Out-of-hospital Cardiac Arrest Care Research Articles

Effect of RapidShockTM Implementation on Perishock Pause in Out-of-Hospital Cardiac Arrest

Objectives Shorter pauses in cardiopulmonary resuscitation (CPR) are associated with better health outcomes after out-of-hospital cardiac arrest (OHCA). Our primary objective was to examine the effect of a RapidShockTM defibrillator software upgrade compared with standard defibrillator software on the length of perishock pause during care for OHCA among adults. Secondary objectives were to assess the effects of RapidShockTM on other CPR pauses. Methods We conducted a retrospective cohort study between September 1, 2015 and September 30, 2020. “Standard” cardiac defibrillator software in manual interpretation mode was used for CPR delivered on or before November 30, 2018, while “RapidShockTM” software (ZOLL® Medical Corporation) was used after this date. For each study group, we calculated the perishock, perianalysis, and total CPR pause; each CPR cycle was considered an independent event. We then calculated the median and interquartile range (IQR) for observed pauses with the “Standard” and “RapidShockTM” software. Percent change in median perishock pause (shockable rhythms), perianalysis pause (non-shockable rhythms), and total CPR pause were compared between CPR administered with each software using the Mann–Whitney test. Results There were 733 and 782 distinct CPR cycles administered using “Standard” and “RapidShockTM” software, respectively. A 31.8% reduction in median perishock pause was observed with “RapidShockTM” software compared with the “Standard” software (22.0 s (IQR 18.0 − 27.0 s) vs. 15.0 s (IQR 13.0 − 19.0 s); p < 0.01). The decrease in median perishock pause was driven by a reduction in the preshock phase (18 s vs. 10 s; 44.4% decrease in median pause; p < 0.01). No differences were observed in median perianalysis pause between the two groups. When combining shockable and non-shockable rhythms, we observed a reduction of 23.5% in median CPR pause (17.0 s (IQR 11.0 − 24.0 s) vs. 13s (IQR 10.0 − 17.0 s); p < 0.01). Conclusions Overall, we observed that the use of “RapidShockTM” defibrillator software was associated with shorter CPR pauses compared with the “Standard” software. Additional studies are required to examine whether further reductions in CPR pauses may be achieved and to investigate associations between shorter CPR pauses and health outcomes.

A Systematic Review of Cost-Effectiveness of Treating Out of Hospital Cardiac Arrest: Implications for Resource-limited Health Systems.

Out-of-hospital cardiac arrest (OHCA) is a prevalent condition with high mortality and poor outcomes even in settings where extensive emergency care resources are available. Interventions to address OHCA have had limited success, with survival rates below 10% in national samples of high-income countries. In resource-limited settings, where scarcity requires careful priority setting, more data is needed to determine the optimal allocation of resources. To establish the cost-effectiveness of OHCA care and assess the affordability of interventions across income settings. The authors conducted a systematic review of economic evaluations on interventions to address OHCA. Included studies were (1) economic evaluations (beyond a simple costing exercise); and (2) assessed an intervention in the chain of survival for OHCA. Article quality was assessed using the CHEERs checklist and data summarised. Findings were reported by major themes identified by the reviewers. Based upon the results of the cost-effectiveness analyses we then conduct an analysis for the progressive realization of the OHCA chain of survival from the perspective of decision-makers facing resource constraints. 468 unique articles were screened, and 46 articles were included for final data abstraction. Studies predominantly used a healthcare sector perspective, modeled for all patients experiencing non-traumatic cardiac OHCA, were based in the US, and presented results in US Dollars. No studies reported results or used model inputs from low-income settings. Progressive realization of the chain of survival could likely begin with investments in TOR protocols, professional prehospital defibrillator use, and CPR training followed by distribution of AEDs in high-density public locations. Finally, other interventions such as indiscriminate defibrillator placement or adrenaline use, would be the lowest priority for early investment. Our review found no high-quality evidence on the cost-effectiveness of treating OHCA in low-resource settings. Existing evidence can be utilized to develop a roadmap for the development of a cost-effective approach to OHCA care, however further economic evaluations using context-specific data are crucial to accurately inform prioritization of scarce resources within emergency care in these settings.

