The impact of double sequential external defibrillation on termination of refractory ventricular fibrillation during out-of-hospital cardiac arrest

Defibrillation strategies for patients with refractory ventricular fibrillation: A systematic review and meta-analysis

AIM

The aim of this study was to summarize the existing evidence about the effectiveness of double defibrillation (DD) in comparison to standard defibrillation for patients with refractory ventricular fibrillation (RVF). DD encompasses double "sequential" external defibrillation (DSeq-D) and double "simultaneous" defibrillation (DSim-D), with the study also shedding light on the respective effects of DSeq-D and DSim-D.

METHODS

Investigators systematically searched PubMed, EMBASE and Cochrane Central databases for randomized controlled trials (RCTs) and cohort studies from their inception until June 06, 2024. The rate of survival to hospital discharge was the primary outcome, while the incidence of return of spontaneous circulation (ROSC), termination of ventricular fibrillation (VF), survival to hospital admission and good neurologic outcome were secondary outcomes. Relative ratios (RR) and 95% confidence intervals (CIs) were calculated for each outcome. Heterogeneity was assessed using I square value.

RESULTS

A total of 6 trials, comprising 1360 patients, were included. One was an RCT, and five were observational cohort studies. The RCT showed that, compared to standard defibrillation, DSeq-D was associated with higher incidences of survival to hospital discharge, termination of VF, ROSC and good neurologic outcome. However, the pooled results of cohort studies found no benefit of DD over standard defibrillation in survival to hospital discharge (RR, 0.91; 95% CI, 0.46-1.78), nor in secondary outcomes. Furthermore, subgroup analysis suggested DSim-D was linked with lower ROSC rate compared to standard defibrillation (RR, 0.65; 95% CI, 0.49-0.86), while there was no significance between DSeq-D and standard defibrillation (RR, 1.00; 95% CI, 0.70-1.42).

CONCLUSIONS

The benefit of DSeq-D in survival to hospital discharge for RVF patients was found in the RCT, but not in cohort studies. Additionally, DSim-D should be applied with greater caution for RVF patients. Further validation is needed through larger-scale and higher-quality trials.

TRIAL REGISTRY

INPLASY; Registration number: INPLASY202340015; URL: https://inplasy.com/.

The impact of double sequential shock timing on outcomes during refractory out-of-hospital cardiac arrest

BACKGROUND

Animal studies suggest the efficacy of double sequential external defibrillation (DSED) may depend on the interval between the two shocks, or "DSED interval". No human studies have examined this concept.

OBJECTIVES

To determine the relationship between DSED interval and termination of ventricular fibrillation (VFT), return of spontaneous circulation (ROSC), survival to hospital discharge, and favourable neurological status (MRS ≤ 2) for patients in refractory VF.

METHODS

We performed a retrospective review of adult (≥18 years) out-of-hospital cardiac arrest between January 2015 and May 2022 with refractory VF who received ≥1 DSED shock. DSED interval was divided into four pre-defined categories. We examined the association between DSED interval and patient outcomes using general estimated equation logistic regression or Fisher's exact test.

RESULTS

Among 106 included patients, 303 DSED shocks were delivered (median 2, IQR 1-3). DSED intervals of 75-125 ms (OR 0.39, 95% CI 0.16-0.98), 125-500 ms (OR 0.36, 95% CI 0.16-0.82), and >500 ms (OR 0.27, 95% CI 0.11-0.63) were associated with lower probability of VF termination compared to <75 ms interval. DSED interval of >75 ms was associated with lower probability of ROSC compared to <75 ms interval (OR 0.37, 95% CI 0.14-0.98). No association was noted between DSED interval and survival to hospital discharge or neurologic outcome.

CONCLUSIONS

Among patients in refractory VF a DSED interval of less than 75 ms was associated with improved rates of VF termination and ROSC. No association was noted between DSED interval and survival to hospital discharge or neurologic outcome.

