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    Dual External Defibrillation

    Cardiovascular

    Last Updated Nov 27, 2020
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    Context

    • Refractory Ventricular Fibrillation (RVF) is defined as ventricular fibrillation that is unresponsive to three or more defibrillation attempts.
    • Dual External Defibrillation (DED) is a technique in which two defibrillators are used to treat RVF after failure of traditional Advanced Cardiovascular Life Support (ACLS) measures and defibrillation. DED includes Dual Simultaneous Defibrillation (DSiD – shocks delivered at exactly the same time) and Dual Sequential Defibrillation (DSD – shocks delivered in close sucession). Because it is practically very difficult to defibrillate at exactly the same time, functionally most studies evaluate DSD, as opposed to DSiD.

    How does DED work?

    • There are several theories why DED might work:
      • More Power – Most commercial defibrillators cannot deliver more than 360J, and some studies have shown that more energy results in higher likelihood of ROSC.
      • The Set Up – The first shock lowers the defibrillation threshold and “sets up” a successful second shock.
      • Multiple Vectors – Multiple vectors of energy delivery ensure more of the myocardium is depolarized by the defibrillation.

    What are the harms of DED?

    • There are unlikely to be any iatrogenic complications of DED for the patient, especially given the premorbid state of cardiac arrest.
    • However, there can be harm to your defibrillator if not performed correctly. Specific pitfalls include:
      • Using different defibrillators (different brand OR different model).
      • Pads in contact with each other.
      • Simultaneous defibrillation.

    How is DED performed?

    • Two IDENTICAL (same brand and model) defibrillators are required. Use of different defibrillators can result in damage to the devices.
    • The original pads (DEFIB 1) are placed in the traditional anterolateral position, and will already be on the patient.
    • The second set of pads (DEFIB 2) can be placed either Anterior-Posterior (Figure 1) or Anterior (Figure 2).
    • NOTE: Defibrillator pads should be close, but NEVER touching each other.

    Figure 1. DEFIB 1 positioned anterolateral and DEFIB 2 positioned anterior-posterior.

    Figure 2. DEFIB 1 positioned anterolateral and DEFIB 2 positioned anterior.

    • One provider should ideally press both shock buttons at approximately (but not exactly) the same time. In theory, simultaneous defibrillation may damage some types of defibrillators and is not recommended by manufacturers.

    When should I consider using DED?

    • DED should be considered in patients with RVF and after traditional ACLS measures (e.g. anti-arrhythmics) have failed. DED should NOT be used for patients with refractory ventricular tachycardia (VT/electrical Storm).
    • Given the low quality of evidence for DED, greater consideration should be given to interventions with higher likelihood of patient benefit, if available in your center. For example, activation of your extracorporeal life support team, or transport of the patient with mechanical CPR for percutaneous coronary intervention should take precedent. However, there are many centers where these interventions are not available without ROSC, or not available at all, and DED may be a reasonable intervention.

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    Quality Of Evidence?

    Justification

    • The overall evidence for DED is low, comprised of case reports and case series with a high risk of bias. DED is not currently recommended by the American Heart Association Emergency Cardiovascular Care (AHA-ECC) Guidelines.
    • In May 2020, a pilot randomized controlled trial called DOSE-VF was published, with promising results. However, the full randomized controlled trial is ongoing and will need evaluation and external validation before widespread use.
    Low

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