Is Distance to the Nearest Registered Public Automated Defibrillator Associated with the Probability of Bystander Shock for Victims of Out-of-Hospital Cardiac Arrest?

Automatic external defibrillator (AED) location - seconds that save lifes

INTRODUCTION AND OBJECTIVE

Sudden cardiac arrest (SCA) is a significant cause of adult mortality, categorized into in-hospital (IHCA) and out-of-hospital (OHCA). Survival in OHCA depends on early diagnosis, alerting Emergency Medical Service (EMS), high-quality bystander resuscitation, and prompt Automatic External Defibrillator (AED) use. Accelerating technological progress supports faster AED retrieval and use, but there are barriers in real-life OHCA situations. The study assesses 6th-year medical students' ability to locate AEDs using smartphones, revealing challenges and proposing solutions.

MATERIAL & METHODS

The study was conducted in 2022-2023 at the Medical University of Lodz, Poland. Respondents completed a survey on AED knowledge and characteristics, followed by a task to find the nearest AED using their own smartphones. As common sources did not list the University AEDs, respondents were instructed to locate the nearest AED outside the research site.

RESULTS

A total of 300 6th-year medical students took part in the study. Only 3.3% had an AED locating app. Only 32% of students claimed to know where the AED nearest to their home is. All 300 had received AED training, and almost half had been witness to a resuscitation. Out of the 291 medical students who completed the AED location task, the median time to locate the nearest AED was 58 s. Most participants (86.6%) found the AED within 100 s, and over half (53%) did so in under 1 min.

CONCLUSIONS

National registration of AEDs should be mandatory. A unified source of all AEDs mapped should be created or added to existing ones. With a median of under one minute, searching for AED by a bystander should be considered as a point in the chain of survival.

Strategic placement of automated external defibrillators (AEDs) for cardiac arrests in public locations and private residences

Aim

The aim of our study was to determine whether businesses can be identified that rank highly for their potential to improve coverage of out-of-hospital cardiac arrests (OHCAs) by automated external defibrillators (AEDs), both in public locations and private residences.

Methods

The cohort comprised 10,422 non-traumatic OHCAs from 2014 to 2020 in Perth, Western Australia. We ranked 115 business brands (across 5,006 facilities) for their potential to supplement coverage by the 3,068 registered public-access AEDs in Perth, while accounting for AED access hours.

Results

Registered public-access AEDs provided 100 m coverage of 23% of public-location arrests, and 4% of arrests in private residences. Of the 10 business brands ranked highest for increasing the coverage of public OHCAs, six brands were ranked in the top 10 for increased coverage of OHCAs in private residences. A public phone brand stood out clearly as the highest-ranked of all brands, with more than double the coverage-increase of the second-ranked brand. If all 115 business brands hosted AEDs with 24-7 access, 57% of OHCAs would remain without 100 m coverage for public arrests, and 92% without 100 m coverage for arrests in private residences.

Conclusion

Many businesses that ranked highly for increased coverage of arrests in public locations also rank well for increasing coverage of arrests in private residences. However, even if the business landscape was highly saturated with AEDs, large gaps in coverage of OHCAs would remain, highlighting the importance of considering other modes of AED delivery in metropolitan landscapes.

International Initiation and Termination of Resuscitation Practices

BACKGROUND

Substantial variation in survival following out-of-hospital cardiac arrest is described both internationally and nationally. The Utstein factors account for half of the variation, but the remaining is not fully understood. Local regulations or guidelines concerning the withholding and termination of resuscitation may influence the reporting of cardiac arrests when comparing outcomes between different EMS systems.

METHOD

We have developed an online cross-sectional mixed-methods explanatory design survey aimed at describing the international and national variations in the initiation, the termination of resuscitation, and the refraining from resuscitation of adult patients (>18 years of age) suffering from non-traumatic OHCA. The respondents will be national experts and the questionnaire will be distributed among members of EUPHOREA, the International Liaison Committee of Resuscitation (ILCOR), the European Resuscitation Council, and the Resuscitation Academy. Each invited country will have to identify at least two national experts with special expertise in prehospital resuscitation practices. We exclude countries with less than two respondents.

RESULTS

The survey will provide both quantitative and qualitative data. Quantitative data will be presented as frequencies and proportions. Qualitative data will be analyzed using content analysis.

CONCLUSION

This survey could be of importance in understanding the multiple factors leading to the substantial variation in survival found following OHCA. Furthermore, the interpretation of future studies on OHCA from different settings may be improved to further increase survival following OHCA.

Out-of-Hospital Cardiac Arrest Bystander Defibrillator Search Time and Experience With and Without Directional Assistance: A Randomized Simulation Trial in a Community Setting

INTRODUCTION

Probability of survival after out-of-hospital cardiac arrest (OHCA) doubles when a bystander initiates cardiopulmonary resuscitation and uses an automated external defibrillator (AED) rapidly. National, state, and community efforts have increased placement of AEDs in public spaces; however, bystander AED use remains less than 2% in the United States. Little is known about the effect of giving bystanders directional assistance to the closest public access AED.