Defibrillation strategies for refractory ventricular fibrillation out-of-hospital cardiac arrest: A systematic review and network meta-analysis

BACKGROUND AND OBJECTIVE

Double sequential external defibrillation (DSED) and vector-change defibrillation (VCD) have been suggested to enhance clinical outcomes for patients with ventricular fibrillation (VF) refractory of standard defibrillation (SD). Therefore, this network meta-analysis aims to evaluate the comparative efficacy of DSED, VCD, and SD for refractory VF.

METHODS

A systematic review and network meta-analysis synthesizing randomized controlled trials (RCTs) and comparative observational studies retrieved from PubMed, EMBASE, WOS, SCOPUS, and Cochrane through November 15th, 2022. R software netmeta and netrank package (R version 4.2.0) and meta-insight software were used to pool dichotomous outcomes using odds ratio (OR) presented with the corresponding confidence interval (CI). Our protocol was prospectively published in PROSPERO with ID: CRD42022378533.

RESULTS

We included seven studies with a total of 1632 participants. DSED was similar to SD in survival to hospital discharge (OR: 1.14 with 95% CI [0.55, 2.83]), favorable neurological outcome (modified Rankin scale ≤2 or cerebral performance category ≤2) (OR: 1.35 with 95% CI [0.46, 3.99]), and return of spontaneous circulation (ROSC) (OR: 0.81 with 95% CI [0.43; 1.5]). In addition, VCD was similar to SD in survival to hospital discharge (OR: 1.12 with 95% CI [0.27, 4.57]), favorable neurological outcome (OR: 1.01 with 95% CI [0.18, 5.75]), and ROSC (OR: 0.88 with 95% CI [0.24; 3.15]).

CONCLUSION

Double sequential external defibrillation and VCD were not associated with enhanced outcomes in patients with refractory VF out-of-hospital cardiac arrest, compared to SD. However, the current evidence is still inconclusive, warranting further large-scale RCTs.

Esmolol, vector change, and dose-capped epinephrine for prehospital ventricular fibrillation or pulseless ventricular tachycardia

BACKGROUND

Refractory ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT) cardiac arrest describes a subset of patients who do not respond to standard Advanced Cardiac Life Support (ACLS) interventions and are associated with poor outcomes. Esmolol administration and vector change defibrillation have shown promise in improving outcomes in these patients, however evidence is limited.

OBJECTIVES

This study compares clinical outcomes between patients with prehospital refractory VF/pVT who received an Emergency Medical Service (EMS) bundle, comprised of esmolol administration, vector change defibrillation, and dose-capped epinephrine at 3 mg, to patients who received standard ACLS interventions.

METHODS

This multicenter, retrospective, cohort study evaluated medical records between October 18, 2017 and March 15, 2022. Patients were enrolled if they experienced a prehospital cardiac arrest with the rhythm VF or pVT, had received at least three standard defibrillations, at least 3 mg of epinephrine, and 300 mg of amiodarone. Patients who received the EMS bundle after its implementation were compared to patients who received standard ACLS interventions prior to its implementation. The primary outcome was sustained return of spontaneous circulation (ROSC), defined as ROSC lasting 20 min without recurrence of cardiac arrest. Secondary outcomes included the incidence of any ROSC, survival to hospital arrival, survival at hospital discharge, and neurologically intact survival at hospital discharge.

RESULTS

Eighty-three patients were included in the study. Thirty-six were included in the pre-EMS bundle group and 47 patients were included in the post-EMS bundle group. Patients in the pre-EMS bundle group achieved significantly higher rates of sustained ROSC (58.3% vs 17%, p < 0.001), any ROSC (66.7% vs 19.1%, p < 0.001), and survival to hospital arrival (55.6% vs 17%, p < 0.001). The rates of survival to hospital discharge (16.7% vs 6.4%, p = 0.17) and neurologically intact survival at hospital discharge (5.9% vs 4.3%, p = 1.00) were not significantly different between groups.

