Out-of-hospital Cardiac Arrest Outcomes Research Articles

Machine learning pre-hospital real-time cardiac arrest outcome prediction (PReCAP) using time-adaptive cohort model based on the Pan-Asian Resuscitation Outcome Study

To save time during transport, where resuscitation quality can degrade in a moving ambulance, it would be prudent to continue the resuscitation on scene if there is a high likelihood of ROSC occurring at the scene. We developed the pre-hospital real-time cardiac arrest outcome prediction (PReCAP) model to predict ROSC at the scene using prehospital input variables with time-adaptive cohort. The patient survival at discharge from the emergency department (ED), the 30-day survival rate, and the final Cerebral Performance Category (CPC) were secondary prediction outcomes in this study. The Pan-Asian Resuscitation Outcome Study (PAROS) database, which includes out-of-hospital cardiac arrest (OHCA) patients transferred by emergency medical service in Asia between 2009 and 2018, was utilized for this study. From the variables available in the PAROS database, we selected relevant variables to predict OHCA outcomes. Light gradient-boosting machine (LightGBM) was used to build the PReCAP model. Between 2009 and 2018, 157,654 patients in the PAROS database were enrolled in our study. In terms of prediction of ROSC on scene, the PReCAP had an AUROC score between 0.85 and 0.87. The PReCAP had an AUROC score between 0.91 and 0.93 for predicting survived to discharge from ED, and an AUROC score between 0.80 and 0.86 for predicting the 30-day survival. The PReCAP predicted CPC with an AUROC score ranging from 0.84 to 0.91. The feature importance differed with time in the PReCAP model prediction of ROSC on scene. Using the PAROS database, PReCAP predicted ROSC on scene, survival to discharge from ED, 30-day survival, and CPC for each minute with an AUROC score ranging from 0.8 to 0.93. As this model used a multi-national database, it might be applicable for a variety of environments and populations.

Abstract 101: Prehospital High-Dose Methylprednisolone Treatment Reduces Norepinephrine Need Following Resuscitated Out-of-Hospital Cardiac Arrest

Background: Resuscitated out-of-hospital cardiac arrest (OHCA) patients are hemodynamically unstable and have high mortality. Norepinephrine (NE) is recommended to maintain mean arterial pressure (MAP) above 65 mmHg, but excessive NE use, and a continuously low MAP are both associated with poor outcomes in OHCA. The glucocorticoid methylprednisolone (MP) has anti-inflammatory properties and may increase arterial sensitivity to NE, thereby improving MAP and reducing NE need. Aims: To determine if prehospital anti-inflammatory MP treatment could lower the need for NE without affecting MAP values following OHCA. Methods: The STEROHCA trial was a randomized, blinded, placebo-controlled, multicenter study, including adult comatose patients resuscitated from OHCA due to presumed cardiac etiology, and with a minimum of five minutes of return of spontaneous circulation. The intervention was intravenous MP 250 mg or placebo, administered prehospitally. In this sub-study, we repeatedly measured NE dose and MAP from admission until 48h and compared differences between the two groups at each time point. Results: In the STEROHCA trial, 137 patients were randomized to MP (n=68) or placebo (n=69). Patients were mainly male (85%) with a median age of 66 years (IQR 56, 75). The MP group demonstrated significantly lower NE use (mcg/kg/min) at 24h (0.22 (0.15; 0.31) vs. 0.38 (0.28; 0.49), p=0.02), 42h (0.13 (0.07; 0.20) vs. 0.25 (0.17; 0.35), p=0.03), and 48h (0.08 (0.03; 0.15) vs. 0.23 (0.15; 0.33), p=0.004), Figure 1 . We observed a higher MAP in the MP group with significantly higher MAP values (mmHg) at 6h (75 (72; 78) vs. 70 (67; 73), p=0.03), 12h (75 (71; 78) vs. 69 (66; 72), p=0.01), 18h (76 (73; 79) vs. 69 (66; 72), p=0.003), 24h (77 (74; 80) vs. 71 (68; 74), p=0.01), and 48h (86 (82; 89) vs. 79 (76; 82), p=0.004), Figure 1 . Conclusions: Prehospital treatment with high-dose MP reduced the need for NE while improving MAP values in resuscitated OHCA patients for the initial 48h of admission.

Abstract 429: The Association Between Naloxone Administration and Outcomes for Out-of-Hospital Cardiac Arrest Due to Suspected Overdose

