Date: February 7, 2023
Reference: Cheskes et al. Defibrillation Strategies for Refractory Ventricular Fibrillation. NEJM 2022
Guest Skeptic: Dr. Sean Moore is an emergency physician working in Kenora Ontario, where he is Chief of Staff at Lake of the Woods District Hospital, Northern Medical Director for the Ornge air medical transport program and associate medical director with CritiCall Ontario. Research interests include simulation-based assessment, transport medicine, and critical care analgesia. He is an assistant professor at the Northern Ontario School of Medicine University and is passionate about health equity for rural and indigenous populations. He has been an ACLS instructor for close to 30 years and notably his first publication focused on out-of-hospital defibrillation.
Case: A 60-year-old health professional suffers a cardiac arrest while working at a clinic outside the hospital. An anesthetist is working with him for the procedures. He confirms pulselessness, initiates CPR, gets a colleague to call 911, and intubates the patient on the floor. He is found to be in ventricular fibrillation and receives two defibrillation attempts with an automatic external defibrillator (AED) at the clinic, and subsequently three more with a primary care ambulance crew enroute to the hospital. He arrives at the hospital 18 minutes into his arrest and his monitor shows persistent ventricular fibrillation.
Background: Out-of-hospital cardiac arrest (OHCA) is something we have covered extensively on the SGEM over the years. This has included things like therapeutic hypothermia (SGEM#54, SGEM#82, SGEM#183 and SGEM#275), supraglottic devices (SGEM#247), crowd sourcing CPR (SGEM#143 and SGEM#306), epinephrine (SGEM#238) and IO vs IV (SGEM#231 and SGEM#340).
One issue that has not been covered on the SGEM is pad placement and double sequential external defibrillation.
Clinical Question: Does refractory ventricular fibrillation respond better to standard defibrillation, vector-change defibrillation, or double sequential external defibrillation?
Reference: Cheskes et al. Defibrillation Strategies for Refractory Ventricular Fibrillation. NEJM 2022
Population: Ontario patients who were at least 18 years of age and had an OHCA and refractory ventricular fibrillation.
Intervention:
Vector Change Defibrillation: Pads are placed in an anterior-posterior pad placement after standard anterior-anterior configuration following the third shock with standard defibrillation.
Double Sequential External Defibrillation: Pads are placed in both the anterior-anterior and the anterior-posterior pad placements following the third shock with standard defibrillation.
Comparison: Standard defibrillation with pads placed in anterior-anterior configuration
Outcome:
Primary Outcome: Survival to hospital discharge
Secondary Outcomes: Termination of ventricular fibrillation, return of spontaneous circulation (ROSC), good Neurologic outcome (modified Rankin scale [mRS] score <3)
Trial: Unblinded, cluster-randomized trial with crossover among six paramedic services in rural and urban Canada
Authors’ Conclusions: “Among patients with refractory ventricular fibrillation, survival to hospital discharge occurred more frequently among those who received DSED defibrillation or VC defibrillation then among those who received standard defibrillation.”
Quality Checklist for Randomized Clinical Trials:
The study population included or focused on those in the emergency department. No
The patients were adequately randomized. Yes
The randomization process was concealed. Yes
The patients were analyzed in the groups to which they were randomized. Yes
The study patients were recruited consecutively (i.e. no selection bias). Yes
The patients in both groups were similar with respect to prognostic factors. Yes
All participants (patients, clinicians,
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