METHODS

We conducted 35 OHCA simulations using a life-sized manikin with participants aged 18 through 65 years who searched for public access AEDs in 5 zones on a university campus. Zones varied by challenges to pedestrian AED acquisition and number of fixed AEDs. Participants completed 2 searches-first unassisted and then with verbal direction to the closest AED-and we compared AED delivery times. We conducted pretest and posttest surveys.

RESULTS

In all 5 zones, the median time from simulated OHCA onset to AED delivery was lower when the bystander received directional assistance. Time savings (minutes:seconds) varied by zone, ranging from a median of 0:53 (P = 0.14) to 3:42 (P = 0.02). Only 3 participants immediately located the closest AED without directional assistance; more than half reported difficulty locating an AED.

CONCLUSIONS

These findings may inform strategies to ensure that AEDs are consistently marked and placed in visible, accessible locations. Continued emphasis on developing strategies to improve lay bystanders' ability to locate and use AEDs may improve AED retrieval times and OHCA outcomes.

How to improve automated external defibrillator placement for out-of-hospital cardiac arrests: A case study

Introduction

In out-of-hospital cardiac arrests (OHCAs), the use of an automatic external defibrillator (AED) by a bystander remains low, as AEDs may be misplaced with respect to the locations of OHCAs. As the distribution of historical OHCAs is potentially predictive of future OHCA locations, the purpose of this study is to assess AED positioning with regard to past locations of OHCAs, in order to improve the efficiency of public access defibrillation programs.

Methods

This is a retrospective observational study from 2014 to 2018. The locations of historical OHCAs and AEDs were loaded into a geodata processing tool. Median distances between AEDs were collected, as well as the number and rates of OHCAs covered (distance of <100 meters from the nearest AED). Areas with high densities of uncovered OHCAs (hotspots) were identified in order to propose the placement of additional AEDs. Areas over-covered by AEDs (overlays) were also identified in order to propose the relocation of overlapping AEDs.

Results

There were 2,971 OHCA, 79.3% of which occurred at home, and 633 AEDs included in the study. The global coverage rate was 7.5%. OHCAs occurring at home had a coverage rate of 4.5%. Forty hotspots were identified, requiring the same number of additional AEDs. The addition of these would increase the coverage from 7.5% to 17.6%. Regarding AED overlays, 17 AEDs were found to be relocatable without reducing the AED coverage of historical OHCAs.

Discussion

This study confirms that geodata tools can assess AED locations and increase the efficiency of their placement. Historical hotspots and AED overlays should be considered, with the aim of efficiently relocating or adding AEDs. At-home OHCAs should become a priority target for future public access defibrillation programs as they represent the majority of OHCAs but have the lowest AED coverage rates.

Assessment of Canadian Public Automated External Defibrillator Registries

BACKGROUND

Public automated external defibrillator (AED) registries aim to increase layperson defibrillation for victims of out-of-hospital cardiac arrest. This study aims to characterize Canadian AED registries and the process by which these databases are updated and used.

METHODS

A survey was administered to representatives from each eligible AED registry. Collected data included information on registry management, AED validation process, linkage to emergency medical dispatch (EMD), and number of AEDs per registry. Three unregistered AEDs in each region were then located and registered into their respective registry. The primary endpoint was the proportion of AEDs that became visible in the registry within 1 month.

RESULTS

Of the 9 Canadian provinces that have registries, 7 are provincial, whereas 2 contain smaller independent registries. The survey was completed by 90% of contacted registries. The number of AEDs per registry ranged from 21 to 443 per 100,000 persons. Six registries are managed by a provincial government, 6 use a standardized validation process, and 8 are linked to EMD. Of the 21 AEDs registered by our study personnel in 7/10 registries, 9 (43%) were made available to the public within 1 month of registration. Only 1 registry employed an AED validation process that included direct contact with AED managers.

CONCLUSIONS

Canadian public AED registries demonstrate significant differences in their governance and administrative processes. A majority of registries are integrated with EMD for out-of-hospital cardiac arrest, but not all registries use a standardized validation process to ensure accuracy of AED information submitted by the public.

Description of Emergency Medical Services, treatment of cardiac arrest patients and cardiac arrest registries in Europe

Background

Variation in the incidence, survival rate and factors associated with survival after cardiac arrest in Europe is reported. Some studies have tried to fill the knowledge gap regarding the epidemiology of out-of-hospital cardiac arrest in Europe but were unable to identify reasons for the reported differences. Therefore, the purpose of this study was to describe European Emergency Medical Systems, particularly from the perspective of country and ambulance service characteristics, cardiac arrest identification, dispatch, treatment, and monitoring.

