Racial, ethnic, and socioeconomic disparities in out-of-hospital cardiac arrest within the United States: Now is the time for change

This review highlights the current evidence on racial, ethnic, and socioeconomic disparities in cardiac arrest outcomes within the United States. Several studies demonstrate that patients from Black, Hispanic, or lower socioeconomic status backgrounds suffer the most from disparities at multiple levels of the resuscitation pathway, including in the provision of bystander cardiopulmonary resuscitation, defibrillator usage, and postresuscitation therapies. These gaps in care may altogether lead to lower survival rates and worse neurological outcomes for these patients. A multisystem, culturally sensitive approach to improving cardiac arrest outcomes is suggested in this article.

Development of a clinical decision rule for the early prediction of Shock-Refractory Out-of-Hospital cardiac arrest

BACKGROUND

Nearly half of ventricular fibrillation or ventricular tachycardia (VF/VT) out-of-hospital cardiac arrest (OHCA) patients receive three or more shocks, often referred to as refractory VF/VT. Our objective was to derive a clinical decision rule (CDR) for the early stratification of patients into risk categories for refractory VF/VT.

METHODS

We included adults with non-traumatic OHCA in the Resuscitation Outcomes Consortium Epistry (2011-2015) with ≥ 1 EMS shock. We used Classification and Regression Tree analysis for CDR building using variables known at initial EMS rhythm analysis including age, sex, witness, location, bystander interventions, initial EMS rhythm, obvious non-cardiac etiology, and dispatch to arrival times. The outcome was refractory VF/VT (≥3 shocks). We calculated sensitivity, specificity, area under the receiver operating curve (AUROC), and odds ratios (OR). The rule was validated using the Portland Cardiac Arrest Epidemiologic Registry (2018-2020).

RESULTS

There were 17,140 eligible patients and 8,146 (47.5%) had refractory VF/VT. The optimal CDR (AUROC = 0.671) defined three groups: high-risk were any patients requiring an EMS shock after a bystander AED shock; moderate-risk were any non-EMS witnessed arrests with shockable initial EMS rhythms; and the remainder were low-risk. Refractory VF/VT increased across the low (30.7%), moderate (58.5%) and high-risk (84.8%) groups. Compared to low-risk, being moderate-risk or higher (OR [95% CI]:3.37 [3.16-3.59]; sensitivity 72.7%; specificity 55.9%) or high-risk (OR:12.63 [9.89-16.13]; sensitivity 5.4%; specificity 99.1%) had higher odds of refractory VF/VT. Results was similar in the validation cohort (n = 765, AUROC = 0.672).

CONCLUSIONS

Patients at higher risk for refractory VF/VT can be identified early in EMS care.

Sports-related sudden cardiac arrest in young adults

AIMS

Data on sports-related sudden cardiac arrest (SrSCA) among young adults in the general population are scarce. We aimed to determine the overall SrSCA incidence, characteristics, and outcomes in young adults.

METHODS AND RESULTS

Prospective cohort study of all cases of SrSCA between 2012 and 2019 in Germany and Paris area, France, involving subjects aged 18-35 years. Detection of SrSCA was achieved via multiple sources, including emergency medical services (EMS) reporting and web-based screening of media releases. Cases and aetiologies were centrally adjudicated. Overall, a total of 147 SrSCA (mean age 28.1 ± 4.8 years, 95.2% males) occurred, with an overall burden of 4.77 [95% confidence interval (CI) 2.85-6.68] cases per million-year, including 12 (8.2%) cases in young competitive athletes. While bystander cardiopulmonary resuscitation (CPR) was initiated in 114 (82.6%), automated external defibrillator (AED) use by bystanders occurred only in a minority (7.5%). Public AED use prior to EMS arrival (odds ratio 6.25, 95% CI 1.48-43.20, P = 0.02) was the strongest independent predictor of survival at hospital discharge (38.1%). Among cases that benefited from both immediate bystander CPR and AED use, survival rate was 90.9%. Coronary artery disease was the most frequent aetiology (25.8%), mainly through acute coronary syndrome (86.9%).