CONCLUSIONS

Patients who received the EMS bundle achieved sustained ROSC significantly less often and were less likely to have pulses at hospital arrival. The incidence of neurologically intact survival was low and similar between groups.

Defibrillation Strategies for Refractory Ventricular Fibrillation

BACKGROUND

Despite advances in defibrillation technology, shock-refractory ventricular fibrillation remains common during out-of-hospital cardiac arrest. Double sequential external defibrillation (DSED; rapid sequential shocks from two defibrillators) and vector-change (VC) defibrillation (switching defibrillation pads to an anterior-posterior position) have been proposed as defibrillation strategies to improve outcomes in patients with refractory ventricular fibrillation.

METHODS

We conducted a cluster-randomized trial with crossover among six Canadian paramedic services to evaluate DSED and VC defibrillation as compared with standard defibrillation in adult patients with refractory ventricular fibrillation during out-of-hospital cardiac arrest. Patients were treated with one of these three techniques according to the strategy that was randomly assigned to the paramedic service. The primary outcome was survival to hospital discharge. Secondary outcomes included termination of ventricular fibrillation, return of spontaneous circulation, and a good neurologic outcome, defined as a modified Rankin scale score of 2 or lower (indicating no symptoms to slight disability) at hospital discharge.

RESULTS

A total of 405 patients were enrolled before the data and safety monitoring board stopped the trial because of the coronavirus disease 2019 pandemic. A total of 136 patients (33.6%) were assigned to receive standard defibrillation, 144 (35.6%) to receive VC defibrillation, and 125 (30.9%) to receive DSED. Survival to hospital discharge was more common in the DSED group than in the standard group (30.4% vs. 13.3%; relative risk, 2.21; 95% confidence interval [CI], 1.33 to 3.67) and more common in the VC group than in the standard group (21.7% vs. 13.3%; relative risk, 1.71; 95% CI, 1.01 to 2.88). DSED but not VC defibrillation was associated with a higher percentage of patients having a good neurologic outcome than standard defibrillation (relative risk, 2.21 [95% CI, 1.26 to 3.88] and 1.48 [95% CI, 0.81 to 2.71], respectively).

CONCLUSIONS

Among patients with refractory ventricular fibrillation, survival to hospital discharge occurred more frequently among those who received DSED or VC defibrillation than among those who received standard defibrillation. (Funded by the Heart and Stroke Foundation of Canada; DOSE VF ClinicalTrials.gov number, NCT04080986.).

Double sequential external defibrillation versus standard defibrillation in refractory ventricular fibrillation: A systematic review and meta-analysis

Introduction

Double sequential external defibrillation (DSED) in cardiopulmonary resuscitation has shown different results in comparison with standard defibrillation in the treatment of refractory ventricular fibrillation (RVF). This review aims to compare the advantages of DSED with standard defibrillation in the treatment of refractory ventricular fibrillation.

Materials and methods

PubMed, Embase, Web of Science, and Cochrane Library were searched from inception to May 1, 2022. Studies included adult patients who developed RVF. The study used random-effects and fixed-effects models for meta-analysis, which was reported by risk ratio (RR) with 95% confidence interval (CI), mean difference (MD), or standardized mean difference (SMD). The risk of bias in individual studies was assessed using the Robins-I tool for observational studies and the Cochrane Risk of Bias 2 (ROB-2) tool for clinical trials. Primary outcomes included the termination of RVF, prehospital return of spontaneous circulation (ROSC), survival to hospital admission, survival to hospital discharge, and good neurological recovery. Secondary outcomes included age, total defibrillation attempts, emergency medical system arrival time, and dose of epinephrine and amiodarone used.

