Out-of-hospital Cardiac Arrest Cases Research Articles

Glasgow Coma Scale score of more than four on admission predicts in-hospital survival in patients after out-of-hospital cardiac arrest.

The aim of the study was to assess the usefulness of the Glasgow Coma Scale (GCS) score assessed by EMS team in predicting survival to hospital discharge in patients after out-of-hospital cardiac arrest (OHCA). Silesian Registry of OHCA (SIL-OHCA) is a prospective, population-based regional registry of OHCAs. All cases of OHCAs between the 1st of January 2018 and the 31st of December 2018 were included. Data were collected by EMS using a paper-based, Utstein-style form. OHCA patients aged ≥18years, with CPR attempted or continued by EMS, who survived to hospital admission, were included in the current analysis. Patients who did not achieve return of spontaneous circulation (ROSC) in the field, with missing data on GCS after ROSC or survival status at discharge were excluded from the study. Two hundred eighteen patients with OHCA, who achieved ROSC, were included in the present analysis. ROC analysis revealed GCS=4 as a cut-off value in predicting survival to discharge (AUC 0.735; 95%CI 0.655-0.816; p<0.001). Variables significantly associated with in-hospital survival were young age, short response time, witnessed event, previous myocardial infarction, chest pain before OHCA, initial shockable rhythm, coronary angiography, and GCS>4. On the other hand, epinephrine administration, intubation, the need for dispatching two ambulances, and/or a physician-staffed ambulance were associated with a worse prognosis. Multivariable logistic regression analysis revealed GCS>4 as an independent predictor of in-hospital survival after OHCA (OR of 6.4; 95% CI 2.0-20.3; p<0.0001). Other independent predictors of survival were the lack of epinephrine administration, previous myocardial infarction, coronary angiography, and the patient's age. The survival to hospital discharge after OHCA could be predicted by the GCS score on hospital admission.

Risk of out-of-hospital cardiac arrest in patients with bipolar disorder or schizophrenia

ObjectivePatients with bipolar disorder and schizophrenia are at high cardiovascular risk; yet, the risk of out-of-hospital cardiac arrest (OHCA) compared with the general population remains scarcely investigated.MethodsWe conducted a nested...

Effect of Machine Learning on Dispatcher Recognition of Out-of-Hospital Cardiac Arrest During Calls to Emergency Medical Services

Emergency medical dispatchers fail to identify approximately 25% of cases of out-of-hospital cardiac arrest (OHCA), resulting in lost opportunities to save lives by initiating cardiopulmonary resuscitation. To examine how a machine learning model trained to identify OHCA and alert dispatchers during emergency calls affected OHCA recognition and response. This double-masked, 2-group, randomized clinical trial analyzed all calls to emergency number 112 (equivalent to 911) in Denmark. Calls were processed by a machine learning model using speech recognition software. The machine learning model assessed ongoing calls, and calls in which the model identified OHCA were randomized. The trial was performed at Copenhagen Emergency Medical Services, Denmark, between September 1, 2018, and December 31, 2019. Dispatchers in the intervention group were alerted when the machine learning model identified out-of-hospital cardiac arrest, and those in the control group followed normal protocols without alert. The primary end point was the rate of dispatcher recognition of subsequently confirmed OHCA. A total of 169 049 emergency calls were examined, of which the machine learning model identified 5242 as suspected OHCA. Calls were randomized to control (2661 [50.8%]) or intervention (2581 [49.2%]) groups. Of these, 336 (12.6%) and 318 (12.3%), respectively, had confirmed OHCA. The mean (SD) age among of these 654 patients was 70 (16.1) years, and 419 of 627 patients (67.8%) with known gender were men. Dispatchers in the intervention group recognized 296 confirmed OHCA cases (93.1%) with machine learning assistance compared with 304 confirmed OHCA cases (90.5%) using standard protocols without machine learning assistance (P = .15). Machine learning alerts alone had a significantly higher sensitivity than dispatchers without alerts for confirmed OHCA (85.0% vs 77.5%; P < .001) but lower specificity (97.4% vs 99.6%; P < .001) and positive predictive value (17.8% vs 55.8%; P < .001). This randomized clinical trial did not find any significant improvement in dispatchers' ability to recognize cardiac arrest when supported by machine learning even though artificial intelligence did surpass human recognition. ClinicalTrials.gov Identifier: NCT04219306.

Advanced do-not-attempt-resuscitation directives and emergency medical services for out-of-hospital cardiopulmonary arrest patients in Japan: a pilot study.