Background: Opioid overdose is increasingly implicated in the development of out-of-hospital cardiac arrest (OHCA) and is a leading cause of death for adults 25 to 64 years old. Aim: Evaluate the association between naloxone use and outcomes after OHCA due to suspected overdose. Methods: This study was a secondary analysis of data collected in the Portland Cardiac Arrest Epidemiologic Registry, a database containing details of Emergency Medical Services (EMS)-treated cases of cardiac arrest around Portland, OR. Eligible patients had non-traumatic OHCA due to presumed overdose with naloxone (exposed) or without naloxone administration (control). We excluded patients with return of spontaneous circulation (ROSC) before the first dose of naloxone. The primary outcome was ROSC at emergency department (ED) arrival. Secondary outcomes included survival to admission; survival to hospital discharge; and cerebral perfusion category score ≤2 at discharge (functional survival). We performed multivariable logistic regressions adjusting for age, sex, arrest location, witness status, bystander interventions, initial EMS rhythm, time from 911 call to EMS arrival, and year of arrest. We separately assessed the subgroup with non-shockable initial rhythms. Results: Of 3,942 OHCA from 2018-2021, EMS documented an overdose etiology in 249. Of these, 236 (94.8%) had all variables and 18 were excluded for achieving ROSC prior to naloxone, resulting in 218 cases for analysis (171 receiving naloxone). Patients receiving naloxone had no difference in adjusted odds (aOR [95% CI]) of ROSC at ED arrival (1.43 [0.64-3.20]), survival to admission (1.87 [0.85-4.10]), survival to discharge (1.99 [0.39-10.30]) and functional survival (1.99 [0.34-11.55]). The subgroup with non-shockable rhythms showed higher odds of survival to admission (2.55 [1.09-5.92]) but not ROSC at ED arrival (1.60 [0.68-3.75]), survival to discharge (8.43 [0.84-84.20]), or good neurologic outcomes (7.26 [0.75-70.42]). Conclusions: For OHCA due to suspected overdose, those with initial non-shockable rhythms who received naloxone had higher adjusted odds of survival to admission than those who did not. Larger studies are necessary to evaluate the impact of naloxone on OHCA outcomes.

Abstract 262: Mediating Factors Between Community Race/Ethnicity and Initial Shockable Rhythm

Background: Initial shockable rhythm is an important predictor of favorable out-of-hospital cardiac arrest (OHCA) outcomes. While patients from minoritized communities suffer from lower rates of initial shockable rhythm, the reason for this disparity is not known. Hypothesis: OHCA characteristics contribute to disparities in initial shockable rhythm. Methods: We performed a retrospective study of the 2014-2021 Texas Cardiac Arrest Registry to Enhance Survival, including adult, non-traumatic OHCAs. Linked to census tract data, we stratified OHCAs based on having a majority of a race/ethnicity: >50% White, >50% Black, and >50% Hispanic/Latino. To evaluate if initial shockable rhythm impacts outcome disparities, we compared logistic regression models between race and OHCA outcomes: 1) unadjusted, 2) adjusted for bystander CPR (bCPR), and 3) adjusted for initial rhythm. Using structural equation modeling, we then performed a mediation analysis between race/ethnicity, OHCA characteristics, and shockable rhythm, reporting the mediations proportions. Results: We included 39,596 OHCAs, 16,702 White, 5,461 Black, and 17,433 Hispanic. The rate of shockable rhythm was 19.0% for White, 14.3% for Black, and 14.6% for Hispanic. Odds of favorable neurologic outcome were lower for Black (OR 0.5, 95% CI 0.4-0.6) and Hispanic (OR 0.6, 95% CI 0.6-0.7). While adjusting for bCPR did not change these odds, adjusting for shockable rhythm increased odds for Black (OR 0.6, 95% CI 0.5-0.7) and Hispanic (OR 0.7, 95% CI 0.6-0.8). On mediation analysis, the proportion of initial shockable rhythm mediated for Black census tract were: age>65 (-7.3%), male gender (6.8%), public location (6.9%), healthcare facility location (-17.2%), bystander witnessed (19.2%), bCPR (4.3%), and bystander AED (6.4%). The proportion mediated for Hispanic census tract were: age>65 (-4.8%), male gender (0.5%), public location (-4.0%), healthcare location (-13.5%), bystander witnessed (20.8%), bCPR (8.7%), and bystander AED (6.2%). Conclusion: Bystander witnessed arrest was the most significant mediator of shockable rhythm for OHCA in Black and Hispanic communities, while bCPR was a modest mediator of shockable rhythm for Hispanic OHCA victims.

Abstract 432: Temporal Trends in End Tidal Capnography and Outcomes in Out of Hospital Cardiac Arrest

Background: While widely measured and used to direct resuscitation, the time-varying relationship between exhaled end-tidal CO2 (ETCO2) and out-of-hospital cardiac arrest (OHCA) outcomes is unclear. We sought to determine the association between temporal trends in ETCO2 and return of spontaneous circulation (ROSC) in the Pragmatic Airway Resuscitation Trial (PART). Methods: We analyzed data from the PART Trial, which tested endotracheal intubation or laryngeal tube strategies in OHCA resuscitation. Emergency medical services collected continuous ETCO2 recordings using defibrillator monitors. We identified maximal ETCO2 values for each ventilation using previously validated automated signal processing. We determined mean ETCO2 in one-minute(min) epochs from advanced airway insertion through ROSC or end of event. We included all cases with interpretable ETCO2 signal in at least one of the epochs. We compared discrete time points between ROSC and non-ROSC using one way Mann-Whitney and determined the association between temporal trends in ETCO2 comparing the slopes of ETCO2 over time. Results: We included 1147 of 3004 patients with available ETCO2 data. There were 225(20%) ROSC and 923(80%) non-ROSC cases. Mean duration of resuscitation was 16 and 27 minutes for ROSC and non-ROSC cases, respectively. In ROSC cases, ETCO2 increased from 26.8 to 48.9 mmHg over 20-min prior to ROSC. In non-ROSC cases, ETCO2 declined from 30.6 to 21.7 mmHg over the 20-min. Mean ETCO 2 between ROSC and non-ROSC cases did not differ at t-10 (30.6 mmHg vs 26.1 mmHg, p=0.07) or t-20 min (26.8 mmHg vs 30.6 mmHg, p=0.71). However, ETCO 2 changes over time differed between ROSC and non-ROSC (p<0.01, figure 1). Conclusions: Upward temporal increases in ETCO 2 are associated with ROSC. Dynamic time-varying changes in ETCO2 may indicate OHCA outcomes.