Impact of the COVID-19 pandemic on pediatric out-of-hospital cardiac arrest outcomes in Japan

This study investigates the impact of the COVID-19 pandemic on pediatric out-of-hospital cardiac arrest (OHCA) outcomes in Japan, aiming to address a critical research gap. Analyzing data from the All-Japan Utstein registry covering pediatric OHCA cases from 2018 to 2021, the study observed no significant changes in one-month survival, neurological outcomes, or overall performance when comparing the pre-pandemic (2018–2019) and pandemic (2020–2021) periods among 6765 cases. However, a notable reduction in pre-hospital return of spontaneous circulation (ROSC) during the pandemic (15.1–13.1%, p = .020) was identified. Bystander-initiated chest compressions and rescue breaths declined (71.1–65.8%, 22.3–13.0%, respectively; both p < .001), while bystander-initiated automated external defibrillator (AED) use increased (3.7–4.9%, p = .029). Multivariate logistic regression analyses identified factors associated with reduced pre-hospital ROSC during the pandemic. Post-pandemic, there was no noticeable change in the one-month survival rate. The lack of significant change in survival may be attributed to the negative effects of reduced chest compressions and ventilation being offset by the positive impact of widespread AED availability in Japan. These findings underscore the importance of innovative tools and systems for safe bystander cardiopulmonary resuscitation during a pandemic, providing insights to optimize pediatric OHCA care.

Out-of-Hospital Cardiac Arrest Following the COVID-19 Pandemic

Out-of-hospital cardiac arrest (OHCA) health care provision may be a good indicator of the recovery of the health care system involved in OHCA care following the COVID-19 pandemic. There is a lack of data regarding outcomes capable of verifying this recovery. To determine whether return to spontaneous circulation, overall survival, and survival with good neurological outcome increased in patients with OHCA since the COVID-19 pandemic was brought under control in 2022 compared with prepandemic and pandemic levels. This observational cohort study was conducted to examine health care response and survival with good neurological outcome at hospital discharge in patients treated following OHCA. A 3-month period, including the first wave of the pandemic (February 1 to April 30, 2020), was compared with 2 periods before (April 1, 2017, to March 31, 2018) and after (January 1 to December 31, 2022) the pandemic. Data analysis was performed in July 2023. Emergency medical services (EMS) serving a population of more than 28 million inhabitants across 10 Spanish regions participated. Patients with OHCA were included if participating EMS initiated resuscitation or continued resuscitation initiated by a first responder. The pandemic was considered to be under control following the official declaration that infection with SARS-CoV-2 was to be considered another acute respiratory infection. The main outcomes were return of spontaneous circulation, overall survival, and survival at hospital discharge with good neurological outcome, expressed as unimpaired or minimally impaired cerebral performance. A total of 14 732 patients (mean [SD] age, 64.2 [17.2] years; 10 451 [71.2%] male) were included, with 6372 OHCAs occurring during the prepandemic period, 1409 OHCAs during the pandemic period, and 6951 OHCAs during the postpandemic period. There was a higher incidence of OHCAs with a resuscitation attempt in the postpandemic period compared with the pandemic period (rate ratio, 4.93; 95% CI, 4.66-5.22; P < .001), with lower incidence of futile resuscitation for OHCAs (2.1 per 100 000 person-years vs 1.3 per 100 000 person-years; rate ratio, 0.81; 95% CI, 0.71-0.92; P < .001). Recovery of spontaneous circulation at hospital admission increased from 20.5% in the pandemic period to 30.5% in the postpandemic period (relative risk [RR], 1.08; 95% CI, 1.06-1.10; P < .001). In the same way, overall survival at discharge increased from 7.6% to 11.2% (RR, 1.45; 95% CI, 1.21-1.75; P < .001), with 6.6% of patients being discharged with good neurological status (Cerebral Performance Category Scale categories 1-2) in the pandemic period compared with 9.6% of patients in the postpandemic period (RR, 1.07; 95% CI, 1.04-1.10; P < .001). In this cohort study, survival with good neurological outcome at hospital discharge following OHCA increased significantly after the COVID-19 pandemic.

