Drone delivery of automated external defibrillators compared with ambulance arrival in real-life suspected out-of-hospital cardiac arrests: a prospective observational study in Sweden

Out-of-hospital cardiac arrest: A 10-year analysis of survival and neurological outcomes

Background Out-of-hospital cardiac arrest (OHCA) is a major public health issue with low survival rates. Objective Identification of predictors for survival and good neurological outcomes following OHCA. Methods This retrospective study included all OHCA patients between January 2014 and December 2023. Data was collected from the local resuscitation registry and hospital electronic medical records. Neurological outcomes were measured using the Cerebral Performance Category (CPC) scale. Results At hospital admission return of spontaneous circulation (ROSC) was achieved in 36 % of cases (411/1128), with overall survival rates of 29 % (328/1128) at 24 h and 16 % (178/1128) at 30 days, respectively. Good neurological outcomes (CPC 1 and 2) were observed in 13 % (144/1128) of patients. The main suspected cause of cardiac arrest was cardiac origin (54 %, 608/1128), followed by hypoxia (11 %, 127/1128). Survivors were significantly younger (60 vs 71 years, p < 0.001), were less disabled (p < 0.001), had a higher incidence of witnessed cardiac arrest (80 % vs 69 %, p = 0.018), received more often bystander cardiopulmonary resuscitation (CPR, 62 % vs 47 %, p = 0.003) or Dispatcher Assisted-CPR (44 % vs 32 %, p = 0.004). Moreover, patients who survived at least 30 days had a higher incidence of shockable initial rhythm (57 % vs 24 %, p < 0.001). Conclusions Patients who survived at least 30 days were younger and male, had less disability, a shockable initial rhythm, and a cardiac arrest in public.

American Heart Association Automated External Defibrillator Symposium: Summary and Recommendations

The American Heart Association (AHA) introduced public access defibrillation more than 30 years ago. Since then, we have seen the growth of public access defibrillation programs across many settings within communities. However, despite high expectations that the availability of automated external defibrillators (AEDs) and more integrated public access defibrillation programs would dramatically increase cardiac arrest survival, AEDs are used in the United States in only 4% of out-of-hospital cardiac arrests and survival rates have remained disappointingly low. In follow-up to a recent International Liaison Committee on Resuscitation report, an AED Symposium was organized by members of the AHA Emergency Cardiovascular Care Committee to establish a strategic roadmap for AED technology, education and training, and real-world use of these devices, including integration with public access defibrillation programs to meet the AHA's goal of doubling out-of-hospital cardiac arrests survival by 2030. The meeting brought together a diverse group of subject matter experts including representatives from the US Food and Drug Administration, the defibrillator industry, clinicians, and scientists. This paper summarizes the proceedings of the AED symposium and suggests a set of strategic recommendations to ultimately improve survival from cardiac arrest.

Cost-effectiveness of drone-delivered automated external defibrillators for cardiac arrest

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) is a significant cause of mortality and morbidity in North America, for which timely defibrillation of shockable rhythms is essential. Drones have been proposed as an intervention to improve response time and are being implemented in practice.

AIM

To determine the cost-effectiveness of drone-delivered automated external defibrillators (AEDs) for OHCAs.

METHODS

Using data from 22,017 OHCAs in Ontario, Canada over 10 years, we developed a comprehensive computational framework combining machine learning, optimization and a Markov microsimulation model to provide an economic evaluation of 964 different drone networks across a wide range of sizes and configurations. We simulated response times, survival outcomes, lifetime quality-adjusted life-years (QALYs), lifetime healthcare costs, and 10-year operational costs for each network.

RESULTS

All 964 drone networks were cost-effective. We identified 20 networks on the cost-QALY efficient frontier, each with shorter response times, more survivors across all categories, and higher costs per survivor. Historical ambulance response (i.e., standard care) had mean response time of 6 min 21 s. On the efficient frontier, average drone response times were 32% to 71% shorter than standard care. There were 1,855 (8.4%) survivors to hospital discharge in standard care, which increased by 21% to 46% across the 20 drone networks. The smallest non-dominated drone network, with 20 drones, cost $20,912 per QALY gained. All drone networks had higher net monetary benefit than standard care. Cost-effectiveness was even greater for shockable and witnessed populations. Extensive sensitivity analyses showed that our results were robust to changes in modelling assumptions.

CONCLUSIONS

Drone-delivered AEDs were associated with reductions in response time, mortality and morbidity, and were found to be highly cost-effective relative to standard ambulance response with no drones.