Results

In this systematic review and meta-analysis, 10 studies containing 1347 patients with available data on treatment outcomes were included. The pooled estimate was (RR 1.03, 95% CI, 0.89 to 1.19; Z = 0.42, P = 0.678 > 0.05) for Termination of RVF, (RR 0.84, 95% CI, 0.63 to 1.11; Z = 1.23, P = 0.219 > 0.05) for ROSC, (RR 0.86, 95% CI, 0.69 to 1.06; Z = 1.4, P = 0.162 > 0.05) for survival to hospital admission, (RR 0.77, 95%CI, 0.52 to 1.15; Z = 1.26, P = 0.206 > 0.05) for survival to hospital discharge, (RR 0.65, 95%CI, 0.35 to 1.22; Z = 1.33, P = 0.184 > 0.05) for good neurologic recovery, (MD -1.01, 95%CI, -3.07 to 1.06; Z = 0.96, P = 0.34 > 0.05) for age, (MD 2.27, 95%CI, 1.80 to 2.73; Z = 9.50, P = 0.001 < 0.05) for total defibrillation attempts, (MD 1.10, 95%CI, -0.45 to 66; Z = 1.39, P = 0.16 > 0.05) for emergency medical system arrival time, (SMD 0.34, 95%CI, 0.17 to 0.50; Z = 4.04, P = 0.001 < 0.05) for epinephrine, and (SMD -0.30, 95%CI, -0.65 to -0.05; Z = 1.66, P = 0.1 > 0.05) for amiodarone.

Conclusion

We discovered no differences between DSED and standard defibrillation in termination of RVF, prehospital return of spontaneous circulation, survival to hospital admission, survival to hospital discharge, good neurological outcome, emergency medical system arrival time, and amiodarone doses in patients with RVF. There were some differences in the number of defibrillations and epinephrine doses utilized during resuscitation.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=329354], identifier [CRD42022329354].

A survey of the incidence of defibrillator damage during double sequential external defibrillation for refractory ventricular fibrillation

Background

Double 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.

Objective

We sought to explore the incidence of defibrillator damage employing DSED for RVF during OHCA.

Methods

We 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.

Results

Our 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.

Conclusion

When 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.

Combination of Multidisciplinary Therapies Successfully Treated Refractory Ventricular Arrhythmia in a STEMI Patient: Case Report and Literature Review

Ventricular fibrillation (VF) is a life-threatening cardiac arrhythmia that can lead to loss of cardiac function and sudden cardiac death. The most common cause of VF is ischemic cardiomyopathy, especially in the context of an acute coronary event. Prompt treatment with resuscitation and defibrillation can be lifesaving. Refractory VF, or pulseless ventricular tachycardia (pVT), refers to cases that do not respond to traditional advanced cardiac life-support (ACLS) measures, and it has a low survival rate. Some new life-saving interventions and novel techniques have been proposed as viable treatment options for patients presenting with refractory VF/pVT out-of-hospital cardiac arrest; these include extracorporeal membrane oxygenation (ECMO), esmolol, stellate ganglion block (SGB), and double sequential defibrillation (DSD). Recently, DSD has been discussed and used more frequently, but its survival rate is still not promising. We report a case of refractory VF caused by acute myocardial infarction that was treated with ACLS, DSD, ECMO, and cardiac catheterization in sequence, with a successful outcome.

[Adult advanced life support]

These European Resuscitation Council Advanced Life Support guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the prevention of and ALS treatments for both in-hospital cardiac arrest and out-of-hospital cardiac arrest.

European Resuscitation Council Guidelines 2021: Adult advanced life support

These European Resuscitation Council Advanced Life Support guidelines, are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the prevention of and ALS treatments for both in-hospital cardiac arrest and out-of-hospital cardiac arrest.

