Double sequential external defibrillation for refractory ventricular fibrillation.
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ABSTRACT:
SUBMITTER: Cheskes S
PROVIDER: S-EPMC9907872 | biostudies-literature | 2023 Apr
REPOSITORIES: biostudies-literature
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Double sequential external defibrillation for refractory ventricular fibrillation.
Cheskes Sheldon S McLeod Shelley S Scales Damon C DC
Intensive care medicine 20230208 4
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Project description:BackgroundDespite high-quality cardiopulmonary resuscitation (CPR), early defibrillation, and antiarrhythmic medications, some patients remain in refractory ventricular fibrillation (VF) during out-of-hospital cardiac arrest. These patients have worse outcomes compared to patients who respond to initial treatment. Double sequential external defibrillation (DSED) and vector change (VC) defibrillation have been proposed as viable options for patients in refractory VF. However, the evidence supporting the use of novel defibrillation strategies is inconclusive. The objective of this study is to compare two novel therapeutic defibrillation strategies (DSED and VC) against standard defibrillation for patients with treatment refractory VF or pulseless ventricular tachycardia (pVT) during out-of-hospital cardiac arrest.Research questionAmong adult (≥ 18 years) patients presenting in refractory VF or pulseless ventricular tachycardia (pVT) during out-of-hospital cardiac arrest, does DSED or VC defibrillation result in greater rates of survival to hospital discharge compared to standard defibrillation?MethodsThis will be a three-arm, cluster randomized trial with repeated crossover conducted in six regions of Ontario, Canada (Peel, Halton, Toronto, Simcoe, London, and Ottawa), over 3 years. All adult (≥ 18 years) patients presenting in refractory VF (defined as patients presenting in VF/pVT and remaining in VF/pVT after three consecutive standard defibrillation attempts during out-of-hospital cardiac arrest of presumed cardiac etiology will be treated by one of three strategies: (1) continued resuscitation using standard defibrillation, (2) resuscitation involving DSED, or (3) resuscitation involving VC (change of defibrillation pads from anterior-lateral to anterior-posterior pad position) defibrillation. The primary outcome will be survival to hospital discharge. Secondary outcomes will include return of spontaneous circulation (ROSC), VF termination after the first interventional shock, VF termination inclusive of all interventional shocks, and number of defibrillation attempts to obtain ROSC. We will also perform an a priori subgroup analysis comparing rates of survival for those who receive "early DSED," or first DSED shock is shock 4-6, to those who receive "late DSED," or first DSED shock is shock 7 or later.DiscussionA well-designed randomized controlled trial employing a standardized approach to alternative defibrillation strategies early in the treatment of refractory VF is urgently required to determine if the treatments of DSED or VC defibrillation impact clinical outcomes.Trial registrationClinicalTrials.gov NCT04080986 . Registered on 6 September 2019.
| S-EPMC7689391 | biostudies-literature
Project description:BackgroundDouble Sequential External Defibrillation (DSED) is a proposed treatment strategy for patients in refractory VF (RVF) during out-of-hospital cardiac arrest (OHCA). Defibrillator damage employing DSED is a theoretical concern expressed by defibrillator manufacturers yet the incidence of damage during resuscitation remains unknown.ObjectiveWe sought to explore the incidence of defibrillator damage employing DSED for RVF during OHCA.MethodsWe conducted a survey of EMS agencies, authors of previous publications, EMS medical directors, base hospital medical oversight groups, and defibrillator manufacturers to assess the incidence of defibrillator damage during DSED. Our survey focused on the frequency of DSED use, number of shocks used during DSED, technique used to employ DSED (simultaneous or sequential), and the incidence of defibrillator damage during DSED. We specifically targeted groups that were known to be using DSED in clinical practice.ResultsOur survey response rate was 50% (65/129): 61% (34/56) EMS medical directors, 60% (6/10) authors, 100% (8/8) base hospitals, 33% (1/3) defibrillator manufacturers, 31% (16/52) paramedic services. In our case-based analysis the overall incidence of defibrillator damage was 0.4%. The incidence of defibrillator damage based on total number of DSED shocks was estimated between 0.11% and 0.22%. All reported cases of defibrillator damage occurred using a simultaneous defibrillation technique.ConclusionWhen DSED is employed using either a sequential or simultaneous technique the rate of defibrillator damage appears to be exceedingly low. Further high-quality evidence is required to determine the impact of DSED on patient centered outcomes, but the incidence of defibrillator damage should not limit it use. Defibrillator damage should continue to be monitored in future trials and clinical practice.
| S-EPMC9464949 | biostudies-literature
Project description:Cardiac arrest in an event of acute myocardial infarction most commonly results in life-threatening ventricular tachycardia or ventricular fibrillation (VF). Patients who remain in VF despite optimal epinephrine, amiodarone, and three or more attempts at 200 joules of biphasic current defibrillation are known to be in an electrical storm. Here, we describe a case of defibrillation refractory VF responding to intravenous esmolol resulting in a successful return of spontaneous circulation. Learning objective. This case reinforces the growing body of evidence supporting esmolol as a novel treatment approach for refractory VF before the cessation of resuscitative efforts.
