bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 230: Epidemiology of Out-of-Hospital Cardiac Arrest Incidence and Field Termination in the US
Authors: Buckler David G , Sondheim Samuel , Abbott Ethan , Carr Brendan G , Redlener Michael , zebrowski alexis
Published: December 2023

Introduction:
While registry-based OHCA research produces high quality information on treatment and outcomes, it lacks the ability to place OHCA in context with EMS-treated conditions. We sought to estimate the rate of OHCA in a national sample of EMS emergency responses and describe national trends in occurrence and field termination.

Methods:
Using the National EMS Information System (NEMSIS) Public-Release Datasets, we conducted a retrospective analysis of EMS runs for OHCA. EMS agencies were analyzed using a masked ID constant across data years. To be included, a run must be documented as “cardiac arrest prior to EMS arrival” and the agency must report more than 10 total Emergency Response runs for each data year. The OHCA rates were calculated and presented as OHCA per 1000 runs. Median rates were compared using Mood’s test. To compare agency level trends in care delivery, agencies had to document >5 OHCA runs in each study year.

Results:
From 2019-2021, there were 83,914,470 Emergency Response runs submitted to NEMSIS. Of these, 840,620 (1.0%) were documented as cardiac arrest (CA) prior to EMS arrival. The OHCA cohort was 37% female, 13% Black, 5% Hispanic/Latinx, 39% White and 41% Not Documented. The mean age was 59 years (SD 21) with 21% missing. The national incidence of OHCA was 10 CA per 1,000 runs. Most agencies saw 13 or fewer OHCA per year (median: 13, IRQ: 5, 44). Agency level rates varied with a median annual rate of 12.6 per 1,000 runs (IQR: 8.5, 18.7). Median agency rates were similar across all three years (11.4 vs 13.0 vs 12.5, p>0.05 for all). Overall, field termination was 47%, with more occurring in 2020 compared to 2019 and 2021 (19-20: 44% vs 49%; 20-21: 49% vs 47%; p <0.001 for all). Agency field termination percentage was positively correlated with ROSC percent among transported patients (ρ = 0.12, p <0.001) but negatively correlated with overall ROSC (ρ = -0.34, p<0.001).

Conclusion:
Despite perceived limitations of non-registry data, significant information about OHCA care is widely available from existing public data. Absent a population-level OHCA rate, by benchmarking OHCA with all EMS runs, we can monitor for significant changes in OHCA incidence. Field terminations appear to be associated with more ROSC among transported patients, but not overall.
Abstract 237: Effect of Hospital Arrival Time on Mortality Rate in Pediatric Patients With Severe Trauma: A Nationwide Database Study in Japan
Authors: Ohki Shingo , Matsuo Ryu , Mitsuaki Nishikimi , Ohshimo Shinichiro , Shime Nobuaki
Published: December 2023

Introduction:
Previous studies have reported that hospital arrival during nighttime was associated with worse outcomes in critically ill pediatric patients. However, this “nighttime effect” in pediatric patients with severe trauma has not yet been well-investigated.

Hypothesis:
We hypothesized that hospital arrival during nighttime is associated with higher mortality rates in pediatric patients with severe trauma.

Methods:
We conducted a nationwide retrospective cohort study in Japan from 2004 to 2019 using the Japan Trauma Data Bank, a nationwide trauma registry. Patients who were aged <18 years and had an Injury Severity Score (ISS) >15 were included. Patients with cardiac arrest on hospital arrival were excluded. Hospital arrival was categorized into daytime (from 8:00 am to 4:59 pm) arrival and nighttime (from 5:00 pm to 7:59 am) arrival. The main outcome was the in-hospital mortality rate, and the secondary outcome was the emergency department (ED) mortality rate. As a main analysis, an inverse probability of treatment weighting (IPTW) analysis was performed using propensity scores to adjust for confounders such as age, sex, type of injury, transport time, vital signs, and ISS. In addition, we conducted 1) a subgroup analysis in patients who underwent operation (OP) or interventional radiology (IR) during hospitalization and 2) sensitivity analysis using a multilevel mixed-effects logistic regression model.