Outcomes of out-of-hospital cardiac arrest in Ireland 2012-2020: Protocol for an observational study

Background Out-of-hospital cardiac arrest (OHCA) is a leading cause of preventable mortality that now affects almost 3,000 people each year in Ireland. Survival is low at 6–7%, compared to a European average of 8%. The Irish Out-of-Hospital Cardiac Registry (OHCAR) prospectively gathers data on all OHCA in Ireland where emergency medical services attempted resuscitation. The Irish health system has undergone several developments that are relevant to OHCA care in the period 2012–2020. OHCAR data provides a means of exploring temporal trends in OHCA incidence, care, and outcomes over time. It also provides a means of exploring whether system developments were associated with a change in key outcomes. This research aims to summarise key trends in available OHCAR data from the period 2012 – 2020, to explore and model predictors of bystander CPR, bystander defibrillation, and survival, and to explore the hypothesis that significant system level temporal developments were associated with improvements in these outcomes. Methods The following protocol sets out the relevant background and research approach for an observational study that will address the above aims. Key trends in available OHCAR data (2012 – 2020) will be described and evaluated using descriptive summaries and graphical displays. Multivariable logistic regression will be used to model predictors of ‘bystander CPR’, ‘bystander defibrillation’ and ‘survival to hospital discharge’ and to explore the effects (if any) of system level developments in 2015/2016 and the COVID-19 pandemic (2020) on these outcomes. Discussion The findings of this research will be used to understand temporal trends in the care processes and outcomes for OHCA in Ireland over the period 2012-2020. The results can further be used to optimise future health system developments for OHCA in both Ireland and internationally.

Out-of-hospital cardiac arrest: assessing the problem status and identifying priority areas for improving the care provision. Data from the 2020-2022 Crimean registry

Aim. To study the regional epidemiological characteristics of out-of-hospital cardiac arrest (OHCA), the process and effectiveness of care for OHCA, and identify priority areas for improving the care provision.Material and methods. An analysis of the data from the "Crimean registry of cases of OHCA and cardiopulmonary resuscitation" was performed. The study used data from 2020 to 2022. The analytical sample consisted of all OHCA cases developed before the ambulance arrival, followed by cardiopulmonary resuscitation (CPR).Results. Of the 356 OHCA cases occurred before the ambulance arrival, followed by CPR (2020 — 141, 2021 — 103, 2022 — 112), in 65,2% of cases (n=232) cardiac arrest developed in men, in 64,0% (n=228) — in city residents, 70,2% (n=250) — in private houses or apartments. The mean age was 59 years (median 62 years). The cause of 89,6% of OHCA cases (n=319) was disease, 3,9% (n=14) — drowning, 2,8% (n=10) — trauma, 2,0% (n=7) — asphyxia, 1,1% (n=4) — toxicity, 0,6% (n=2) — electrical injury. In addition, 7,3% (n=26) of patients survived. Bystanders attempted CPR before ambulance arrived in 27,2% (n=97) of cases. In cases where CPR was performed by bystanders, ambulance specialists were 2,5 times more likely to register a potentially shockable rhythm on the primary electrocardiogram (19,6% and 7,7%, respectively; p=0,001), 2,2 times more often performed defibrillation (22,7% and 10,4%, respectively; p=0,003). When defibrillation was performed, the proportion of survivors was 3,9 times higher than without defibrillation (20,4% and 5,2%, respectively; p=0,001).Conclusion. Conducting CPR by OHCA bystanders increases the success rate of CPR performed by ambulance team. However, bystanders rarely provide first aid, which causes a high mortality rate. To reduce mortality in OHCA, the attention should be focused on the development, implementation and regulatory support of measures aimed at involving the population in providing first aid. This should include regular population training in CPR, widespread popularization of first aid, remote provision of CPR instructions by emergency dispatchers to untrained OHCA bystanders and ensuring the availability of automated external defibrillators.

A cross-stakeholder approach to improving out-of-hospital cardiac arrest survival

Out-of-hospital cardiac arrest (OHCA) affects over 300,000 individuals per year in the United States with poor survival rates overall. A remarkable 5-fold difference in survival-to-hospital discharge rates exist across United States communities. We conducted a study using qualitative research methods comparing the system of care across sites in Michigan communities with varying OHCA survival outcomes, as measured by return to spontaneous circulation with pulse upon emergency department arrival. Major themes distinguishing higher performing sites were (1) working as a team, (2) devoting resources to coordination across agencies, and (3) developing a continuous quality improvement culture. These themes spanned the chain of survival framework for OHCA. By examining the unique processes, procedures, and characteristics of higher- relative to lower-performing sites, we gleaned lessons learned that appear to distinguish higher performers. The higher performing sites reported being the most collaborative, due in part to facilitation of system integration by progressive leadership that is willing to build bridges among stakeholders. Based on the distinguishing features of higher performing sites, we provide recommendations for toolkit development to improve survival in prehospital systems of care for OHCA.

