Non-traumatic Out-of-hospital Cardiac Arrest Research Articles

Pre-Hospital Critical Care for Out-of-Hospital Cardiac Arrests with Return of Spontaneous Circulation: A Retrospective Observational Study

Background/Objectives: Out-of-hospital cardiac arrests (OHCAs) are common, with return of spontaneous circulation (ROSC) achieved in approximately 25% of patients. However, it remains unknown whether post-ROSC care delivered by a pre-hospital critical care team (CCT) improves patient outcomes. We therefore aimed to investigate this in OHCA patients admitted to our intensive care unit (ICU). Methods: In this retrospective observational study, consecutive adults with ROSC after non-traumatic OHCA admitted to our ICU between 1 September 2019 and 31 August 2022 were included. We compared patients who received post-ROSC care from a CCT to those who received standard care. The primary outcome was a good neurological outcome on hospital discharge (defined as Cerebral Performance Category 1–2). Descriptive statistics, Area Under the Receiver Operating Characteristic Curve (AUC) values, and adjusted Odds Ratios (ORs) are reported. We constructed multivariable logistic regression models that adjusted for the component variables of the MIRACLE2 score. Results: We included 126 OHCAs (median age 63 years, 69% male), which were largely witnessed (82%), involved bystander cardiopulmonary resuscitation (87%), and had an initial shockable rhythm (61%). The prevalence of good neurological outcomes was higher in patients who received post-ROSC care from a pre-hospital CCT (37% vs. 17%, p = 0.012). The MIRACLE2 score was a strong predictor of good neurological outcomes (AUC 0.932), and in our multivariable analysis, good neurological outcome was associated with both CCT presence post-ROSC (aOR 3.77, 95% CI 1.02–13.89) and the delivery of PHEA (aOR 4.10, 95% CI 1.10–15.27, p = 0.035). Furthermore, in patients meeting the Utstein criteria (n = 69), good neurological outcomes were also more prevalent with CCT presence post-ROSC (62% vs. 29%, p < 0.001). Conclusions: We found that post-ROSC care delivered by a pre-hospital CCT was associated with good neurological outcomes on hospital discharge.

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

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

Classifying Race in Out-of-Hospital Cardiac Arrest and Potential Disparities: A Retrospective Cohort Study.

Although racial disparities have been described in resuscitation, little is known about potential bias in race classification of out-of-hospital cardiac arrest (OHCA). We conducted a retrospective cohort study of adults treated by emergency medical services (EMS) for nontraumatic OHCA in King County, WA between January 1, 2018, and December 31, 2021. We assessed agreement using κ and evaluated patterns of missingness between EMS-assessed race versus comprehensive race classification from hospital and death records. Using multivariable logistic regression adjusting for Utstein data elements, we analyzed the association between race and OHCA survival across different sources. Among 5909 eligible OHCA patients, the average age was 64.0 years, 35.4% were female, and 16.1% survived to hospital discharge. Based on comprehensive race classification, 68.7% were White, 12.8% Black, 12.1% Asian, 2.5% multiracial, 2.3% Native Hawaiian/other Pacific Islander, and 1.6% American Indian/Alaska Native. EMS did not classify race in 43.7%. The κ coefficient between EMS and comprehensive race classification was 0.88 (95% CI, 0.86-0.90), though agreement varied substantially by specific race and was lowest among American Indian/Alaska Native (39.5%). Missingness in EMS records varied according to race and was greater among those classified as American Indian/Alaska Native (60.8%), Native Hawaiian/other Pacific Islander (58.8%), Asian (57.8%), or multiracial (54.1%) compared with White (40.6%) or Black (40.4%). In multivariable models using EMS-classified race, the odds ratio (OR) of survival was not significantly different for any race group compared with the White race, that is, OR. However, when using comprehensive race classification, OR of survival was significantly lower among Native Hawaiian/other Pacific Islander (OR, 0.57 [95% CI, 0.33-0.97]) and among multiracial (OR, 0.40 [95% CI, 0.20-0.75]) compared with White race. In adult OHCA, race misclassification and missingness influenced its association with survival. Efforts should continue to evaluate best practices to classify race correctly and comprehensively.

A retrospective 'target trial emulation' comparing amiodarone and lidocaine for adult out-of-hospital cardiac arrest resuscitation.