Results:
In total, 6,574 pediatric patients with severe trauma were included, and the overall in-hospital mortality rate was 6.5%. The IPTW analysis showed that compared with daytime arrivals, nighttime arrivals were associated with significantly higher in-hospital mortality (odds ratio [OR], 1.41; 95% confidence interval [CI], 1.09-1.83;
P
= 0.010) and ED mortality rates (OR, 2.42; 95% CI, 1.07-5.45;
P
= 0.034) in the entire cohort but not in the subgroup who underwent OP or IR during hospitalization. The sensitivity analysis consistently supported the results of the main analysis.

Conclusions:
Hospital arrival during nighttime was associated with a higher in-hospital mortality rate in pediatric patients with severe trauma. Further investigations are needed to elucidate the reasons for this “nighttime effect.”
Abstract 242: Assessment of Biomarkers After Standard Cardiopulmonary Resuscitation versus Extracorporeal Cardiopulmonary Resuscitation
Authors: Brodska Helena , Kavalkova Petra , Lavage Dani R , Smalcova Jana , Dusík Milan , Belohlavek Jan , Drabek Tomas
Published: December 2023

Background:
Multiple biomarkers have been used in prognostication of outcome after out-of-hospital cardiac arrest (OHCA) and standard cardiopulmonary resuscitation (CPR). Limited evidence exists for patients resuscitated with extracorporeal CPR (ECPR). We hypothesized that (1) the time course and (2) prognostic performance of biomarkers will differ between CPR and ECPR.

Methods:
This is a pre-planned sub-analysis of Prague-OHCA study. Patients were randomized to either CPR or ECPR. The primary outcome was poor neurologic outcome at 180 days, defined as a cerebral performance category (CPC) of 3-5. Secondary outcomes included assessment of biomarkers of neurologic injury (NSE), inflammation (procalcitonin - PCT, C-reactive protein - CRP, neutrophil-lymphocyte ratio - NLR) and hematology (platelets - Plt, D-dimers - D-dim, and fibrinogen - Fg) using Mann-Whitney test with Bonferroni correction, and ROC analysis of data at 24-72 h.

Results:
In as-treated analysis, ECPR was used in 92 patients. The primary outcome was not different between groups: CPR, CPC 1-2 48 (29.3%) vs CPC 3-5 116 (70.7%); ECPR, CPC 1-2 20 (21.7%) vs CPC 3-5 72 (78.3%); p= 0.191. In general, individual biomarkers exhibited similar trajectories over 72 h, with worse values in patients with CPC 3-5 in both CPR and ECPR groups. PCT was higher in ECPR group at 24-72 h (all p<0.01). NSE, CRP and NLR did not differ between groups. Plt, D-dim and Fg were lower in ECPR vs CPR groups at 24-72 h (all p<0.001). ROC analysis showed the best performance of NSE in both CPR and ECPR groups (AUC 24 h: 0.89 vs 0.78; 48 h: 0.9 vs 0.9; 72 h: 0.91 vs 0.9). PCT showed good performance specifically in ECPR (AUC 24 h: 0.72 vs 0.84; 48 h 0.73 vs 0.87; 72 h: 0.73 vs 0.86). Optimal cutoff points were higher in ECPR vs CPR in NSE (24 h: 60 vs 84; 48 h: 65 vs 61; 72 h: 39 vs 57) and PCT (24 h: 1.8 vs 11, 48 h: 1.0 vs 5.3, 72 h: 0.9 vs 5.6).