Incidence, characteristics and outcomes of out-of-hospital cardiac arrest due to ventricular fibrillation in the general population: data from a single-center long-term registry

Abstract Funding Acknowledgements: Type of funding sources: None. Out-of-hospital cardiac arrest (OHCA) is a major public health problem and ventricular fibrillation (VF) is the most common initial rhythm when cardiac disease is the cause of arrest. It can be favorably treated with defibrillation but rapidly tends to deteriorate to non-shockable rhythms over time, so that reported survival rates vary from 3% to 10%. Early defibrillation strategy has led to a considerable survival improvement; however, automated external defibrillators are still used in &amp;lt;3% of episodes of OHCA. Here, we analyze data from a single-center emergency-medical-service (EMS) registry, involving all consecutive OHCA occurring from January 2013 to June 2022 in whom resuscitation or defibrillation has been attempted. The "Progetto Vita" initiative has been developed in our province since 1999 with the aim of improving deployment of automated external defibrillators into the public space so that the first line involved in the chain of survival (laic bystander or policemen/health care staff) and the use of automatic external defibrillators (AED) by policemen/citizens before the arrival of the EMS personnel are crucial indicators involved in the registry. Patients presenting with OHCA due to VF were considered eligible for this analysis. During the 10-year period of examination, 3,124 patients received medical care for OHCA; 323 of them presented VF and were considered for subsequent analysis. VF occurred prevalently at home (73%), in men (75%); mean age was 70. Bystander or laic citizen CPR was performed in 35 cases (11%) with a survival rate of 63%. AED used by either laic bystander or police was used in 30 cases (9%) with a success rate of 77%. Cardiac comorbidities were noted in 67 patients (21%), predominantly males, and CAD was the most common disease. Main historical, clinical, ECG, instrumental features and therapeutic management and differences in sex groups are listed in Table 1. As expected, incidence increased with age; male predominance was observed in all age subgroups although we observed a different distribution between sexes in age subgroups (Table 1). There were 237 deaths (mortality rate 73%), 41 (17%) of them occurring after arrival at Emergency Service.Among successfully admitted patients, VF was mostly related to coronary artery disease (70%) and STEMI was the most frequent manifestation of acute ischemic heart disease, both in males and females. Overall, 87 (27%) patients survived and were successfully admitted to intensive care unit (57%) or coronary care unit (43%). Multivariate logistic regression analysis showed that laic-performed CPR (OR 2.52, 95% CI 1.04, 6.1, p=0.04) and use of AED (OR 7.15; 95% CI 2.66, 19.19, p&amp;lt;0.001) were both independent predictors of survival. VF in the general population is still poorly predictable and mortality remains high: implementation of community involvement in early-defibrillation through publicly available AEDs appears effective in improving survival. Study population Population characteristics

A retrospective review of out of hospital cardiac arrest at Gillette Stadium: 10 years of experience at a large sports venue

IntroductionRates of out-of-hospital cardiac arrest (OHCA) at major sporting events are as high as 0.7 per 100,000 attendees. However, factors contributing to OHCA at mass gatherings have not been well-described. We describe our experience with ten years of medical oversight and OHCA care at a professional football stadium. MethodsWe performed a retrospective review of OHCA events between August 2010 and January 2020 at a 65,878-seat football stadium, with a single transporting EMS agency and a single receiving hospital. We analyzed EMS incident reports and matched patients to hospital records for outcome data. ResultsA total of 7,767,345 people attended 115 football games during the study period. There were 21 OHCAs (0.27 per 100,000 attendees). Ninety-five percent of OHCAs were witnessed and 71.4% had an initial shockable rhythm, with bystander AED use in 47.6%. Median EMS response time was 2 minutes (IQR 1–6). For 7 patients defibrillated by EMS, time to defibrillation was 4 minutes (IQR 4–11). Return of spontaneous circulation (ROSC) occurred in 71%, with 47% having good 30-day neurologic survival. All patients with an initial rhythm of asystole died. ConclusionThe ROSC rate at our stadium exceeded 70% with almost half surviving with good neurologic outcomes, substantially higher than that reported for the general public. We hope that our experience will provide valuable lessons to other similarly sized stadiums.

Outcomes of out-of-hospital cardiac arrest in Ireland 2012-2020: Protocol for an observational study.