Semi-autonomous drone delivering automated external defibrillators for real out-of-hospital cardiac arrest: A Danish feasibility study

AIM

To assess the feasibility and safety of drone-delivered automated external defibrillators (AEDs) in real out-of-hospital cardiac arrests (OHCAs) in Denmark, addressing the critical need for timely defibrillation in OHCAs.

METHODS

In this prospective clinical study in Aalborg, Denmark, an AED-carrying drone was dispatched for suspected OHCAs, from June 2022 to April 2023. The drone was stationed in an urban area (maximum flight-radius 6 km, covering 110,000 inhabitants) within designated airspace not requiring preflight approval from air-traffic control. Upon OHCA-suspicion, the emergency medical dispatcher activated the drone, which autonomously took off and flew beyond-visual-line-of-sight to the OHCA-location. On-site, a remote drone pilot (stationed cross-border) winched down the AED near the patient's location. Flights were restricted to dry weather, mean windspeeds < 8 m/s, and 8 am to 10 pm.

RESULTS

Of 76 suspected OHCAs, 27 occurred during non-operating hours (nighttime). Of the remaining 49 OHCAs, 16 (33%) were eligible for drone take-off, all of which resulted in successful AED-delivery, without any adverse events. Weather caused 14 cancellations (29%), technical issues (dispatch centre, drone, or hangar problems) 13 (27%), and closed airspace 6 (12%). The median drone response time from activation to AED-delivery was 04:47 min (IQR 03:45-05:27), and the corresponding ambulance response time was 03:25 min (IQR 02:43-04:14). No drone-delivered AEDs were attached.

CONCLUSION

This study demonstrates the safety and feasibility of drone-delivered AEDs to real OHCAs. Improved time to AED delivery was limited due to swift ambulance service, highlighting the importance of strategic AED drone placement.

Flight testing of drone-delivered automated external defibrillators for simulated out-of-hospital cardiac arrest in suburban Thailand

The use of automated external defibrillators (AEDs) in a timely manner is critical for improving survival rates in out-of-hospital cardiac arrest (OHCA) cases. However, in developing countries, logistical and infrastructural challenges often result in delays, particularly in suburban areas. This study evaluates the feasibility and safety of using drones to deliver AEDs in suburban OHCA scenarios. A series of ninety test flights were conducted using a DJI Matrice 600 drone (DJI, China) to deliver a Philips HeartStart AED (Philips, Netherlands) across varying payloads. Bystanders in simulated OHCA situations identified their location via mobile applications, enabling the drone operator to dispatch the drone beyond the pilot's line of sight. The results showed a 97.7% success rate in AED delivery, with a median flight distance of 4042 m and a median response time of 7 min and 39 s. Despite payload variations, the drone maintained adequate speed and landing accuracy, with a mean speed of 9.17 m per second and a median landing error of 122 centimeters. The findings suggest that drones have significant potential for improving emergency medical responses in suburban areas of developing countries. Integration into emergency services could address current delays, though further research is necessary to optimize performance under varying conditions.

Gaps in Public Access Defibrillation: Analysis of International Legislation

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) is a global health issue, for which rapid public access defibrillation (PAD) increases survival.

OBJECTIVES

The purpose of this study was to evaluate international legislation relating to PAD and develop legal recommendations to improve PAD in OHCA.

METHODS

Searches covering 5 domains (automated external defibrillator [AED] provision, funding, identification, maintenance, lay responder training) were conducted in 99 jurisdictions worldwide: United States (50) and Canada (13) analyzed at state/province level; 36 other countries analyzed at national level. Forty-nine legislation sources were searched from September 27, 2021, to May 5, 2022. Legislative data were classified: Enabling Legislation (facilitating PAD) or Disabling Legislation (hindering PAD). Based on retrieved data, recommendations for international AED laws were developed.

RESULTS

Searches identified 419,248 legal records. Enabling Legislation regarding AED provision in public areas was present in 60% U.S. states, 8% Canadian provinces, and 22% of nations studied from the rest of world. Disabling Legislation regarding registration of AEDs, that could potentially discourage AED ownership, was found in 37 North American jurisdictions. Enabling Legislation regarding AED signage was found in 66% U.S. states and 39% of all jurisdictions worldwide. Overall, 48% of worldwide jurisdictions studied had legislative requirements for AED maintenance, including 80% of all U.S. states. Internationally, 49.5% of jurisdictions studied had Enabling Legislation mandating AED training, and 66% United States had this for schools. Only 4 jurisdictions worldwide gave implicit authorization to laypersons for AED use in emergencies.