Presentation and Outcomes of Adults With Overdose-Related Out-of-Hospital Cardiac Arrest

Drug overdose (OD) is a public health challenge and an important cause of out-of-hospital cardiac arrest (OHCA). Existing studies evaluating OD-related OHCA (OD-OHCA) either aggregate all drugs or focus on opioids. The epidemiology, presentation, and outcomes of drug-specific OHCA are largely unknown. To evaluate the temporal pattern, clinical presentation, care, and outcomes of adult patients with OHCA overall and according to the drug-specific profile. This cohort study of adults with OHCA in King County Washington was conducted between January 1, 2015, and December 31, 2021. Etiology of OHCA was determined using emergency medical service, hospital, and medical examiner records. Etiology was classified as non-OD OHCA or OD-OHCA, with drug-specific profiles categorized as (1) opioid without stimulant, (2) stimulant without opioid, (3) opioid and stimulant, or (4) all other nonstimulant, nonopioid drugs. Statistical analysis was performed on July 1, 2023. Out-of-hospital cardiac arrest. The primary outcome was survival to hospital discharge. The secondary outcome was survival with favorable functional status defined by Cerebral Performance Category 1 or 2 based on review of the hospital record. In this cohort study, there were 6790 adult patients with emergency medical services-treated OHCA from a US metropolitan system. During the 7-year study period, there were 702 patients with OD-OHCA (median age, 41 years [IQR, 29-53 years]; 64% male [n = 450] and 36% female [n = 252]) and 6088 patients with non-OD OHCA (median age, 66 years [IQR, 56-77 years]; 65% male [n = 3944] and 35% female [n = 2144]). The incidence of OD-OHCA increased from 5.2 (95% CI, 3.8-6.6) per 100 000 person-years in 2015 to 13.0 (95% CI, 10.9-15.1) per 100 000 person-years in 2021 (P < .001 for trend), whereas there was no significant temporal change in the incidence of non-OD OHCA (P = .30). OD-OHCA were more likely to be unwitnessed (66% [460 of 702] vs 41% [2515 of 6088]) and less likely to be shockable (8% [56 of 702] vs 25% [1529 of 6088]) compared with non-OD OHCA. Unadjusted survival was not different (20% [138 of 702] for OD vs 18% [1095 of 6088] for non-OD). When stratified by drug profile, combined opioid-stimulant OHCA demonstrated the greatest relative increase in incidence. Presentation and outcomes differed by drug profile. Patients with stimulant-only OHCA were more likely to have a shockable rhythm (24% [31 of 129]) compared with patients with opioid-only OHCA (4% [11 of 295]) or patients with combined stimulant-opioid OHCA 5% [10 of 205]), and they were more likely to have a witnessed arrest (50% [64 of 129]) compared with patients with OHCA due to other drugs (19% [14 of 73]) or patients with combined stimulant-opioid OHCA (23% [48 of 205]). Patients with a combined opioid-stimulant OHCA had the lowest survival to hospital discharge (10% [21 of 205]) compared with patients with stimulant-only OHCA (22% [29 of 129]) or patients with OHCA due to other drugs (26% [19 of 73]), a difference that persisted after multivariable adjustment. In a population-based cohort study, the incidence of OD-OHCA increased significantly from 2015 to 2021, with the greatest increase observed among patients with a combined stimulant-opioid OHCA. Presentation and outcome differed according to the drug-specific profile. The combination of increasing incidence and lower survival among among patients with a opioid-stimulant OHCA supports prevention and treatment initiatives that consider the drug-specific profile.

Abstract 341: Regional Variation in Cardiac Arrest Response and Outcomes in North Carolina - A Call to Action

Background: In the United States, despite advances in cardiac arrest systems of care, out of hospital cardiac arrest (OHCA) treatment and survival are highly variable. In North Carolina, intensive efforts to improve prehospital care are ongoing. We sought to investigate the variation in OHCA community response and outcomes in North Carolina (NC), and to assess underlying differences in system-, patient- and county-level characteristics in an effort to optimize regional cardiac arrest care. Methods: All adult (age &gt;18 years) OHCAs from 2016-2020 in 36 counties of North Carolina were included from the Cardiac Arrest Registry to Enhance Survival. We excluded cases that were EMS witnessed and that occurred in nursing homes. Response and outcome variation as well as county characteristics were described according to tertile of survival with good neurologic outcome (CPC 1/2). Results: Overall, 18,563 OHCAs occurred of which 22.4% had a shockable rhythm, 84.7% occurred at home and 50.7% were witnessed. Overall survival to hospital discharge with good neurologic outcome was 8.1%, with a state-wide variation among counties between 0% and 21.2% while Utstein survival was 26.1% overall, ranging between 0% and 47.8%. Bystander CPR rates were 41.8% (variation between 22.6% - 64.5%). First responder or bystander AED application was 42.9% of cases (variation between 8.6% - 66.6%) and 11.1% (variation between 2.7% and 19.7%) received defibrillation before EMS arrival. Counties within the highest tertile of survival were characterized by higher population density, lower unemployment rates and higher average household income. Such counties were further characterized by higher rates of bystander and first responder CPR and AED use prior to EMS arrival (Table 1). Conclusion: In NC, cardiac arrest response metrics and survival rates showed a dramatic regional variation, with particularly low survival in rural settings, calling for regional efforts to optimize cardiac arrest care.