Double external defibrillation for shock-refractory ventricular fibrillation cardiac arrest: A step towards standardization

Double (or dual) external defibrillation (DED) has increasingly been used in the last few years by a number of emergency medical services (EMS) as a last resort to terminate ventricular fibrillation and pulseless ventricular tachycardia in adult patients who remain refractory to standard defibrillation. However, no randomized controlled trials comparing DED with standard defibrillation focusing on patient-oriented outcomes as the primary objective have been published to date. Selection criteria, procedure techniques, and protocol are not clearly defined and vary across observational studies. The terms and/or nomenclature used to describe DED are confusing and vary throughout the literature. Despite increased use of DED, many questions remain as to which patients will derive the most benefit from DED, when to implement DED, and the optimal form of delivering DED. The present paper provides a brief overview of the background, procedure techniques, pad placement, and factors affecting how DED is delivered. A further objective of this paper is to offer a proposal for a uniform nomenclature and a standardized protocol in the form of a flowchart for EMS agencies to guide further clinical trials and best practices. This paper should not only help give background on novel definitions and clarify nomenclature for this practice, but more importantly should help institutions lay the groundwork for performing EMS-based large trials to further investigate the effectiveness of DED.

DOuble SEquential External Defibrillation for Refractory Ventricular Fibrillation (DOSE VF): study protocol for a randomized controlled trial

Background

Despite 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 question

Among 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?

Methods

This 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.

Discussion

A 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 registration

ClinicalTrials.gov NCT04080986. Registered on 6 September 2019.

Supplementary information

The online version contains supplementary material available at 10.1186/s13063-020-04904-z.

Adult Advanced Life Support: 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations

This 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations for advanced life support includes updates on multiple advanced life support topics addressed with 3 different types of reviews. Topics were prioritized on the basis of both recent interest within the resuscitation community and the amount of new evidence available since any previous review. Systematic reviews addressed higher-priority topics, and included double-sequential defibrillation, intravenous versus intraosseous route for drug administration during cardiac arrest, point-of-care echocardiography for intra-arrest prognostication, cardiac arrest caused by pulmonary embolism, postresuscitation oxygenation and ventilation, prophylactic antibiotics after resuscitation, postresuscitation seizure prophylaxis and treatment, and neuroprognostication. New or updated treatment recommendations on these topics are presented. Scoping reviews were conducted for anticipatory charging and monitoring of physiological parameters during cardiopulmonary resuscitation. Topics for which systematic reviews and new Consensuses on Science With Treatment Recommendations were completed since 2015 are also summarized here. All remaining topics reviewed were addressed with evidence updates to identify any new evidence and to help determine which topics should be the highest priority for systematic reviews in the next 1 to 2 years.

Successful resuscitation of refractory ventricular fibrillation with double sequence defibrillation

In cardiac arrest, if the initial rhythm is ventricular fibrillation (VF) or pulseless ventricular tachycardia, the survival rates are high and good neurologic outcomes are expected. However, the mortality rate increases when refractory ventricular fibrillation (RVF) occurs. We report a case of RVF that was successfully resuscitated with double sequence defibrillation (DSD). A 51-year-old man visited the emergency department with chest pain. The initial electrocardiography showed markedly elevated ST-segment on V1–V5 leads, and VF arrest occurred. Although 10 defibrillations were administered over 20 minutes, there was no response. Two rounds of DSD were performed by placing additional pads on the patient’s anterior-posterior areas and sequentially applying the maximum energy setting. The patient returned to spontaneous circulation and was discharged with cerebral performance category 1 after 14 days of hospital admission. Therefore, DSD could be an option for treatment and termination of RVF.