Conclusions:
Biomarkers have similar trajectories after OHCA rescued with either CPR or ECPR although absolute values were higher in ECPR. NSE had superior prognostic value in both groups while PCT showed a good prognostic performance specifically in the ECPR group. Additional studied biomarkers may have modest incremental value. Prognostication algorithms using biomarkers should reflect a mode of resuscitation.
Abstract 252: End-Tidal CO2 and Glasgow Coma Scale in Non-Intubated Traumatic Brain Injury Patients: Evaluation of Prehospital Nasal Capnography and Level of Consciousness
Authors: Barnhart Bruce J , Spaite Daniel W , Jorgenson Dawn B , Burgett Kevin S , Adam Seiver , Rice Amber D , Gaither Joshua B , Keim Samuel M , Hu Chengcheng
Published: December 2023

Background:
The EMS traumatic brain injury (TBI) guidelines recommend limiting intubation (ETI) to patients with profoundly-depressed level of consciousness (LOC) and who cannot protect their airway or adequately ventilate with basic maneuvers. Thus, many major TBIs are managed without ETI in the field. Monitoring ETCO2 via nasal sensors (NC-CO2) in non-ETI patients may provide valuable information about ventilatory status and trends. However, EMS NC-CO2 remains unstudied. Objective: To evaluate the association between LOC and NC-CO2 in non-intubated TBI.

Methods:
Cases from 7 EMS agencies reporting continuous monitor data (Philips MRx™) in the EPIC TBI Study (NIH 1R01NS071049) were evaluated (4/13-4/18). Comparisons in patient-level mean, median, lowest and highest NC-CO2 levels were made across GCS categories using clinically meaningful thresholds: <15, <12, <9, 3.

Results:
Included: 177 cases [median age: 52 (range: 9-94), 66% male]. Overall, while not statistically significant, NC-CO2 tended to be lower in patients with lower GCS (Table). In addition, minimum NC-CO2 was significantly lower (p=0.01) in patients with compromised LOC (Table). O2 management (Hi-flow/Lo-flow/No O2) was documented in 176 patients (99.4%). Among the 107 patients with all GCS = 15, 44 (41%) had Hi-flow administered compared to 47/69 (68%) with any GCS <15 (p=0.0008).

Conclusion:
The utility of prehospital capnography in non-intubated patients is unknown. In this study, NC-CO2 tended to be lower in TBI patients with lower GCS. Whether this reflects physiological/respiratory differences with changes in LOC, or variations in methods of managing oxygenation is unclear. These intriguing new findings require future study to determine if NC-CO2 is directly reflective of LOC-related ventilatory patterns. Furthermore, studies are needed to evaluate whether NC-CO2 monitoring has clinical utility as a non-invasive adjunct to care in spontaneously-breathing, non-ETI patients.
Abstract 256: Quantitative Assessment and Visualization of Hypoxic Ischemic Brain Injury in Survivors of Cardiac Arrest Using Unenhanced Computed Tomography Images
Authors: Lee Dong Young , Park Jung Soo , Changshin Kang
Published: December 2023

Aim:
This study aimed to investigate whether the distribution of Hounsfield units (HU) values in head computed tomography (HCT) images can serve as an effective tool for assessing the severity of hypoxic ischemic brain injury (HIBI) in survivors of out-of-hospital cardiac arrest (OHCA).

Methods:
This retrospective study included adult comatose OHCA survivors who underwent first HCT scans within 6 hours and second HCT scans between 72-96 hours on the same CT machine after the return of spontaneous circulation. Automated quantitative analysis was used on CT images to eliminate artifacts and identify differences in the proportion of HU values (HUp) at specific intervals across the intracranial area based on neurological outcome. Additionally, correlation analysis was conducted between serum levels of neuron-specific enolase (NSE) at 48 hours post-ROSC and the sum of HUp values in the aforementioned intervals. Poor outcome was defined as cerebral performance categories 3-5 at 6 months post-ROSC.

Results:
Of the 55 included patients (84% male), 23 (42%) had poor outcome. Significant differences in HU values were observed between outcomes in the second HCT scan at HU=1-14, 23-35, and 39-56 (P<0.05). Within the same HU interval, the poor outcome group showed a greater change between the first and second HCT scans compared to the good outcome group (Figure). The correlations between the sum of HUp and NSE levels within the range of HU=1-14, 23-35, and 39-56 in the second HCT were 0.34, 0.60, and 0.49, respectively (Figure). The second HCT scans demonstrated better prognostic performance than the first HCT scan for HU=1-14 (area under the curve 0.75 vs. 0.60), 23-35 (0.85 vs. 0.62), and 39-56 (0.75 vs. 0.59), while no significant difference was observed compared to GWR (0.78) (all P≥0.05).

