Perishock Pause

An Independent Predictor of Survival From Out-of-Hospital Shockable Cardiac Arrest

Sheldon Cheskes, MD; Robert H. Schmicker, MS; Jim Christenson, MD; David D. Salcido, MPH; Tom Rea, MD;Judy Powell, RN; Dana P. Edelson, MD; Rebecca Sell, MD; Susanne May, PhD; James J. Menegazzi, PhD;Lois Van Ottingham, RN, BSN; Michele Olsufka, BSN; Sarah Pennington, RN; Jacob Simonini, ACP;Robert A. Berg, MD; Ian Stiell, MD, MSc; Ahamed Idris, MD; Blair Bigham, MSc; Laurie Morrison, MD, MSc, on behalf of the Resuscitation Outcomes Consortium (ROC) Investigators

From the University of Toronto, Toronto, ON, Canada (S.C., B.B., L.M.); University of Washington, Seattle (R.H.S., T.R., J.P., S.M., L.V.O., M.O.); University of British Columbia, Vancouver, BC, Canada (J.C.); University of Pittsburgh, Pittsburgh, Pennsylvania (J.J.M., D.D.S.); St. Paul’s Hospital, Vancouver, BC, Canada (S.P.); Region of Peel, Emergency Medical Services, Brampton, ON, Canada (J.S.); University of Chicago Medical Center, Chicago, IL (D.E.); University of Ottawa, Ottawa, ON, Canada (I.S.); Children’s Hospital of Philadelphia and University of Pennsylvania, Philadelphia (R.A.B.); University of Texas Southwestern Medical Center, Dallas (A.I.); and University of California/San Diego, San Diego (R.S.).

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.

Methods and 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.
Key Words: cardiopulmonary resuscitation • heart arrest • resuscitation • survival

Article courtesy of Circulation and the AHA