Background Out-of-hospital cardiac arrest (OHCA) is a leading cause of preventable mortality that now affects almost 3,000 people each year in Ireland. Survival is low at 6-7%, compared to a European average of 8%. The Irish Out-of-Hospital Cardiac Registry (OHCAR) prospectively gathers data on all OHCA in Ireland where emergency medical services attempted resuscitation. The Irish health system has undergone several developments that are relevant to OHCA care in the period 2012-2020. OHCAR data provides a means of exploring temporal trends in OHCA incidence, care, and outcomes over time. It also provides a means of exploring whether system developments were associated with a change in key outcomes. This research aims to summarise key trends in available OHCAR data from the period 2012 - 2020, to explore and model predictors of bystander CPR, bystander defibrillation, and survival, and to explore the hypothesis that significant system level temporal developments were associated with improvements in these outcomes. Methods The following protocol sets out the relevant background and research approach for an observational study that will address the above aims. Key trends in available OHCAR data (2012 - 2020) will be described and evaluated using descriptive summaries and graphical displays. Multivariable logistic regression will be used to model predictors of 'bystander CPR', 'bystander defibrillation' and 'survival to hospital discharge' and to explore the effects (if any) of system level developments in 2015/2016 and the COVID-19 pandemic (2020) on these outcomes. Discussion The findings of this research will be used to understand temporal trends in the care processes and outcomes for OHCA in Ireland over the period 2012-2020. The results can further be used to optimise future health system developments for Out-of-Hospital Cardiac Arrest in both Ireland and internationally.

Impact of COVID-19 on out-of-hospital cardiac arrest care processes.

Early bystander cardiopulmonary resuscitation, use of defibrillators (including automated external defibrillators) and timely treatment by emergency medical services are known to increase the chances of survival for a patient experiencing an out-of-hospital cardiac arrest (OHCA); however, the impact of the COVID-19 pandemic on this is unclear from examining previous literature. This commentary critically appraises a recent systematic review and meta-analysis which assesses the effect of the COVID-19 pandemic on pre-hospital care for OHCA.

Sex disparities in prehospital advanced cardiac life support in out-of-hospital cardiac arrests in Japan

ObjectiveSex disparities in out-of-hospital cardiac arrest (OHCA) care processes have been reported. This study aimed to investigate the association between sex and prehospital advanced cardiac life support (ACLS) interventions provided by emergency medical services in Japan. MethodsWe analyzed data from January 1, 2013, to December 31, 2020, from the All-Japan Utstein Registry of patients with OHCA aged ≥18 years who were resuscitated by bystanders. The primary outcomes were prehospital ACLS interventions, including advanced airway management (AAM) and epinephrine administration. Sex-based disparities in receiving prehospital ACLS interventions were assessed via multivariable logistic regression analyses. ResultsAmong 314,460 eligible patients, females with OHCA received fewer prehospital ACLS interventions than males: 83,571/187,834 (44.5%) males vs. 55,086/126,626 (43.5%) females (adjusted odds ratio [AOR] = 0.94, 95% confidence interval [CI] = 0.93–0.96) for AAM and 60,097/187,834 (32.0%) males vs. 35,501/126,626 (28.0%) females (AOR = 0.84, 95% CI = 0.83–0.85) for epinephrine administration. Similar results were also obtained in the subgroup analysis (groups included patients aged 18–74 years and ≥75 years and those with cardiac origin, ventricular fibrillation (VF), non-VF, non-family member witnessed, and family member witnessed). ConclusionCompared with males, females were less likely to receive prehospital ACLS. Emergency medical service staff must be made aware of this disparity, and off-the-job training on intravenous cannulation or AAM replacement must be conducted. Investigation of the impact of sex disparity on OHCA care processes can facilitate planning of future public health policies to improve survival outcomes.

Impact of COVID-19 on out-of-hospital cardiac arrest: A registry-based cohort-study from the German Resuscitation Registry.