Conclusions:
The proportional sum of HU values within specific intervals in the entire cerebral area on CT images can effectively assess and visualize the extent of HIBI in survivors of OHCA.
Abstract 264: Impact of Receiving Hospital on Disparities in Out-of-Hospital Cardiac Arrest
Authors: Huebinger Ryan , Del Rios Marina , McNally Bryan F , Abella Benjamin , Witkov Richard , Waller-Delarosa John , Bobrow Bentley
Published: December 2023

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: >50% White, >50% Black, and >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 267: Neighborhood Socioeconomic Status Influences Rates of Pre-EMS Cardiac Arrest Resuscitation
Authors: Shekhar Aditya C , Mann N. Clay
Published: December 2023

Introduction:
Out-of-hospital cardiac arrest is a leading cause of both morbidity and mortality in the United States and globally. After cardiac arrest onset, emergency medical services (EMS) might not arrive before irreversible injury takes place. Thus, pre-EMS resuscitation - including CPR and automated external defibrillator (AED) use - is associated with improvements in outcomes. We sought to determine if rates of pre-EMS CPR and pre-EMS AED use vary across neighborhood socioeconomic status using a database of EMS activations throughout the United States.

Methods:
The National Emergency Medical Services Information System (NEMSIS) is a large and nationally-representative database of EMS activations populated from more than ten-thousand EMS agencies throughout the US. We examined cardiac arrests in adult patients (18+ years of age) between January 2017 and December 2019 where EMS providers documented the ZIP code of the arrest, whether CPR prior to EMS arrival was provided, and whether an AED was applied prior to EMS arrival. The ZIP code of the arrest was used to group arrests based on socioeconomic status data from the US Census Bureau. Rates of pre-EMS CPR and pre-EMS AED use were then compared, and ZIP codes with under 5% of residents below the poverty line served as benchmarks.

Results:
366,280 cardiac arrests met inclusion criteria. Both Pre-EMS CPR and pre-EMS AED use were highest in ZIP Codes where less than 5% of the population is below the poverty line (p< .00001). Furthermore, a consistent decrease in rates of pre-EMS interventions was seen as the percent of individuals below the poverty line increased (Figure 1).

Conclusion:
We found a strong relationship between neighborhood socioeconomic status and pre-EMS cardiac arrest interventions. One explanation may be access to CPR training. Further studies should continue to interrogate cardiac arrest disparities that have already been reported and seek to identify new unreported disparities as well.
Abstract 279: Sustained Inflation and Chest Compression versus 3:1 Chest Compression to Ventilation Ratio During Cardiopulmonary Resuscitation of Asphyxiated Newborns A Cluster Randomized Controlled Trial
Authors: Schmolzer Georg , Pichler Gerhard , Solevag Anne Lee , law Brenda , Mitra Souvik , Wagner Michael , Pfurtscheller Daniel , Yaskina Maryna , Cheung Po-yin
Published: December 2023

Background:
Neonatal resuscitation guidelines recommend 3:1 compression to ventilation ratio (C:V) ratio during chest compression (CC). In piglets, continuous CC superimposed by sustained inflation (CC+SI) resulted in faster time to return of spontaneous circulation (ROSC), lower mortality, improved hemodynamics and ventilation compared to 3:1 C:V. Similar a pilot trial in preterm infants reported significant faster ROSC with CC+SI compared to 3:1 C:V.

Objective:
To test the hypothesis that in newborn infants receiving chest compression with CC+SI compared with 3:1 C:V time to ROSC will be reduced or increased.