The administration of amiodarone or lidocaine is recommended during the resuscitation of out-of-hospital cardiac arrest (OHCA) patients presenting with defibrillation-refractory or recurrent ventricular fibrillation or ventricular tachycardia. Our objective was to use 'target trial emulation' methodology to compare the outcomes of patients who received amiodarone or lidocaine during resuscitation. Adult, non-traumatic OHCA patients in the ESO Data Collaborative 2018-2023 datasets who experienced OHCA prior to EMS arrival, presented with a shockable rhythm, and received amiodarone or lidocaine during resuscitation were evaluated for inclusion. We used propensity score matching (PSM) to investigate the association between antiarrhythmic and outcomes. Return of spontaneous circulation (ROSC) was the primary outcome. Secondary outcomes included the number of post-drug defibrillations and survival to hospital discharge. After application of exclusion criteria, 23,263 patients from 1,707 EMS agencies were eligible for analysis. Prior to PSM, 6,010/20,284 (29.6%) of the patients who received amiodarone and 1,071/2,979 (35.9%) of the patients who received lidocaine achieved prehospital ROSC. Following PSM, lidocaine administration was associated with greater odds of prehospital ROSC (36.0 vs. 30.4%; aOR: 1.29 [1.16, 1.44], n=2,976 matched pairs). Lidocaine administration was also associated with fewer post-drug defibrillations (median: 2 [0-4] vs. 2 [0-6], mean: 3.3 vs. 3.9, p<0.01, n=2,976 pairs), and greater odds of survival to discharge (35.1 vs. 25.7%; OR: 1.54 [1.19, 2.00], n=538 pairs). Our 'target trial emulation' suggested that lidocaine was associated with greater odds of prehospital ROSC in comparison to amiodarone when administered during resuscitation from shock refractory or recurrent VF/VT.

High Normocapnia and Better Functional Outcome in Patients Undergoing Veno-Arterial Extracorporeal Membrane Oxygenation After Out-of-Hospital Cardiac Arrest.

The optimal target for partial pressure of arterial carbon dioxide (PaCO₂) remains uncertain in patients undergoing veno-arterial extracorporeal membrane oxygenation (VA-ECMO) following out-of-hospital cardiac arrest (OHCA). Are PaCO₂ levels associated with functional outcomes in patients receiving VA-ECMO after OHCA? and Methods: This multicenter, registry-based observational study, conducted from 2014 to 2020, included non-traumatic adult OHCA patients on VA-ECMO with PaCO₂ levels measured within six hours of initiation (initial PaCO₂ set) and at 18-30 hours post-initiation (24-hour PaCO₂ set). PaCO₂ levels were categorized into five groups: hypocapnia (<30 mmHg), low normocapnia (30-<40 mmHg), high normocapnia (40-<50 mmHg), mild hypercapnia (50-<60 mmHg), and moderate to severe hypercapnia (≥60 mmHg). The primary outcome was the favorable functional outcome at 30 days, analyzed using multivariable logistic regression. PaCO₂ trajectories from initial to 24-hour levels were also explored. A total of 1,454 and 572 patients were analyzed in the initial and 24-hour PaCO₂ sets, respectively. Compared to high normocapnia, low normocapnia was associated with worse functional outcomes in both initial and 24-hour PaCO₂ analyses, with adjusted odds ratios of 0.59 (95% CI, 0.38-0.89) for initial low normocapnia and 0.56 (95% CI, 0.33-0.95) for 24-hour low normocapnia. Other categories were similarly associated with worse functional outcomes in both PaCO₂ analyses. In exploratory analyses, trajectories ending in high normocapnia demonstrated higher proportions of the favorable functional outcome than those ending in low normocapnia, regardless of initial PaCO₂ levels. In non-traumatic adult OHCA patients on VA-ECMO, high normocapnia was associated with better functional outcomes than low normocapnia in both initial and 24-hour PaCO₂ analyses. These findings suggest a hypothesis that maintaining high normocapnia levels, irrespective of initial PaCO2, may improve functional outcomes for patients on VA-ECMO after OHCA.

The “invisible ceiling” of bystander CPR in three Asian countries: Descriptive study of national OHCA registry

BackgroundBystander cardiopulmonary resuscitation (CPR) for out-of-hospital cardiac arrest (OHCA) has increased in Singapore, Japan, and South Korea following the implementation of several public health, bystander-focused interventions, such as dispatcher-assisted CPR and community CPR training. It is unclear whether bystander CPR prevalence will continue on this trajectory over time. This study aimed to investigate the temporal trends of bystander CPR prevalence over a ten-year period in these three Asian countries. MethodUsing the national OHCA registries of Singapore, Japan and South Korea, we included witnessed, non-traumatic adult OHCA registered between 2010 and 2020 in Singapore and Japan, and between 2012 and 2020 in South Korea. We excluded those for whom resuscitation was not attempted or was terminated at scene. The study analysed the proportion of bystander CPR in the three countries, presenting the data annually and further breaking it down by age and gender. ResultsThis study included 491,067 patients in Japan [male 59 %, median, age 79 years (Q1-Q3, 69–87)], 13,143 patients in Singapore [male 66 %, median, age 69 years (Q1-Q3, 57–80)], and 87,997 patients in South Korea [male 64 %, median age 72 years (Q1-Q3, 59–81)]. The proportion of bystander CPR in each country had increased (Japan: 39 % in 2010 to 45 % in 2015, Singapore: 22 % in 2010 to 53 % in 2015, and South Korea: 37 % in 2012 to 56 % in 2015); however, these proportions have plateaued in 2020 (Japan: 46 %, Singapore: 54 %, and South Korea: 57 %) despite continued efforts. These trends were consistent across different age groups, gender and location. ConclusionThis study investigated the trend of bystander CPR over 10 years in three Asian countries. Although the proportion of bystander CPR has increased, it has now plateaued between 50–60 %. Further research is necessary to identify the contributing factors and advance beyond this “invisible ceiling”.

