Double Sequence Defibrillation (ALS): Systematic Review

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Conflict of Interest Declaration

The ILCOR Continuous Evidence Evaluation process is guided by a rigorous ILCOR Conflict of Interest policy. The following Task Force members and other authors were recused from the discussion as they declared a conflict of interest: none

The following Task Force members and other authors declared an intellectual conflict of interest and this was acknowledged and managed by the Task Force Chairs and Conflict of Interest committees: Drennan – involved in RCT of defibrillation strategies

CoSTR Citation

Deakin CD, Drennan I, Morley PT, Soar J, on behalf of the International Liaison Committee on Resuscitation Advanced Life Support Task Force. Double Sequence Defibrillation. Consensus on Science with Treatment Recommendations [Internet] Brussels, Belgium: International Liaison Committee on Resuscitation (ILCOR) Advanced Life Support Task Force, 2020 January 3. Available from:

Methodological Preamble

The continuous evidence evaluation process for the production of Consensus on Science with Treatment Recommendations (CoSTR) started with a systematic review Conducted by Deakin, Drennan, Morley, Soar with involvement of clinical content experts. These data were taken into account when formulating the Treatment Recommendations.


The PICOST (Population, Intervention, Comparator, Outcome, Study Designs and Timeframe)

Population: Adults in any setting (in-hospital or out-of-hospital) with a shockable VF/pVT) cardiac arrest rhythm

Intervention: Double (or dual or sequential) manual defibrillation strategy

Comparators: Standard manual defibrillation strategy

Outcomes: Critical – Survival to hospital discharge or good neurological survival at discharge/30 days, or greater than 30 days. Important – Return of Spontaneous Circulation (ROSC), survival to hospital admission. Other – termination of VF/pVT,

Study Designs: Randomized controlled trials (RCTs) and non-randomized studies (non-randomized controlled trials, interrupted time series, controlled before-and-after studies, cohort studies) are eligible for inclusion.

Timeframe: All years and all languages were included as long as there was an English abstract; unpublished studies (e.g., conference abstracts, trial protocols) were excluded. Literature search up to 27 September 2019

PROSPERO Registration Submitted 1 Oct 2019

Consensus on Science

For the critical outcomes of good neurological survival at discharge (n=3; Mapp 2019 994, Ross 2016 14, Cortez 2016 82), and survival to hospital discharge’ (n=6; Mapp 2019 994, Beck 2019 597, Emmerson 2017 97, Ross 2016 14, Cortez 2016, Cabanas 2015 126), the important outcomes of survival to hospital admission (n=4; Mapp 2019 994, Beck 2019 597, Emmerson 2017 97, Ross 2016 14), and ROSC (n=7; Mapp 2019 994, Cheskes 2019 275, Beck 2019 597, Emmerson 2017; 97, Ross 2016 14, Cortez 2016, Cabanas 2015 126, and the outcome of termination of VF (n=4; Cheskes 2019 275, Cortez 2016, Cabanas 2015 126) we identified only observational studies.

The overall quality of evidence was rated as very low for all outcomes primarily due to a very serious risk of bias. The individual studies were all at a critical risk of bias due to confounding. Because of this and a high degree of heterogeneity, no meta-analyses could be performed and individual studies are difficult to interpret.

Treatment Recommendations

We suggest against routine use of dual (or double) sequential defibrillation strategy in comparison to a standard defibrillation strategy for cardiac arrest with a shockable rhythm (weak recommendation, very low certainty of evidence).

Justification and Evidence to Decision Framework Highlights

The Task force noted that double defibrillation is used by some EMS systems for refractory shockable cardiac arrest.

  • Approximately 20% of VF patients, however, will remain in VF (after 5 shocks) despite standard resuscitation interventions. Patients in refractory VF have significantly lower rates of survival than patients who respond to standard resuscitation treatments.
  • The available evidence for the double defibrillation approach is limited.
  • There is no agreed standardised approach to double defibrillation such that a double dose strategy could be two overlapping shocks or sequential shocks. TF discussed whether any potential benefit was from increased shock energy, the fact that two shocks were delivered sequentially, different pad placement and vector for the second shock, or some other reason.
  • The limited observational data shows lower rates of survival and neurological outcome for patients treated with double defibrillation.
  • The available case reports are likely to represent publication bias
  • Double shocks require the availability of two defibrillators and this has resource implications.
  • There is potential harm from an excessive shock energy, and potential of damage to defibrillators.

Knowledge Gaps

No RCTs of double defibrillation compared with standard defibrillation studying long term outcomes.

No studies describing optimal ‘double/dual/sequential’ defibrillation strategy including timing or pad placement.


Evidence-to-Decision Table: Double Defibrillation


Beck LR, Ostermayer DG, Ponce JN, Srinivasan S, Wang HE. Effectiveness of Prehospital Dual Sequential Defibrillation for Refractory Ventricular Fibrillation and Ventricular Tachycardia Cardiac Arrest. Prehosp Emerg Care. 201;23:597-602.

Cabañas JG, Myers JB, Williams JG, De Maio VJ, Bachman MW. Double Sequential External Defibrillation in Out-of-Hospital Refractory Ventricular Fibrillation: A Report of Ten Cases. Prehosp Emerg Care. 2015;19:126-130.

Cheskes S, Wudwud A, Turner L, McLeod S, Summers J, Morrison LJ, Verbeek PR.

The impact of double sequential external defibrillation on termination of refractory ventricular fibrillation during out-of-hospital cardiac arrest. Resuscitation. 2019;139:275-281.

Cortez E, Krebs W, Davis J, Keseg DP, Panchal AR. Use of double sequential external defibrillation for refractory ventricular fibrillation during out-of-hospital cardiac arrest. Resuscitation. 2016;108:82-86.

Emmerson AC, Whitbread M, Fothergill RT. Double sequential defibrillation therapy for out-of-hospital cardiac arrests: The London experience. Resuscitation. 2017;117:97-101.

Mapp JG, Hans AJ, Darrington AM, Ross EM, Ho CC, Miramontes DA, Harper SA, Wampler DA; Prehospital Research and Innovation in Military and Expeditionary Environments (PRIME) Research Group. Prehospital Double Sequential Defibrillation: A Matched Case-Control Study. Acad Emerg Med. 2019;26:994-1001.

Ross EM, Redman TT, Harper SA, Mapp JG, Wampler DA, Miramontes DA. Dual defibrillation in out-of-hospital cardiac arrest: A retrospective cohort analysis. Resuscitation. 2016;106:14-7.


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