| S-EPMC7251428 | biostudies-literature
Project description:Understanding the mechanisms that drive ventricular fibrillation is essential for developing improved defibrillation techniques to terminate ventricular fibrillation (VF). Distinct organization patterns of chaotic, regular, and synchronized activity were previously demonstrated in VF that persisted over 1 to 2 minutes (long-duration VF [LDVF]). We hypothesized that activity on the endocardium may be driving these activation patterns in LDVF and that unsuccessful defibrillation shocks may alter activation patterns. The study was performed using a 64-electrode basket catheter on the left ventricle endocardium and 54 6-electrode plunge needles inserted into the left ventricles of 6 dogs. VF was induced electrically, and after short-duration VF (10 seconds) and LDVF (7 minutes), shocks of increasing strengths were delivered every 10 seconds until VF was terminated. Endocardial activation patterns were classified as chaotic (varying cycle lengths and nonsynchronous activations), regular (highly repeatable cycle lengths), and synchronized (activation that spreads rapidly over the endocardium with diastolic periods between activations). The results showed that the chaotic pattern was predominant in early VF, but the regular pattern emerges as VF progressed. The synchronized pattern only emerged occasionally during late VF. Failed defibrillation shocks changed chaotic and regular activation patterns to synchronized patterns in LDVF but not in short-duration VF. The regular and synchronized patterns of activation were driven by rapid activations on the endocardial surface that blocked and broke up transmurally, leading to an endocardial to epicardial activation rate gradient as LDVF progressed.
| S-EPMC5737741 | biostudies-literature
Project description:AIM:Amplitude Spectrum Area (AMSA) and Median Slope (MS) are ventricular fibrillation (VF) waveform measures that predict defibrillation shock success. Cardiopulmonary resuscitation (CPR) obscures electrocardiograms and must be paused for analysis. Studies suggest waveform measures better predict subsequent shock success when combined with prior shock success. We determined whether this relationship applies during CPR. METHODS:AMSA and MS were calculated from 5-second pre-shock segments with and without CPR, and compared to logistic models combining each measure with prior return of organized rhythm (ROR). RESULTS:VF segments from 692 patients were analyzed during CPR before 1372 shocks and without CPR before 1283 shocks. Combining waveform measures with prior ROR increased areas under receiver operating characteristic curves for AMSA/MS with CPR (0.66/0.68 to 0.73/0.74, p<0.001) and without CPR (0.71/0.72 to 0.76/0.76, p<0.001). CONCLUSIONS:Prior ROR improves prediction of shock success during CPR, and may enable waveform measure calculation without chest compression pauses.
| S-EPMC5776045 | biostudies-literature
Project description:BackgroundExternal defibrillators are used for arrhythmia cardioversion and for defibrillating during cardiac arrest. During defibrillation, short-duration biphasic pulses cause intense motion due to rapid chest-wall muscle contraction. A reduced motion external defibrillator (RMD) was constructed by integrating a commercial defibrillator with a Tetanizing-waveform generator. A long-duration, low-amplitude, tetanizing waveform slowly stimulated the chest musculature before the biphasic pulse, reducing muscle contraction during the shock.ObjectiveThe purpose of this study was to evaluate RMD defibrillation in swine for subject motion during defibrillation pulses and for defibrillation effectiveness. RMD defibrillation can reduce the duration of arrhythmia ablation therapy or simplify cardioversion procedures.MethodsThe tetanizing unit delivered a triangular 1-kHz pulse of 0.25- to 2.0-second duration and 10- to 100-V peak amplitude, subsequently triggering the conventional defibrillator to output standard 1- to 200-J energy biphasic pulses at the next R wave. Forward limb motion was evaluated by measuring peak acceleration and limb work during RMD (tetanizing + biphasic) or biphasic pulse-only waveforms at 10-3-second sampling rate. Seven swine were arrested electrically and subsequently defibrillated. Biphasic pulse-only and RMD defibrillations were repeated 25-35 times per swine, varying tetanizing parameters and biphasic pulse energy. Defibrillation thresholds (DFTs) were established by measuring the minimum energy required to restore sinus rhythm with biphasic pulse-only or RMD defibrillations.ResultsTwo forward-limb acceleration peaks occurred during both the tetanizing waveform and biphasic pulse, indicating rapid and slower nociceptic (pain sensation) nerve fiber activation. Optimal RMD tetanizing parameters (25-35 V, 0.25- to 0.75-second duration), relative to biphasic pulse-only defibrillations, resulted in 74% ± 10% smaller peak accelerations and 85% ± 10% reduced limb work. DFT energies were identical when comparing RMD to biphasic pulse-only defibrillations.ConclusionRelative to conventional defibrillations, RMD defibrillations maintain rhythm restoration efficiency with drastically reduced subject motion.