Design/Methods:
Multicenter cluster randomized trial of CC+SI vs. 3:1 C:V in newborn infants receiving CC. Hospitals were randomized to CC+SI or 3:1 C:V for 12 months then switched to 2
nd
intervention for another 12 months. Infants were eligible if bradycardic with heart rate <60/min or asystolic. Primary outcome was time to ROSC (heart rate >60 for one minute). Analysis was performed according to intention-to-treat. The trial was stopped to slow enrolment, Covid-19 pandemic, and funding constrains.

Results:
Four sites (Edmonton, Graz, Halifax, and Vienna) included infants, which were randomized to either CC+SI (n=11) and 3:1 C:V (n=14). The groups were balanced in relation to demographics and delivery room interventions.The median (IQR) time to ROSC with CC+SI was 90 (60-270)sec and with 3:1 C:V was 615 (174-780)sec (p=0.0502 - log rank, and 0.16 cox proportional hazards regression) (Figure).Survival was 9/11 (82%) with CC+SI and 7/14 (50%) with 3:1 C:V [relative risk (RR) 0.36, 95% Confidence interval (CI) 0.094 to 1.42]. There were no differences in secondary outcomes between groups.

Conclusion:
CC+SI resulted in a reduction in time to ROSC. There was a trend towards higher survival rates with CC+SI.
Abstract 280: Effectiveness of Bag-Valve-Mask Ventilation During Out-of-Hospital Pediatric CPR
Authors: Issioui Yacine B , Pierce Ava E , Idris Ahamed H
Published: December 2023

Background:
Few studies have measured ventilation during early cardiopulmonary resuscitation (CPR) before advanced airway placement. Resuscitation guidelines recommend pauses after every 15 or 30 chest compressions to deliver ventilations for children. The effectiveness of bag-valve-mask (BVM) ventilation delivered during the pause in chest compressions is unknown.

Hypothesis:
Lung inflation occurs infrequently with BVM ventilation during 30:2 (and 15:2) CPR.

Aim:
To determine the incidence of lung inflation with BVM ventilation during 15:2 or 30:2 CPR for pediatric OHCA.

Methods:
This is a retrospective, observational study of 63 OHCA patients, <18 years of age, with non-traumatic cardiac arrest from the Dallas-Fort Worth Center for Resuscitation Research registry. Emergency medical service rescuers provided 30:2 or 15:2 CPR with BVM ventilation and ≥ 2 min of recorded CPR. We measured bioimpedance ventilation (lung inflation) waveforms in the pauses between chest compression segments recorded through defibrillation pads. A detectable ventilation waveform had a bioimpedance amplitude ≥0.5 Ohm and duration ≥1 sec. We measured the incidence of ventilation in two pre-specified groups: patients with ventilation waveforms in <50% of pauses (Group 1) vs. those with waveforms in ≥50% of pauses (Group 2).

Results:
The mean duration of 30:2 or 15:2 CPR was 15(8) min prior to advanced airway placement. During this period, we identified 683 pauses in chest compressions, 386 measurable ventilations, and the median (IQR) number of ventilations was 2 (0-4). Of 20 advanced airway attempts, nine were successful.Group 1 (N=48) had a median 8 pauses and 1.5 ventilations/patient, Group 2 (N= 15) had a median 10 pauses and 12 ventilations/patient (Table). Return of spontaneous circulation for Group 1 (15%, 7/48) vs. Group 2 (33%, 5/15).

Conclusion:
This study shows that use of a BVM device results in infrequent lung inflation during 30:2 or 15:2 CPR in pediatric patients.
Abstract 289: Volunteer Responders Find It Meaningful to Attend to Pediatric Out-of-Hospital Cardiac Arrests
Authors: Kjærholm Sofie Have , Kragh Astrid Rolin R , Juul Grabmayr Anne , Borch-Johnsen Liv , Folke Fredrik , Tjørnhøj-Thomsen Tine , Malta Hansen Carolina
Published: December 2023

Background:
In Denmark, volunteer responders have been dispatched to suspected pediatric out-of-hospital cardiac arrests (OHCAs) through a smartphone application since February 2022. However, it is unknown how volunteer responders experience assisting pediatric OHCAs.