The global COVID-19 pandemic effects people and the health system. Some international studies reported an increasing number of out-of-hospital cardiac arrest (OHCA). Comparable studies regarding the impact of COVID-19 on incidence and outcome of OHCA are not yet available for Germany. This epidemiological study from the German Resuscitation Registry (GRR) compared a non-pandemic period (01.03.2018-28.02.2019) and a pandemic period (01.03.2020-28.02.2021) regarding the pandemic-related impact on OHCA care. A total of 18,799 cases were included. The incidence of OHCA (non-pandemic 117.9 vs. pandemic period 128.0/100,000 inhabitants) and of OHCA with resuscitation attempted increased (66.0 vs. 69.1/100,000). OHCA occurred predominantly and more often at home (62.8% vs. 66.5%, p<0.001). The first ECG rhythm was less often shockable (22.2% vs. 20.3%, p = 0.03). Fewer cases of OHCA were observed (58.6% vs. 55.6% p = 0.02). Both the bystander resuscitation rate and the proportion of telephone guided CPR remained stable (38.6% vs. 39.8%, p = 0.23; and 22.3% vs. 22.5%, p = 0.77). EMS arrival times increased (08:39 min vs. 09:08 min, p<0.001). Fewer patients reached a return of spontaneous circulation (ROSC) (45.4% vs. 40.9%, p<0.001), were admitted to hospital (50.2% vs. 45.0%, p<0.001), and discharged alive (13.9% vs. 10.2%, p<0.001). Survival after OHCA significantly decreased while the bystander resuscitation rate remained stable. However, longer EMS arrival times and fewer cases of witnessed OHCA may have contributed to poorer survival. Any change to EMS systems in the care of OHCA should be critically evaluated as it may mean a real loss of life-regardless of the pandemic situation.

Observational study on implications of the COVID-19-pandemic for cardiopulmonary resuscitation in out-of-hospital cardiac arrest: qualitative and quantitative insights from a model region in Germany

BackgroundThe city of Freiburg has been among the most affected regions by the COVID-19 pandemic in Germany. In out of hospital cardiac arrest (OHCA) care, all parts of the rescue system were exposed to profound infrastructural changes. We aimed to provide a comprehensive overview of these changes in the resuscitation landscape in the Freiburg region.MethodsUtstein-style quantitative data on OHCA with CPR initiated, occurring in the first pandemic wave between February 27th, 2020 and April 30th, 2020 were compared to the same time periods between 2016 and 2019.Additionally, qualitative changes in the entire rescue system were analyzed and described.ResultsIncidence of OHCA with attempted CPR did not significantly increase during the pandemic period (11.1/100.000 inhabitants/63 days vs 10.4/100.000 inhabitants/63 days, p = 1.000). In witnessed cases, bystander-CPR decreased significantly from 57.7% (30/52) to 25% (4/16) (p = 0.043). A severe pre-existing condition (PEC) was documented more often, 66.7% (16/24) vs 38.2% (39/102) there were longer emergency medical services (EMS) response times, more resuscitation attempts terminated on scene, 62.5% (15/24) vs. 34.3% (35/102) and less patients transported to hospital (p = 0.019). Public basic life support courses, an app-based first-responder alarm system, Kids Save Lives activities and a prehospital extracorporeal CPR (eCPR) service were paused during the peak of the pandemic.ConclusionIn our region, bystander CPR in witnessed OHCA cases as well as the number of patients transported to hospital significantly decreased during the first pandemic wave. Several important parts of the resuscitation landscape were paused. The COVID-19 pandemic impedes OHCA care, which leads to additional casualties. Countermeasures should be taken.

Drone Network Design for Cardiac Arrest Response

Problem definition: Our objective is to design a defibrillator-enabled drone network that augments the existing emergency medical services (EMS) system to rapidly respond to out-of-hospital cardiac arrest (OHCA). Academic/practical relevance: OHCA claims more than 400,000 lives each year in North America and is one of the most time-sensitive medical emergencies. Drone-delivered automated external defibrillators (AEDs) have the potential to be a transformative innovation in the provision of emergency care for OHCA. Methodology: We develop an integrated location-queuing model that incorporates existing EMS response times and is based on the p-median architecture, where each base constitutes an explicit [Formula: see text] queue (i.e., Erlang loss). We then develop a reformulation technique that exploits the existing EMS response times, allowing us to solve real-world instances to optimality using an off-the-shelf solver. We evaluate our solutions using a tactical simulation model that accounts for the effects of congestion and dispatching, and we use a machine-learning model to translate our response-time reductions into survival estimates. Results: Using real data from an area covering 26,000 square kilometers around Toronto, Canada, we find that a modest number of drones are required to significantly reduce response times in all regions. An objective function that minimizes average response time results in drone resources concentrated in cities, with little impact on the tail of the distribution. In contrast, optimizing for the tail of the response-time distribution produces larger and more geographically dispersed drone networks that improve response-time equity across the regions. We estimate that the response-time reductions achieved by the drone network are associated with between a 42% and 76% higher survival rate and up to 144 additional lives saved each year across the geographical region we consider. Managerial implications: Overall, this paper provides a realistic framework that can be leveraged by system designers and/or EMS personnel seeking to investigate design questions associated with a drone network. An objective function focused on improving the tail of the response-time distribution is well-suited for use in practice because the model provides equitable solutions that reduce the entire response-time distribution and corresponds to the real-world metrics, on which EMS systems are most commonly evaluated.