Methods

An online questionnaire with 51 questions about ambulance and dispatch characteristics, on-scene management of cardiac arrest and the availability and dataset in cardiac arrest registries, was sent to all national coordinators who participated in the European Registry of Cardiac Arrest studies. In addition, individual invitations were sent to the remaining European countries.

Results

Participants from 28 European countries responded to the questionnaire. Results were combined with official information on population density. Overall, the number of Emergency Medical Service missions, level of training of personnel, availability of Helicopter Emergency Medical Services and the involvement of first responders varied across and within countries. There were similarities in team training, availability of key resuscitation equipment and permission for ongoing performance of cardiopulmonary resuscitation during transported. The quality of reporting to cardiac arrest registries varied, as well as the data availability in the registries.

Conclusions

Throughout Europe there are important differences in Emergency Medical Service systems and the response to out-of-hospital cardiac arrest. Explaining these differences is complicated due to significant variation in how variables are reported to and used in registries.

Optimal in-hospital defibrillator placement

AIMS

To determine if mathematical optimization of in-hospital defibrillator placements can reduce in-hospital cardiac arrest-to-defibrillator distance compared to existing defibrillators in a single hospital.

METHODS

We identified treated IHCAs and defibrillator placements in St. Michael's Hospital in Toronto, Canada from Jan. 2013 to Jun. 2017 and mapped them to a 3-D computer model of the hospital. An optimization model identified an equal number of optimal defibrillator locations that minimized the average distance between IHCAs and the closest defibrillator using a 10-fold cross-validation approach. The optimized and existing defibrillator locations were compared in terms of average distance to the out-of-sample IHCAs. We repeated the analysis excluding intensive care units (ICUs), operating theatres (OTs), and the emergency department (ED). We also re-solved the model using fewer defibrillators to determine when the average distance matched the performance of existing defibrillators.

RESULTS

We identified 433 treated IHCAs and 53 defibrillators. Of these, 167 IHCAs and 31 defibrillators were outside of ICUs, OTs, and the ED. Optimal defibrillator placements reduced the average IHCA-to-defibrillator distance from 16.1 m to 2.7 m (relative decrease of 83.0%; P = 0.002) compared to existing defibrillator placements. For non-ICU/OT/ED IHCAs, the average distance was reduced from 24.4 m to 11.9 m (relative decrease of 51.3%; P = 0.002. 8-9 optimized defibrillator locations were sufficient to match the average IHCA-to-defibrillator distance of existing defibrillator placements.

CONCLUSIONS

Optimization-guided placement of in-hospital defibrillators can reduce the distance from an IHCA to the closest defibrillator. Equivalently, optimization can match existing defibrillator performance using far fewer defibrillators.

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.

Automated External Defibrillator Geolocalization with a Mobile Application, Verbal Assistance or No Assistance: A Pilot Randomized Simulation (AED G-MAP)

OBJECTIVE

Shockable rythms are common among victims of witnessed public out-of-hospital cardiac arrest (OHCA), but bystander defibrillation with a public automated external defibrillator (PAED) is rare. Instructions from the emergency medical dispatcher and mobile applications were developed to expedite the localization of PAEDs, but their effectiveness has not been compared.

METHODS

Participants were enrolled in a three-armed randomized simulation where they witnessed a simulated OHCA on a university campus, were instructed to locate a PAED and provide defibrillation. Participants were stratified and randomized to: (1) no assistance in finding the PAED, (2) assistance from a geolocalization mobile application (AED-Quebec), or (3) verbal assistance. Data collectors tracked each participant's time elapsed and distance traveled to shock.

RESULTS

Of the 52 volunteers participating in the study (46% male, mean age 37), 17 were randomized to the no assistance group, 18 to the mobile application group and 17 to the verbal group. Median (IQR) time to shock was, respectively, 10:00 min (7:49-10:00), 9:44 (6:30-10:00), and 5:23 (4:11-9:08), with statistically significant differences between the verbal group and the other groups (p ≤ 0.01). The success rate for defibrillation in <10 minutes was 35%, 56% and 76%. Multivariate regression of all participants pooled showed that knowledge of campus geography was the strongest predictor of shock in <10 minutes (aOR =14.3, 95% CI 1.85-99.9). Among participants without prior geographical knowledge, verbal assistance provided a trend towards decreased time to shock, but the differences over no assistance (7:28 vs. 10:00, p = 0.10) and over the mobile app (7:28 vs. 10:00, p = 0.11) were not statistically significant.

CONCLUSION

In a simulated environment, verbally providing OHCA bystanders with the nearest PAED's location appeared to be effective in reducing the time to defibrillation in comparison to no assistance and to an AED geolocalizing mobile app, but further research is required to confirm this hypothesis, ascertain the external validity of these results, and evaluate the real-life implications of these strategies.