Adult Advanced Life Support: 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

This 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations for advanced life support includes updates on multiple advanced life support topics addressed with 3 different types of reviews. Topics were prioritized on the basis of both recent interest within the resuscitation community and the amount of new evidence available since any previous review. Systematic reviews addressed higher-priority topics, and included double-sequential defibrillation, intravenous versus intraosseous route for drug administration during cardiac arrest, point-of-care echocardiography for intra-arrest prognostication, cardiac arrest caused by pulmonary embolism, postresuscitation oxygenation and ventilation, prophylactic antibiotics after resuscitation, postresuscitation seizure prophylaxis and treatment, and neuroprognostication. New or updated treatment recommendations on these topics are presented. Scoping reviews were conducted for anticipatory charging and monitoring of physiological parameters during cardiopulmonary resuscitation. Topics for which systematic reviews and new Consensuses on Science With Treatment Recommendations were completed since 2015 are also summarized here. All remaining topics reviewed were addressed with evidence updates to identify any new evidence and to help determine which topics should be the highest priority for systematic reviews in the next 1 to 2 years.

A review of pre-hospital case series among those with time to double external defibrillation and neurologic outcomes

BACKGROUND

Double external defibrillation (DED) has been used as a final effort to terminate refractory ventricular fibrillation/pulseless ventricular tachycardiac (rVF/pVT). Data surrounding time to DED and patient-centered outcomes remains limited.

OBJECTIVES

This study summarizes patient-level data from case-series of observed survival and neurologic outcomes following the use of DED for rVF/pVT among those with data regarding time to DED.

METHODS

We conducted a literature search of PubMed, MEDLINE (OVID interface), and Scopus from January 1, 2000, through January 5, 2020. The literature was screened according to inclusion and exclusion criteria. Two investigators independently conducted the literature search, study selection, and data extraction.

RESULTS

Our database search identified 3139 records. Of these, 1660 studies were eliminated following inspection of the titles and 22 studies underwent full-text screening, three included in the final analysis, describing a total of 29 cases. All studies were considered to have critical risk of bias. For the critical outcomes of survival to discharge and neurologically intact survival we identified that patients who received DED before 30 min from collapse compared to those who received DED after 30 min had better survival to discharge (33.3% [5/15] vs. 7.1% [1/14]) and neurologically intact survival (20.0% [3/15] vs. 7.1% [1/14]). Overall, 20.6% of patients survived to discharge, 13.8% with neurologically intact survival. It is noteworthy that the patients who were discharged with a CPC of 1 received two, four, five, and three standard shocks before receiving DED, and the time between their onset of cardiac arrest to their first DED attempt was recorded to be 15, 26, 26, and 32 min, respectively.

CONCLUSION

We would like to indicate that there is not enough evidence to suggest that early use of pre-hospital DED is associated with improved outcomes. Further research should strive to address these issues before conclusions can be drawn.

Time to change the times? Time of recurrence of ventricular fibrillation during OHCA

AIM OF THE STUDY

For out-of-hospital-cardiac-arrest (OHCA) due to ventricular fibrillation (VF) guidelines recommend early defibrillation followed by chest compressions for two minutes before analyzing shock success. If rhythm analysis reveals VF again, it is obscure whether VF persisted or reoccurred within the two-minutes-cycle of chest compressions after successful defibrillation. We investigated the time of VF-recurrence in OHCA.

METHODS

We examined all cases of OHCA presenting with initial VF rhythm at arrival of ALS-ambulance (Marburg-Biedenkopf-County, 246.648 inhabitants) from January 2014 to March 2018. Three independent investigators analyzed corpuls3® ECG-recordings. We included ECG-data from CPR-beginning until four minutes after the third shock. VF termination was defined as the absence of a VF-waveform within 5 s of shock delivery. VF recurrence was defined as the presence of a VF-waveform in the interval 5 s post shock delivery.

RESULTS

We included 185 shocks in 82 patients. 74.1% (n = 137) of all shocks terminated VF, but VF recurred in 81% (n = 111). The median (IQR) time of VF-recurrences was 27 s (13.5 s/80.5 s) after shock. 51.4% (n = 57) of VF-recurrence occurred 5-30 s after shock, 13.5% (n = 15) VF-recurrence occurred 31-60 s after shock, 21.6% (n = 24) of VF-recurrence occurred 61-120 s after shock, 13.5% (n = 15) of VF-recurrence occurred 121-240 s after shock.