Urban-Rural Differences in Cardiac Arrest Outcomes: A Retrospective Population-Based Cohort Study

BackgroundApproximately 10% of people who suffer an out-of-hospital cardiac arrest (OHCA) treated by paramedics survive to hospital discharge. Survival differs by up to 19.2% between urban centres and rural areas. Our goal was to investigate the differences in OHCA survival between urban centres and rural areas. MethodsThis was a retrospective cohort study of OHCA patients treated by Nova Scotia Emergency Medical Services (EMS) in 2017. Cases of traumatic, expected, and noncardiac OHCA were excluded. Data were collected from the Emergency Health Service electronic patient care record system and the discharge abstract database. Geographic information system analysis classified cases as being in urban centres (population > 1000 people) or rural areas, using 2016 Canadian Census boundaries. The primary outcome was survival to hospital discharge. Multivariable logistic regression covariates were age, sex, bystander resuscitation, whether the arrest was witnessed, public location, and preceding symptoms. ResultsA total of 510 OHCAs treated by Nova Scotia Emergency Medical Services were included for analysis. A total of 12% (n = 62) survived to discharge. Patients with OHCAs in urban centres were 107% more likely to survive than those with OHCAs in rural areas (adjusted odds ratio = 2.1; 95% confidence interval = 1.1 to 3.8; P = 0.028). OHCAs in urban centres had a significantly shorter mean time to defibrillation of shockable rhythm (11.2 minutes ± 6.2) vs those in rural areas (17.5 minutes ± 17.3). ConclusionsNova Scotia has an urban vs rural disparity in OHCA care that is also seen in densely populated OHCA centres. Survival is improved in urban centres. Further improvements in overall survival, especially in rural areas, may arise from community engagement in OHCA recognition and optimized healthcare delivery.

Abstract 14264: National Comparison of Hospital Market Share for Out-of-Hospital Cardiac Arrest and Elective Cardiac Surgery

Introduction: Competition in the healthcare market is a theoretical driver of innovation, cost-savings, and improved quality. When patients are treated for certain emergent conditions, such as out-of-hospital cardiac arrest (OHCA), individuals have less choice in their treating hospital. For patients undergoing elective cardiac valve replacement surgery (EVRS), hospital choice may reflect distinct referral patterns and preferences. Our objective was to compare hospital market share for different cardiac services, thus allowing for better understanding of the care landscape and target interventions to improve outcomes. Methods: Using age-eligible Medicare fee-for-service institutional claims, an emergency department (ED) treated OHCA cohort was identified via ICD-9/10 diagnosis codes and ED charges. EVRS, an inpatient referral procedure, were identified from in-patient summary claims using procedure codes. Market shares were built for each hospital by sequential addition of ZIP-code areas and calculating the hospital’s cumulative market share. Geographic market share areas were defined for each hospital at 90%, 25% and 10% cut-offs if present. Correlation between corresponding market shares and patient counts were assessed using Pearson’s r. Results: Between 1/2013 and 12/2015, we identified 206,162 EVRS claims and 222,018 OHCA claims. Median age was similar (77 vs 78 yrs), as was percent of female patient (43% vs 44%). Very few beneficiaries (0.38%) appeared in both cohorts. Many more hospitals cared for OHCA than EVRS (4482 vs 1170). More OHCA treating hospitals achieved a 25% market share (68% vs 57%) however, EVRS hospital with a 25% market share covered more population (420,294 vs 66,394) and had a greater client radius (21 vs 15 miles). Among the hospitals providing care to both cohorts, the cumulative market share and patient counts were positively correlated (r = 0.49 and 0.46 respectively, p&lt;0.001 for both). Conclusion: Despite many more hospitals providing care for OHCA, the market share for EVRS and OHCA trend together. This market trend, combined with the association of better outcomes with higher OHCA volume suggests that OHCA should be regionalized within markets to facilities that provide elective cardiac surgical procedures.

