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Double sequential external defibrillation (DSED) is a novel treatment option for cardiac arrest patients in refractory ventricular fibrillation (VF). There is limited research, however, examining the efficacy of this treatment in clinical practice. Previous research is further confounded by the use of other treatments such as advanced cardiac life...
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Context 1
... initial set of pads were not removed or reapplied in preparation for DSED as they were properly spaced with good adherence to the patient. Both defibrillators were charged to 200 J and DSED was delivered by a single BLS provider pressing the shock buttons of both defibrillators in sequential fashion (Figure 2). A second DSED shock was delivered following an additional two minutes of CPR as the patient remained in VF (Figure 3 increase in GCS from 3 to 8 at the time of transfer of care at the receiving facility. ...
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Introduction:
Defibrillation is effective and the most common treatment for ventricular fibrillation (VF) and pulseless ventricular tachycardia in patients with cardiac arrest.
Patient concerns:
Recently we experienced 3 cases refractory ventricular fibrillation (RVF) which was successfully terminated with double sequence defibrillation (DSD) in...
Citations
Out-of-hospital cardiac arrest (OHCA) accounts for a majority of mortality worldwide. Survivability from an OHCA highly depends on timely and effective defibrillation. Most of the OHCA cases are due to ventricular fibrillation (VF), a lethal form of cardiac arrhythmia. During VF, previous studies have shown the presence of spatiotemporally organized electrical activities called rotors and that terminating these rotor-like activities could modulate or terminate VF in an in-hospital or research setting. However, such an approach is not feasible for OHCA scenarios. In the case of an OHCA, external defibrillation remains the main therapeutic option despite the low survival rates. In this study, we evaluated whether defibrillation effectiveness in an OHCA scenario could be improved if a shock vector directly targets rotor-like, spatiotemporal electrical activities on the myocardium. Specifically, we hypothesized that the position of defibrillator pads with respect to a rotor’s core axis and shock current density could influence the likelihood of rotor termination and thereby result in successful defibrillation. We created a bidomain cardiac model based on porcine heart data using Aliev–Panfilov bidomain equations. We simulated localized rotors, which we attempted to terminate using different defibrillation pad orientations relative to the rotor axis (i.e., perpendicular, parallel, and oblique). In addition, we gradually increased current densities for each defibrillation pad orientation from 4 to 12 A/m2. We repeated the above defibrillation procedure for rotors originating from four different locations on the ventricles. The shock parameters and the outcomes were analyzed using a Generalized Linear Mixed Model (GLMM) with Logistic Regression to link rotor termination with the defibrillation pad orientation and current density. Our results suggest the highest average likelihood of terminating rotors during VF is when defibrillator pads are placed perpendicular to the rotor axis (0.99 ± 0.03), with an average current density of 7.2 A/m2, compared to any other orientation (parallel: 0.76 ± 0.26 and oblique: 0.08 ± 0.12). Our simulations suggest that optimal defibrillator pad orientation, combined with sufficient current density magnitude, could improve the likelihood of rotor termination during VF and thereby improving defibrillation success in OHCA patients.
Background
Double/dual defibrillation (DD) has been proposed as an alternative treatment for refractory ventricular fibrillation (VF). This topic has been poorly researched and data on survival rates are limited.
Objective
This systematic review and meta-analysis evaluates whether DD improves outcomes among patients with refractory VF in- and out-of-hospital cardiac arrest compared with standard defibrillation.
Methods
A literature search was conducted on July 20, 2019 using MEDLINE via PubMed, Embase, Scopus, and the Cochrane Database of Systematic Reviews. We gave all results as a pooled odds ratio (OR) and 95% confidence interval (CI). Heterogeneity was assessed by calculating the I² statistic and was deemed significant for a p value of < 0.10 or I² ≥ 50%. The quality of evidence was evaluated according to Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines.
Results
We included 27 records, of which 4 cohort studies totaling 1061 patients were included in the quantitative analysis. Of these, 20.5% (n = 217) received the intervention. DD had no effect on return of spontaneous circulation (OR 0.68; 95% CI 0.44–1.04; I² = 41%, p = 0.08) (GRADE: Very low), survival to admission (OR 0.77; 95% CI 0.51–1.17; I² = 18%, p = 0.22) (GRADE: Very low), or survival to discharge (OR 0.66; 95% CI 0.38–1.15; I² = 0%, p = 0.14) (GRADE: Very low).
Conclusions
DD did not improve any outcomes of interest. Therefore, it is imperative that a well-designed study in this area be conducted. Ideally, conducting a randomized controlled trial in this population should be attempted to obtain a higher level of scientific evidence.