The association between initial defibrillation dose and outcomes following adult out-of-hospital cardiac arrest resuscitation: A retrospective, multi-agency study.

Effective defibrillation is essential to out-of-hospital cardiac arrest (OHCA) survival. International guidelines recommend initial defibrillation energies between 120 and 360 Joules, which has led to widespread practice variation. Leveraging this natural experiment, we aimed to explore the association between initial defibrillation dose and outcome following OHCA. The ESO Data Collaborative (2018-2022) was used for this nationwide, retrospective study of adult (18-80years of age) non-traumatic OHCA patients who presented with an initially shockable ECG rhythm. We excluded patients if they had ROSC prior to initial defibrillation, a resuscitation-limiting advanced directive, or were residents in a healthcare institution. The primary exposure was initial defibrillation dose, defined as Joules per kilogram of body weight, and the primary outcome was return of spontaneous circulation (ROSC). We included survival to discharge as a secondary outcome. We used multivariable logistic regression modeling to assess the relationship between defibrillation dose and outcome. We analyzed data from 21,121 patients. Of the 12,160 patients linked to a defibrillator manufacturer, 7,240 (59.5%) were treated using a biphasic truncated exponential (BTE) waveform and 4,920 (40.5%) were treated using a rectilinear biphasic (RLB) waveform. Defibrillation dose (per 1J/kg increase) was not associated with ROSC (BTE aOR: 0.97 [0.92, 1.01], n=7,240; RLB aOR: 1.00 [0.92, 1.09], n=4,920; all aOR: 1.01 [0.98, 1.04], 21,121) or survival (BTE aOR: 0.98 [0.87, 1.10], n=1,245; RLB aOR: 0.89 [0.70, 1.12], n=775; all aOR: 1.00 [0.92, 1.08], n=2,981). Initial defibrillation dose was not associated with outcome in this nationwide cohort.

Preexisting hemodialysis and survival outcome in out-of-hospital cardiac arrest patients: Ulsan, South Korea.

Although the incidence of sudden cardiac death is higher in hemodialysis (HD) patients, whether out-of-hospital cardiac arrest (OHCA) survival outcomes are poorer in this group remains unclear. This study aimed to assess the impact of HD on survival outcomes among adult nontraumatic OHCA patients and to compare these outcomes between HD and non-HD groups. This observational cohort study retrospectively analyzed data from adult nontraumatic OHCA patients in Ulsan, South Korea, from January 2017 through December 2022. Multivariable logistic regression analysis was applied to evaluate whether HD was a risk factor for survival in OHCA patients. Survival was compared between the two groups in unadjusted, balanced groups by propensity score matching (PSM) and inverse probability of the treatment weighting (IPWT). The study included 2,489 patients (64 HD group and 2,425 non-HD group). Undergoing HD was not significantly associated with any return of spontaneous circulation (ROSC) (adjusted odds ratio [95% confidence interval], p-value, 1.648 [0.934-2.907], 0.085), survival to discharge (1.544 [0.734-3.250], 0.252), or neurological outcomes (0.394 [0.017-9.346], 0.564). There were also no significant differences observed in any ROSC (1.648 [0.934-2.907], 0.085), survival to discharge (1.544 [0.734-3.250], 0.252), or favorable neurological outcome (0.394 [0.017-9.346], 0.564) between the two unadjusted groups. The insignificant survival differences were persistently observed in the PSM group and IPWT group. Although HD may pose a risk factor for cardiac arrest, our study did not find a significant association with survival outcomes in OHCA patients. Additionally, no notable survival difference was observed between HD and non-HD groups. Therefore, resuscitation efforts in HD patients should not be underestimated.

The role of hospital performance on race and ethnicity outcome disparities for US non-traumatic out-of-hospital cardiac arrests.

