The impact of double sequential shock timing on outcomes during refractory out-of-hospital cardiac arrest

Mahbod Rahimi; Ian R Drennan; Linda Turner; Paul Dorian; Sheldon Cheskes

doi:10.1016/j.resuscitation.2023.110082

The impact of double sequential shock timing on outcomes during refractory out-of-hospital cardiac arrest

Resuscitation. 2024 Jan:194:110082. doi: 10.1016/j.resuscitation.2023.110082. Epub 2023 Dec 11.

Authors

Mahbod Rahimi¹, Ian R Drennan², Linda Turner³, Paul Dorian⁴, Sheldon Cheskes⁵

Affiliations

¹ Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada.
² Sunnybrook Centre for Prehospital Medicine, Toronto, Ontario, Canada; Sunnybrook Research Institute, Sunnybrook Health Science Centre, Toronto, Ontario, Canada; Department of Family and Community Medicine, Division of Emergency Medicine, University of Toronto, Toronto, Ontario, Canada; Institute of Health Policy, Management and Evaluation, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
³ Sunnybrook Centre for Prehospital Medicine, Toronto, Ontario, Canada.
⁴ Division of Cardiology, Unity Health, Department of Medicine, Temerty Faculty of Medicine, University of Toronto, Ontario, Canada.
⁵ Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada; Sunnybrook Centre for Prehospital Medicine, Toronto, Ontario, Canada; Sunnybrook Research Institute, Sunnybrook Health Science Centre, Toronto, Ontario, Canada; Department of Family and Community Medicine, Division of Emergency Medicine, University of Toronto, Toronto, Ontario, Canada; Li Ka Shing Knowledge Institute, St. Michaels Hospital, Toronto, Ontario, Canada. Electronic address: sheldon.cheskes@sunnybrook.ca.

PMID: 38092182
DOI: 10.1016/j.resuscitation.2023.110082

Abstract

Background: Animal studies suggest the efficacy of double sequential external defibrillation (DSED) may depend on the interval between the two shocks, or "DSED interval". No human studies have examined this concept.

Objectives: To determine the relationship between DSED interval and termination of ventricular fibrillation (VFT), return of spontaneous circulation (ROSC), survival to hospital discharge, and favourable neurological status (MRS ≤ 2) for patients in refractory VF.

Methods: We performed a retrospective review of adult (≥18 years) out-of-hospital cardiac arrest between January 2015 and May 2022 with refractory VF who received ≥1 DSED shock. DSED interval was divided into four pre-defined categories. We examined the association between DSED interval and patient outcomes using general estimated equation logistic regression or Fisher's exact test.

Results: Among 106 included patients, 303 DSED shocks were delivered (median 2, IQR 1-3). DSED intervals of 75-125 ms (OR 0.39, 95% CI 0.16-0.98), 125-500 ms (OR 0.36, 95% CI 0.16-0.82), and >500 ms (OR 0.27, 95% CI 0.11-0.63) were associated with lower probability of VF termination compared to <75 ms interval. DSED interval of >75 ms was associated with lower probability of ROSC compared to <75 ms interval (OR 0.37, 95% CI 0.14-0.98). No association was noted between DSED interval and survival to hospital discharge or neurologic outcome.

Conclusions: Among patients in refractory VF a DSED interval of less than 75 ms was associated with improved rates of VF termination and ROSC. No association was noted between DSED interval and survival to hospital discharge or neurologic outcome.

Keywords: Cardiac arrest; Cardiopulmonary resuscitation; Defibrillation; Double sequential external defibrillation; Prehospital care; Resuscitation.

MeSH terms

Adult
Cardiopulmonary Resuscitation*
Electric Countershock
Emergency Medical Services*
Humans
Out-of-Hospital Cardiac Arrest*
Patient Discharge
Retrospective Studies
Ventricular Fibrillation / complications
Ventricular Fibrillation / therapy