Abstract 275: Point-of-Use Ultrasound in Out-of-Hospital Cardiac Arrest: A Meta-Analysis of Diagnostic Accuracy and Outcome Prediction

Background: Out-of-hospital cardiac arrest (OHCA) is a significant global health issue where accurate and rapid decision-making can often be the difference between life and death. Point-of-use ultrasound has been proposed as a potential tool to assist in such decisions by predicting patient outcomes. However, the current body of literature presents diverse results, thus emphasizing the need for an all-encompassing meta-analysis to assess the diagnostic accuracy of point-of-use ultrasound. Aim: This study aimed to determine the diagnostic accuracy of point-of-use ultrasound in predicting the outcomes of adult OHCA. Methods: We undertook a search of databases, including PubMed, Embase, and Cochrane Library, for studies published until November 2022 that investigated the role of point-of-use ultrasound in adult OHCA and its relation to patient outcomes. We utilized R software (version 4.0.3) equipped with the mada package for our statistical analysis, which allowed for pooling sensitivity, specificity, and false-positive rate estimates. Results: Nine studies were included in the final analysis. For survival to hospital discharge (four studies with a total of 1144 patients), the pooled sensitivity was 6.4% (95% Confidence Interval (CI): 1.2%-27.2%, I2=97.5%), specificity was 1.9% (95% CI: 0.9%-4.2%, I2=58.2%), the false-positive rate was 98.1% (95% CI: 95.8%-99.1%), the diagnostic odds ratio was 0.001 (95% CI: 0-0.009), positive LR was 0.065 (95% CI: 0.013-0.319), and negative LR was 49.15 (95% CI: 22.08-109.37). For the return of spontaneous circulation (ROSC) (six studies with a total of 1476 patients), the pooled sensitivity was 26.1% (95% CI: 17%-37.8%, I2=91.2%), specificity was 76.1% (95% CI: 42.1%-93.3%, I2=94.1%), the false-positive rate was 23.9% (95% CI: 6.7%-57.9%), diagnostic odds ratio was 1.13 (95% CI: 0.23-5.44), positive LR was 1.09 (95% CI: 0.33-3.61), and negative LR was 0.97 (95% CI: 0.66-1.42). Conclusion: Our study suggests that point-of-use ultrasound's predictive value for survival and ROSC in adult OHCA may be lower than anticipated, given high false-positive rates and low diagnostic odds ratios. These results underscore the need for further research before integrating ultrasound into OHCA decision-making.

Abstract 12704: Racial, Ethnic, and Socioeconomic Disparities in Incidence and Survival for Pediatric Out-of-Hospital Cardiac Arrest in the United States: A Report From the Cardiac Arrest Registry to Enhance Survival (CARES)

Introduction: Racial, ethnic, and socioeconomic disparities in pediatric out-of-hospital cardiac arrest (OHCA) exist; however, pediatric OHCA incidence and survival outcomes among race, ethnicity, and socioeconomic status (SES) are unknown. We evaluated the incidence and outcomes of pediatric OHCA among race, ethnicity, and SES, hypothesizing that Black and Hispanic children, and children from a lower SES, would have higher incidence rates and lower survival compared to White children. Methods: We conducted a retrospective cohort study using the Cardiac Arrest Registry to Enhance Survival database, analyzing nontraumatic OHCAs in children&lt;18 years old between 2015 and 2019. A previously validated SES risk score, incorporating race, ethnicity, household income, high school graduation rates, and unemployment rates, was developed on a scale from 0-4, with 4 indicating the highest-risk neighborhood. Results: Among 6945 OHCAs, 33% occurred in Black children, 11% in Hispanic children, 31% in White children, and 41% in the highest-risk neighborhood. Black children had the highest OHCA incidence (15.5 per 100,000 children) compared to White children (3.8 per 100,000 children) and Hispanic children (3.3 per 100,000 children) (p&lt;0.001). OHCA incidence was higher in high-risk neighborhoods (11.6 per 100,000) compared to low-risk neighborhoods (4.3 per 100,000) (p&lt;0.001). In multivariable analysis, Black children had lower odds of survival to hospital discharge (aOR 0.74, CI 0.59-0.92) and neurologically favorable survival (aOR 0.64, CI 0.50-0.82) compared to White children. Hispanic children did not have significantly worse survival outcomes compared to White children. Children from the lowest-risk neighborhoods had higher odds of survival to hospital discharge (aOR 1.45, CI 1.12-1.87) and neurologically favorable survival (aOR 1.65, CI 1.24-2.20) compared to children from the highest-risk neighborhoods. Conclusions: Significant racial, ethnic, and socioeconomic disparities exist in pediatric OHCA. Black children have over four times the incidence of OHCA compared to White and Hispanic children and significantly worse survival outcomes. Children from low-risk neighborhoods have significantly better survival outcomes.