Factors contributing to worse outcomes for out-of-hospital cardiac arrests (OHCA) from minoritized communities are poorly understood. We sought to evaluate the impact of receiving hospital performance on OHCA outcome disparities. We performed a retrospective cohort study of non-traumatic OHCAs from the National Cardiac Arrest Registry to Enhance Survival from 2013 to 2022 that survived hospital admission. We created cohorts based on census-tract race/ethnicity: >50% White, >50% Black, and >50% Hispanic/Latino. We stratified hospitals into performance quartiles based on hospital good neurologic outcome rates. We evaluated the association between race/ethnicity and care at better-performing hospitals. Using hierarchical modeling, we compared models evaluating the association between community race/ethnicity and outcomes, ignoring and adjusting for receiving hospital. We included 202,117 OHCAs. Compared to White, OHCAs from Black (OR 0.12[0.12-0.13]) and Hispanic/Latino (OR 0.21[0.20-0.21]) communities had lower odds of care at higher-performing hospitals, but care at higher-performing hospitals improved outcomes for all groups: White - OR 1.43[1.41-1.44]), Black - OR 1.54[1.50-1.59]), Hispanic/Latino - 1.51[1.46-1.56]. Ignoring receiving hospital, outcomes were worse for OHCAs from Black (aOR 0.56[0.54-0.58]) and Hispanic/Latino (aOR 0.63[0.61-0.66]) communities. Although adjusting for bystander cardiopulmonary resuscitation did not change results, adjusting for hospital performance quartile improved outcome odds (Black - aOR 0.80[0.76-0.84]; Hispanic/Latino - aOR 0.82[0.78-0.86]). Adjusting for receiving hospital random effect also improved outcome odds (Black - aOR 0.84[0.81-0.87]; Hispanic Latino - aOR 0.86[0.83-0.90]). OHCAs from Black and Hispanic/Latino communities received care at high-performing hospitals less often, and adjusting for receiving hospital significantly diminished OHCA outcome disparities.

Real-world cost-effectiveness of targeted temperature management in out-of-hospital cardiac arrest survivors: results from an academic medical center.

Targeted temperature management (TTM) is a common therapeutic intervention, yet its cost-effectiveness remains uncertain. This study aimed to evaluate the real-world cost-effectiveness of TTM compared with that of conventional care in adult out-of-hospital cardiac arrest (OHCA) survivors using clinical patient-level data. We conducted a retrospective cohort study at an academic medical center in the USA to assess the cost-effectiveness of TTM in adult non-traumatic OHCA survivors between 1 January, 2019 and 30 June, 2023. The primary outcome was survival to hospital discharge. Incremental cost-effectiveness ratios (ICERs) were calculated and compared with various decision makers' willingness to pay. Cost-effectiveness acceptability curves were utilized to evaluate the economic attractiveness of TTM. Uncertainty about the incremental cost and effect was explored with a 95% confidence ellipse. Among 925 non-traumatic OHCA survivors, only 30 (3%) received TTM. After adjusting for potential confounders, the TTM group did not demonstrate a significantly lower cost (delta cost -$5,141, 95% confidence interval [95% CI]: $-35,347 to $25,065, P=0.79) and higher survival to hospital discharge (delta effect 6%, 95% CI: -11% to 23%, P=0.41). Additionally, a 95% confidence ellipse indicated uncertainty reflected by evidence that the true value of the ICER could be in any of the quadrants of the cost-effectiveness plane. Although TTM did not demonstrate a clear survival benefit in this study, its potential cost-effectiveness warrants further investigation with larger sample sizes. These findings highlight the need for additional research to optimize TTM use in OHCA care and inform resource allocation decisions.

Abstract 4137878: Trends in Survival After Out-of-Hospital Cardiac Arrest Across Community Demographics Since the COVID-19 Pandemic

Background: The COVID-19 pandemic in 2020 was marked by a sharp decrease in out-of-hospital cardiac arrest (OHCA) survival. Whether OHCA survival has recovered to pre-pandemic levels, and whether changes in OHCA survival are similar across communities of different racial and ethnic composition, is unknown. Methods: We included adult patients with non-traumatic OHCA from 2015-2022 in the Cardiac Arrest Registry to Enhance Survival registry. Using hierarchical multivariable regression, we calculated risk-adjusted rates of survival to hospital discharge during 2015-2019 (reference period) and compared this to survival rates during 2020, 2021, and 2022. We also examined whether the trajectory of survival over this period differed based on the racial/ethnic composition of the community served by the emergency medical service (EMS) agency, defined as predominantly White (&gt;80% White residents), majority Black or Hispanic (&gt;50% Black or Hispanic residents), or integrated (neither). Results: Of 485,079 patients with OHCA, mean age was 61.9 years; 64% were male, and 22% were of Black race with 7% of Hispanic ethnicity. Overall, risk-adjusted survival rates to hospital discharge for OHCA decreased from 10.1% in 2015-2019 to 8.4% in 2020 (P&lt;0.0001). The relative decrease was similar at EMS agencies serving predominantly Black and Hispanic communities (-17.2%) as compared to predominantly White (-17.5%) or integrated communities (-16.8%). Risk-adjusted survival rates recovered partially in 2021 (8.7%) and 2022 (8.9%) but remained below the pre-pandemic period. As of 2022, OHCA survival in majority Black and Hispanic communities was still 9.7% lower, as compared to pre-pandemic years, whereas it was 10.9% lower in integrated communities and 13.6% lower in predominately White communities. Moreover, the survival disparity for OHCAs in Black/Hispanic vs. White communities narrowed to 0.4% (8.4% vs. 8.8%) in 2022, as compared to 1.0% (9.3% vs. 10.3%) prior to the pandemic. Conclusions: OHCA survival has improved in the U.S. since the initial pandemic year of 2020, but remains lower than the pre-pandemic years. The survival disparity for OHCAs occurring in majority Black and Hispanic relative to predominately White communities decreased since 2020, although absolute survival remained lower in majority Black and Hispanic communities throughout the study period.