CONCLUSIONS

There is significant variability in international legislation relating to PAD. All countries should consider Enabling Legislation that could decrease delays to PAD. Similarly, Disabling Legislation potentially hindering prompt PAD during OHCA should be withdrawn.

Out-of-Hospital Cardiac Arrest Ambulance Delay Zones and AED Placement in a Southern Brazilian City

Out-of-hospital cardiac arrests (OHCAs) have high mortality rates, worsened by limited access to automated external defibrillators (AEDs). This study analyzed OHCA response times, identified areas with prolonged ambulance travel times, and proposed optimal AED locations in a medium-sized city in southern Brazil. Data from 278 non-traumatic OHCA cases (2019-2022) in patients over 18 years old, with ambulance response times under 20 min, were included. Spatial survival analysis assessed the probability of exceeding the recommended 5-min (300 s) ambulance response time. The maximal covering location problem identified 100 strategic AED sites within a 150-s reach for bystanders. AED and ambulance travel times were compared using the Wilcoxon test (p < 0.01). Defibrillation occurred in 89 cases (31.01%), and bystander CPR was performed in 149 cases (51.92%). Despite these efforts, 77% of patients died. The median ambulance response time was 11.63 min, exceeding 5 min in most cases, particularly at peak times like 11 a.m. AED placement in selected locations could cover 76% of OHCA occurrences, with a mean AED travel time of 320 s compared to 709 s for ambulances. Strategic AED placement could enhance early defibrillation and improve survival outcomes.

Advancements in automated external and wearable cardiac defibrillators

PURPOSE OF REVIEW

Survival statistics for out-of-hospital cardiac arrests remain unsatisfactory. Prompt defibrillation of shockable rhythms, such as ventricular fibrillation and pulseless ventricular tachycardia, is crucial for improving survival. Automated external defibrillators (AEDs) and wearable cardiac defibrillators (WCDs) seek to improve the survival rates following out-of-hospital cardiac arrests. We aim to review the indications, utility, advancements, and limitations of AEDs and WCDs, as well as their role in contemporary and future clinical practice.

RECENT FINDINGS

Recent advancements in these technologies, such as smartphone applications and drone delivery of AEDs and less inappropriate shocks and decreased size of WCDs, have increased their ubiquity and efficacy. However, implementation of this technology remains limited due to lack of resources and suboptimal patient adherence.

SUMMARY

Out of hospital cardiac arrests continue to pose a significant public health challenge. Advancements in AEDs and WCDs aim to facilitate prompt defibrillation of shockable rhythms with the goal of improving survival rates. However, they remain underutilized due to limited resources and suboptimal patient adherence. As these technologies continue to evolve to become smaller, lighter and more affordable, their utilization and accessibility are expected to improve.

Drones delivering automated external defibrillators for out-of-hospital cardiac arrest: A scoping review

Out-of-hospital cardiac arrest (OHCA) remains a critical health concern, where prompt access to automated external defibrillators (AEDs) significantly improves survival. This scoping review broadly investigates the feasibility and impact of dronedelivered AEDs for OHCA response.

METHODS

PubMed, Cochrane, and Web of Science were searched from inception to August 6, 2024, with eligibility broadly including empirical data. The charting process involved iterative data extraction for thematic analysis.

RESULTS

We identified 306 titles and, after duplicate removal, title/abstract screening, and full text review, included 39 studies. These were divided into three categories: 1) Real-world observational studies (n = 3), 2) Test flights/simulation studies and qualitative analyses (n = 15), and 3) Computer/prediction models (n = 21). Real-world studies demonstrated the feasibility of drone AED delivery, with a time advantage of 01:52 - 03:14 min over ambulances observed in 64-67 % of cases. Test flight/simulation and qualitative studies consistently reported feasibility and positive bystander experiences. Computer/prediction models exhibited considerable heterogeneity, yet all indicated significant time savings for AED delivery compared to traditional EMS methods. Moreover, seven studies estimated improved survival rates, with five assessing cost-effectiveness and favouring drone systems. Regional factors such as EMS response times, volunteer responder programmes, terrain, weather, and budget constraints influenced the system's effectiveness.

