Today on EMCrit, I am joined by Sheldon Cheskes (Lead Author of the DoseVF trial) to discuss all things defibrillation.
Sheldon Cheskes, MD
@DrCheskes
- Professor, Emergency Medicine, Family and Community Medicine, Faculty of Medicine, University of Toronto, Ontario, Canada
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Scientist, Keenan Research Institute, Li Ka Shing Knowledge Institute, St. Michael’s Hospital
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Medical Director, Regions of Halton and Peel, Sunnybrook Centre for Prehospital Medicine, Sunnybrook Health Sciences Centre
Conflict of Interest
Dr. Cheskes has COI: he is on the speakers' bureau of Zoll, received a Zoll Medical Honorarium for CPR Quality and Ventilation during Cardiac Arrest, and received grant funding for studies from Laerdal and Zoll. As such, we will not offer CME for this episode and will make up for it in a subsequent episode.
What We Spoke About…
- Research and clinical teaching in this area has consistently been hindered by poor descriptive terms. Let's nail the terminology–refractory=electrical storm, recurrent if you shock them, they go to PEA/Sinus or asytole and they pop right back into VF. Dose-VF was only studying Refractory, but it seems even in the refractory group there were really 2 groups, true refractory and recurrent that came out of VF just briefly so the operators did not discern it as recurrent. Do you have better words for all of this?
- See through
- AHA get back on the chest–we really don't know. Shock earlier. stacked shocks?
- Change in impedance is the mechanism of VC?? Coverage of every myocyte in DSD? AP is a better vector. Drop in impedance.
- AP is better than AL in terms of current delivered to the heart
- Vector Change only works by chnaging to the superior pad position
- Vector Change is gone
- Why are we not pushing on the pads?
- Mechanism of DSD homogenous shock, leave no residual VF
- Mech cpr timing of down beat
- AEDs were sometimes used in the trial, AEDs have a horrible period of hands-off, would the results be even better with only manual?
- Initial Pad Position in 2025. Posterior Pad and mechanical support backboard
- In 2025, would you still wait till the 4th shock until we change something?
- Vector change seems markedly less effective, should we ever be doing that if we have 2 machines. You mentioned you would actually study this in Dose-VF2–why???
- You said in your lecture that you didn't blow any of the machines up, but that is less my fear than the situation in the Resuscitation case report, a machine that looked fine, tested fine on daily check, but was not actually providing in-spec shocks when actually used after exposure to DSD. Is this a real fear?
- Baffling that the manufacturers are upset, as your study is going to be worth millions in revenue. When will the manufacturers have machines made for dual-sequential?
- In the Dose-VF you waited 1 second, should people be doing that still?
- Not really simultaneous, but we can get closer
- Does the 360J matter?
- Will they actually be simultaneous at that point
- Should we still be giving non-dual shocks
- Secondary analysis shows closer the better, were you worried about your machines?
- Is it worth doing DSD in recurrent? (Mention new paper in the hidden recurrent)
- Not just more effective at getting them out, but more effective at keeping them out?
- DSD reduces the time in VF (intermittent ROSC is game changing)
- DSD vs. ECMO. Do both, intermittent ROSC changes the game
Papers Mentioned in the Podcast
- DoseVF Trial
- The impact of double sequential shock timing on outcomes during refractory out-of-hospital cardiac arrest
- Initial Defibrillator Pad Position and Outcomes for Shockable Out-of-Hospital Cardiac Arrest
- The impact of time to defibrillation on return of spontaneous circulation in out-of-hospital cardiac arrest patients with recurrent shockable rhythms
Dr. Cheskes' Full Lecture on the Dose-VF Trial
from Kongress der Arbeitsgemeinschaft fur Notfallmedizin
Dr. Cheskes' Site
Additional New Information
More on EMCrit
- Dual External Defibrillation: Close, but Not Touching by Mark Ramzy(Opens in a new browser tab)
- EMCrit 191 – Cardiac Arrest Update
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Editor-in-Chief, at EMCrit.org
An ED Intensivist from NY.
Professor
Nassau University Medical Center
No conflicts of interest (coi).
Professor
Nassau University Medical Center
No conflicts of interest (coi).
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Hey there! Really enjoyed this episode, thanks so much! I’m an ED nurse and educator in Portland Oregon. At my hospital, we’ve been struggling to determine the best pad placement when utilizing mechanical CPR (Lucas). We do use the Lucas routinely for all of our cardiac arrests. We use the Zoll OneStep complete AP defib pads. The anterior pad is a very large triangle shape. When the pad is placed in the anterior position (left side of anterior chest), it prevents the Lucas suction cup from sealing with the patients skin because part of the pad lays right where the… Read more »
I think the key message that came out of the podcast was AP is superior to AL, not just in DSED but in all situations–if you buy that, then you either need to reposition that anterior pad to not impinge under lucas piston or stop caring about the suction aspects. we do the latter.
I think that one exception for AL being superior to AP is in cardioversion of AF patients. Although the literature I’ve read is based in elective patients, it makes sanse if you’re mainly seeking to depolarize atrial myocites.
Great podcast, thanks. I’m wondering what your suggestion on energy levels. I always start at the biphasic defaults for everything… A. flutter, A. fib, V. tach, etc. but the nurses always quote ACLS recommendation to start with lower energies. I’m pretty sure I’ve read, but can’t find the literature, that higher energies are more effective. Thanks!
I always start as high as the machine goes–there is no additional myocyte damage from higher energy (based on a bunch of EP lab studies) and I’d rather just shock once. ACLS is a baseline, not a arbiter of care for resus doctors.