Abstract Su703: Racial/Ethnic Disparities in Bystander Cardiopulmonary Resuscitation after Witnessed Out-of-Hospital Cardiac Arrest: A NEMSIS Database Study

Introduction: Out of hospital cardiac arrest (OHCA) is a leading cause of death in the United States, with upwards of 360,000 OHCAs annually. Receiving bystander cardiopulmonary resuscitation (CPR) almost doubles an individual’s odds of survival compared to those who don’t receive bystander CPR. Unfortunately, in the US, bystander application of CPR only occurs in 40% of OHCA. Improving the rate of bystander CPR and AED use will improve survival rates for OHCA. Minoritized populations experience worse outcomes from OHCA. Compared to non-Hispanic whites, they are less likely to survive to hospital discharge. A cross-sectional study of witnessed OHCA patients found that Black and Hispanic patients had lower rates of bystander CPR. Less is known about disparities in care for Asian American persons who experience OHCA. Studies using the Resuscitation Outcomes Consortium Epidemiologic Registry (ROC) and the Cardiac Arrest Registry to Enhance Survival (CARES) have concluded discrepant results, with ROC finding that Asian Americans were less likely to receive bystander CPR and CARES finding that they were just as likely to receive bystander CPR compared to non-Hispanic Whites. To that end, we sought to evaluate the association between bystander CPR and Asian race after witnessed OHCA. Objective: To evaluate the association between race/ethnicity and the odds of receiving bystander cardiopulmonary resuscitation (bCPR) after witnessed out-of-hospital cardiac arrest (OHCA). Methods: Data were obtained from the National Emergency Medical Services Information System (NEMSIS) database for adults (≥18 years) with a witnessed non-traumatic OHCA in the year 2022. Patients were separated into two groups: Non-Hispanic White and Asians. The primary outcome was the odds of receiving bCPR. Exclusions included traumatic etiology, do-not-resuscitate orders, and arrests witnessed by healthcare providers. Pearson’s chi-square test was used to test significance. Results: A total of 73,215 witnessed OHCA activations were included in this study. Overall, bystander CPR rates were lower for the Asian group (59.8%) compared to the Non-Hispanic White group (65.0%). Pearson’s chi-square test showed a statistically significant difference between the bCPR rates of the Asian group and Non-Hispanic White group, with a p-value of less than 0.001. Conclusion: Racial/ethnic disparities exist for Asian individuals in the odds of receiving bCPR after a witnessed non-traumatic OHCA.

Abstract Su804: Use of Machine Learning Models to Predict Neurologically Intact Survival for Advanced Age Adults Following Out-of-hospital Cardiac Arrest

Background: We recently published a multivariable logistic regression model that successfully predicted neurologic outcomes in advanced age adults (≥ 65 years old) who achieve return of spontaneous circulation following out-of-hospital cardiac arrest (OHCA). Prior to externally validating this model, we sought to compare the predictive performance of our logistic regression model against common machine learning (ML) algorithms using the same dataset. Methods: We performed a retrospective observational analysis of the Cardiac Arrest Registry to Enhance Survival database from 2013-2021. All non-traumatic OHCA occurring in adults (≥65 years) who survived to hospital admission were included. The primary outcome measure was neurologically intact survival defined as a cerebral performance category (CPC) score of 1 or 2 at hospital discharge. Our original logistic regression model was compared to Boosted Trees and Decision Tree ML algorithms and assessed using accuracy, Area Under the Receiver Operating Characteristic Curve (AUC-ROC) and Area Under the Precision-Recall Curve (AUC-PR). The model variables included age, gender, race/ethnicity, location, witnessed status, who initiated cardiopulmonary resuscitation, whether an automated external defibrillator was applied prior to emergency medical services arrival, and first monitored rhythm. Results: A total of 83,561 OHCA were included. Median age was 75 years (IQR 69-82), 58.9% were male, 53% were White, 67% experienced an OHCA at home, 52% were witnessed by a bystander, 44% received bystander CPR, and 34% were found in shockable rhythm. Neurologically intact survival (CPC 1 or 2) occurred in 23% of patients. The logistic regression model had an accuracy of 79.6%, AUC-PR 0.542, and AUC-ROC of 0.774. The Boosted Trees model had an accuracy of 79.2%, AUC-PR 0.555, and AUC-ROC of 0.774. The Decision Tree Model had an accuracy of 79.3%, AUC-PR 0.490, and AUC-ROC of 0.717. Conclusion: Boosted Trees and Decision Tree ML models performed comparably to the logistic regression model in predicting favorable versus unfavorable neurological outcomes following successful resuscitation from OHCA in advanced-age adults. Given their similar performance, logistic regression may be preferred for its simplicity and interpretability over alternative ML models. Future efforts to improve and ultimately externally validate the model are warranted.

