title: Perishock pause: an independent predictor of survival from out-of-hospital shockable cardiac arrest.
abstract: BACKGROUND
  Perishock pauses are pauses in chest compressions before and after defibrillatory shock. We examined the relationship between perishock pauses and survival to hospital discharge.
  
  
  RESULTS
  We included out-of-hospital cardiac arrest patients in the Resuscitation Outcomes Consortium Epistry-Cardiac Arrest who suffered arrest between December 2005 and June 2007, presented with a shockable rhythm (ventricular fibrillation or pulseless ventricular tachycardia), and had cardiopulmonary resuscitation process data for at least 1 shock (n=815). We used multivariable logistic regression to determine the association between survival and perishock pauses. In an analysis adjusted for Utstein predictors of survival, the odds of survival were significantly lower for patients with preshock pause ≥20 seconds (odds ratio, 0.47; 95% confidence interval, 0.27 to 0.82) and perishock pause ≥40 seconds (odds ratio, 0.54; 95% confidence interval, 0.31 to 0.97) compared with patients with preshock pause <10 seconds and perishock pause <20 seconds. Postshock pause was not independently associated with a significant change in the odds of survival. Log-linear modeling depicted a decrease in survival to hospital discharge of 18% and 14% for every 5-second increase in both preshock and perishock pause interval (up to 40 and 50 seconds, respectively), with no significant association noted with changes in the postshock pause interval.
  
  
  CONCLUSIONS
  In patients with cardiac arrest presenting in a shockable rhythm, longer perishock and preshock pauses were independently associated with a decrease in survival to hospital discharge. The impact of preshock pause on survival suggests that refinement of automatic defibrillator software and paramedic education to minimize preshock pause delays may have a significant impact on survival.
authors.affiliation: University of Toronto, Toronto, ON, Canada. scheskes@socpc.ca
authors.forename: Sheldon
authors.initials: S
authors.lastname: Cheskes
authors.forename: Robert H
authors.initials: RH
authors.lastname: Schmicker
authors.forename: Jim
authors.initials: J
authors.lastname: Christenson
authors.forename: David D
authors.initials: DD
authors.lastname: Salcido
authors.forename: Tom
authors.initials: T
authors.lastname: Rea
authors.forename: Judy
authors.initials: J
authors.lastname: Powell
authors.forename: Dana P
authors.initials: DP
authors.lastname: Edelson
authors.forename: Rebecca
authors.initials: R
authors.lastname: Sell
authors.forename: Susanne
authors.initials: S
authors.lastname: May
authors.forename: James J
authors.initials: JJ
authors.lastname: Menegazzi
authors.forename: Lois
authors.initials: L
authors.lastname: Van Ottingham
authors.forename: Michele
authors.initials: M
authors.lastname: Olsufka
authors.forename: Sarah
authors.initials: S
authors.lastname: Pennington
authors.forename: Jacob
authors.initials: J
authors.lastname: Simonini
authors.forename: Robert A
authors.initials: RA
authors.lastname: Berg
authors.forename: Ian
authors.initials: I
authors.lastname: Stiell
authors.forename: Ahamed
authors.initials: A
authors.lastname: Idris
authors.forename: Blair
authors.initials: B
authors.lastname: Bigham
authors.forename: Laurie
authors.initials: L
authors.lastname: Morrison
mesh_terms: D000368:Aged; D000488:Allied Health Personnel / Q000193:education; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D047548:Defibrillators; D004554:Electric Countershock / Q000379:methods*; D005260:Female; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D058687:Out-of-Hospital Cardiac Arrest / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy*; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome