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DSED after ROSC and recurrent ventricular fibrillation

Question #82

If a patient achieves return of spontaneous circulation (ROSC) after three shocks, then rearrests in ventricular fibrillation, should we immediately use double sequential external defibrillation (DSED), or start a new sequence of conventional shocks?

Answer:

Use DSED for the fourth consecutive shock when VF or pulseless VT persists after three consecutive conventional shocks, where authorized (Ontario Ministry of Health, 2025).

If the third shock produces ROSC, that sequence has worked. A later rearrest in VF starts a new sequence of conventional shocks. The three shocks before ROSC do not automatically make the next shock a DSED attempt.

If VF/pulseless VT persists after three consecutive shocks in the new arrest, consider DSED for the fourth shock. The key distinction is persistent shockable arrest versus rearrest after ROSC. The DOSE VF trial studied a change in strategy after three failed consecutive shocks; it did not establish that every episode of VF after ROSC requires DSED (Cheskes et al., 2022).

References

Ontario Ministry of Health. (2025). Advanced life support patient care standards (Version 5.4), Medical Cardiac Arrest Medical Directive. https://www.ontario.ca/files/2025-04/moh-advanced-life-support-als-patient-care-standards-pcs-5.4-en-2025-04-23.pdf

Cheskes, S., Verbeek, P. R., Drennan, I. R., McLeod, S. L., Turner, L., Pinto, R., Feldman, M., Davis, M., Vaillancourt, C., Morrison, L. J., Dorian, P., & Scales, D. C. (2022). Defibrillation strategies for refractory ventricular fibrillation. The New England Journal of Medicine, 387, 1947–1956. https://doi.org/10.1056/NEJMoa2207304

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Medical Directive Category

Cardiac Arrest

Published

24 October 2026

ALSPCS Version

5.4

Views

1

Please reference the MOST RECENT ALS PCS for updates and changes to these directives.