Abstract Su1205: The Effect of Targeted Temperature Management on Five-Year Mortality in Comatose Out-of-Hospital Cardiac Arrest Survivors: A Real-World Experience

Background: Hypothermia-Induced Targeted Temperature Management (TTM) is a neuroprotective treatment after the return of spontaneous circulation (ROSC) in comatose survivors of out-of-hospital cardiac arrest (OHCA). However, its effectiveness in all patient subpopulations is debated. While short-term survival has been well studied, the impact of TTM on long-term survival is still unknown. Methods: In a prospective cohort study, 98 comatose survivors of non-traumatic OHCA were recruited from four tertiary-level hospitals in Buffalo, Western New York and followed up for five years. Patients with active cancer, infection, cardiac pathology or surgery in three-month prior to presentation, were excluded. Cardiac arrest characteristics, demographics, comorbidities, and therapeutic interventions were recorded. According to TTM protocols, a target body temperature of 33°C was reached and maintained for 24 hours using either an intravascular cooling catheter or a surface cooling system. This was followed by gradual controlled rewarming over 12-24 hours to normothermia. Factors associated with the receipt of TTM were determined. The effect of TTM on five-year survival was studied using cox-regression analysis. Results: Among comatose patients with mean age of 60.1±14.9 years, 49% received TTM. Females were significantly less likely to receive TTM (35.1% vs 59.3%, p=0.021). In TTM group, the time to ROSC was significantly longer: median [IQR] 14.5 mins (5-19.7) vs 20 mins (12-27), p=0.018. TTM group was more likely to have a history of coronary artery disease (CAD) (12.5% vs 35.4%, p=0.009). Overall, 5-year mortality did not differ significantly between TTM vs. non-TTM: 72.9% vs 66.0%, (HR: 1.134, 95% CI: 0.705-1.826, p=0.603) in univariate and multivariate Cox-regression analysis (Table 1). Conclusion: While females are less likely to receive TTM treatment, TTM is more likely to be used in patients with a longer time to ROSC and a history of CAD. The overall five-year survival remains high in both treatment groups in all eligible patients, as well as in shockable and non-shockable rhythm groups studied separately. Larger cohort studies are needed to determine the patients who may benefit most from TTM.

Clinical Significance of Whole-Body Computed Tomography Scans in Pediatric Out-of-Hospital Cardiac Arrest Patients Without Prehospital Return of Spontaneous Circulation.

Background. Whole-body computed tomography (WBCT) is commonly employed for primary screening in pediatric patients experiencing out-of-hospital cardiac arrest (OHCA) without prehospital return of spontaneous circulation (ROSC). This study aimed to evaluate the cause of OHCA on WBCT and compare WBCT findings between ROSC and non-ROSC groups in non-traumatic pediatric OHCA cases in an emergency department setting. Methods. A retrospective analysis was conducted on 27 pediatric patients (mean age: 32.4 months; median age: 10 months) who experienced non-traumatic OHCA without prehospital ROSC and were transported to our tertiary care hospital between January 2013 and December 2023. WBCT scans were performed to investigate the cause of OHCA, with recorded findings in the head, chest, abdomen, and subcutaneous tissues. Results. In all cases, the direct causes of OHCA were undetermined, and WBCT identified no fatal findings. Statistical comparisons of CT findings between the ROSC and non-ROSC groups revealed significant differences. The non-ROSC group had a higher incidence of brain swelling, loss of cerebral gray-white matter differentiation, symmetrical lung consolidation/ground-glass opacity, cardiomegaly, hyperdense aortic walls, narrowed aorta, gas in the mediastinum, and hepatomegaly compared to the ROSC group. Conclusions. Although WBCT did not reveal the direct cause of OHCA, several CT findings were significantly more frequent in the non-ROSC group, including brain swelling, loss of cerebral gray-white matter differentiation, symmetrical lung consolidation/ground-glass opacity, cardiomegaly, hyperdense aortic wall, narrowed aorta, gas in the mediastinum, and hepatomegaly. These findings, resembling postmortem changes, may aid in clinical decision making regarding the continuation or cessation of resuscitation efforts in pediatric OHCA cases.

The Association of Time to Key Prehospital Interventions Recorded by EMT-Worn video Devices and Sustained Return of Spontaneous Circulation in Out-of-Hospital Cardiac Arrest

Objectives The quality of prehospital resuscitation provided by emergency medical technicians (EMTs) is essential to ensure better outcomes following out-of-hospital cardiac arrests (OHCA). We assessed the quality of prehospital resuscitation by recording time to key prehospital interventions using EMT-worn video devices and investigated its association with outcomes of patients with OHCA. Methods This retrospective, cross-sectional study included cases of non-traumatic OHCA in adults treated by emergency medical services (EMS) in Hsinchu City, Taiwan, during 2022 and 2023. We used data from high-resolution, chest-mounted wearable cameras to define and measure six quality indices (QIs) for prehospital resuscitation interventions (i.e., time spent recognizing OHCA). To evaluate the association between QI performance and sustained return of spontaneous circulation (ROSC), we used multivariable logistic regression. Results Of 745 patients eligible for this study, 187 (25.1%) achieved sustained ROSC. Six core QIs were analyzed: recognition of OHCA (median time: 9.0 s), time from recognizing OHCA to initiating cardiopulmonary resuscitation (cardiopulmonary resuscitation [CPR]; 9.0 s), automated external defibrillator setup (34.0 s), time from recognizing OHCA to beginning ventilation (160.0 s), advanced airway management (300 s), and deploying a mechanical CPR device (50 s). The performance of the six QIs were not associated with sustained ROSC (Adjusted odds ratio [95% confidence interval]: 1.00 [0.99–1.00], 0.99 [0.98–1.00], 1.00 [1.00–1.01], 1.00 [1.00–1.00], 1.00 [1.00–1.00], and 0.99 [0.99–1.00], respectively). Conclusions This study describes the rate of sustained ROSC and time to key interventions captured by EMT-worn video devices in non-traumatic OHCA patients. Although we found no direct link between QI performance and improved OHCA outcomes, this study highlights the potential of video-assisted QIs to enhance the documentation and understanding of prehospital resuscitation processes. These findings suggest that further refinement and application of these QIs could support more effective resuscitation strategies and training programs.

The Route to ROSC: Evaluating the Impact of Route and Timing of Epinephrine Administration in Out-of-Hospital Cardiac Arrest Outcomes

Objectives Previous investigations comparing intraosseous (IO) and intravenous (IV) epinephrine delivery in out-of-hospital cardiac arrest (OHCA) suggest that epinephrine is oftentimes more expeditiously administered via the IO route, but this temporal benefit doesn’t always translate to clinical benefit. However, very few studies adequately controlled for indication and resuscitation time biases, making the influence of first epinephrine route on OHCA outcomes unclear. To determine the association between first epinephrine route and return of spontaneous circulation (ROSC) while controlling for resuscitation time bias and other potential confounders. Methods We conducted a retrospective analysis using the 2020 ESO Data Collaborative dataset. Adult patients with a witnessed, non-traumatic OHCA prior to EMS arrival were included. Logistic regression was used to determine the association between medication route and ROSC. Linear regression was then used to calculate the probability of ROSC for each route across all call receipt-to-drug delivery intervals. Using these linear equations, the call receipt-to-drug delivery intervals were calculated that would yield equivalent probabilities of ROSC between the IV and IO routes. Results Data were available for 10,350 patients, of which 27.4% presented with a shockable rhythm, 29.7% received bystander CPR, and 39.6% experienced ROSC. After controlling for confounders, IO epinephrine was associated with decreased likelihood of ROSC (OR = 0.77, p < 0.001). The linear regression models provided differing slope coefficients for ROSC between each route, with the IV route associated with a higher likelihood of ROSC for any given call receipt-to-drug-delivery interval. From these equations, the additional time allowed to establish an IV and administer epinephrine intravenously beyond the time required for IO delivery, yet with an equivalent predicted probability of ROSC via the IO route, was calculated. This additional time interval for intravenous administration declined linearly from 9 min at a call receipt-to-intraosseous epinephrine interval of 4 min to no additional time at a call receipt-to-intraosseous epinephrine interval of 29 min. Conclusions This retrospective analysis of a national EMS database revealed that IO epinephrine was negatively associated with ROSC. Additionally, there appears to be a finite time window during which intravenous epinephrine remains superior to the intraosseous route even if there are brief initial delays in IV drug delivery.

Derivation of a clinical decision rule for termination of resuscitation in non-traumatic pediatric out-of-hospital cardiac arrest

AimPrehospital termination of resuscitation (ToR) rules are used to predict medical futility in adult out-of-hospital cardiac arrest (OHCA), however, the available evidence for pediatric patients is limited. The primary aim of this study is to derive a Pediatric Termination of Resuscitation (PToR) prediction rule for use in pediatric non-traumatic OHCA patients. MethodsWe analyzed a retrospective cohort of pediatric OHCA patients within the CARES database over a 10-year period (2013–2022). We split the dataset into training and test datasets and fit logistic regressions with Least Absolute Shrinkage and Selection Operator (LASSO) to select predictor variables and estimate predictive test characteristics for the primary outcome of death and a secondary composite outcome of death or survival to hospital discharge with unfavorable neurologic status. ResultsWe analyzed a sample of 21,240 children where 2,326 (11.0%) survived to hospital discharge, and 1,894 (8.9%) survived to hospital discharge with favorable neurologic status. We derived a PToR rule for death demonstrating a specificity of 99.1% and a positive predictive value (PPV) of 99.8% and a PToR rule for death or survival with poor neurologic status with a specificity of 99.7% and PPV of 99.9% within the test dataset. ConclusionWe derived a clinical prediction rule with high specificity and positive predictive value in prehospital settings utilizing Advanced Life Support (ALS) providers which may inform termination of resuscitation considerations in pediatric patients. Further prospective and validation studies will be necessary to define the appropriateness and applicability of these PToR criteria for routine use.

Association between pre-arrest left ventricular ejection fraction and survival in nontraumatic out-of-hospital cardiac arrest.

Out-of-hospital cardiac arrest (OHCA) poses major public health issues. Pre-arrest heart function is a prognostic factor, but the specific contribution of pre-arrest echocardiographic evaluation in predicting OHCA outcome remains limited. The primary objective was to investigate the association between left ventricular ejection fraction (LVEF) measured in echocardiography prior to OHCA and survival to hospital discharge. This multicenter retrospective cohort study analyzed data from the National Taiwan University Hospital and its affiliated hospitals. We included adult nontraumatic OHCA patients who were treated by the emergency medical services (EMS) and underwent echocardiography within 6 months prior to the OHCA event from January 2016 to December 2022. Data included demographics, preexisting diseases, resuscitation events, and echocardiographic reports. The primary outcome was the survival to hospital discharge after post-arrest care. Statistical analysis involved multivariable logistic regression to modify potential confounders, reported as adjusted odds ratio (aOR) and 95% confidence interval (CI), and evaluate the association between echocardiographic findings and survival to hospital discharge. This study analyzed 950 patients, with 33.6% surviving to discharge. A higher pre-arrest LVEF was independently associated with increased survival. Compared to patients with LVEF < 40%, those with LVEF between 40% and 60% had significantly higher odds of survival (aOR = 3.68, 95% CI = 2.14-6.35, P < 0.001), and those with LVEF > 60% had even greater odds of survival (aOR = 5.46, 95% CI = 3.09-9.66, P < 0.001). There was also an association between lower tricuspid regurgitation pressure gradient and survival (aOR = 0.98, 95% CI = 0.97-1.00, P = 0.015). Younger age, male gender, dyslipidemia, stroke, cancer, witnessed arrest, initial shockable rhythm, and shorter low-flow time are other significant predictors of survival. In adult, nontraumatic, EMS-treated OHCA patients, a higher LVEF 6 months prior to OHCA was associated with improved survival at hospital discharge.

Incidence, characteristics, and prehospital outcomes of out-of-hospital cardiac arrest in Qatar: a nationwide gender-based investigation

BackgroundResearch on incidence and characteristics of Out-of-Hospital Cardiac Arrest (OHCA) in the Middle East is limited. We assessed the incidence, prehospital characteristics, and outcomes of OHCA in Qatar, a Middle Eastern country. Subsequently, we performed gender-specific analysis.MethodsThis was a retrospective examination of data obtained from the OHCA registry at Hamad Medical Corporation (HMC) in Qatar from 2017 to 2022. We included adults, non-traumatic, EMS-treatment OHCA. We calculated the incidence of adult OHCA and conducted descriptive analyses for prehospital characteristics, and prehospital outcomes presented by return of spontaneous circulation (ROSC). We evaluated gender differences in prehospital characteristics and ROSC using Student’s t-test and the Chi-Square test as appropriate. Furthermore, we conducted a multivariable logistic regression analysis to investigate the correlation between gender and achieving ROSC.ResultsWe included 4,306 adult OHCA patients, with 869 (20.2%) being females. The mean annual incidence of adult OHCA was 27.4 per 100,000 population-year. Males had a higher annual incidence of OHCA than females. Among all cases, 36.3% occurred in a public location, 25.8% had an initial shockable rhythm, and 28.8% achieved ROSC. Males had a higher proportion of bystander CPR, arrests in public locations, and initial shockable rhythms. While unadjusted analysis showed no significant gender differences in achieving ROSC, adjusted analysis revealed that male gender was associated with higher odds of achieving ROSC (adjusted OR male vs. female 1.38, 95% CI 1.15–1.66, p < 0.001).ConclusionsApproximately 720 adults undergo non-traumatic OHCA in Qatar every year, with a higher incidence observed in males. Male gender was associated with higher odds of achieving ROSC. Further gender-specific research in OHCA intervention and outcome in the Middle East is required.