Bruce D. Adams, MD
Is perishock pause in chest compressions associated with survival to hospital discharge in patients with out-of-hospital shockable cardiac arrest?
Cohort study using prospectively collected data from Resuscitation Outcomes Consortium Epistry—Cardiac Arrest.
5 emergency medical services (EMS) agencies in Canada and the USA.
815 patients (mean age 64 y, 79% men) who had an out-of-hospital cardiac arrest and presented with a first shockable rhythm of ventricular fibrillation or pulseless ventricular tachycardia. Exclusion criteria included public-access defibrillation before arrival of EMS.
Longest perishock pause (time from chest compression cessation to defibrillatory shock [preshock pause] plus time from defibrillatory shock to chest compression resumption [postshock pause]) assessed in the first 3 shocks for each patient. Analyses were adjusted for Utstein predictors of survival (age, sex, public location, witness status, bystander use of cardiopulmonary resuscitation, and time from EMS dispatch to arrival) and EMS site.
Survival to hospital discharge and return of spontaneous circulation (ROSC) on arrival at emergency department.
Mean EMS response time was 5.9 minutes, median preshock pause was 15.6 seconds, and median postshock pause was 8.3 seconds. Longer perishock and preshock pauses were associated with decreased survival to hospital discharge (Table); length of postshock pause was not associated with survival (Table). Survival decreased with every 5-second increase in perishock pause (odds ratio [OR] 0.86, 95% CI 0.77 to 0.95) and preshock pause (OR 0.82, CI 0.73 to 0.93) but not postshock pause (OR 1.04, CI 0.92 to 1.16). Longer perishock and preshock pauses were associated with lower rates of ROSC (perishock < 20 s vs ≥ 40 s, OR 0.52, CI 0.27 to 0.97; preshock < 10 s vs ≥ 20 s, OR 0.37, CI 0.20 to 0.71); length of postshock pause was not associated with ROSC.
Longer perishock and preshock pauses in chest compressions were associated with decreased survival to hospital discharge after out-of-hospital cardiac arrest.
*OH = out of hospital; OR = odds ratio; CI defined in Glossary.
†Unadjusted data for first 3 shocks.
‡Adjusted for age, sex, public location of arrest, witness status, bystander use of cardiopulmonary resuscitation, time from dispatch to arrival of emergency medical services, and emergency medical services site.
Adams BD. Longer perishock pauses were associated with decreased survival to hospital discharge after out-of-hospital shockable cardiac arrest. Ann Intern Med. 2011;155:JC4–12. doi: 10.7326/0003-4819-155-8-201110180-02012
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Published: Ann Intern Med. 2011;155(8):JC4-12.
Cardiology, Emergency Medicine, Hospital Medicine, Rhythm Disorders and Devices.
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Print ISSN: 0003-4819 | Online ISSN: 1539-3704
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