Abstract 330: Severe Adverse Safety Events in Pediatric Out-of-Hospital Cardiac Arrest Resuscitation

Introduction: Survival for children with out-of-hospital cardiac arrest (OHCA) remains poor in spite of improvements in adult OHCA survival. Hypothesis: We hypothesized that severe adverse safety events (ASEs) are common during pediatric OHCA resuscitation and that specific patterns can be identified. Methods: Retrospective cohort study of patient care reports from 51 Emergency Medical Services (EMS) agencies across the US for children less than 18 years of age with an OHCA where resuscitation was attempted by EMS providers between 2013-2019. Results: We evaluated 1,019 encounters of EMS-treated pediatric OHCA; 46% were under 12 months of age. At least one severe ASE occurred in 610 patients (60%), and 310 patients (30%) had two or more. Children under 28 days of age had the highest frequency of ASEs. The most common severe ASEs involved epinephrine administration (30%), ventilation (14%), and vascular access (19%). Logistic regression modeling found that the only factor consistently associated with severe ASEs was young age. Birth-related OHCA had 4-fold greater odds of a severe ASE compared to adolescents (95% CI 1.7-10.7) and neonates with non-birth-related OHCA had 3.2-fold greater odds of a severe ASE (95% CI 1.1-9.0). Conclusions: In this large geographically diverse cohort of children with EMS-treated OHCA, 60% experienced at least one severe ASE. The odds of a severe ASE were over 3-fold higher for neonates than adolescents, and even higher when the cardiac arrest was birth-related. Given the national increase in out of hospital births and ongoing poor outcomes of OHCA in young children, these findings are an important and urgent call to action to focus on improving care delivery and training.

Abstract 220: Association Between Initial Defibrillator Pad Position And Outcomes For Out-of-hospital Cardiac Arrest Patients Presenting With Shockable Rhythms

Background: Ventricular fibrillation (VF) or ventricular tachycardia (VT) are the most treatable causes of out-of-hospital cardiac arrest (OHCA). Yet, it remains unknown if defibrillator pad position, placement in the anterior-posterior (AP) or anterior-lateral (AL) positions, impacts patient outcomes in VF/VT OHCA. Aim: Evaluate the association between initial defibrillator pad placement (AP vs. AL) and OHCA outcomes for patients presenting with VF/VT. Methods: This was a prospective observational study of non-traumatic OHCA patients with initial VF/VT on EMS rhythm analysis treated by a single EMS agency in the Portland Cardiac Arrest Epidemiologic Registry (PDX Epistry) from July 1st, 2019 through October 15th, 2022. Our primary outcome was return of spontaneous circulation (ROSC) at any time and secondary outcomes were ROSC at emergency department (ED) arrival, survival to admission, survival to discharge, and functional survival (cerebral perfusion category score of ≤2). We performed t-tests, chi-squared tests, and multivariable logistic regressions adjusting for age, sex, witness status, bystander interventions, arrest location, 911 call to EMS arrival time, and year of arrest. Results: A total of 243 OHCA patients met inclusion criteria and 232 (95.5%) had initial pad positioning documented (133 AP and 99 AL). Patients with AP placement had higher rates of ROSC at any time (72.2% vs. 47.5%, p&lt;0.001), survival to admission (56.4% vs. 41.4%, p=0.024), survival to discharge (36.1% vs. 24.2%, p=0.050), and functional survival (36.1% vs. 21.2%, p=0.012) compared to AL, with no difference for ROSC at ED arrival (52.6% vs. 40.4%, p=0.065). AP versus AL placement showed higher adjusted odds (aOR [95% CI]) for ROSC at any time (2.76 [1.55-4.93]) and functional survival (2.06 [1.05-4.05]), but not ROSC at ED arrival (1.50, [0.85-2.64]), survival to admission (1.69 [0.96-2.96]) or survival to discharge (1.68 [0.86-3.27]). Among patients with ROSC at ED arrival, patients with AP placement, had shorter times from 911 call to sustained ROSC (21.0 vs. 28.4 min, p=0.013). Conclusions: Initial AP pad placement, compared to AL, was associated with higher ROSC, a reduction in time to sustained ROSC, and higher functional survival for patients with VF/VT OHCA.

