Sponsored by: 

Dr Sheldon Cheskes

Dr. Sheldon Cheskes is an Professor with the Division of Emergency Medicine, Department of Family and Community Medicine at the University of Toronto, and a scientist at the Li Ka Shing Knowledge Institute at St. Michael’s Hospital in Toronto, Ontario, Canada. He is the Medical Director for the Regions of Halton and Peel with the Sunnybrook Centre for Prehospital Medicine. He is one of the principal investigators for the Canadian Resuscitation Outcomes Consortium (CanROC) and is a recognized international authority in the area of CPR quality and out-of-hospital cardiac arrest resuscitation. Dr. Cheskes has published over 100 manuscripts in high impact journals such as the New England Journal of Medicine, Circulation, CMAJ and Resuscitation that have changed resuscitation practice around the world.

He is the principal investigator of the DOuble Sequential External Defibrillation in Refractory Ventricular Fibrillation (DOSE VF) trial. This study will be the first cluster randomized trial to clinically evaluate two novel therapeutic defibrillation strategies (double sequential external defibrillation and vector change defibrillation) against standard practice for patients remaining in refractory ventricular fibrillation during out-of-hospital cardiac arrest. He is also studying methods to improve public access defibrillation in rural and remote areas through the use of community responder programs and drone delivery of automated external defibrillators.

On this episode, we’re breaking down the landmark DOSE VF study – DOuble SEquential External Defibrillation for Refractory Ventricular Fibrillation (DOSE VF) – that was recently published in the NEJM with lead investigator Dr. Sheldon Cheskes.

Study Design: Cluster randomized controlled trial

Research Question: The objective of this trial (Double Sequential External Defibrillation for Refractory Ventricular Fibrillation [DOSE VF]) was to evaluate DSED and VC defibrillation as compared with standard defibrillation in patients who remain in refractory ventricular fibrillation during out-of-hospital cardiac arrest.

P-I-C-O

Patients:

–       Six paramedic services in Ontario, Canada (approx. 4000 paramedics) that provide rural and urban care to approximately 6.6 million residents. Recruitment occurred from March 2020 – May 2022 (with a pause do to COVID)

–       Inclusion criteria:

o   >18 years old

o   Refractory rhythm

–       Exclusion criteria:

o   Traumatic arrest, DNR, hypothermia, hanging, suspected OD

Interventions:

• Vector change
  • pads were changed from their original anterior-lateral position to an anterior-posterior position after the third “standard” shock, and all subsequent shocks were done with the new AP pad position
• Double sequential external defibrillation
  • a second set of pads were applied in the anterior-posterior position after the third “standard” shock, and all shocks after the third were provided from 2 defibrillators

Control:

• Standard defibrillation

Outcome:

• Primary outcome: survival to hospital discharge
• Secondary outcomes:
  • Termination of rhythm
  • ROSC
  • Good neurological outcome as hospital discharge (defined as a modified Rankin scare score of 2 or lower)

Results:

N = 405 (136 in standard arm; 144 in VC; 125 in DSED)

Conclusion:

In this randomized, controlled trial of DSED or VC defibrillation for the treatment of refractory ventricular fibrillation during out-of-hospital cardiac arrest, survival to hospital discharge was more common among patients who received DSED or VC defibrillation than among those who received standard defibrillation. 

Termination of ventricular fibrillation, return of spontaneous circulation, and a good neurologic outcome at hospital discharge appeared to be more common with the DSED strategy, as did termination of ventricular fibrillation with the VC defibrillation strategy.

Timestamps:

02:48: Dr. Cheskes Intro

06:15: Study Intro

16:45: Patients

18:18: Intervention – Vector Change

25:45: Intervention – DSED

37:12: Comparison/Outcome

40:23: Results

54:15: Critical Appraisal