An investigation of inter-shock timing and electrode placement for double-sequential defibrillation

• Published in: Resuscitation Vol. 140; pp. 194 - 200
• Main Authors: Taylor, Tyson G., Melnick, Sharon B., Chapman, Fred W., Walcott, Gregory P.
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier B.V 01.07.2019
• Subjects: Defibrillator damage; Double-sequential defibrillation; Refractory ventricular fibrillation; Defibrillator damage; Refractory ventricular fibrillation; Double-sequential defibrillation
• ISSN: 0300-9572; 1873-1570
• DOI: 10.1016/j.resuscitation.2019.04.042

Double-Sequential Defibrillation (DSD) is the near-simultaneous use of two defibrillators to treat refractory VF. We hypothesized that (1) risk of DSD-associated defibrillator damage depends on shock vector and (2) the efficacy of DSD depends on inter-shock time. Part 1: risk of defibrillator damage was assessed in three anaesthetized pigs by applying two sets of defibrillation electrodes in six different configurations (near-orthogonal or near-parallel vectors). Ten 360J shocks were delivered from one set of pads and peak voltage was measured across the second set. Part 2: the dependence of DSD efficacy on inter-shock time was assessed in ten anaesthetized pigs. Electrodes were applied in lateral-lateral (LL) and anterior-posterior positions. Control (LL Stacked Shocks; one vector, two shocks ∼10 s apart) and DSD therapies (Overlapping, 10 ms, 50 ms, 100 ms, 200 ms, 500 ms, 1000 ms apart) were tested in a block randomized design treating electrically-induced VF (n = ∼89 VF episodes/therapy). Shock energies were selected to achieve 25% shock success for a single LL shock. Part 1: peak voltage delivered was 1833 ± 48 V (mean ± 95%CI). Peak voltage exposure was, on average, 10-fold higher for parallel than orthogonal vectors (p < 0.0001). Part 2: DSD efficacy compared to Stacked LL shocks was higher for Overlapping, 10 ms, and 100 ms (p < 0.05); lower at 50 ms (p < 0.05); and not different at 200 ms or longer inter-shock times. Risk of DSD-associated defibrillator damage can be mitigated by using near-orthogonal shock vectors. DSD efficacy is highly dependent on the inter-shock time and can be better, worse, or no different than stacked shocks from a single vector. University of Alabama at Birmingham Institutional Animal Care and Use Committee (IACUC) Protocol Number 06860.