CONCLUSIONS

Although VF was terminated by defibrillation in 74.1%, VF recurred in 81% subsequent to the chest compression interval. Thus, VF reappears frequently and early. It is unclear to which extend chest compressions influence VF-relapse. Further studies need to re-evaluate the algorithm, timing of antiarrhythmic therapy or novel defibrillation strategies to minimize refibrillation during shockable OHCA.

Prehospital Double Defibrillation for Refractory Ventricular Fibrillation: A Scoping Review Protocol

Double defibrillation (DD) has been proposed as an alternative treatment for patients with refractory ventricular fibrillation/pulseless ventricular tachycardia (VF/pVT) out-of-hospital cardiac arrest (OHCA) nonresponsive to the best current standard of care. Treatment results are promising, but the efficacy and safety of the procedure remain unclear. Currently, there is a paucity of evidence in the literature on DD suggesting the optimal strategy for treating this challenging patient population. Thus, we aim to perform a scoping review to explore the current literature addressing resuscitative parameters, survival rates, and neurological outcomes in refractory VF/pVT OHCA patients treated with DD as well as to identify gaps in the literature that may require further research. Here, we discuss the anticipated study protocol.

Double (dual) sequential defibrillation for refractory ventricular fibrillation cardiac arrest: A systematic review

INTRODUCTION

Cardiac arrests associated with shockable rhythms such as ventricular fibrillation or pulseless VT (VF/pVT) are associated with improved outcomes from cardiac arrest. The more defibrillation attempts required to terminate VF/pVT, the lower the survival. Double sequential defibrillation (DSD) has been used for refractory VF/pVT cardiac arrest despite limited evidence examining this practice. We performed a systematic review to summarize the evidence related to the use of DSD during cardiac arrest.

METHODS

This review was performed according to PRISMA and registered on PROSPERO (ID: CRD42020152575). We searched Embase, Pubmed, and the Cochrane library from inception to 28 February 2020. We included adult patients with VF/pVT in any setting. We excluded case studies, case series with less than five patients, conference abstracts, simulation studies, and protocols for clinical trials. We predefined our outcomes of interest as neurological outcome, survival to hospital discharge, survival to hospital admission, return of spontaneous circulation (ROSC), and termination of VF/pVT. Risk of bias was examined using ROBINS-I or ROB-2 and certainty of studies were reported according to GRADE methodology.

RESULTS

Overall, 314 studies were identified during the initial search. One hundred and thirty studies were screened during title and abstract stage and 10 studies underwent full manuscript screening, nine included in the final analysis. Included studies were cohort studies (n = 4), case series (n = 3), case-control study (n = 1) and a prospective pilot clinical trial (n-1). All studies were considered to have serious or critical risk of bias and no meta-analysis was performed. Overall, we did not find any differences in terms of neurological outcome, survival to hospital discharge, survival to hospital admission, ROSC, or termination of VF/pVT between DSD and a standard defibrillation strategy.

CONCLUSION

The use of double sequential defibrillation was not associated with improved outcomes from out-of-hospital cardiac arrest, however the current literature has a number of limitations to interpretation. Further high-quality evidence is needed to answer this important question.

Electrical storm: A focused review for the emergency physician

BACKGROUND

Electrical storm is a dangerous condition presenting to the Emergency Department that requires rapid diagnosis and management.

OBJECTIVE

This article provides a review of the diagnosis and management of electrical storm for the emergency clinician.

DISCUSSION

Electrical storm is defined as ≥3 episodes of sustained ventricular tachycardia, ventricular fibrillation, or shocks from an implantable cardioverter defibrillator within 24 h. Patients may present with a wide array of symptoms. Initial evaluation should include an electrocardiogram with a rhythm strip and continuous cardiac monitoring, a medication history, assessment of hemodynamic stability, and identification of potential triggers. Management includes an antiarrhythmic and a beta blocker. Refractory patients may benefit from double-sequential defibrillation or more invasive procedures such as intra-aortic balloon pumps, catheter ablation and extracorporeal membrane oxygenation for critically ill patients. These patients will typically require admission to an intensive care unit.