Abstract 264: Impact of Receiving Hospital on Disparities in Out-of-Hospital Cardiac Arrest

Background: Minority out-of-hospital cardiac arrest (OHCA) victims suffer from worse outcomes. The factors contributing to these disparities are not completely understood, and little is known about the impact of receiving hospital on OHCA. Hypothesis: Receiving hospital plays an important role in OHCA outcome disparities. Methods: We performed a retrospective, cohort study of the national Cardiac Arrest Registry to Enhance Survival (CARES). We included OHCAs from 2014- 2021 that survived to hospital admission. Based on census tract data, we stratified OHCAs based on majority race/ethnicity: &gt;50% White, &gt;50% Black, and &gt;50% Hispanic/Latino. We stratified hospitals into quartiles based on hospital rate of the outcome, survival with favorable neurologic outcome, cerebral performance category of 1 of 2. We evaluated the association between race/ethnicity and care at increasing hospital performance quartile. We compared four models evaluating the association between race/ethnicity and outcome: 1) omitting receiving hospital and bystander CPR (B-CPR), 2) adjusting for B-CPR, 2) additionally adjusting for receiving hospital as a random intercept, and 3) adjusting for hospital performance quartile. We adjusted all models for possible confounders. Results: We include 124,908 OHCAs that survived to hospital admission; 90,034 majority White, 20,600 majority Black, and 14,338 majority Hispanic. Compared to White, Black (OR 0.1, 95% CI 0.1-0.1) and Hispanic OHCAs were less likely to be cared for at high performing hospitals. Ignoring receiving hospital, outcomes were worse for Black (19.7%, aOR 0.43, 95% CI 0.40-0.46) and Hispanic (22.1%, aOR 0.49, 95% CI 0.45-0.54) than White (33.5%). While adjusting for B-CPR did not change survival odds, adjusting for receiving hospital as a random intercept improved outcome odds for Black (aOR 0.60, 95% CI 0.54-0.67) and Hispanic (aOR 0.61, 95% CI 0.53-0.69). Adjusting for hospital performance quartile also improved outcome odds for Black (aOR 0.79, 95% CI 0.73-0.85) and Hispanic/Latino (aOR 0.78, 95% CI 0.70-0.86). Conclusion: OHCAs from minority communities were less likely to be cared for at higher performing hospitals, and adjusting for receiving hospital significantly diminished OHCA outcome disparities.

Abstract 236: Agency Factors Associated With First Response Systems That Improve Out-of-Hospital Cardiac Arrest Outcomes

Background: Data are conflicting regarding the association between first responder (FR) cardiopulmonary resuscitation (CPR) and automated external defibrillator (AED) with improved outcomes after out-of-hospital cardiac arrest (OHCA). Additionally, little is known about why this association varies between EMS agencies, with FR interventions being associated with better survival for only some agencies. Hypothesis: Agency characteristic differ between agencies that do a do not successfully implement FR CPR/AED for OHCA. Methods: We studied the 2016-2021 national cardiac arrest registry to enhance survival (CARES) database. We defined the exposures as FR CPR and FR AED. The outcome was survival with favorable neurologic status. We used logistic regression models to evaluate the association between FR CPR/AED and OHCA outcome for each individual agency. Based on each agency’s association between FR AED/CPR and outcomes, we stratified agencies into positive association (95% confidence interval falling entirely above 1) and no association (95% confidence below or including 1). Agencies with poor model fit were excluded. We then compared characteristics between strata. Results: For the association between FR CPR and outcomes, 21 agencies caring for 42,856 patients had a positive association; 371 agencies caring for 449,824 OHCAs had no association. For FR AED, 47 agencies caring for 103,120 OHCAs had a positive association;262 agencies caring for 327,761 OHCAs had no association. For FR CPR and compared to the no association strata, agencies with a positive association had more annual OHCAs (+300), a lower rate of FR CPR (-11.3%), and a lower rate of FR AED (-10.8%). For FR AED and compared to the no association strata, agencies with a positive association FR AED and outcomes had more OHCAs per year (+150.5), a lower rate of FR CPR (-6.8%), a lower rate of FR AED (-13.3%), lower response times (-0.6 minutes), and more OHCAs from high-income neighborhoods (+3.7%). Conclusion: More agencies had a positive association between FR AED and survival with favorable neurologic outcome than between FR CPR and survival with favorable neurologic outcome. Agencies with better outcomes from FR interventions treated more OHCAs and had lower rates of FR intervention.

Abstract 417: Advanced vs. Basic Life Support Outcome Variation in the Treatment of Out-of-Hospital-Cardiac-Arrest in Detroit

Background: Out-of-Hospital-Cardiac-Arrest (OHCA) may be treated with Advanced Life Support (ALS) and Basic Life Support (BLS). Previous literature has indicated that ALS provides no additional benefit to OHCA patients. This study compared OHCA outcomes between prehospital ALS or BLS care in a city with a preponderance of BLS only care. Study Objectives: To test for associations between prehospital ALS or BLS care stratified by initial cardiac rhythm on ROSC, discharged alive from the hospital, and on favorable neurological outcome at hospital discharge in OHCA of a presumed cardiac origin. Methods: A retrospective cohort of 6746 patients with non-traumatic OHCA who received CPR from a transporting EMS agency was collected using the Cardiac Arrest Registry to Enhance Survival (CARES) database. Patients were sorted into 4 cohorts based on ALS vs BLS care and initial shockable vs non-shockable cardiac rhythms. Cohorts were compared utilizing chi-squared and multivariable logistic regression analysis against the outcome variables of sustained ROSC, discharged alive from the hospital, and a favorable neurological outcome at hospital discharge. Results: After controlling for covariates, the odds of sustained ROSC were statistically significantly higher for S-ALS vs. NS-BLS (OR=4.4, p.001), S-BLS vs. NS-BLS (OR=1.8, p.001), and NS-ALS vs. NS-BLS (OR=2.2, p.001). The association between cohort and discharged alive from the hospital was also statistically significant (p.001), and discharged alive rates were S-ALS (17.9%); S-BLS (11.8%); NS-ALS (3.7%); NS-BLS (4.0%). The association between cohort and favorable neurological outcome was also statistically significant (p.001), and outcome rates were S-ALS (74.6%); S-BLS (58.2%); NS-ALS (36.5%); NS-BLS (41.6%). The odds of favorable neurological outcome were higher for S-ALS vs. NS-BLS (OR=2.6, p.001). Conclusion: In contrast to previous literature, ALS care in the study was superior to BLS care. ALS care was associated with higher rates of ROSC in OHCA patients regardless of rhythm. Further, ALS care was associated with higher rates of being discharged alive from the hospital and favorable neurological outcomes among patients with a shockable rhythm.