CONCLUSION

Across all categories, studies confirmed the feasibility of drone-delivered AED systems, with significant potential for reducing time to AED arrival compared to EMS arrival. Prediction models suggested enhanced survival alongside costeffectiveness. Further research, including more extensive real-world studies and regulatory advancements, is imperative to integrate drones effectively into OHCA response systems.

Survival in relation to number of defibrillation attempts in out-of-hospital cardiac arrest

INTRODUCTION/AIM

Out-of-hospital cardiac arrest (OHCA) with shockable pulseless ventricular tachycardia or fibrillation not responding to defibrillation is a medical challenge. Novel treatment strategies have emerged for so-called refractory ventricular fibrillation not responding to three or more defibrillations but the evidence for optimal timing for these strategies is sparse. The primary aim of this observational study was to assess survival in relation to total numbers of defibrillations in OHCA.

METHODS

This is a registry-based retrospective cohort study based on data reported by the emergency medical services to the Swedish Registry of Cardiopulmonary Resuscitation and the National Patient Registry. All OHCA patients aged 18 years or older with an initial shockable rhythm in Sweden from January 1, 2010 and December 31, 2020 were included. Exposure was total number of defibrillations, and primary outcome was survival to 30 days. Logistic regression was used to adjust for patient and resuscitation characteristics.

RESULTS

Over the study period a total of 10,549 patients were included. Among them, 3,006 (28.5%) received only one shock, 1,665 (15.8%) two shocks, 1,336 (12.9%) three shocks, 1,064 (10.1%) four shocks and 3,478 (33.0%) five or more shocks. In the adjusted analysis an exponential decrease in the 30-day survival was found for each additional defibrillation. For patients receiving one, two, three and four defibrillations, the adjusted probability of survival was 42%, 36%, 30% and 25% respectively.

CONCLUSIONS

In this registry-based retrospective cohort study, additional defibrillations were associated with a lower survival. This association persisted after adjustments for patient and resuscitation characteristics.

Drones can be used to provide dispatch centres with on-site photos before arrival of EMS in time critical incidents

BACKGROUND

Drones are able to deliver automated external defibrillators in cases of out-of-hospital cardiac arrest (OHCA) but can be deployed for other purposes. Our aim was to evaluate the feasibility of sending live photos to dispatch centres before arrival of other units during time-critical incidents.

METHODS

In this retrospective observational study, the regional dispatch centre implemented a new service using five existing AED-drone systems covering an estimated 200000 inhabitants in Sweden. Drones were deployed automatically over a 4-month study period (December 2022-April 2023) in emergency calls involving suspected OHCAs, traffic accidents and fires in buildings. Upon arrival at the scene, an overhead photo was taken and transmitted to the dispatch centre. Feasibility of providing photos in real time, and time delays intervals were examined.

RESULTS

Overall, drones were deployed in 59/440 (13%) of all emergency calls: 26/59 (44%) of suspected OHCAs, 20/59 (34%) of traffic accidents, and 13/59 (22%) of fires in buildings. The main reasons for non-deployment were closed airspace and unfavourable weather conditions (68%). Drones arrived safely at the exact location in 58/59 cases (98%). Their overall median response time was 3:49 min, (IQR 3:18-4:26) vs. emergency medical services (EMS), 05:51 (IQR: 04:29-08:04) p-value for time difference between drone and EMS = 0,05. Drones arrived first on scene in 47/52 cases (90%) and the largest median time difference was found in suspected OHCAs 4:10 min, (IQR: 02:57-05:28). The time difference in the 5/52 (10%) cases when EMS arrived first the time difference was 5:18 min (IQR 2:19-7:38), p = NA. Photos were transmitted correctly in all 59 alerts. No adverse events occurred.

CONCLUSION

In a newly implemented drone dispatch service, drones were dispatched to 13% of relevant EMS calls. When drones were dispatched, they arrived at scene earlier than EMS services in 90% of cases. Drones were able to relay photos to the dispatch centre in all cases. Although severely affected by closed airspace and weather conditions, this novel method may facilitate additional decision-making information during time-critical incidents.

Emerging Evidence in Out-of-Hospital Cardiac Arrest-A Critical Appraisal of the Cardiac Arrest Center

The morbidity and mortality of out-of-hospital cardiac arrest (OHCA) due to presumed cardiac causes have remained unwaveringly high over the last few decades. Less than 10% of patients survive until hospital discharge. Treatment of OHCA patients has traditionally relied on expert opinions. However, there is growing evidence on managing OHCA patients favorably during the prehospital phase, coronary and intensive care, and even beyond hospital discharge. To improve outcomes in OHCA, experts have proposed the establishment of cardiac arrest centers (CACs) as pivotal elements. CACs are expert facilities that pool resources and staff, provide infrastructure, treatment pathways, and networks to deliver comprehensive and guideline-recommended post-cardiac arrest care, as well as promote research. This review aims to address knowledge gaps in the 2020 consensus on CACs of major European medical associations, considering novel evidence on critical issues in both pre- and in-hospital OHCA management, such as the timing of coronary angiography and the use of extracorporeal cardiopulmonary resuscitation (eCPR). The goal is to harmonize new evidence with the concept of CACs.

Combinations of First Responder and Drone Delivery to Achieve 5-Minute AED Deployment in OHCA

Background

Defibrillation in the critical first minutes of out-of-hospital cardiac arrest (OHCA) can significantly improve survival. However, timely access to automated external defibrillators (AEDs) remains a barrier.

Objectives

The authors estimated the impact of a statewide program for drone-delivered AEDs in North Carolina integrated into emergency medical service and first responder (FR) response for OHCA.

Methods

Using Cardiac Arrest Registry to Enhance Survival registry data, we included 28,292 OHCA patients ≥18 years of age between 1 January 2013 and 31 December 2019 in 48 North Carolina counties. We estimated the improvement in response times (time from 9-1-1 call to AED arrival) achieved by 2 sequential interventions: 1) AEDs for all FRs; and 2) optimized placement of drones to maximize 5-minute AED arrival within each county. Interventions were evaluated with logistic regression models to estimate changes in initial shockable rhythm and survival.

Results

Historical county-level median response times were 8.0 minutes (IQR: 7.0-9.0 minutes) with 16.5% of OHCAs having AED arrival times of <5 minutes (IQR: 11.2%-24.3%). Providing all FRs with AEDs improved median response to 7.0 minutes (IQR: 6.2-7.8 minutes) and increased OHCAs with <5-minute AED arrival to 22.3% (IQR: 16.4%-30.9%). Further incorporating optimized drone networks (326 drones across all 48 counties) improved median response to 4.8 minutes (IQR: 4.3-5.2 minutes) and OHCAs with <5-minute AED arrival to 56.3% (IQR: 46.9%-64.2%). Survival rates were estimated to increase by 34% for witnessed OHCAs with estimated drone arrival <5 minutes and ahead of FR and emergency medical service.

Conclusions

Deployment of AEDs by FRs and optimized drone delivery can improve AED arrival times which may lead to improved clinical outcomes. Implementation studies are needed.

Challenges & barriers for real-time integration of drones in emergency cardiac care: Lessons from the United States, Sweden, & Canada

Importance

Out-of-hospital cardiac arrest (OHCA) is a leading cause of morbidity and mortality in the US and Europe (∼600,000 incident events annually) and around the world (∼3.8 million). With every minute that passes without cardiopulmonary resuscitation or defibrillation, the probability of survival decreases by 10%. Preliminary studies suggest that uncrewed aircraft systems, also known as drones, can deliver automated external defibrillators (AEDs) to OHCA victims faster than ground transport and potentially save lives.

Objective

To date, the United States (US), Sweden, and Canada have made significant contributions to the knowledge base regarding AED-equipped drones. The purpose of this Special Communication is to explore the challenges and facilitators impacting the progress of AED-equipped drone integration into emergency medicine research and applications in the US, Sweden, and Canada. We also explore opportunities to propel this innovative and important research forward.

Evidence review

In this narrative review, we summarize the AED-drone research to date from the US, Sweden, and Canada, including the first drone-assisted delivery of an AED to an OHCA. Further, we compare the research environment, emergency medical systems, and aviation regulatory environment in each country as they apply to OHCA, AEDs, and drones. Finally, we provide recommendations for advancing research and implementation of AED-drone technology into emergency care.

Findings

The rates that drone technologies have been integrated into both research and real-life emergency care in each country varies considerably. Based on current research, there is significant potential in incorporating AED-equipped drones into the chain of survival for OHCA emergency response. Comparing the different environments and systems in each country revealed ways that each can serve as a facilitator or barrier to future AED-drone research.

Conclusions and relevance

The US, Sweden, and Canada each offers different challenges and opportunities in this field of research. Together, the international community can learn from one another to optimize integration of AED-equipped drones into emergency systems of care.