CONCLUSION

Electrical storm is a condition associated with significant morbidity and mortality. It is important for clinicians to be aware of the current evidence regarding the evaluation and management of these patients.

Double sequential defibrillation for out-of-hospital refractory ventricular fibrillation: A scoping review

BACKGROUND

Double sequential defibrillation (DSD) has been proposed as a viable treatment option for patients in refractory ventricular fibrillation/pulseless ventricular tachycardia (VF/pVT) out-of-hospital cardiac arrests (OHCA). However, currently there is insufficient evidence to support a widespread implementation of this therapy.

STUDY OBJECTIVES

The aim of this scoping review was to summarize the current available evidence of DSD for patients with refractory VF/pVT OHCA as well as to identify gaps in the literature that may require further research.

METHODS

We conducted a comprehensive literature search of MEDLINE via PubMed, Embase via Ovid, and Scopus on August 19, 2019. We also checked reference lists of relevant papers to identify additional studies. Any controlled clinical study design (randomized controlled trials and non-randomized controlled trials), and observational studies (cohort studies and case-control studies) providing information on resuscitative parameters, survival rates and neurological outcomes in adults (≥ 18 years old) treated with DSD for refractory VF/pVT OHCA were included. Two investigators independently conducted the literature search, study selection, and data extraction.

RESULTS

The search yielded 1612 unique records, of which 4 peer-reviewed articles were found relating to the research purpose, totaling 1061 patients of who 20.5% (n = 217) received DSD. Most studies evaluated if pre-hospital DSD was associated with improved survival to discharge after refractory VF/pVT. No randomized controlled trials were identified.

CONCLUSION

To date, it is difficult to conclude the real benefit of DSD for patients in refractory VF based on the available evidence. The findings of this scoping review suggest there is limited evidence to support at large-scale the use of DSD for refractory VF/pVT OHCA. Further research is needed to better characterize and understand the use of DSD for refractory VF/pVT, in order to implement best practices to maximize the effectiveness and efficiency of care.

Successful Resuscitation from Refractory Ventricular Fibrillation by BLS Providers Employing Double Sequential External Defibrillation: A Case Report

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 support medications. We present the case of the successful use of DSED for refractory out-of-hospital cardiac arrest without the use of advanced life support care.

The evolving role of novel treatment techniques in the management of patients with refractory VF/pVT out-of-hospital cardiac arrest

STUDY OBJECTIVES

The purpose of this review is to provide a brief overview of new life-saving interventions and novel techniques that have been proposed as viable treatment options for patients presenting with refractory ventricular fibrillation/pulseless ventricular tachycardia (VF/pVT) out-of-hospital cardiac arrest (OHCA).

METHODS

We conducted a comprehensive literature search of PubMed recent, Medline and Embase databases via the Ovid interface and Google Scholar from inception to July 2019. Eligible studies were observational in nature reporting outcomes of extracorporeal membrane oxygenation (ECMO), esmolol, double sequential defibrillation (DSD), and stellate ganglion block (SGB). Two investigators conducted the literature search, study selection, and data extraction. Any disagreements were resolved by consensus.

RESULTS

Our database search identified 5331 records. We included in our review 23 articles that met our inclusion criteria. The selected studies included 16 observational studies on ECMO, 2 observational studies on esmolol, and 5 observational studies on DSD.

CONCLUSION

We would like to suggest that there is not enough evidence in the existing literature to support at large-scale the effects of these techniques in the treatment of refractory VF/pVT OHCA. Randomized studies are warranted to evaluate the significant effects of these approaches against the best current standard of care.