Impact of Receiving Hospital on Out-of-Hospital Cardiac Arrest Outcome: Racial and Ethnic Disparities in Texas.

Background Factors associated with out-of-hospital cardiac arrest (OHCA) outcome disparities remain poorly understood. We evaluated the role of receiving hospital on OHCA outcome disparities. Methods and Results We studied people with OHCA who survivedto hospital admission from TX-CARES (Texas Cardiac Arrest Registry to Enhance Survival), 2014 to 2021. Using census data, we stratified OHCAs into majority (>50%) strata: non-Hispanic White race and ethnicity, non-Hispanic Black race and ethnicity, and Hispanic or Latino ethnicity. We stratified hospitals into performance quartiles based on the primary outcome, survival with good neurologic outcome. We evaluated the association between race and ethnicity and care at higher-performance hospitals. We compared 3 models evaluating the association between race and ethnicity and outcome: (1) ignoring hospital, (2) adjusting for hospital as a random intercept, and (3) adjusting for hospital performance quartile. We adjusted models for possible confounders. We included 10 434 OHCAs. Hospital performance quartile outcome rates ranged from 11.3% (fourth) to 37.1% (first). Compared with OHCAs in neighborhoods of majority White race, those in neighborhoods of majority Black race (odds ratio [OR], 0.1 [95% CI, 0.1-0.1]) and Hispanic or Latino ethnicity (OR, 0.2 [95% CI, 0.2-0.2]) were less likely to be cared for at higher-performing hospitals. Compared with White neighborhoods (30.1%) and ignoring hospital, outcomes were worse in Black neighborhoods (15.4%; adjusted OR [aOR], 0.5 [95% CI, 0.4-0.5]) and Hispanic or Latino neighborhoods (19.2%; aOR, 0.6 [95% CI, 0.5-0.7]). Adjusting for hospital as a random intercept, outcomes improved for Black neighborhoods (aOR, 0.9 [95% CI, 0.7-1.05]) and Hispanic or Latino neighborhoods (aOR, 0.9 [95% CI, 0.8-0.99]). Adjusting for hospital performance quartile, outcomes improved for Black neighborhoods (aOR, 0.8 [95% CI, 0.7-1.01]) and Hispanic or Latino neighborhoods (aOR, 0.9 [95% CI, 0.8-0.996]). Conclusions In Black and Hispanic or Latino communities, OHCAs were less likely to be cared for at higher-performing hospitals, and adjusting for receiving hospital improved OHCA outcome disparities.

The association of tibial vs. humeral intraosseous vascular access with patient outcomes in adult out-of-hospital cardiac arrests

AimHumeral and tibial intraosseous (IO) vascular access can deliver resuscitative medications for out-of-hospital cardiac arrest (OHCA), however the optimal site is unclear. We examined the association between IO tibia vs. humerus as the first-attempted vascular access site with OHCA outcomes. MethodsWe used prospectively-collected data from the British Columbia Cardiac Arrest registry, including adult OHCAs treated with IO humerus or IO tibia as the first-attempted intra-arrest vascular access. We fit logistic regression models on the full study cohort and a propensity-matched cohort, to estimate the association between IO site and both favorable neurological outcomes (Cerebral Performance Category 1–2) and survival at hospital discharge. ResultsWe included 1041 (43%) and 1404 (57%) OHCAs for whom IO humerus and tibia, respectively, were the first-attempted intra-arrest vascular access. Among humerus and tibia cases, 1010 (97%) and 1369 (98%) had first-attempt success, and the median paramedic arrival-to-successful access interval was 6.7 minutes (IQR 4.4–9.4) and 6.1 minutes (IQR 4.1–8.9), respectively. In the propensity-matched cohort (n = 2052), 31 (3.0%) and 44 (4.3%) cases had favourable neurological outcomes in the IO humerus and IO tibia groups, respectively; compared to IO humerus, we did not detect an association between IO tibia with favorable neurological outcomes (OR 1.44; 95% CI 0.90–2.29) or survival to hospital discharge (OR 1.29; 95% CI 0.83–2.01). Results using the full cohort were similar. ConclusionsWe did not detect an association between the first-attempted intra-arrest IO site (tibia vs. humerus) and clinical outcomes. Clinical trials are warranted to test differences between vascular access strategies.

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.

Emergency Medicine Perspectives: The Importance of Bystanders and Their Impact on On-Site Resuscitation Measures and Immediate Outcomes of Out-of-Hospital Cardiac Arrest.