AimsWe investigated how do‐not‐attempt‐resuscitation (DNAR) orders are currently used, and we examined the emergency medical team responses for out‐of‐hospital cardiac arrest (OHCA) cases in Japan.MethodsThe sample for this prospective study comprised all OHCA cases attended to by the Sagamihara Municipal Fire Department emergency medical services between May 30, 2019 and February 15, 2020. Data were recorded by the responding emergency medical team.ResultsThere were 396 OHCA cases. The mean age was 75 ± 18 years, and individuals aged 65 years or older accounted for 80.6%. Approximately 70% of the patients had an underlying disease. A DNAR order was available in only 45 (11.4%) of the cases, of which 12 (26.7%) were written, 27 (60%) were verbally confirmed, and six (13.3%) were confirmed in some other way or both. The home physician was present and able to confirm the patient’s death in only one of the DNAR cases. In 43 (95.6%) of the cases, the emergency medical team carried out cardiopulmonary resuscitation despite a DNAR order; of them, a total of 17 (37.8%) patients were transported to a tertiary emergency hospital.ConclusionsOur analyses indicate the under‐utilization of DNAR advance directives and advance care planning (which are important for better end‐of‐life care) in Japan. Currently, an emergency medical team could be required to attempt resuscitation against an individuals’ clear DNAR order. In the future, legal arrangements regarding the handling of DNAR directives on site may be required to respect patients’ wishes.

Gender Disparities Among Adult Recipients of Layperson Bystander Cardiopulmonary Resuscitation by Location of Cardiac Arrest in Pan-Asian Communities

Background: Bystander cardiopulmonary resuscitation (BCPR) is a critical component of the ‘chain of survival’ in reducing mortality among out-of-hospital cardiac arrest (OHCA) victims. Inconsistent findings on gender disparities among adult recipients of layperson BCPR have been reported in the literature. We aimed to fill this knowledge gap by investigating the extent of gender disparities in a cross-national setting within Pan-Asian communities. Methods: We utilized data collected from the Pan-Asian Resuscitation Outcomes Study (PAROS), an international, multicenter, prospective study conducted between 2009 and 2018. We included all OHCA cases with non-traumatic arrest etiology transported by emergency medical services and excluded study sites that did not consistently collect information about the location of cardiac arrest. Logistic regression was used to analyze the association between gender and BCPR, stratified by location. Findings: We analyzed a cohort of 56,192 OHCA cases with an overall BCPR rate of 36.2% (20,329/56,192). At public locations, BCPR rate was 31.2% (631/2022) for female and 36.4% (3235/8892) for male OHCA victims; while at home, the rate was 38.3% (6838/17,842) for females and 35.1% (9625/27,436) for males. Controlling for country differences and several factors in multivariable logistic regression, we found females less likely to receive BCPR than males in public locations (odds ratio [OR]=0.89, 95% confidence interval [CI]: 0.70–0.99), but more likely to receive BCPR at home (OR=1.16, 95% CI: 1.11–1.21). Interpretation: In Pan-Asian communities, gender differences exist in adult recipients of BCPR and differ between home and public locations. Funding Statement: The study is supported by grants from the National Medical Research Council (NMRC/CSA/0049/2013) and Laerdal Foundation (20040). Declaration of Interests: MEH Ong reports funding from the ZOLL Medical Corporation for a study involving mechanical cardiopulmonary resuscitation devices; grants from the Laerdal Foundation, Laerdal Medical, and Ramsey Social Justice Foundation for funding of the Pan-Asian Resuscitation Outcomes Study; an advisory relationship with Global Healthcare SG, a commercial entity that manufactures cooling devices; and funding from Laerdal Medical on an observation program to their Community CPR raining Centre Research Program in Norway. MEH Ong has a licensing agreement and patent filed (Application no: 13/047,348) with ZOLL Medical Corporation for a study titled “Method of predicting acute cardiopulmonary events and survivability of a patient. NL and MEH Ong are the co-founders and scientific advisors of TIIM Healthcare, a commercial entity which develops real-time prediction and risk stratification solutions at triage. All other authors have no conflict of interest to declare. Ethics Approval Statement: The study was granted approval from SingHealth Centralised Institutional Review Board and Domain Specific Review Board with waiver of patient informed consent.

Epidemiology, management, and survival rate of out-of-hospital cardiac arrest in Upper Silesia, Poland: an Utstein-style report.