Aim:
To explore how volunteer responders experienced being involved in pediatric OHCAs.

Method:
The study population comprised volunteer responders alerted to an OHCA patient <6 years of age in Denmark (2020-2023). Data was collected through individual, semi-structured interviews. Data analysis followed an inductive process with a phenomenology-hermeneutical interpretative approach. Using thematic analysis data was indexed into codes and themes, generated to draw out meaning from the text.

Results:
Eight volunteer responders had assisted at six different pediatric OHCAs. Participant age ranged from 24-60 years, five were men, three were healthcare workers, and four provided CPR. Among the pediatric OHCAs, three were < 6 months and three were 2-5 years old, none survived. Five themes emerged from the analysis: “The shock when realizing the patient is a child”, “Volunteer responders’ capability to act and initiate CPR in a child”, “Doubts and thoughts during resuscitating a child”, “Interaction with the family during resuscitation” and “The aftermath: the overwhelming fact, that it was a child”. Despite experiencing the sight of a child with OHCA as overwhelming, volunteer responders managed to act and provide CPR. Volunteer responders also considered the provision of psychological support to the parents as an important task. Taken together, volunteer responders found it meaningful to be alerted to a child and were ready to do it again, even though it is a severe experience.

Conclusion:
Volunteer responders found it meaningful to assist a pediatric OHCA, despite the shock of discovering that the patient was a child. Including information on suspicion of pediatric OHCA in the app alert may mitigate this shock and better prepare volunteer responders to assist pediatric OHCAs.
Abstract 315: Endovascular Aortic Occlusion Preferentially Improves Hemodynamics and Return of Spontaneous Circulation After Longer Periods of Cardiopulmonary Resuscitation: A Translational Study in Swine
Authors: Siemieniak Steven , Nowadly Craig , Greiving Tanner , Rall Jason , Shepard Nola
Published: December 2023

Introduction:
Non-traumatic cardiac arrest (NTCA) is associated with low survival and substantial societal cost. Standard-of-care treatments, such as cardiopulmonary resuscitation (CPR) and advanced cardiac life support (ACLS), have limitations in restoring cardiac function and improving outcomes. Resuscitative endovascular balloon occlusion of the aorta (REBOA) has emerged as an adjunct to CPR for NTCA. However, the optimal patient population that will benefit most from REBOA remains uncertain.

Goals:
This translational study investigated the impact of varying low-flow duration (15- vs 30-mins) on REBOA's hemodynamic performance and ability to achieve return of spontaneous circulation (ROSC) in a swine model of NTCA.

Methods:
Thirty-two swine were anesthetized and placed into ventricular fibrillation. All animals received a 4-min “no-flow” period before mechanical CPR was initiated. Animals were randomized into four groups to receive: 1) 15- vs 30-minutes of CPR; 2) REBOA vs. no-REBOA (control). After completion of the 15- or 30-minute low-flow period, ACLS was initiated and REBOA was fully-inflated in experimental animals.

Results:
There were no differences in demographics or hemodynamics at baseline (T = -10-mins) or at randomization (T = +10-mins). In the 15-mins groups, there were no differences in the rates of ROSC between REBOA (4 / 8, 50%) and control (4 / 8, 50%; p = 0.99). However, in the 30-min group the REBOA animals had a significantly higher rate of ROSC (6 / 8, 75%) compared to control (1 / 8, 12.5%; p = 0.04). In the 7-mins (T = 34 - 41 mins) after REBOA deployment in the 30-min animals there was a statistically significant difference in diastolic blood pressure (repeated measures ANOVA; p = 0.027). Importantly, 5 / 6 (83%) animals that received ROSC in the 30-min group with REBOA re-arrested at least once with 3 / 6 (50%) maintaining ROSC until study completion.