Abstract 13027: Investigating the Airway Opening Index During Cardiopulmonary Resuscitation

Introduction: In 40-70% of out-of-hospital cardiac arrest (OHCA) cases, chest compressions (CCs) during CPR induce measurable oscillations in capnography (E T CO 2 ). Recent studies suggest the magnitude and frequency of oscillations are due to intrathoracic airflow dependent on airway patency. These oscillations can be quantified by the Airway Opening Index (AOI), ranging from 0-100%. We sought to develop, automate, and evaluate multiple methods of computing AOI throughout CPR. Methods: We conducted a retrospective study of all OHCA cases in Seattle, WA during 2019. E T CO 2 and impedance waveforms from LifePak 15 defibrillators were annotated for the presence of intubation and CPR, and imported into MATLAB for analysis. Four proposed methods for computing AOI were developed (Fig. 1) using peak E T CO 2 in conjunction with ΔE T CO 2 (oscillations in E T CO 2 from CCs). We examined the feasibility of automating ΔE T CO 2 and AOI calculation during CCs throughout OHCA resuscitation and evaluated differences in mean AOI using each method. Statistical significance was assessed with ANOVA (alpha = 0.05). Results: AOI was measurable in 312 of 465 cases. Mean [95% confidence interval] AOI across all cases was 34.3% [32.0-36.5%] for method 1, 27.6% [25.5-29.7%] for method 2, 22.7% [21.1-24.3%] for method 3, and 28.8% [26.6-31.0%] for method 4. Mean AOI was significantly different across the four methods (p&lt;0.001), with the greatest difference between method 1 and 3 (11.6%, p&lt;0.001), but no significant difference between methods 2 and 4 (p=0.44). Mean ΔE T CO 2 was 7.76 [7.08-8.44] mmHg. Conclusion: We implemented four proposed methods of automatically calculating AOI during OHCA. Each method produced a different average AOI. Consistent, automated methods to measure AOI provide the foundation to evaluate if, and how, AOI may change with treatment or predict outcomes. These four approaches require additional investigation to understand which may be best suited to improve OHCA care.

Interim Guidance for Emergency Medical Services Management of Out-of-Hospital Cardiac Arrest During the COVID-19 Pandemic.

Interim Guidance for Emergency Medical Services Management of Out-of-Hospital Cardiac Arrest During the COVID-19 Pandemic.

Community Variations in Out-of-Hospital Cardiac Arrest Care and Outcomes in Texas

Background: Large and unacceptable variation exists in cardiac resuscitation care and outcomes across communities. Texas is the second most populous state in the US with wide variation in community and emergency response infrastructure. We utilized the Texas-CARES registry to perform the first Texas state analysis of out-of-hospital cardiac arrest (OHCA) in Texas, evaluating for variations in incidence, care, and outcomes. Methods: We analyzed the Texas-CARES registry, including all adult, non-traumatic OHCAs from 1/1/2014 through 12/31/2018. We analyzed the incidence and characteristics of OHCA care and outcome, overall and stratified by community. Utilizing mixed models accounting for clustering by community, we characterized variations in bystander CPR, bystander AED in public locations, and survival to hospital discharge across communities, adjusting for age, gender, race, location of arrest, and rate of witnessed arrest (bystander and 911 responder witnessed). Results: There were a total of 26,847 (5,369 per year) OHCAs from 13 communities; median 2,762 per community (IQR 444-2,767, min 136, max 9161). Texas care and outcome characteristics were: bystander CPR (43.3%), bystander AED use (9.1%), survival to discharge (9.1%), and survival with good neurological outcomes (4.0%). Bystander CPR rate ranged from 19.2% to 55.0%, and there were five communities above and five below the adjusted 95% confidence interval. Bystander AED use ranged from 0% to 19.5%, and there was one community below the adjusted 95% confidence interval. Survival to hospital discharge ranged from 6.7% to 14.0%, and there were three communities above and two below the adjusted 95% confidence interval. Conclusion: While overall OHCA care and outcomes were similar in Texas compared to national averages, bystander CPR, bystander AED use, and survival varied widely across communities in Texas. These variations signal opportunities to improve OHCA care and outcomes in Texas.