CONCLUSION

Sports-related sudden cardiac arrest in the young occurs mainly in recreational male sports participants. Public AED use remains disappointingly low, although survival may reach 90% among those who benefit from both bystander CPR and early defibrillation. Coronary artery disease is the most prevalent cause of SrSCA in young adults.

Protocol for a cluster randomised controlled feasibility study of Prehospital Optimal Shock Energy for Defibrillation (POSED)

AIMS

The Prehospital Optimal Shock Energy for Defibrillation (POSED) study will assess the feasibility of conducting a cluster randomised controlled study of clinical effectiveness in UK ambulance services to identify the optimal shock energy for defibrillation.

METHODS

POSED is a pragmatic, allocation concealed, open label, cluster randomised, controlled feasibility study. Defibrillators within a single UK ambulance service will be randomised in an equal ratio to deliver one of three shock strategies 120-150-200 J, 150-200-200 J, 200-200-200 J. Consecutive adults (≥18 years) presenting with out of hospital cardiac arrest requiring defibrillation will be eligible. The study plans to enrol 90 patients (30 in each group). Patients (or their relatives for non-survivors) will be informed about trial participation after the initial emergency has resolved. Survivors will be invited to consent to participate in follow-up (i.e., at 30 days or discharge).The primary feasibility outcome is the proportion of eligible patients who receive the randomised study intervention. Secondary feasibility outcomes will include recruitment rate, adherence to allocated treatment and data completeness. Clinical outcomes will include Return of an Organised Rhythm (ROOR) at 2 minutes post-shock, refibrillation rate, Return of Spontaneous Circulation (ROSC) at hospital handover, survival and neurological outcome at 30 days.

CONCLUSION

The POSED study will assess the feasibility of a large-scale trial and explore opportunities to optimise the trial protocol.Trial registration: ISRCTN16327029.

[Effects of automated external defibrillators on hands-off intervals in lay rescuers]

Background

Survival chances after out-of-hospital cardiac arrests caused by hyperdynamic electric cardiac rhythms can be significantly improved by early defibrillation with automated external defibrillators (AEDs). As postulated in international guidelines, the resulting hands-off intervals should not exceed 10 s.

Objectives

We investigated delay in onset of chest compressions and the length of hands-off intervals during defibrillation associated with the application of AEDs.

Materials and methods

In a prospective, randomized, single-blinded observational study, the resuscitation efforts by first year medical students were analyzed in different emergency scenarios on manikins. Delay in onset of chest compressions and the length of hands-off intervals between voice prompts from four conventional devices were compared during shockable and nonshockable rhythms. Satisfaction with the device, difficulties with the application, and suggested improvements were assessed by questionnaire.

Results

In a total of 70 applications, the start with thoracic compressions was delayed by a mean of 115 s. On average, the first shock was administered after 125 s in shockable heart rhythms. Perishock pauses of less than 10 s were achieved with none of the tested devices. Hands-off intervals during defibrillation differed significantly between the devices (p < 0.001). Improvements were suggested regarding marking, voice prompts, and electrodes.

Conclusions

Perishock pause of less than 10 s was not achieved with any of the tested devices. Shortened and more precise voice prompts as well as more clearly arranged labeling and layout of pads are needed to simplify application, reduce delayed onset of chest compressions and shorten hands-off intervals.

Effectiveness of alternative shock strategies for out-of-hospital cardiac arrest: A systematic review

Aim

To determine the optimal first-shock energy level for biphasic defibrillation and whether fixed or escalating protocols for subsequent shocks are most effective.

Methods

We searched Medline, Embase, Cochrane CENTRAL, CINAHL, the Web of Science and national and international trial registry databases for papers published from database inception to January 2022. We reviewed reference lists of key papers to identify additional references. The population included adults sustaining non traumatic out-of-hospital cardiac arrest subject to attempted defibrillation. Studies of internal or monophasic defibrillation and studies other than randomised controlled trials or prospective cohorts were excluded. Two reviewers assessed study relevance. Data extraction and risk of bias assessment, using the ROBINS-I tool, were conducted by one reviewer and checked by a second reviewer. Data underwent intention-to-treat analysis.

Results

We identified no studies evaluating first shock energy. Only one study (n = 738) comparing fixed versus escalating energy met eligibility criteria: a prospective cohort analysis of a randomised controlled trial of manual versus mechanical CPR. High fixed (360 J) energy was compared with an escalating (200-200/300-360 J) strategy. Researchers found 27.5% (70/255) of patients in the escalating energy group and 27.61% (132/478) in the fixed high energy group survived to hospital discharge (unadjusted risk ratio 0.99, 95% CI 0.73, 1.23). Results were of very low certainty as the study was at serious risk of bias.

Conclusion

This systematic review did not identify an optimal first-shock energy for biphasic defibrillation. We identified no survival advantage at 30 days when comparing 360 J fixed with 200 J escalating strategy.

Cardiopulmonary resuscitation and defibrillation for cardiac arrest when patients are in the prone position: A systematic review

AIM

To perform a systematic review of cardiopulmonary resuscitation (CPR) and/or defibrillation in the prone position compared to turning the patient supine prior to starting CPR and/or defibrillation.

METHODS

The search included PubMed, Embase, Web of Science, Cochrane, CINAHL Plus, and medRxiv on December 9, 2020. The population included adults and children in any setting with cardiac arrest while in the prone position. The outcomes included arterial blood pressure and end-tidal capnography during CPR, time to start CPR and defibrillation, return of spontaneous circulation, survival and survival with favorable neurologic outcome to discharge, 30 days or longer. ROBINS-I was performed to assess risk of bias for observational studies.

RESULTS

The systematic review identified 29 case reports (32 individual cases), two prospective observational studies, and two simulation studies. The observational studies enrolled 17 patients who were declared dead in the supine position and reported higher mean systolic blood pressure from CPR in prone position (72 mmHg vs 48 mmHg, p < 0.005; 79 ± 20 mmHg vs 55 ± 20 mmHg, p = 0.028). One simulation study reported a faster time to defibrillation in the prone position. Return of spontaneous circulation, survival to discharge or 30 days were reported in adult and paediatric case reports. Critical risk of bias limited our ability to perform pooled analyses.

CONCLUSIONS

We identified a limited number of observational studies and case reports comparing prone versus supine CPR and/or defibrillation. Prone CPR may be a reasonable option if immediate supination is difficult or poses unacceptable risks to the patient.

Alert system-supported lay defibrillation and basic life-support for cardiac arrest at home

Aims

Automated external defibrillators (AEDs) are placed in public, but the majority of out-of-hospital cardiac arrests (OHCA) occur at home.

Methods and results

In residential areas, 785 AEDs were placed and 5735 volunteer responders were recruited. For suspected OHCA, dispatchers activated nearby volunteer responders with text messages, directing two-thirds to an AED first and one-third directly to the patient. We analysed survival (primary outcome) and neurologically favourable survival to discharge, time to first defibrillation shock, and cardiopulmonary resuscitation (CPR) before Emergency Medical Service (EMS) arrival of patients in residences found with ventricular fibrillation (VF), before and after introduction of this text-message alert system. Survival from OHCAs in residences increased from 26% to 39% {adjusted relative risk (RR) 1.5 [95% confidence interval (CI): 1.03–2.0]}. RR for neurologically favourable survival was 1.4 (95% CI: 0.99–2.0). No CPR before ambulance arrival decreased from 22% to 9% (RR: 0.5, 95% CI: 0.3–0.7). Text-message-responders with AED administered shocks to 16% of all patients in VF in residences, while defibrillation by EMS decreased from 73% to 39% in residences (P < 0.001). Defibrillation by first responders in residences increased from 22 to 40% (P < 0.001). Use of public AEDs in residences remained unchanged (6% and 5%) (P = 0.81). Time from emergency call to defibrillation decreased from median 11.7 to 9.3 min; mean difference –2.6 (95% CI: –3.5 to –1.6).

Conclusion

Introducing volunteer responders directed to AEDs, dispatched by text-message was associated with significantly reduced time to first defibrillation, increased bystander CPR and increased overall survival for OHCA patients in residences found with VF.

Non-transvenous ICD therapy: current status and beyond

Subcutaneous implantable cardioverter/defibrillators (S-ICDs) have been developed to offer ICD treatment to patients without venous access to the heart and to overcome complications associated with transvenous leads, particularly lead fracture/insulation defects and endocarditis. Several studies and registries have demonstrated the feasibility and safety of S‑ICD in different groups of patients. Further developments in S‑ICD technology involve the combination with devices that can provide anti-bradycardia and anti-tachycardia pacing if needed. The extravascular ICD (EV-ICD) is a new system that similarly offers ICD therapy without a transvenous lead but uses a substernal instead of a subcutaneous lead to facilitate detection of ventricular fibrillation and to provide anti-tachycardia and also temporary anti-bradycardia pacing. The first animal but also clinical data on EV-ICDs have been published. This review discusses the current state, potential advantages and limitations, and future research of both S‑ICD and EV-ICD.

Low-energy, single-pulse surface stimulation defibrillates large mammalian ventricles

BACKGROUND

Strong electric shocks are the gold standard for ventricular defibrillation but are associated with pain and tissue damage. We hypothesized that targeting the excitable gap (EG) of reentry with low-energy surface stimulation is a less damaging and painless alternative for ventricular defibrillation.

OBJECTIVE

The purpose of this study was to determine the conditions under which low-energy surface stimulation defibrillates large mammalian ventricles.

METHODS

Low-energy surface stimulation was delivered with five electrodes that were 7 cm long and placed 1-2 cm apart on the endocardial and epicardial surfaces of perfused pig left ventricle (LV). Rapid pacing (>4 Hz) was used to induce reentry from a single electrode. A 2 ms defibrillation pulse ≤0.5 A was delivered from all electrodes with a varied time delay from the end of the induction protocol (0.1-5 seconds). Optical mapping was performed and arrhythmia dynamics analyzed. For mechanistic insight, simulations of the VF induction and defibrillation protocols were performed in silico with an LV model emulating the experimental conditions and electrodes placed 0.25-2 cm apart.

RESULTS

In living LV, reentry was induced with varying complexity and dominant frequencies ranging between 3.5 to 6.2 Hz over 8 seconds postinitiation. Low-energy defibrillation was achieved with energy <60 mJ and electrode separations up to 2 cm for less complex arrhythmia. In simulations, defibrillation consistently occurred when stimulation captured >75% of the EG, which blocked reentry <2.9 mm in front of the leading reentrant wavefront.

CONCLUSION

Defibrillation with low-energy, single-pulse surface stimulation is feasible with energies below the human pain threshold (100 mJ). Optimal defibrillation occurs when arrhythmia complexity is minimal and electrodes capture >75% of the EG.

Pre-charging the defibrillator before rhythm analysis reduces hands-off time in patients with out-of-hospital cardiac arrest with shockable rhythm

AIM

To evaluate the effect of pre-charging the defibrillator before rhythm analysis on hands-off time in patients suffering from out-of-hospital cardiac arrest with shockable rhythm.

METHODS

Pre-charging was implemented in the Emergency Medical Service in the Central Denmark Region in June 2018. Training consisted of hands-on simulation scenarios, e-learning material, and written instructions. Data were extracted from the Danish Cardiac Arrest Registry for a 14-month period spanning the implementation of pre-charging. Patients having received at least one shock were included. Transthoracic impedance data were analysed. We recorded hands-off time and peri-shock pauses for all defibrillation procedures and the total hands-off fraction for all cardiac arrests.

RESULTS

Impedance and outcome data were available for 178 patients. 523 defibrillation procedures were analysed. The pre-charge method was associated with shorter median hands-off time per defibrillation procedure (7.6 (IQR 5.8-9.9) vs. 12.6 (IQR 10-16.4) seconds, p < 0.001) but longer pre-shock pause (4 (IQR 2.7-6.1) vs 1.7 (IQR 1.2-3) seconds, p < 0.001) when compared to the current guideline-recommended defibrillation method. The total hands-off fraction per cardiac arrest was reduced after implementation of the pre-charge method (16.5% vs. 20.4%, p = 0.003). No increase in shocks to non-shockable rhythms or personnel was registered. Patients who received only pre-charge defibrillations had an increased odds ratio of return of spontaneous circulation (aOR 2.91; 95%CI 1.09-7.8, p = 0.03).

CONCLUSION

Pre-charging the defibrillator reduced hands-off time during defibrillation procedures, reduces the total hands-off fraction and may be associated with increased return of spontaneous circulation in out-of-hospital cardiac arrest with shockable rhythm.

The feasibility of medical unmanned aerial systems in suburban areas

Out-of-Hospital Cardiac Arrests (OHCA) are one of the biggest challenges facing medical systems world-wide. Each year, more than 420,000 Americans experience cardiac arrests with a survival rate of approximately 10%.¹ A large challenge to treating OHCA continues to be rapid access to AEDs which can increase survival rates up to 40%.¹ While pivotal to an OHCA patient's survival, AEDs are not always readily available. Advances in unmanned aerial systems (UAS) - commonly referred to as drones - can provide a solution since UAS have the ability to rapidly carry an AED payload to an emergency site. This study examined the potential use of UAS delivered AEDs in suburban areas by using the Charlottesville-Albemarle area as an example. This study was carried out by using Geographical Information Systems mapping. Specifications of the Eagle drone model by Flirtey were used to develop a beneficial drone placement plan. Models were created with drones at first responder stations. Coverage area of the drones at first responder stations was compared to coverage area of drone units placed at "ideal" locations in the Charlottesville-Albemarle County area. Population statistics were gathered from the GIS program Social Explorer, using data from the U.S. Census Bureau. The "ideal" location placement plan was then evaluated for an estimate of total population covered by the system. Finally, ideal drone placements were evaluated and compared to response time and distances versus a local EMS ground unit. With the derived ideal placements, 70.08% of the area would have drone coverage that could deliver an AED in less than five minutes and 97.97% of the area would have coverage in less than 10 min. At minimum, 94.72% of the population would be covered by the ideal placements of drones within the area. Drone response time was significantly faster than ground EMS response by a factor of 5× (P value < .05). Drones were able to get to the incident scene of a theoretical OHCA faster without and with vertical response challenges. The results show that UAS delivery of AEDs is not only possible in the Charlottesville-Albemarle County area, but an effective way to decrease response time to improve chances of survival for a person experiencing an OHCA in similar suburban areas.

Implantable vagus nerve stimulation system performance is not affected by internal or external defibrillation shocks

Purpose

Autonomic regulation therapy (ART) for heart failure (HF) is delivered using vagus nerve stimulation (VNS), and has been associated with improvement in cardiac function and HF symptoms. VNS is delivered using an implantable pulse generator (IPG) and a lead placed around the cervical vagus nerve. Because HF patients may receive concomitant cardiac defibrillation therapy, testing was conducted to determine the effect of defibrillation (DF) on VNS system performance.

Methods

Normal swine (n = 4) with VNS system implants on the right cervical vagus nerve received sequential defibrillation shocks with three defibrillation systems: an implantable cardioverter defibrillator (ICD), a subcutaneous ICD (S-ICD), and an external cardioverter defibrillator (ECD). Each system delivered a series of bipolar high-energy shocks and reverse-polarity high-energy shocks.

Results

The specified cardiac defibrillation shocks were delivered successfully from each of the three defibrillation systems to all animals. After each shock series, interrogation of the IPG confirmed that software and data were unchanged from pre-programmed values. After all of the defibrillation shocks were delivered, the IPGs underwent and passed comprehensive electrical testing demonstrating proper system function. No shifts in IPG parameters or ART system failures were observed, and histologic evaluation of the vagus nerve revealed no anatomic changes.

Conclusions

Implantable VNS systems were tested in vivo for immunity to defibrillation via ICD, S-ICD, and ECD, and were found to be unaffected by a series of high-energy defibrillation shocks. These results confirm that ART systems are capable of continuing to function after defibrillation and the cervical vagus nerve is anatomically unaffected.

Out of hospital cardiac arrest: Past, present, and future

Advances in resuscitation following out-of-hospital cardiac arrest (OHCA) provide an opportunity to improve public health. This review reflects on past developments, present status, and future possibilities using the science-education-implementation framework of the Utstein Formula and the clinical framework of the links in the chain of survival. With the discovery of CPR and defibrillation in the mid 20th century, resuscitation developed a scientific construct for progress. Systems of emergency community response provided operational efficiency to treat OHCA. Contemporary resuscitation involves integrated interventions in the chain of survival: early recognition, early CPR, early defibrillation, expert and timely advanced life support and hospital care, and multidimensional rehabilitation. Implementation of scientific advances is especially challenging given the unexpected nature of OHCA, the need for time-sensitive interventions, and the substantial collective of stakeholders involved in the chain of survival. Systematic measurement provides the foundation to evaluate performance and guide implementation initiatives. For many systems, telecommunicator CPR and high-performance CPR by emergency professionals are accessible, near-term programs to improve OHCA outcome. Smart technologies that activate, coordinate, and/or coach community "volunteers" to accelerate early CPR and defibrillation have conceptual promise, though robust implementation has been achieved by only a handful of systems. Longer-term strategies may leverage technology to develop a high-fidelity "life-detector" or engineer and disseminate a specialized consumer defibrillator designed to bridge care until arrival of professional response.

[Paediatric Life Support]

The European Resuscitation Council (ERC) Paediatric Life Support (PLS) guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations of the International Liaison Committee on Resuscitation (ILCOR). This section provides guidelines on the management of critically ill or injured infants, children and adolescents before, during and after respiratory/cardiac arrest.

Right ventricular insertion promotes reinitiation of ventricular fibrillation in defibrillation failure

BACKGROUND

Shocks near defibrillation threshold (nDFT) strength commonly extinguish all ventricular fibrillation (VF) wavefronts, but a train of rapid, well-organized postshock activations (PAs) typically appears before sinus rhythm ensues. If one of the PA waves undergoes partial propagation block (wavebreak), reentry may be induced, causing VF to reinitiate and the shock to fail.

OBJECTIVE

The purpose of this study was to determine whether wavebreak leading to VF reinititation following nDFT shocks occurs preferentially at the right ventricular insertion (RVI), which previous studies have identified as a key site for wavebreak.

METHODS

We used panoramic optical mapping to image the ventricular epicardium of 6 isolated swine hearts during nDFT defibrillation episodes. After each experiment, the hearts were fixed and their geometry scanned with magnetic resonance imaging (MRI). The MRI and mapping datasets were spatially coregistered. For failed shocks, we identified the site of the first wavebreak of a PA wave during VF reinitiation.

RESULTS

We recorded 59 nDFT failures. In 31 of these, the first wavebreak event occurred within 1 cm of the RVI centerline, most commonly on the anterior side of the right ventricular insertion (aRVI) (23/31). The aRVI region occupies 16.8% ± 2.5% of the epicardial surface and would be expected to account for only 10 wavebreaks if they were uniformly distributed. By χ2 analysis, aRVI wavebreaks were significantly overrepresented.

CONCLUSION

The anterior RVI is a key site in promoting nDFT failure. Targeting this site to prevent wavebreak could convert defibrillation failure to success and improve defibrillation efficacy.

Asymptomatic ventricular fibrillation in continuous flow left-ventricular assist device

Left ventricular assist devices (LVADs) have increased survival for heart failure patients. Individuals with LVADs are a growing patient population with frequent complications and Emergency Department (ED) visits. A 50-year-old female presented to the ED due to a low flow alarm on her LVAD. Upon arrival in the ED she was noted to be in ventricular fibrillation. She was defibrillated with restoration to normal sinus rhythm and was started on amiodarone. An implantable cardiac defibrillator was placed during hospital admission. Amiodarone was continued as an outpatient. Patients with continuous flow LVADs can be in dysrhythmias including ventricular tachycardia and ventricular fibrillation and remain relatively asymptomatic. We present a rare case of a patient with an LVAD and ventricular fibrillation who was completely asymptomatic in the ED.

Effectiveness of public-access automated external defibrillators at Tokyo railroad stations

AIM

To investigate the effectiveness of public-access automated external defibrillators (AEDs) at Tokyo railroad stations.

METHODS

We analysed data from a population-based registry of out-of-hospital cardiac arrests in Tokyo, Japan (2014-2018). We identified patients aged ≥18 years who experienced bystander-witnessed cardiac arrest due to ventricular fibrillation of presumed cardiac origin at railroad stations. The primary outcome was survival at 1 month after cardiac arrest with favourable neurological outcomes (cerebral performance category 1-2).

RESULTS

Among 280 eligible patients who had bystander-witnessed cardiac arrest and received defibrillation at railroad stations, 245 patients (87.5%) received defibrillation using public-access AEDs and 35 patients (12.5%) received defibrillation administered by emergency medical services (EMS). Favourable neurological outcomes at 1 month after cardiac arrest were significantly more common in the group that received defibrillation using public-access AEDs (50.2% vs. 8.6%; adjusted odds ratio: 11.2, 95% confidence interval: 1.43-88.4) than in the group that received defibrillation by EMS. Over a 5-year period, favourable neurological outcomes at 1 month after cardiac arrest of 101.9 cases (95% confidence interval: 74.5-129.4) were calculated to be solely attributable to public-access AED use. The incremental cost-effectiveness ratio to gain one favourable neurological outcome obtained from public-access AEDs at railroad stations was lower than that obtained from nationwide deployment (48.5 vs. 2133.4 AED units).

CONCLUSION

Deploying public-access AEDs at Tokyo railroad stations presented significant benefits and cost-effectiveness. Thus, it may be prudent to prioritise metropolitan railroad stations in public-access defibrillation programs.

Strategies on locations of public access defibrillator: A systematic review

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) is a critical condition with poor outcomes. Although the survival rate increases in those who undergo defibrillation, the utility of on-time defibrillation among bystanders remained low. An evaluation of the deployment strategy for public access defibrillators (PADs) is necessary to increase their use and accessibility. This study was to conduct a systematic review for deployment strategies of PADs.

METHODS

Two authors independently searched for articles published before October 2019 from PubMed, Embase, Web of Science, and Cochrane Library. An independent librarian provided the search strategy and assisted the literature research. We included articles that were focused on the main topic, but excluded those which were missing results or that used an unclear definition. The qualitative outcomes were the utility and OHCA coverage of PADs. We performed a qualitative analysis across the studies, but a quantitative analysis was not available due to the studies' heterogeneity in design and variety of outcomes.

RESULTS

We eventually included 15 studies. Three strategies were presented: guidelines-based, grid-based, and landmark-based. The guidelines-based deployment was common fit for OHCA events. The grid-based method increased the use of bystander defibrillation 3-fold, and 30-day survival doubled. The top 3 landmarks in the landmark-based strategy were offices (18.6%), schools (13.3%), and sports facilities (12.9%). Utility of PADs might increase if we optimize PAD location by mathematical modeling and evaluation feedback.

CONCLUSION

Three deployment strategies were presented. Although the optimal method could not be fully identified, a more efficient PAD deployment could benefit the population in terms of OHCA coverage and survival among patients with OHCA.

European Resuscitation Council Guidelines 2021: Paediatric Life Support

These European Resuscitation Council Paediatric Life Support (PLS) guidelines, are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the management of critically ill infants and children, before, during and after cardiac arrest.

Automatic external defibrillator provided by unmanned aerial vehicle (drone) in Greater Paris: A real world-based simulation

AIM

To reduce the delay in defibrillation of out-of-hospital cardiac arrest (OHCA) patients, recent publications have shown that drones equipped with an automatic external defibrillator (AED) appear to be effective in sparsely populated areas. To study the effectiveness of AED-drones in high-density urban areas, we developed an algorithm based on emergency dispatch parameters for the rate and detection speed of cardiac arrests and technical and meteorological parameters.

METHODS

We ran a numerical simulation to compare the actual time required by the Basic Life Support team (BLSt) for OHCA patients in Greater Paris in 2017 to the time required by an AED-drone. Endpoints were the proportion of patients with "AED-drone first" and the defibrillation time gained. We built an open-source website (https://airborne-aed.org/) to allow modelling by modifying one or more parameters and to help other teams model their own OHCA data.

RESULTS

Of 3014 OHCA patients, 72.2 ± 0.7% were in the "no drone flight" group, 25.8 ± 0.2% in the "AED-drone first" group, and 2.1 ± 0.2% in the "BLSt-drone first" group. When a drone flight was authorized, it arrived an average 190 s before BLSt in 93% of cases. The possibility of flying the drone during the aeronautical night improved the results of the "AED-drone first" group the most (+60%).

CONCLUSIONS

In our very high-density urban model, at most 26% of OHCA patients received an AED from an AED-drone before BLSt. The flexible parameters of our website model allows evaluation of the impact of each choice and concrete implementation of the AED-drone.

Effect of defibrillation on the performance of an implantable vagus nerve stimulation system

Background

Vagus Nerve Stimulation (VNS) delivers Autonomic Regulation Therapy (ART) for heart failure (HF), and has been associated with improvement in cardiac function and heart failure symptoms. VNS is delivered using an implantable pulse generator (IPG) and lead with electrodes placed around the cervical vagus nerve. Because HF patients may receive concomitant cardiac defibrillation therapy, testing was conducted to determine the effect of defibrillation (DF) on the VNS system.

Methods

DF testing was conducted on three ART IPGs (LivaNova USA, Inc.) according to international standard ISO14708-1, which evaluated whether DF had any permanent effects on the system. Each IPG was connected to a defibrillation pulse generator and subjected to a series of high-energy pulses.

Results

The specified series of pulses were successfully delivered to each of the three devices. All three IPGs passed factory electrical tests, and interrogation confirmed that software and data were unchanged from the pre-programmed values. No shifts in parameters or failures were observed.

Conclusions

Implantable VNS systems were tested for immunity to defibrillation, and were found to be unaffected by a series of high-energy defibrillation pulses. These results suggest that this VNS system can be used safely and continue to function after patients have been defibrillated.

Diathermy-induced Ventricular Fibrillation

Diathermy is extensively used in patients for intracardiac device implant and extraction. While diathermy helps with adequate hemostasis, it may rarely be associated with fatal dysrhythmias. We report a case of diathermy-induced ventricular fibrillation during device extraction. The case highlights the importance and supports the involvement of a defibrillation facility during pacemaker revisions requiring diathermy.

Use and coverage of automated external defibrillators according to location in out-of-hospital cardiac arrest

AIMS

To evaluate 1) the relative use of automated external defibrillators (AEDs) at different types of AED locations 2) the percentage of AEDs crossing location types during OHCA before use 3) the AED coverage distance at different types of AED locations, and 4) the 30-day-survival in different subgroups.

METHODS

From 2014-2018, AEDs used by bystanders during out-of-hospital cardiac arrest (OHCA) in the Region of Southern Denmark were collected. Data regarding registered AEDs was retrieved from the national AED-network. The OHCA site and AED placement was categorized into; 1) Residential; 2) Public; 3) Nursing home, 4) Company/workplace; 5) Institution; 6) Health clinic and 7) Sports facility/recreational. To evaluate 30-day-survival, groups 4-7 were pooled into one Mixed group.

RESULTS

In total 509 OHCAs were included. There was high relative usage of AEDs from public places, nursing homes, health clinics and sports facilities, and low relative usage from companies/workplaces, residential areas and institutions. Of AEDs used during residential OHCAs 39% were collected from public places. AEDs placed in residential areas and public places had a coverage of 575 m (IQR 130-1300) and 270 m (IQR5-550), respectively. Thirty-day- survival in public, residential and mixed groups were 49%, 14% and 67%, respectively.

CONCLUSION

The relative use of AEDs from public places, nursing homes, sports facilities and health clinics was high, and AEDs used during OHCA in residential areas were most frequently collected from public places. AEDs placed in both residential areas and public places may have a wider coverage area than proposed in current literature.