| S-EPMC9250595 | biostudies-literature
Project description:Extracorporeal cardiopulmonary resuscitation (ECPR) for refractory ventricular fibrillation/ventricular tachycardia in out-of-hospital cardiac arrest has recently been recommended for selected patients with favorable prognostic features. We aimed to identify factors affecting the willingness of emergency physicians to implement extracorporeal cardiopulmonary resuscitation (ECPR). We conducted a factorial survey with nine experimental vignettes by combining three different scene time intervals and transportation time intervals. Emergency physicians reported willingness to implement ECPR (1–100 points). Respondent characteristics that could affect the willingness were studied. Multilevel analysis of vignettes and respondent factors was conducted using a mixed-effects regression model. We obtained 486 vignette responses from 54 emergency physicians. In the case of longer scene time intervals, there was a significant difference in the willingness scores at 9 and 12 min transportation time intervals. When the pre-hospital time interval was > 40 min, emergency physicians demonstrated lower willingness to implement ECPR. Clinical experience of 15–19 years showed a significant favorable effect on willingness to implement extracorporeal membrane oxygenation (ECMO). However, the mean willingness scores of EPs for ECMO implementation were more than 75 across all vignettes. In ECPR, the prehospital time interval is an important factor, and the willingness of emergency physicians to implement ECMO could be mutually affected by scene time intervals, transportation time intervals, and total prehospital time.
| S-EPMC9879451 | biostudies-literature
Project description: Not available
| S-EPMC6034480 | biostudies-literature
Project description:BackgroundVentricular fibrillation (VF) waveform analysis has been proposed as a potential non-invasive guide to optimize timing of defibrillation.MethodsThe AMplitude Spectrum Area (AMSA) trial is an open-label, multicenter randomized controlled study reporting the first in-human use of AMSA analysis in out-of-hospital cardiac arrest (OHCA). The primary efficacy endpoint was the termination of VF for an AMSA ≥ 15.5 mV-Hz. Adult shockable OHCAs randomly received either an AMSA-guided cardiopulmonary resuscitation (CPR) or a standard-CPR. Randomization and allocation to trial group were carried out centrally. In the AMSA-guided CPR, an initial AMSA ≥ 15.5 mV-Hz prompted for immediate defibrillation, while lower values favored chest compression (CC). After completion of the first 2-min CPR cycle, an AMSA < 6.5 mV-Hz deferred defibrillation in favor of an additional 2-min CPR cycle. AMSA was measured and displayed in real-time during CC pauses for ventilation with a modified defibrillator.FindingsThe trial was early discontinued for low recruitment due to the COVID-19 pandemics. A total of 31 patients were recruited in 3 Italian cities, 19 in AMSA-CPR and 12 in standard-CPR, and included in the data analysis. No difference in primary outcome was observed between the two groups. Termination of VF occurred in 74% of patients in the AMSA-CPR compared to 75% in the standard CPR (OR 0.93 [95% CI 0.18-4.90]). No adverse events were reported.InterpretationAMSA was used prospectively in human patients during ongoing CPR. In this small trial, an AMSA-guided defibrillation provided no evidence of an improvement in termination of VF.Trial registrationNCT03237910.FundingEuropean Commission - Horizon 2020; ZOLL Medical Corp., Chelmsford, USA (unrestricted grant); Italian Ministry of Health - Current research IRCCS.
| S-EPMC10060104 | biostudies-literature
Project description:BackgroundMeasures of the ventricular fibrillation (VF) waveform may enable better allocation of cardiac arrest treatment by discriminating which patients should receive immediate defibrillation versus alternate therapies such as CPR. We derive a new measure based on the 'roughness' of the VF waveform, the Logarithm of the Absolute Correlations (LAC), and assess and contrast how well the LAC and the previously published scaling exponent (ScE) predict the duration of VF and the likelihood of return of spontaneous circulation (ROSC) under both optimal experimental and commercial-defibrillator sampling conditions.Methods and resultsWe derived the LAC and ScE from two different populations--an animal study of 44 swine and a retrospective human sample of 158 out-of-hospital VF arrests treated with a commercial defibrillator. In the animal study, the LAC and ScE were calculated on 5s epochs of VF recorded at 1000 samples/s and then down sampled to 125 samples/s. In the human study, the LAC and ScE were calculated using 6s epochs recorded at 200 samples/s that occurred immediately prior to the initial shock. We compared the LAC and ScE measures using the Spearman correlation coefficients (CC) and areas under the receiver operating characteristic curve (AUC).ResultsIn the animal study, the LAC and ScE were highly correlated at 1000 sample/s (CC=0.93) but not at 125 samples/s (CC=-0.06). These correlations were reflected in how well the measures discriminated VF of < or =5 versus >5 min: AUC at 1000 samples/s was similar for LAC compared to ScE (0.71 versus 0.76). However AUC at 125 samples was greater for LAC compared to ScE (0.75 versus 0.62). In the human study, the LAC measure was a better predictor of ROSC following initial defibrillation as reflected by an AUC of 0.77 for LAC compared to 0.57 for ScE.ConclusionsThe LAC is an improvement over the ScE because the LAC retains its prognostic characteristics at lower ECG sampling rates typical of current clinical defibrillators. Hence, the LAC may have a role in better allocating treatment in resuscitation of VF cardiac arrest.
| S-EPMC2561072 | biostudies-literature