
  To describe temporal trends in the time interval between first and second attempts at defibrillation and the association between this time interval and outcomes in patients with persistent ventricular tachycardia or ventricular fibrillation (VT/VF) arrest in hospital.
  
  
  METHODS
  Retrospective cohort study
  
  
  METHODS
  172 hospitals in the United States participating in the Get With The Guidelines-Resuscitation registry, 2004-12.
  
  
  METHODS
  Adults who received a second defibrillation attempt for persistent VT/VF arrest within three minutes of a first attempt.
  
  
  METHODS
  Second defibrillation attempts categorized as early (time interval of up to and including one minute between first and second defibrillation attempts) or deferred (time interval of more than one minute between first and second defibrillation attempts).
  
  
  METHODS
  Survival to hospital discharge.
  
  
  RESULTS
  Among 2733 patients with persistent VT/VF after the first defibrillation attempt, 1121 (41%) received a deferred second attempt. Deferred second defibrillation for persistent VT/VF increased from 26% in 2004 to 57% in 2012 (P<0.001 for trend). Compared with early second defibrillation, unadjusted patient outcomes were significantly worse with deferred second defibrillation (57.4% v 62.5% for return of spontaneous circulation, 38.4% v 43.6% for survival to 24 hours, and 24.7% v 30.8% for survival to hospital discharge; P<0.01 for all comparisons). After risk adjustment, deferred second defibrillation was not associated with survival to hospital discharge (propensity weighting adjusted risk ratio 0.89, 95% confidence interval 0.78 to 1.01; P=0.08; hierarchical regression adjusted 0.92, 0.83 to 1.02; P=0.1).
  
  
  CONCLUSIONS
  Since 2004, the use of deferred second defibrillation for persistent VT/VF in hospital has doubled. Deferred second defibrillation was not associated with improved survival.
authors.affiliation: VA Eastern Colorado Health Care System, Denver, CO, USA University of Colorado School of Medicine, Aurora, CO, USA Colorado Cardiovascular Outcomes Research Consortium, Denver, CO, USA Steven.Bradley@va.gov.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Bradley
authors.affiliation: VA Eastern Colorado Health Care System, Denver, CO, USA University of Colorado School of Public Health, Aurora, CO, USA.
authors.forename: Wenhui
authors.initials: W
authors.lastname: Liu
authors.affiliation: Saint Luke's Mid America Heart Institute and University of Missouri-Kansas City, MO, USA.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Chan
authors.affiliation: University of Michigan Medical School, Ann Arbor, MI, USA.
authors.forename: Brahmajee K
authors.initials: BK
authors.lastname: Nallamothu
authors.affiliation: VA Eastern Colorado Health Care System, Denver, CO, USA University of Colorado School of Public Health, Aurora, CO, USA.
authors.forename: Gary K
authors.initials: GK
authors.lastname: Grunwald
authors.affiliation: University of Colorado School of Medicine, Aurora, CO, USA.
authors.forename: Alyssa
authors.initials: A
authors.lastname: Self
authors.affiliation: American Heart Association, Dallas, TX, USA.
authors.forename: Comilla
authors.initials: C
authors.lastname: Sasson
authors.affiliation: VA Eastern Colorado Health Care System, Denver, CO, USA University of Colorado School of Medicine, Aurora, CO, USA Colorado Cardiovascular Outcomes Research Consortium, Denver, CO, USA.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Varosy
authors.affiliation: Duke Clinical Research Institute, Durham, NC, USA.
authors.forename: Monique L
authors.initials: ML
authors.lastname: Anderson
authors.affiliation: University of Colorado School of Medicine, Aurora, CO, USA Colorado Cardiovascular Outcomes Research Consortium, Denver, CO, USA.
authors.forename: Preston M
authors.initials: PM
authors.lastname: Schneider
authors.affiliation: VA Eastern Colorado Health Care System, Denver, CO, USA University of Colorado School of Medicine, Aurora, CO, USA Colorado Cardiovascular Outcomes Research Consortium, Denver, CO, USA.
authors.forename: P Michael
authors.initials: PM
authors.lastname: Ho
mesh_terms: D000368:Aged; D004554:Electric Countershock / Q000706:statistics & numerical data*; D005260:Female; D006323:Heart Arrest / Q000628:therapy*; D006761:Hospitals; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D017063:Outcome Assessment, Health Care; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D017180:Tachycardia, Ventricular / Q000628:therapy*; D013997:Time Factors; D014481:United States; D014693:Ventricular Fibrillation / Q000628:therapy*