BACKGROUND:In patients with out-of-hospital cardiac arrest (OHCA) who receive multiple shocks, it is often unclear whether they are experiencing refractory or recurrent ventricular fibrillation (VF). Understanding into the cause of refractory VF is limited and the foundational evidence for alternative defibrillation strategies are lacking. To gain further insight into these patients we studied the incidence and possible predictors of refractory VF, and compared outcomes between patients with recurrent VF and those with refractory VF. METHODS:Using the ARREST registry, we included patients with VF at the first three rhythm checks between 2016 and 2019. ECG waveforms were analysed for successful termination of VF at five seconds after each shock delivered. Patients were classified as having refractory VF if all three shocks failed to terminate VF. The remaining patients were classified as having recurrent VF. Outcomes and possible predictors between both groups were compared. RESULTS:Out of 436 patients who met the inclusion criteria, 22 (5%) had refractory VF and 414 (95%) had recurrent VF. Rates of return of spontaneous circulation (ROSC) and 30-day survival were 9/22 (41%) vs 243/409 (59%) (RR 0.69 [95% CI, 0.41-1.15]) and 5/22 (23%) vs 187/408 (46%) (RR 0.49 [95% CI, 0.23-1.08]) in patients with refractory and recurrent VF, respectively. Predictors for refractory VF were absence of CPR and AED use before emergency medical services arrival, a longer delay to the first shock, and a lower amplitude spectral area value. CONCLUSIONS:The small group of refractory VF patients were characterised by unfavourable resuscitation characteristics. Clinical outcomes in refractory VF versus recurrent VF patients remain uncertain due to low patient numbers.

AIM:European guidelines suggest an escalating defibrillation energy protocol for cases of out-of-hospital cardiac arrest (OHCA) with a shockable rhythm. Our regional manual defibrillators are by default set to deliver 200 J for the initial shock and 360 J for subsequent shocks. In case of a prior AED shock, Emergency Medical Services (EMS) personnel need to deliberately adjust the energy level to 360 J before delivering the first shock with their manual defibrillator to adhere to the escalating energy protocol. We investigated adherence to this escalating energy protocol by EMS and the association with clinical outcomes. METHODS:Data were collected from the ARREST-registry in (the) Netherlands. We analysed OHCA cases in adults with shockable rhythms who had received at least one shock from an AED and from a manual defibrillator. The primary outcome was the adherence to the escalating energy protocol. Secondary outcomes were the relationships of adherence with various clinical outcomes. RESULTS:In 827 cases, adherence to the escalating energy protocol was 20.3 % (95 % CI 17.7 %-23.2 %). No baseline characteristics were significantly associated with increased adherence. Shockable rhythms were terminated by the first manual defibrillator shock in 521/659 (79.1 %) cases with 200 J and 139/168 (82.7 %) cases with 360 J (p = 0.33). Overall 30-day survival rate was 38.4 %. Adherence to protocol was not significantly associated with differences in clinical outcomes after multivariable analyses. CONCLUSION:Adherence to escalating energy protocol by EMS during transition from defibrillation with AED to manual defibrillator is limited. Our data did not provide evidence for a relationship between adherence and clinical outcomes.

Aim Emergency medical services target to reduce time to cardiopulmonary resuscitation and defibrillation by alerting additional individuals to out-of-hospital cardiac arrest (OHCA). Multiple terms are used to describe these individuals, potentially causing confusion and hindering comparisons. This international consensus study aimed to establish standardised terminology. Methods Forty-six interdisciplinary researchers from four continents participated in a symposium on “Community First Responders” with the objective of standardising relevant terminology. Initially, terms were proposed anonymously for individuals alerted during work hours and those alerted during leisure time. Each term was rated on a 5-point Likert scale. Terms receiving a high level of agreement were included in the final voting process. Results Seven terms were suggested for individuals alerted during work hours. In the first voting “first responder”, “professional first responder”, and “on-duty first responder” achieved high agreement. Ultimately, consensus was reached on the term “on-duty first responder”.For individuals alerted during leisure time, ten terms were proposed. Among these, “first responder”, “citizen first responder”, “community emergency responder”, “community first responder”, “volunteer first responder”, “volunteer responder”, and “volunteer community first responder” reached high agreement. In the final vote “community first responder” was selected.The consensus group agreed that the overarching term “first responder” should be used to describe all community-based individuals, who are alerted, regardless of whether they are on duty or off duty. Conclusion This consensus study recommends using the terms “on-duty first responder” and “community first responder” to describe individuals additionally alerted by medical dispatch centres to facilitate early intervention in OHCA.

BACKGROUND:In patients with out-of-hospital cardiac arrest who present with an initial shockable rhythm, a longer delay to the first shock decreases the probability of survival, often attributed to cerebral damage. The mechanisms of this decreased survival have not yet been elucidated. Estimating the probability of successful defibrillation and other factors in relation to the time to first shock may guide prehospital care systems to implement policies that improve patient survival by decreasing time to first shock. METHODS:Patients with a witnessed out-of-hospital cardiac arrest and ventricular fibrillation (VF) as an initial rhythm were included using the prospective ARREST registry (Amsterdam Resuscitation Studies). Patient and resuscitation data, including time-synchronized automated external defibrillator and manual defibrillator data, were analyzed to determine VF termination at 5 seconds after the first shock. Delay to first shock was defined as the time from initial emergency call until the first shock by any defibrillator. Outcomes were the proportion of VF termination, return of organized rhythm, and survival to discharge, all in relation to the delay to first shock. A Poisson regression model with robust standard errors was used to estimate the association between delay to first shock and outcomes. RESULTS:Among 3723 patients, the proportion of VF termination declined from 93% when the delay to first shock was <6 minutes to 75% when that delay was >16 minutes (Ptrend<0.001). Every additional minute in VF from emergency call was associated with 6% higher probability of failure to terminate VF (adjusted relative risk, 1.06 [95% CI, 1.04-1.07]), 4% lower probability of return of organized rhythm (adjusted relative risk, 0.96 [95% CI, 0.95-0.98]), and 6% lower probability of surviving to discharge (adjusted relative risk, 0.94 [95% CI, 0.93-0.95]). CONCLUSIONS:Every minute of delay to first shock was associated with a significantly lower proportion of VF termination and return of organized rhythm. This may explain the worse outcomes in patients with a long delay to defibrillation. Reducing the time interval from emergency call to first shock to <= 6 minutes could be considered a key performance indicator of the chain of survival.

BACKGROUND:Automated external defibrillators (AEDs) from community first responder systems (CFR-system) are important to achieve early defibrillation in out-of-hospital cardiac arrest (OHCA). It is unclear how far community first responders (CFR) can travel to fetch and connect an AED to achieve this goal. This study aims to evaluate the relation of the distance between OHCA and the dispatched CFR-system AED and speed of AED-connection. METHODS:Within the Dutch prospective ARREST registry, OHCA patients from 2016 to 2021 with a connected CFR AED were identified. The location of each connected AED was retrieved. Straight-line distances between patient and AED-location were calculated using Google Maps. Time intervals between emergency-call and AED-connection were compared according to straight-line distances and degree of urbanization. RESULTS:Out of 3231 OHCAs with the CFR-system activated, 2037 (63%) patients had an AED connected before emergency medical services arrival, of which 426 by a CFR. Exact AED-locations were known in 387 OHCA (study population). Overall, the AEDs connected by a CFR where located within 949 m straight-line distance of the OHCA. AEDs connected within 6, 8, or 10 min of the emergency-call, were located within 506 m, 796 m and 838 m straight-line distance, respectively. In 44% of these cases, the CFR connected an AED to which he/she was not referred to, but taken from another address, which significantly impacted the maximal distance covered: 773 m for CFR-system referred AEDs versus 1126 m for not CFR-system referred (p = 0.001). CONCLUSION:To facilitate early AED-connection (≤6 min), any address should have a CFR-system AED located within approx. 500 m.

BACKGROUND:Throughout Europe there are important differences in the structure and characteristics of Emergency Medical Services (EMS) and their response to out-of-hospital cardiac arrest (OHCA). The primary aim of EuReCa-THREE was to examine the epidemiology of cardiac arrest in Europe and explore the association between EMS response time and survival. METHODS:EuReCa-THREE was an international, prospective, registry-based, cohort study, for which data were collected from 1 September to 30 November 2022 from 28 countries. Primary research questions were focused on assessing time intervals and their impact on outcomes. RESULTS:Of the 45,251 confirmed OHCA cases, 32,033 were treated by the EMS i.e. resuscitation started or continued. The mean response time was 12.2 min (range 6.4-22.8), with 25% of patients were reached within 7 min. For all cases where resuscitation was started or continued by EMS, the rate of any ROSC was 31.2% (range 17.0-42.7), ROSC sustained until arrival at the emergency department and transfer of care (survived event) was 22.5%(range 12.3-25.5) and overall survival was 7.5% (range 3.1-35.0), (incidence 4.0 per 100,000 inhabitants, range 1.7-24.6). CONCLUSION:The results of EuReCa-THREE highlight continuing variation in the incidence, management and outcomes from OHCA across Europe. For patients who were EMS-treated, results indicate clear associations between response times and the likelihood of survival.

Volunteer responder systems (VRS) alert and guide nearby lay rescuers towards the location of an emergency. An application of such a system is to out-of-hospital cardiac arrests, where early cardiopulmonary resuscitation (CPR) and defibrillation with an automated external defibrillator (AED) are crucial for improving survival rates. However, many AEDs remain underutilized due to poor location choices, while other areas lack adequate AED coverage. In this paper, we present a comprehensive data-driven algorithmic approach to optimize deployment of (additional) public-access AEDs to be used in a VRS. Alongside a binary integer programming (BIP) formulation, we consider two heuristic methods, namely Greedy and Greedy Randomized Adaptive Search Procedure (GRASP), to solve the gradual Maximal Covering Location (MCLP) problem with partial coverage for AED deployment. We develop realistic gradually decreasing coverage functions for volunteers going on foot, by bike, or by car. A spatial probability distribution of cardiac arrest is estimated using kernel density estimation to be used as input for the models and to evaluate the solutions. We apply our approach to 29 real-world instances (municipalities) in the Netherlands. We show that GRASP can obtain near-optimal solutions for large problem instances in significantly less time than the exact method. The results indicate that relocating existing AEDs improves the weighted average coverage from 36% to 49% across all municipalities, with relative improvements ranging from 1% to 175%. For most municipalities, strategically placing 5 to 10 additional AEDs can already provide substantial improvements.

Introduction: Public housing areas have a high incidence of out-of-hospital cardiac arrest (OHCA) and are potential targets to improve OHCA survival. A fast emergency medical services (EMS) response is crucial to achieve OHCA survival. However, EMS response times in public housing areas remain unexplored. Research Question: Are EMS response times longer in public housing areas than in other residential areas? Aim: The primary objective was to investigate EMS response times for OHCA in public housing compared to other residential areas; differences in initial shockable rhythm and 30-day survival were secondary objectives. Method: Non-EMS witnessed OHCAs within residential areas from Amsterdam (2016-2021), Copenhagen (2016-2021), and Vienna (2018-2021) were included from the Amsterdam Resuscitation Studies and the Danish and Viennese Cardiac Arrest registries, excluding missing data on age, sex, and EMS response times. OHCAs were divided into public housing and other residential areas. Early dispatch was defined as <90 seconds from incoming call until dispatch of EMS vehicle; early arrival as < 6 minutes from dispatch of EMS vehicle until arrival on scene. We compared early dispatch, early arrival, initial shockable rhythm, and 30-day survival in public housing vs. other residential areas using a generalized estimation equation model adjusted for age, sex, and city and presented as adjusted odds ratios (aOR). Results: We included 8,659 patients, of which 2,883 (33,3%) occurred in public housing areas. OHCA patients in public housing areas were younger, more often female, less likely bystander witnessed, and less often received bystander interventions compared to other residential areas (Table 1). Comparing OHCAs in public housing vs. other residential areas (reference), early dispatch was 38.0% vs. 39.3%, aOR 0.83 [95% CI 0.73-0.93]; early arrival, 41.6% vs. 45.7%, aOR 0.84 [95% CI 0.76-0.92]; initial shockable rhythm, 17.0% vs. 22.8%, aOR 0.70 [95% CI 0.62-0.78]; and 30-day survival, 8.7% vs. 14.1%, aOR 0.57 [95% CI 0.48-0.66] (Figure 1). Conclusion: Dispatch and arrival of EMS vehicles took longer for OHCA patients in public housing compared to other residential areas, followed by a lower probability of initial shockable rhythm and 30-day survival. These findings suggest the EMS system as a relevant target for improving OHCA survival in public housing areas.

Objectives : Volunteer responder systems (VRSs) aim to decrease time to defibrillation by dispatching trained volunteers to automated external defibrillators (AEDs) and out-of-hospital cardiac arrest (OHCA) victims. AEDs are often underutilized due to poor placement. This study provides a cost-effectiveness analysis of adding AEDs at strategic locations to maximize quality-adjusted life years (QALYs). Methods : We simulated combined volunteer, police, firefighter, and emergency medical service response scenarios to OHCAs, and applied our methods to a case study of Amsterdam, the Netherlands. We compared the competing strategies of placing additional AEDs, using steps of 40 extra AEDs (0, 40, ..., 1480), in addition to the existing 369 AEDs. Incremental cost-effectiveness ratios (ICERs) were calculated for each increase in additional AEDs, from a societal perspective. The effect of AED connection and time to connection on survival to hospital admission and neurological outcome at discharge was estimated using logistic regression, using OHCA data from Amsterdam from 2006 to 2018. Other model inputs were obtained from literature. Results : Purchasing up to 1120 additional AEDs (ICER 75,669/QALY) was cost-effective at a willingness-to-pay threshold of 80,000/QALY, when positioned strategically. Compared to current practice, adding 1120 AEDs resulted in a gain of 0.111 QALYs (95% CI 0.110-0.112) at an increased cost of 3792 per OHCA (95% CI 3778-3807). Health benefits per AED diminished as more AEDs were added. Conclusions : Our study identified cost-effective strategies to position AEDs at strategic locations in a VRS. The case study findings advocate for a substantial increase in the number of AEDs in Amsterdam.

BACKGROUND: Strategies to reach out-of-hospital cardiac arrests (called cardiac arrest) in residential areas and reduce disparities in care and outcomes are warranted. This study investigated incidences of cardiac arrests in public housing areas. METHODS: This register-based cohort study included cardiac arrest patients from Amsterdam (the Netherlands) from 2016 to 2021, Copenhagen (Denmark) from 2016 to 2021, and Vienna (Austria) from 2018 to 2021. Using Poisson regression adjusted for spatial correlation and city, we compared cardiac arrest incidence rates (number per square kilometer per year and number per 100 000 inhabitants per year) in public housing and other residential areas and examined the proportion of cardiac arrests within public housing and adjacent areas (100-m radius). RESULTS: Overall, 9152 patients were included of which 3038 (33.2%) cardiac arrests occurred in public housing areas and 2685 (29.3%) in adjacent areas. In Amsterdam, 635/1801 (35.3%) cardiac arrests occurred in public housing areas; in Copenhagen, 1036/3077 (33.7%); and in Vienna, 1367/4274 (32.0%). Public housing areas covered 42.4 (12.6%) of 336.7 km 2 and 1 024 470 (24.6%) of 4 164 700 inhabitants. Across the capitals, we observed a lower probability of 30-day survival in public housing versus other residential areas (244/2803 [8.7%] versus 783/5532 [14.2%]). The incidence rates and rate ratio of cardiac arrest in public housing versus other residential areas were incidence rate, 16.5 versus 4.1 n/km 2 per year; rate ratio, 3.46 (95% CI, 3.31–3.62) and incidence rate, 56.1 versus 36.8 n/100 000 inhabitants per year; rate ratio, 1.48 (95% CI, 1.42–1.55). The incidence rates and rate ratios in public housing versus other residential areas were consistent across the 3 capitals. CONCLUSIONS: Across 3 European capitals, one-third of cardiac arrests occurred in public housing areas, with an additional third in adjacent areas. Public housing areas exhibited consistently higher cardiac arrest incidences per square kilometer and 100 000 inhabitants and lower survival than other residential areas. Public housing areas could be a key target to improve cardiac arrest survival in countries with a public housing sector.

AIMS:Out-of-hospital cardiac arrest (OHCA) is a leading cause of death worldwide, with cardiovascular disease (CVD) being a key risk factor. This study aims to investigate disparities in patient/OHCA characteristics and survival after OHCA among patients with vs. without depression. METHODS AND RESULTS:This is a retrospective cohort study using data from the AmsteRdam REsuscitation Studies (ARREST) registry from 2008 to 2018. History of comorbidities, including depression, was obtained from the patient's general practitioner. Out-of-hospital cardiac arrest survival was defined as survival at 30 days post-OHCA or hospital discharge. Logistic regression models were used to obtain crude and adjusted odds ratios (ORs) for the association between depression and OHCA survival and possible effect modification by age, sex, and comorbidities. The potential mediating effects of initial heart rhythm and provision of bystander cardiopulmonary resuscitation were explored. Among 5594 OHCA cases, 582 individuals had pre-existing depression. Patients with depression had less favourable patient and OHCA characteristics and lower odds of survival after adjustment for age, sex, and comorbidities [OR 0.65, 95% confidence interval (CI) 0.51-0.82], with similar findings by sex and age groups. The association remained significant among the Utstein comparator group (OR 0.63, 95% CI 0.45-0.89) and patients with return of spontaneous circulation (OR 0.60, 95% CI 0.42-0.85). Initial rhythm and bystander cardiopulmonary resuscitation partially mediated the observed association (by 27 and 7%, respectively). CONCLUSION:Out-of-hospital cardiac arrest patients with depression presented more frequently with unfavourable patient and OHCA characteristics and had reduced chances of survival. Further investigation into potential pathways is warranted.