Double sequential defibrillation therapy for out-of-hospital cardiac arrests: The London experience

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/.

Time difference between pad placement in single versus double external defibrillation: A live patient simulation model

Background

Out-of-hospital cardiac arrest (OHCA) cause significant patient morbidity and mortality. Double sequential external defibrillation (DSED) represents an alternative treatment for OHCA patients, but the use is currently reserved for patients in refractory ventricular fibrillation. However, OHCA patients may achieve return of spontaneous circulation earlier with the use of DSED as initial treatment. This study compares the necessary times needed to establish pad placement in DSED compared to normal pad placement in a live patient simulation model.

Methods

This study was an observational cohort study with ambulance personnel and live patient models. The procedure was performed on two patient categories, with BMI 20.9 (patient A) and BMI 32.8 (patient B). Two-member teams established two defibrillators ready for rhythm analysis. Time spent for standard and DSED procedure was registered in the same procedure. All team members performed the procedure on both patient categories.

Results

In total, 108 procedures were performed on both patient categories. Mean time to standard pad placement was 24.6 ± 3.3 s for patient A, and 27.4 ± 3.7 s for patients B. Mean time to DSED pad placement was 38.3 ± 7.0 s for patient A, and 41.3 ± 7.4 s for patient B. Mean difference in time needed for DSED versus standard pad placement was 13.7 ± 4.8 s for patient A, and 13.9 ± 4.6 s for patient B. There was no significant difference in time spent between the two patient categories (p = 0.725).

Conclusion

The necessary time to establish DSED versus standard defibrillation pad placement was short. This may support clinical studies on DSED as initial treatment for OHCA patients without risk of significant increase in time to first defibrillation.

Temporal trends in the incidence and outcomes of shock-refractory ventricular fibrillation out-of-hospital cardiac arrest

Aim

We aimed to describe trends in the incidence and outcomes of refractory ventricular fibrillation (RVF) compared to non-refractory ventricular fibrillation (non-RVF) in out-of-hospital cardiac arrest (OHCA).

Methods

Between 2010 and 2019, we included all OHCA cases involving adults ≥ 16 years old with an initial shockable rhythm and who received an attempted resuscitation by Emergency Medical Services (EMS) or a bystander shock prior to EMS arrival in Victoria, Australia. Trends in incidence and survival outcomes over the study period were examined. Adjusted logistic regression analyses were conducted to examine factors associated with RVF, as well as the association of RVF on survival to hospital discharge. RVF refers to patients receiving three or more consecutive shocks without a return of spontaneous circulation (ROSC).

Results

Of the 57,749 OHCA attended by EMS, 7,267 met the inclusion criteria. Of these, 4,168 (57.4%) were non-RVF and 3,099 (42.6%) were RVF. The incidence of RVF decreased significantly from 7.7 per 100,000 population in 2010 to 5.6 per 100,000 population in 2019 (p-trend = 0.01). Survival to hospital discharge increased significantly for both the RVF and non-RVF groups (26% vs 41% in 2010 to 31% vs 53% in 2019, p-trend = 0.004 for RVF; and p-trend = 0.01 for non-RVF). Compared to non-RVF, RVF was associated with reduced odds of survival to hospital discharge (Odds Ratio = 0.503 [95% confidence interval 0.448 - 0.565]). Factors associated with a lower likelihood of RVF and improved survival to hospital discharge included being witnessed to arrest by EMS, receiving bystander defibrillation and bystander cardiopulmonary resuscitation (CPR).

Conclusion

The incidence of RVF is declining, and survival rates are improving. Early treatment of VF patients with bystander CPR and defibrillation is likely to reduce RVF incidence.

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.

Out-of-hospital cardiac arrest treated with prehospital double sequential external defibrillation during eCPR in refractory VF - a case report

BACKGROUND

Double sequential external defibrillation (DSED) has demonstrated increased survival with good neurological outcome in a recent randomized controlled trial. DSED has not been studied in patients with extracorporeal cardiopulmonary resuscitation (eCPR).

CASE

We present the first case of prehospital eCPR with ongoing refractory ventricular fibrillation (VF), terminated by DSED. After six shocks, return of spontaneous circulation was initially achieved; however, the patient went into recurrent VF. ECPR was performed prehospital, with VF still refractory after three more shocks. DSED successfully terminated VF and showed a further increase in etCO2 and near-infrared spectroscopy cerebral oximetry values.

CONCLUSION

DSED can be a sufficient strategy for patients in refractory VF while on eCPR and should be evaluated in further studies.

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.

The Year in Electrophysiology: Selected Highlights From 2022

This special article is the fifth in an annual series for the Journal of Cardiothoracic and Vascular Anesthesia. The authors would like to thank the Editor-in-Chief, Dr Kaplan, the Associate Editor-in-Chief, Dr Augoustides, and the editorial board for the opportunity to author this series, which summarizes the key research papers in the electrophysiology (EP) field relevant to cardiothoracic and vascular anesthesiologists. These articles are shaping perioperative EP procedures and practices, such as pulsed-field ablation, cryoablation for first-line treatment for atrial fibrillation, advancements in conduction system pacing, safety issues related to smartphones and cardiac implantable electronic devices, and alterations in EP workflow as the world emerges from the COVID-19 pandemic. Special emphasis is placed on the implications of these advancements for the anesthetic care of patients undergoing EP procedures.

Keep shocking: Double sequential defibrillation for refractory ventricular fibrillation

Double sequential defibrillation is proposed as a novel modality of managing refractory ventricular fibrillation (VF). However, existing evidence has not been enough to support this. Here, we report an interesting case of a 54-year-old male who suffered from cardiac arrest with VF rhythm. The patient did not respond to 11 consecutive shocks along with antiarrhythmic medications. However, double sequential defibrillation terminated the VF. He had another episode of VF unresponsive to thirty minutes of standard defibrillation on his way to the catheterization laboratory. Again, the VF was terminated by double sequential defibrillation. Five days later, the patient was discharged home without neurological sequels.

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].

[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.

Association between the number of prehospital defibrillation attempts and neurologic outcomes in out-of-hospital cardiac arrest patients without on-scene return of spontaneous circulation

Objective

Delivery of prehospital defibrillation for shockable rhythms by emergency medical service providers is crucial for successful resuscitation in out-of-hospital cardiac arrest (OHCA) patients. The optimal range of prehospital defibrillation attempts for refractory shockable rhythms is unknown. This study evaluated the association between the number of prehospital defibrillation attempts and neurologic outcomes in OHCA patients.

Methods

A retrospective observational study was conducted using the nationwide OHCA registry. Adult OHCA patients who were treated by emergency medical service providers due to presumed cardiac origin with initial shockable rhythm were enrolled from 2013 to 2016. The final analysis was performed on patients without on-scene return of spontaneous circulation. The number of prehospital defibrillation attempts was categorized as follows: 2–3, 4–5, and ≥6 attempts. The primary outcome was a good neurologic recovery at hospital discharge. Multivariate logistic regression analysis was performed to evaluate the association between neurologic outcomes and the number of prehospital defibrillation attempts.

Results

A total of 4,513 patients were included in the final analysis. The numbers of patients for whom 2–3, 4–5, and ≥6 defibrillation attempts were made were 2,720 (60.3%), 1,090 (24.2%), and 703 (15.5%), respectively. Poorer outcomes were associated with ≥6 defibrillation attempts: survival to hospital discharge (adjusted odds ratio, 0.38; 95% confidence interval, 0.21–0.65) and good neurologic recovery (adjusted odds ratio, 0.42; 95% confidence interval, 0.21–0.84).

Conclusion

Six or more prehospital defibrillation attempts were associated with poorer neurologic outcomes in OHCA patients with an initial shockable rhythm who were unresponsive to on-scene defibrillation and resuscitation.

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.

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.

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.

Refractory Ventricular Fibrillation Treated with Double Simultaneous Defibrillation: Pilot Study

Introduction

Refractory shockable rhythm has a high mortality rate and poor neurological outcome. Treatments for refractory shockable rhythm presenting after defibrillation and medical treatment are not definite. We conducted research on the application of double simultaneous defibrillation (DSiD) for refractory shockable rhythms.

Methods

This is a retrospective pilot study performed using medical records from 1 January 2016 to 31 December 2017. The prephase was from January to December 2016. The post-phase was from January to December 2017. During the prephase, we conducted conventional defibrillation with one defibrillator, and during the post-phase, we conducted DSiD using two defibrillators. Primary outcome was survival to hospital discharge. Secondary outcomes included survival to hospital admission and good neurological outcome at 12 months. Statistical analysis was conducted using Fisher's exact test. Data were regarded statistically significant when p < 0.05.

Result

A total of 38 patients were included. Twenty-one patients underwent conventional defibrillation, and 17 underwent DSiD. The DSiD group had a higher survival to admission rate (14/17 (82.4%) vs. 6/21 (28.6%), p=0.001) and showed a trend for higher survival to discharge (7/17 (41.2%) vs. 3/21 (14.3%), p=0.078). Good neurological outcome at 12 months of the DSiD group was higher than that of the conventional defibrillation group, but the difference was not statistically significant (5/17 (29.4%) vs 2/21 (9.5%), p=0.207).

Conclusion

In patients with refractory shockable rhythms, DSiD has increased survival to hospital admission and a trend of increased survival to hospital discharge. However, DSiD did not improve neurological outcome at 12 months.

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.

Prehospital Double Sequential Defibrillation: A Matched Case-Control Study

OBJECTIVES

The goal of our study was to determine whether prehospital double sequential defibrillation (DSD) is associated with improved survival to hospital admission in the setting of refractory ventricular fibrillation/pulseless ventricular tachycardia (VF/pVT).

METHODS

This project is a matched case-control study derived from prospectively collected quality assurance/quality improvement data obtained from the San Antonio Fire Department out-of-hospital cardiac arrest (OHCA) database between January 2013 and December 2015. The cases were defined as OHCA patients with refractory VF/pVT who survived to hospital admission. The control group was defined as OHCA patients with refractory VF/pVT who did not survive to hospital admission. The primary variable in our study was prehospital DSD. The primary outcome of our study was survival to hospital admission.

RESULTS

Of 3,469 consecutive OHCA patients during the study period, 205 OHCA patients met the inclusion criterion of refractory VF/pVT. Using a predefined algorithm, two blinded researchers identified 64 unique cases and matched them with 64 unique controls. Survival to hospital admission occurred in 48.0% of DSD patients and 50.5% of the conventional therapy patients (p > 0.99; odds ratio = 0.91, 95% confidence interval = 0.40-2.1).

CONCLUSION

Our matched case-control study on the prehospital use of DSD for refractory VF/pVT found no evidence of associated improvement in survival to hospital admission. Our current protocol of considering prehospital DSD after the third conventional defibrillation in OHCA is ineffective.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

INSTITUTIONAL PROTOCOL NUMBER

University of Alabama at Birmingham Institutional Animal Care and Use Committee (IACUC) Protocol Number 06860.

Effectiveness of Prehospital Dual Sequential Defibrillation for Refractory Ventricular Fibrillation and Ventricular Tachycardia Cardiac Arrest

Objective: Dual sequential defibrillation (DSD) - successive defibrillations with two defibrillators - offers a novel approach to refractory ventricular fibrillation (RVF) and tachycardia (VF/VT). While associated with rescue shock success, the effect of DSD upon out-of-hospital cardiac arrest (OHCA) is unknown. We evaluated the association of DSD with survival after refractory VF/VT OHCA. Methods: We used data from a large metropolitan fire-based EMS service. We included all adult OHCA during 2013-2016 with ≥3 standard defibrillations. Physicians authorized subsequent DSD use by two separate defibrillators (PhysioControl LIFEPAK® 12/15) with pads placed anterior-lateral and anterior-posterior. Evaluated outcomes included return of spontaneous circulation (ROSC), survival to hospital admission, survival to 72 hours, and survival to hospital discharge. Using multivariable logistic regression, we evaluated the association between defibrillation type and OHCA outcomes, adjusting for patient demographics and event characteristics. Results: We included 310 patients in the analysis, 71 patients receiving DSD and 239 receiving conventional defibrillation. Patient demographics and event characteristics were similar between both groups. ROSC was lower for DSD than standard defibrillation: 39.4% vs. 60.3%, adjusted OR 0.46 (95% CI: 0.25-0.87). There were no differences in survival to hospital admission (35.2% vs. 49.2%, adjusted OR 0.57 [95% CI: 0.30-1.08]), survival to 72 hours (21.4% vs. 32.3%, adjusted OR 0.52 [95% CI: 0.26-1.10]), or survival to hospital discharge (14.3% vs. 20.9%, adjusted OR 0.63 [95% CI: 0.27-1.45]). Conclusions: Compared with conventional defibrillation, DSD was associated with lower odds of prehospital ROSC. Defibrillation type was not associated with other OHCA endpoints. DSD may not be beneficial in refractory VF/VT OHCA.

Double Sequential Defibrillation

Ventricular fibrillation (VF) is the most commonly encountered arrhythmia following out-of-hospital cardiac arrest. Previous studies have demonstrated early defibrillation and bystander cardiopulmonary resuscitation as essential in reducing patient mortality. What remains a clinical concern, however, is the treatment of patients experiencing VF refractory to defibrillation. Although current guidelines advocate pharmacotherapy for the management of shock-refractory VF, double sequential defibrillation has become a popular topic of discussion. This article provides a discourse regarding refractory VF, and a review of double sequential defibrillation literature. Further study is required before the recommendation for widespread implementation of this defibrillation technique.

The prognostic significance of repeated prehospital shocks for out-of-hospital cardiac arrest survival

OBJECTIVES

Patients suffering from an out-of-hospital cardiac arrest (OHCA) associated with an initial shockable rhythm have a better prognosis than their counterparts. The implications of recurrent or refractory malignant arrhythmia in such context remain unclear. The objective of this study is to evaluate the association between the number of prehospital shocks delivered and survival to hospital discharge among patients in OHCA.

METHODS

This cohort study included adult patients with an initial shockable rhythm over a 5-year period from a registry of OHCA in Montreal, Canada. The relationship between the number of prehospital shocks delivered and survival to discharge was described using dynamic probabilities. The association between the number of prehospital shocks delivered and survival to discharge was assessed using multivariable logistic regression.

RESULTS

A total of 1,788 patients (78% male with a mean age of 64 years) were included in this analysis, of whom 536 (30%) received treatments from an advanced care paramedic. A third of the cohort (583 patients, 33%) survived to hospital discharge. The probability of survival was highest with the first shock (33% [95% confidence interval 30%-35%]), but decreased to 8% (95% confidence interval 4%-13%) following nine shocks. A higher number of prehospital shocks was independently associated with lower odds of survival (adjusted odds ratio=0.88 [95% confidence interval 0.85-0.92], p &lt; 0.001).

CONCLUSION

Survival remains possible even after a high number of shocks for patients suffering from an OHCA with an initial shockable rhythm. However, requiring more shocks is independently associated with worse survival.