IntroductionDespite the growing number of studies on the epidemiology of out-of-hospital cardiac arrest (OHCA) in Poland, this issue has not been sufficiently studied. Notably, there has been a lack of uniform Utstein-style data reporting.AimTo evaluate the epidemiology of OHCA, patient characteristics, the laypeople and emergency medical service (EMS) response to cardiac arrest, and outcomes of OHCA patients, based on a prospective registry encompassing a population of 2.7 million Poles.Material and methodsConsecutive, adult, EMS-treated OHCA cases in 2018 were analyzed. Prehospital data were collected using case report forms by EMS. Information on in-hospital procedures and outcomes was based on data from the public payer of health care services. Multivariable logistic regression analysis was performed to find independent predictors of survival to discharge.ResultsA total of 1392 patients were included. Most OHCA occurred at home (74.7%). In 66.8% of OHCA cases, the cardiac arrest was witnessed by bystanders and in another 20.4% by EMS. Laypeople performed cardiopulmonary resuscitation (CPR) in 54.4% of non-EMS-witnessed events, and an automated external defibrillator (AED) was used in 4.6% of patients who received bystander CPR. Finally, 30.7% of all patients were transported to the hospital, and 9.2% survived to hospital discharge. Epinephrine administration, unwitnessed OHCA, longer response time, older age, and initial non-shockable rhythm were independently associated with lower survival to discharge.ConclusionsThe prognosis of OHCA patients in Poland is poor. There is still room for improvement in increasing the prevalence of bystander CPR and AED use before EMS arrival.

OHCA survey in Lombardy: comparison between years 2014 and 2019 (pre COVID-19).

Background and aim:The incidence of Out of Hospital Cardiac Arrest (OHCA) is estimated at 1/1000 persons/year. In the pre-Covid-19 era world, OHCA survival rate in Europe was 7-6%. The main objective is to analyze OHCA survival in the Lombardy region by highlighting the factors related to both the victims’ characteristics and the chain of survival.Methods:All OHCAs were grouped into four pre-established periods in 2019 (14-23 January; 15-24 April; 15-24 July; 14-23 October). Following the Utstein method, we selected witnessed OHCAs with presumed cardiac etiology. The outcome of each case was collected in four moments in time: Return of spontaneous circulation (ROSC), Emergency Department (ED), 24 hours and 30 days. The neurological outcome 30 days after OHCA was also investigated and stratified with the Cerebral Performance Category Score (CPC).Results:We selected 456 cases of OHCA with witnessed cardiac etiology. ROSC was achieved in 121 cases (26.5%), survival in the Emergency Departments in 110 patients (24.1%), after 24 hours in 86 (18.86%) and after 30 days in 72 (15.8%). Male sex was shown to improve OHCA survival. A shockable presentation rhythm, Cardiopulmonary Resuscitation (CPR) performed by bystanders and the activation of Public Access Defibrillation (PAD) positively influenced OHCA outcome.Conclusions:Males are more predisposed to incur an OHCA event than females, but they have greater chances of survival. Factors most related to survival are: shockable rhythm, bystanders CPR and the activation of a PAD. (www.actabiomedica.it)

The effect of the COVID-19 pandemic on acute coronary syndrome hospitalizations and out-of-hospital cardiac arrest in Greece

ObjectivesAfter coronavirus disease 2019 (COVID-19) outbreak, striking decreases in the number of hospital admissions for acute coronary syndromes (ACSs) and rises in rates of out-of-hospital cardiac arrest (OHCA) have been noted. Study designThis is an analysis of prospectively collected data from a cardiology department in a single, large volume hospital of the National Health System of the Metropolitan area of Athens. MethodsWe investigated the numbers of OHCA and hospital admissions for ACS during a 1-year period and made comparisons between the pre-COVID-19 and the COVID-19 outbreak periods. ResultsOne hundred and eighty five patients were admitted during the total period of observation with the diagnosis of ACS. The mean monthly number of admissions for ACS for the pre-COVID-19 era was significantly higher than that for the post-COVID-19 era (20.1 ± 7.8 vs 8.8 ± 6.5 admissions, Ρ = 0.024). The cases of OHCA which were transferred to our emergency room department by emergency medical services during the same period were nominally lower in the prepandemic compared with the postpandemic era (1.9 ± 1.7 vs 4.0 ± 4.6, P = 0.28). ConclusionsThe present study provides hints on the potential unintended consequences of the pandemic in countries characterized by fewer COVID-19 cases and fatalities but prompt measures of social contact restrictions and lockdown.

Extended cardiopulmonary resuscitation: from high fidelity simulation scenario to the first clinical applications in Poznan out-of-hospital cardiac arrest program.

The outcomes of out-of-hospital cardiac arrest (OHCA) patients are poor. In some OHCA cases, the reason is potentially reversible cardiac or aortic disease. It was suggested previously that high-quality cardiopulmonary resuscitation (CPR) followed by extracorporeal membrane oxygenation (ECMO) support may improve the grave prognosis of OHCA. However, extended CPR (ECPR) with ECMO application is an extremely invasive and cutting-edge procedure. The purpose of this article is to describe how high-fidelity medical simulation as a safe tool enabled implementation of the complex, multi-stage ECPR procedure. A high fidelity simulation of OHCA in street conditions was prepared and carried out as part of a ECPR procedure implemented in an in-hospital area. The simulation tested communication and collaboration of several medical teams from the pre-hospital to in-hospital phases along with optimal use of equipment in management of a sudden cardiac arrest (SCA) patient. The critical and weak points of an earlier created scenario were collected into a simulation scenario checklist of ECPR algorithm architecture. A few days later, two ECPR procedures followed by cardiologic interventions for OHCA patients (one pulmonary artery embolectomy for acute pulmonary thrombosis and one percutaneous coronary artery angioplasty with drug eluting stent implantation for acute occlusion of the left anterior descending artery), were performed for the first time in Poland. The protocol was activated five times in the first 2 months of the POHCA Program. High fidelity medical simulation in real-life conditions was confirmed to be a safe, useful tool to test and then implement the novel and complex medical procedures. It enabled to find, analyze and solve the weakest points of the earlier developed theoretical protocol and eventually succeed in clinical application of complete ECPR procedure.

Outcomes of out-of-hospital cardiac arrest in relation to prehospital care services in Hospital Canselor Tuanku Muhriz: A prospective study

Background: The role of prehospital care (PHC) services in out-of-hospital cardiac arrest (OHCA) is well established in developed countries. The American Heart Association has defined PHC as the ‘chain of survival’ between public and advanced medical care. For developing countries such as Malaysia, the importance of PHC services in OHCA is evolving; however, data are lacking. Objective: This study aimed to investigate OHCA outcomes in relation to PHC services in Hospital Canselor Tuanku Muhriz, Kuala Lumpur, Malaysia. Method: This was a prospective study conducted on OHCA cases attended by the PHC staff of Hospital Canselor Tuanku Muhriz. Independent variables were patient background, OHCA nature, and PHC interventions, while dependent variables were patient outcomes. Results: A total of 82 OHCA cases were identified. The survival rate to admission was 12.2% (n = 10), while the survival rate to discharge was 1.2% (n = 1) with cerebral performance categories of 1 or 2. The mean ambulance response time was 14.91 min. Among the variables, only OHCA location and adrenaline administration show significant association with OHCA outcome. OHCA location was significant in both outcomes (admission χ2(4) = 16.354, p &lt; 0.03, Cramer&apos;s V = 0.447, discharge χ2(4) = 19.741, p &lt; 0.001, Cramer&apos;s V = 0.491). However, adrenaline administration was significant only for survival to admission (χ2(1) = 3.776, p &lt; 0.052, Cramer&apos;s V = 0.215) but not for survival to discharge (χ2(1) = 0.964, p &lt; 0.326). Conclusion: Improvement in ambulance response time, public availability of automated external defibrillator, and public awareness of early cardiac arrest and cardiopulmonary resuscitation are required to increase the survivability of OHCA in developing countries.

Variation in pre-hospital outcomes after out-of-hospital cardiac arrest in Michigan

AimCare by emergency medical service (EMS) agencies is critical for optimizing prehospital outcomes following out-of-hospital cardiac arrest (OHCA). We explored whether substantial differences exist in prehospital outcomes across EMS agencies in Michigan—specifically focusing on rates of sustained return of spontaneous circulation (ROSC) upon emergency department (ED) arrival. MethodsUsing data from Michigan Cardiac Arrest Registry to Enhance Survival (MI-CARES) for years 2014–2017, we calculated rates of sustained ROSC upon ED arrival across EMS agencies in Michigan. We used hierarchical logistic regression models that accounted for patient, arrest-, community-, and response-level characteristics to determine adjusted rates of sustained ROSC among EMS agencies. ResultsA total of 103 EMS agencies and 20,897 OHCA cases were included. Average age of the cohort was 62.5 years (SD = 19.6), 39.7% were female, and 17.9% had an initial shockable rhythm due to ventricular fibrillation or pulseless ventricular tachycardia. The adjusted rate of sustained ROSC upon ED arrival across all EMS agencies was 23.8% with notable variation across EMS agencies (interquartile range [IQR], 20.5–29.2%). The top five EMS agencies had mean adjusted rates of sustained ROSC upon ED arrival of 42.7% (95% CI: 34.6–51.1%) while the bottom five had mean adjusted rates of 9.8% (95% CI: 7.6–12.7%). ConclusionsSubstantial variation in sustained ROSC upon ED arrival exists across EMS agencies in Michigan after adjusting for patient-, arrest, community-, and response-level features. Such differences suggest opportunities to identify and improve best practices in EMS agencies to advance OHCA care.

Shorter Interval from Witnessed Out-Of-Hospital Cardiac Arrest to Reaching the Target Temperature Could Improve Neurological Outcomes After Extracorporeal Cardiopulmonary Resuscitation with Target Temperature Management: A Retrospective Analysis of a Japanese Nationwide Multicenter Observational Registry.

Extracorporeal cardiopulmonary resuscitation (ECPR) with extracorporeal membrane oxygenation is a more promising treatment for out-of-hospital cardiac arrest (OHCA) than conventional cardiopulmonary resuscitation (CCPR). However, previous studies that compared ECPR and CCPR included mixed groups of patients with or without target temperature management (TTM). In this study, we compared the neurological outcomes of OHCA between ECPR and CCPR with TTM in all patients. We performed retrospective subanalyses of the Japanese Association for Acute Medicine OHCA registry. Witnessed adult cases of cardiogenic OHCA treated with TTM were eligible for this study. We used univariate and multivariable analyses in all eligible patients to compare the neurological outcomes after ECPR or CCPR. We also conducted propensity score analyses of all patients and according to the interval from witnessed OHCA to reaching the target temperature (IWT) of ≤600, ≤480, ≤360, ≤240, and ≤120 minutes. We analyzed 1146 cases. The propensity score analysis did not show a significant difference in favorable neurological outcomes (defined as a Glasgow-Pittsburgh Cerebral Performance Category of 1-2 at 1 month after collapse) between EPCR and CCPR (odds ratio: OR 4.683 [95% confidence interval: CI 0.859-25.535], p = 0.747). However, ECPR was associated with more favorable neurological outcomes in patients with IWT of ≤600 minutes (OR 7.089 [95% CI 1.091-46.061], p = 0.406), ≤480 minutes (OR 10.492 [95% CI 1.534-71.773], p = 0.0168), ≤360 minutes (OR 17.573 [95% CI 2.486-124.233], p = 0.0042), ≤240 minutes (OR 38.908 [95% CI 5.045-300.089], p = 0.0005), and ≤120 minutes (OR 200.390 [95% CI 23.730-1692.211], p < 0.001). This study revealed significant differences in the neurological outcomes between ECPR and CCPR in patients with TTM whose IWT was ≤600 minutes.

Use of out-of-hospital cardiac arrest registries to assess COVID-19 home mortality

BackgroundIn most countries, the official statistics for the coronavirus disease 2019 (COVID-19) take account of in-hospital deaths but not those that occur at home. The study’s objective was to introduce a methodology to assess COVID-19 home deaths by analysing the French national out-of-hospital cardiac arrest (OHCA) registry (RéAC).MethodsWe performed a retrospective multicentre cohort study based on data recorded in the RéAC by 20 mobile medical teams (MMTs) between March 1st and April 15th, 2020. The participating MMTs covered 10.1% of the French population. OHCA patients were classified as probable or confirmed COVID-19 cases or as non-COVID-19 cases. To achieve our primary objective, we computed the incidence and survival at hospital admission of cases of COVID-19 OHCA occurring at home. Cardiac arrests that occurred in retirement homes or public places were excluded. Hence, we estimated the number of at-home COVID-19-related deaths that were not accounted for in the French national statistics.ResultsWe included 670 patients with OHCA. The extrapolated annual incidence of OHCA per 100,000 inhabitants was 91.9 overall and 17.6 for COVID-19 OHCA occurring at home. In the latter group, the survival rate after being taken to the hospital after an OHCA was 10.9%. We estimated that 1322 deaths were not accounted in the French national statistics on April 15, 2020.ConclusionsThe ratio of COVID-19 out-of-hospital deaths to in-hospital deaths was 12.4%, and so the national statistics underestimated the death rate.

Impact of temporal changes in the epidemiology and management of traumatic out-of-hospital cardiac arrest on survival outcomes

AimWe aimed to investigate the impact of temporal changes in the epidemiology and management of traumatic out-of-hospital cardiac arrest (OHCA) on emergency medical service (EMS) attempted resuscitations and survival outcomes. MethodsA retrospective observational study of traumatic OHCA cases involving patients aged > 16 years in Victoria, Australia, who arrested between 2001 and 2018. Unadjusted and adjusted logistic regression was performed to assess trends in survival outcomes over the study period. ResultsBetween 2001 and 2018, the EMS attended 5,631 cases of traumatic OHCA, of which 1,237 cases (22.0%) received an attempted resuscitation. EMS response times increased significantly over time (from 7.0 min in 2001–03 to 9.8 min in 2016−18; p trend < 0.001) as did rates of bystander cardiopulmonary resuscitation (CPR) (from 37.8% to 63.6%; p trend < 0.001). Helicopter EMS attendance on scene increased from 7.1% to 12.4% (p trend = 0.01), and transports of patients with return of spontaneous circulation (ROSC) to designated major trauma centres also increased from 36.6% to 82.4% (p trend < 0.001). The frequency of EMS trauma-specific interventions increased over the study period, including needle thoracostomy from 7.7% to 61.6% (p trend < 0.001). Although the risk-adjusted odds of ROSC (OR 1.06, 95% CI: 1.03–1.10) and event survival (OR 1.05, 95% CI: 1.01–1.09) increased year-on-year, there were no temporal changes in survival to hospital discharge. ConclusionDespite higher rates of bystander CPR and EMS trauma interventions, rates of survival following traumatic OHCA did not change over time in our region. More studies are needed to investigate the optimal EMS interventions for improved survival in traumatic OHCA.

Abstract 134: Survival After Out-of-hospital Cardiac Arrest: The Role of Urban-rural Residence and Demographic Factors

Introduction: Survival to discharge after out-of-hospital cardiac arrest (OHCA) exhibits significant regional variability across communities in the US with differences in outcomes following arrest between rural, suburban, and urban communities. We examined the relationship between urban-rural residential county classification and survival following OHCA to determine if racial composition of a county and community health indicators contribute to improved outcomes following OHCA. Methods: Utilizing age-eligible Medicare fee-for-service claims data from January 2013 - December 2014, we identified OHCA patients by ICD-9-CM diagnosis code 427.5 and determined survival to discharge and at 30 days. Additional data sources included the 2013 National Center for Health Statistics (NCHS) urban-rural classification, US Census data, and County Health Rankings. Mixed effect logistic regression was used to determine the association of OHCA outcomes and NCHS classified residence, when accounting for individual age, sex, and race, county-level racial composition, poverty status, and community health measures. Results: 256,107 cases of OHCA were identified with a mean age of age of 78.7 (SD 8.5) years, 22.8% nonwhite, 47.5% female. Overall survival to discharge was 21.8% and survival at 30 days was 15.1%. Patients living in the most rural counties had increased likelihood of initial survival (aOR1.1, CI 1.0-1.1), but were associated with lower survival at 30 days (aOR 0.9, CI 0.8-0.9). Nonwhite patient race and residing in a majority nonwhite county were associated with significant decreases in the likelihood of survival to discharge and at 30 days (7% and 11%, respectively). Conclusions: Among Medicare beneficiaries, survival to discharge after OHCA was higher if residing in a non-urban community but did not persist at 30 days. OHCA patients residing in majority non-white counties were significantly less likely to survive the initial hospitalization and to 30-days post discharge. More study is needed to elucidate these disparities and determine if modifiable county level health factors exist that could contribute to improvements in OHCA survival.

Abstract 256: Outcome Prediction of Out of Hospital Cardiac Arrest with Environmental Information Using Machine Learning

Background: The lethality of out-of-hospital cardiac arrest (OHCA) among minority and low income patients in large urban centers has been extensively described. Neighborhood disparities in OHCA survival outcomes cannot be fully explained by clinical variables alone. Machine Learning (ML) is a sub-field of Artificial Intelligence where algorithms can learn and improve themselves by studying high volumes of data and evaluating interactions that affect OHCA. We sought to determine whether incorporating neighborhood variables into a ML model of OHCA can increase its predictive accuracy of survival outcomes. Methods: Using OHCA data from the Cardiac Arrest Registry to Enhance Survival (CARES) database, we geocoded Chicago incidents that occurred outside of healthcare facilities and nursing homes from 2014 - 2019 into the 77 Chicago community areas. Neighborhood characteristics (e.g., access to healthcare, educational attainment, crime rates) were assigned to OHCA cases based on community area using publicly available data from the Chicago Health Atlas (CHA). The merged CARES and CHA data were used to train, validate, test, and analyze ML models for OHCA survival outcomes, defined as a binary outcome based on Cerebral Performance Category or CPC (Good = CPC 1 or 2; Poor=CPC 3, 4, or 5). ML models including deep neural networks were developed and compared using average class sensitivity to models developed using only CARES data. Results: ML algorithms were tested on 9,595 cases of OHCA. Baseline results using only CARES data on the Embedded Fully Convolutional Network (EFCN) show an average class sensitivity of 84%. Including neighborhood variables from the CHA dataset increased the average class sensitivity of the EFCN model to 86.5-86.9%. Conclusion: The use of neighborhood variables in combination with CARES data can predict neurologic outcomes with a higher level of accuracy than using CARES registry data alone. Future studies will use this newly developed model to perform simulation experiments to identify neighborhood level interventions to improve OHCA survival outcomes.

Abstract 203: Thoracic Impedance Reflects Differences Between Endotracheal and Laryngeal Advanced Airway During Mechanical Chest Compressions

Background: Ventilations during out-of-hospital cardiac arrest (OHCA) produce thoracic impedance(TI) waveforms due to air volume changes in the lungs. Different airway management techniques, i.e. laryngeal tube (LT) and endotracheal intubation (ETI), may produce distinct TI waveforms as a result of different air flows and dead space volumes. Methods: Adult OHCA cases from the Pragmatic Airway Resuscitation Trial were analyzed. Cases recorded with Philips MRx monitor-defibrillators and treated with LUCAS mechanical CPR devices were considered, ensuring homogeneous TI acquisition and compression therapy. Impedance and capnogram signal intervals were extracted after successful airway insertion and during ongoing chest compressions. Ventilations were confirmed in the capnogram, and the associated TI waveforms were analyzed. Adaptive filtering was applied to remove compression artifacts, and the amplitudes (A i , A e ) and durations (D i , D e ) of the insufflation and exhalation phases were computed (see Figure). Each case was characterized by its observed median values. Differences between airway groups were assessed with a Wilcoxon rank sum test. Results: Data from 100 OHCA cases (57 LT and 43 ETI) were analyzed, totaling 10348 ventilations, with median (IQR) of 87 (51 - 146) ventilations per case. Median TI amplitudes for ETI and LT groups showed significant differences (p&lt;0.05), with 1.1 (0.7 - 1.8) Ω and 0.7 (0.3 - 1.3) Ω for A i , and 1.0 (0.7 - 1.6) Ω and 0.6 (0.3 - 1.2) Ω for A e . No significant differences were observed for phase durations, 1.6 (1.3 - 2.0) s and 1.6 (1.2 - 1.8) s for D i , and 2.3 (1.8 - 3.3) s and 2.6 (2.0 - 3.3) s for D e . Conclusions: Significant differences on ventilation impedance waveform amplitudes were observed between patients treated with ETI and LT. This might be related to higher insufflated air volumes for ETI or larger dead space volumes for LT.

Abstract 344: Comparing the Efficacy of Real-Time Audiovisual Feedback Devices and Active Compression-Decompression Devices in Out-of-Hospital Cardiac Arrest: A Network Meta-Analysis

Introduction: Nearly 350,000 out-of-hospital cardiac arrest (OHCA) cases occur annually in the United States, with a fatality rate nearing 90%. Quality of cardiopulmonary resuscitation (CPR) is known to significantly influence survival. Randomized controlled trials (RCT) on real-time audiovisual feedback (RTAVF) and active compression-decompression (ACD) devices show both provide substantial advantages to standard CPR. We conducted the first network meta-analysis comparing the efficacy of RTAVF and ACD devices in OHCA based on a literature review. Methods: Studies examining the efficacy of RTAVF or ACD devices to standard CPR by emergency medical personnel in OHCA cases were identified in PubMed, SCOPUS, Cochrane, Google Scholar, and Embase. Outcomes of interest were return of spontaneous circulation (ROSC), survival to hospital discharge (SHD), and favorable neurological recovery. Both a frequentist and Bayesian network meta-analysis were conducted. The p-values, P-scores and Surface under the Cumulative Ranking (SUCRA) scores were computed to analyze significance and effect size. Results: The search yielded 31 eligible studies (n = 35,575). RTAVF devices significantly improved ROSC (Risk Ratio (RR) 1.15, 95% CI: 1.09 - 1.22, p &lt; 0.001, P-score &gt; 0.999) and SHD (RR 1.16, 1.07 - 1.26, p &lt; 0.001, P-score &gt; 0.91), but did not significantly improve favorable neurological recovery (RR 1.05, 0.92 - 1.19, p &gt; 0.05). ACD devices did not report significant improvement in either ROSC (RR 1.03, 0.99 - 1.08, p &gt; 0.05) or SHD (RR 1.10, 0.99 - 1.21, p &gt; 0.05), but did report significant benefits in favorable neurological outcome (RR 1.30, 1.07 - 1.58, p &lt; 0.01, P-score &gt; 0.97). Similar findings were also seen in SUCRA scores. Conclusion: We found RTAVF devices increased ROSC and SHD, while ACD devices increased favorable neurological recovery. Our meta-analysis supports the adoption of RTAVF devices, but an RCT directly comparing RTAVF with ACD devices is recommended.