Out-of-hospital cardiac arrests (OHCAs) represent critical medical emergencies in which timely interventions can make a significant difference in patient outcomes. Despite their importance, the role of on-scene witnesses during such events remains relatively unexplored. This research seeks to shed light on the influence of witnesses, especially family members, during OHCAs and the effect of their interventions, or the absence thereof, on outcomes. Drawing from existing literature, our working hypothesis suggests that the presence of a witness, particularly one who is knowledgeable about CPR, can increase the likelihood of obtaining the return of spontaneous circulation (ROSC), potentially enhancing overall survival rates. Using a retrospective analytical method, we thoroughly reviewed medical records from the Lublin Voivodeship between 2014-2017. Out of 5111 events identified using ICD-10 diagnosis codes and ICD-9 medical procedure codes, 4361 cases specifically related to sudden cardiac arrest were chosen. Concurrently, 750 events were excluded based on predefined criteria. Both basic and advanced EMS teams showed higher rates of CPR initiation and an increased likelihood of obtaining ROSC. Notably, the presence of a trained EMS professional as a witness significantly increased the chances of CPR initiation. The presenting rhythms most often detected were ventricular tachycardia (VT) and ventricular fibrillation (VF). Different urgency codes were directly linked to varying ROSC outcomes. When witnesses, especially family members, began chest compressions, the use of amiodarone was notably higher. A significant finding was that 46.85% of OHCA patients died without witnesses, while family members were present in 23.87% of cases. Actions taken by witnesses, especially chest compressions, generally extended the overall duration of patient care. The crucial influence of witnesses, particularly family members, on OHCA outcomes is evident. Therefore, it is essential to increase public awareness of CPR techniques and rapid intervention strategies to improve outcomes in emergency situations.

Prehospital factors associated with out-of-hospital cardiac arrest outcomes in a metropolitan city: a 4-year multicenter study

BackgroundPrehospital factors play a vital role in out-of-hospital cardiac arrest (OHCA) survivability, and they vary between countries and regions. We investigated the prehospital factors associated with OHCA outcomes in a single metropolitan city in the Republic of Korea.MethodsThis study included adult medical OHCA patients enrolled prospectively, using data from the citywide OHCA registry for patients registered between 2018 and 2021. The primary outcome was survival to hospital discharge. Multivariable logistic regression analysis was conducted to determine the factors associated with the study population’s clinical outcomes, adjusting for covariates. We performed a sensitivity analysis for clinical outcomes only for patients without prehospital return of spontaneous circulation prior to emergency medical service departure from the scene.ResultsIn multivariable logistic regression analysis, older age (odds ratio [OR] 0.96; 95% confidence interval [CI] 0.95–0.97), endotracheal intubation (adjusted odds ratio [aOR] 0.29; 95% [CIs] 0.17–0.51), supraglottic airway (aOR 0.29; 95% CI 0.17–0.51), prehospital mechanical chest compression device use (OR 0.13; 95% CI 0.08–0.18), and longer scene time interval (OR 0.96; 95% CI 0.93–1.00) were negatively associated with survival. Shockable rhythm (OR 24.54; 95% CI 12.99–42.00), pulseless electrical activity (OR 3.11; 95% CI 1.74–5.67), and witnessed cardiac arrest (OR 1.59; 95% CI 1.07–2.38) were positively associated with survival. In the sensitivity analysis, endotracheal intubation, supraglottic airway, prehospital mechanical chest compression device use, and longer scene time intervals were associated with significantly lower survival to hospital discharge.ConclusionsRegional resuscitation protocol should be revised based on the results of this study, and modifiable prehospital factors associated with lower survival of OHCA should be improved.

Predictors, Prevalence, and Clinical Outcomes of Out-of-Hospital Cardiac Arrests in Croatia: A Nationwide Study.

Out-of-hospital cardiac arrest (OHCA) remains a pivotal health challenge globally. In Croatia, there has been a knowledge gap regarding the prevalence, predictors, and outcomes of OHCA patients. This study aims to determine the prevalence, prediction, and outcomes of OHCA patients in Croatia. An extensive one-year analysis was performed on all OHCA treated by the Emergency Medical Service in Croatia, based on the Utstein recommendations. Data were extracted from Croatian Institute of Emergency Medicine databases, focusing on adult individuals who experienced sudden cardiac arrest in out-of-hospital settings in Croatia. From 7773 OHCA cases, 9.5% achieved spontaneous circulation pre-hospital. Optimal outcomes corresponded to EMS intervention within ≤13 min post-arrest onset AUC = 0.577 (95% CI: 0.56-0.59; p < 0.001) and female gender OR = 1.81 (95% CI: 1.49-2.19; p < 0.001). Northern Croatia witnessed lower success rates relative to the capital city Zagreb OR = 0.68 (95% CI: 0.50-0.93; p = 0.015). Early intervention by EMS, specifically within a 13-min period following the onset of a cardiac arrest, significantly enhances the probability of achieving successful OHCA outcomes. Gender differences and specific initial heart rhythms further influenced the likelihood of successful outcomes. Regional disparities, with reduced success rates in northern Croatia compared to the City of Zagreb, were evident.