DOuble SEquential External Defibrillation for Refractory VF – DOSE VF Randomized Control Trial
PI: Sheldon Cheskes
Status: Enrolling. Pilot Closes Sept 10 2019
Introduction: Despite significant advances in resuscitation efforts such as cardiopulmonary resuscitation (CPR) quality, defibrillation, airway management and antiarrhythmic medications given in hopes of promoting the return of an organized rhythm; there are some patients who remain in refractory ventricular fibrillation (VF) during out-of-hospital cardiac arrest. Double sequential external defibrillation (DSED) and vector change defibrillation have been proposed as a viable option for patients in refractory VF.
Objective: The objective of this study is to compare two novel therapeutic defibrillation strategies (DSED and vector change defibrillation) against standard practice for patients remaining in refractory VF during out-of-hospital cardiac arrest.
Research Question: Among adult (≥ 18 years) patients presenting in refractory VF or pulseless ventricular tachycardia (pVT) during out-of-hospital cardiac arrest, does DSED or vector change defibrillation (anterior-posterior compared to anterior-anterior pad position) result in greater rates of survival to hospital discharge compared to standard defibrillation?
Methods: This will be a three-arm, cluster randomized trial with crossover conducted in six regions of Ontario, Canada (Peel, Halton, Toronto, Simcoe, London and Ottawa) over a three year period of time. According to randomized cluster assignment, all adult (≥ 18 years) patients presenting in refractory VF (defined as patients presenting in VF/pVT and remaining in VF/pVT after three consecutive standard defibrillation attempts each separated by 2 minutes of CPR) during out-of-hospital cardiac arrest of presumed cardiac etiology will be treated by one of three strategies: (1) continued resuscitation using standard defibrillation; (2) resuscitation involving DSED; or (3) resuscitation involving vector change (change of defibrillation pads from anterior-anterior to an anterior-posterior pad position) defibrillation. The primary outcome will be survival to hospital discharge. Secondary outcomes will include return of spontaneous circulation (ROSC), termination of VF after the first interventional shock, termination of VF inclusive of all interventional shocks, and number of defibrillation attempts to obtain ROSC. Based on our previous cohort study research and the DOSE VF pilot RCT, we will also perform an a priori subgroup analysis comparing rates of survival to hospital discharge for those randomized to DSED who receive DSED after three failed successive standard shocks (early DSED or first DSED shock is shock 4-6) to those who receive DSED after six failed successive standard shocks (late DSED or first DSED shock is shock 7 or later).
Impact: A well-designed randomized controlled trial employing a standardized approach to alternative defibrillation strategies early in the treatment of refractory VF is urgently required to determine if the treatments of vector change defibrillation or DSED impact clinical outcomes.
Dose RCT is a continuation of Pilot study with addition of two new sites (Ottawa and London). Planning to enroll 930 patients over three years with survival to hospital discharge as primary outcome. Funding from HSF-GIA grant for three years.