Abstract 15568: Profound Increases in Out-of-Hospital Cardiopulmonary Arrest Cases Within Most Metropolitan Municipalities During the COVID-19 Pandemic

Introduction: Even though most EMS systems globally experienced dramatic decreases in call volumes during the COVID-19 pandemic, many also reported unexpected increases in out-of-hospital cardiac arrest (OHCA) cases. Hypothesis: The pervasiveness of COVID-19 in metropolitan cities might be associated with a greater number of OHCA cases as compared to prior years. Methods: Large city EMS system medical directors responsible for about one-quarter of the U.S. population and millions of others in Europe/Australia were asked to tabulate the absolute number of OHCA cases to which EMS responded within their jurisdictions during the first 4 months of 2020. Results were compared to average numbers encountered during 2018 and 2019. A priori, considering the large populations (high corresponding OHCA frequencies) and case complexities, a 15% increase/decrease was to be considered highly significant (usual variation + 4-8% within the 28-31 days/month). Results: Of 35 major U.S. cities reporting to date, most had significant increases in OHCA, particularly in April with 71% (25/35) of the cities seeing a very large (&gt;15%) increase. Nine cities (26%), all experiencing a high prevalence of COVID-19, had &gt;50% (1.5-fold) increases. Three cities with highly-publicized inundations of COVID-19, experienced more than twice as many arrests (3.5-fold in the worst case). Meanwhile, 3 other cities with relatively low COVID-19 impact to date, had significantly fewer cases. Still, combining all of the 35 cities studied, OHCA increased from 5,009 (2 prior years’ average) to 8,701 (74% increase) during April (Fig 1). Participating cities outside the U.S. (e.g., Paris, London, Perth) mirrored these findings. Conclusions: To date, most, but not all, metropolitan cities have clearly experienced significant increases in OHCA that appear to parallel the prevalence of COVID-19 in their respective jurisdictions. These observations and available forensic data are now part of a work in progress.

Abstract 335: The Impact of Early Coronary Angiography on Outcomes in Out-of-hospital Cardiac Arrest: The Singapore Experience

Background and Aim: The benefit of early coronary angiography (CAG) and revascularization in resuscitated out-of-hospital cardiac arrest (OHCA) is unclear. We evaluated the association between early CAG and clinical outcomes in these patients. Methods: Data on all resuscitated adult OHCA cases of cardiac etiology between 2011-2015 were extracted from the prospective Singapore Pan-Asian Resuscitation Outcomes Study and linked with data from the national database of cardiac procedures. The 30-day survival and neurological outcomes (good outcome defined as Cerebral Performance Category [CPC] 1 or 2) were compared between patients undergoing early CAG (within 1-calender day) and patients not undergoing early CAG. Inverse probability weighted estimator was used to adjust for propensity to perform early CAG and PCI. Results: Of 976 consecutive patients who survived to admission (mean age 64±13, 73.7% males), 401 (41.1%) patients underwent CAG and obstructive coronary artery disease (CAD) was present in 352 (87.8%), of whom 284 (70.8%) underwent revascularization. Patients who underwent early CAG (n=337[34.5%]) were significantly different compared to those who underwent delayed or no CAG (n=639[65.5%]) (Table 1). Early CAG and PCI patients had improved survival and better neurological outcomes (adjusted odds ratio [AOR] 3.806 [95% CI 1.675 - 8.648] and AOR 3.075 [95% CI 1.119 - 8.451]), compared to those without. The odds of survival decreased with epinephrine administration (AOR 0.357 [95% CI 0.199 - 0.640]), but increased with an initial shockable rhythm (AOR 6.587 [95% CI 3.659 - 11.861]). The rates of bleeding (2% vs 0%, p=0.300) and stroke (1.6% vs 1.9%, p=0.880) were not increased with early intervention. Conclusion: Early CAG and PCI after OHCA were associated with improved clinical outcomes after OHCA without increasing complications. Further studies are required to identify the characteristics of patients who would benefit most from this invasive strategy.