Conclusion:
In our swine model of NTCA, REBOA preferentially improved hemodynamics and ROSC after a 30-mins period of low-flow CPR, compared to 15-mins of low-flow CPR. REBOA may be a viable strategy to improve ROSC after prolonged downtime. More hemodynamic support will be required to maintain ROSC. This has implications for patient selection in upcoming human trials of REBOA in NTCA.
Abstract 318: Glibenclamide May Have a Neuroprotective and Cardioprotective Role Beyond Cerebral Edema in an Asphyxial Model of Cardiac Arrest
Authors: zhuang Zhen W , Zheng Ming-qiang , Beekman Rachel , Sheth Kevin N , Huang Henry , Simons Michael
Published: December 2023

Background:
Cardiac arrest (CA) is a leading cause of mortality and long-term disability. There are no therapeutics approved for neuro- and cardio-protection. Novel therapeutics are urgently needed to improve patient outcomes. Glibenclamide is a second-generation sulfonylurea drug and inhibitor of SUR1-TRPM4. Little is known about its role in cardioprotection and synaptic density.

Aims:
To evaluate the effect of glibenclamide on coronary flow reserve (CFR), blood-brain barrier (BBB) permeability, and synaptic density in an asphyxial mouse model of CA.

Methods:
We used an asphyxial mouse model of CA; potassium chloride was injected into the right internal jugular vein, resulting in asystole. Chest compressions and epinephrine were administered following 12 minutes of no-flow time. Successfully resuscitated mice (n=24) were randomized to receive intravenous glibenclamide or vehicle; the glibenclamide group received a loading dose of 10 μg/kg immediately upon return of spontaneous circulation followed by 1.6 μg every 12 hours up to day 3. Pulse Doppler Velocity (PWV) was used to monitor the CFR and left carotid artery velocity. Synaptic density was quantified with
ex vivo
autoradiographs after injection of
18
F-SynVesT-2 in the brain (3, 24, and 72 hrs). Evans blue staining and general neurologic deficit scores were assessed 24 hours post-resuscitation.

Results:
Treatment with glibenclamide resulted in an increase in CFR (1.37±0.11 vs. 1.17±0.06, p=0.01) and carotid peak velocity (61.38±12.81 cm/s vs. 46.83±6.3 cm/s, p<0.05). Whole brain synaptic density was increased in the mice treated with glibenclamide, suggesting a reduction in synaptic density loss. BBB disruption in the cerebrum was significantly lower in Glibenclamide treated mice (0.00022±0.000014/mg vs. 0.000471±0.000088/mg, p<0.01). Mice treated with Glibenclamide had lower neurologic deficit scores (1.83±2.89 vs 4.75±3.84, p<0.05).

Conclusions:
Glibenclamide given immediately following the return of spontaneous circulation improved CFR, decreased BBB disruption, reduced synaptic density loss, and improved neurologic deficit scores, suggesting both cardio- and neuro-protective effects.
Abstract 321: Manual vs Automated Ventilation During Automated Head-Up Cardiopulmonary Resuscitation in a Porcine Model
Authors: Pourzand Pouria , Lick Mike , Richardson Stephen , Moore Johanna C , Arango Susana , Suresh Mithun , Salverda Bayert , Metzger Anja , Lurie Keith G
Published: December 2023

Background:
The efficacy of mechanical ventilation during CPR with the combination of active compression-decompression, an impedance threshold device, and head-up positioning, collectively termed automated head-up (AHUP)-CPR, is unknown.

Hypothesis:
Hemodynamic and ventilatory parameters will be similar with manual bag ventilation (MBV) versus automated bag ventilation (ABV) during AHUP-CPR in a porcine model of cardiac arrest.

Aim:
Assess the proof-of-concept that ABV is safe and effective during AHUP-CPR.

Methods:
Nine male and female swine (~40 kg) were anesthetized and ventilated. VF was induced and left untreated for 8 min. AHUP-CPR was performed at 105 compressions/min for 7 min using MBV, followed by 6 min using an automated mechanical bag compressor to deliver 10ml/kg of tidal volume (TV) over 1 sec at 10 breaths/min. Pigs were randomized during ABV to a synchronized (Sync) breath delivered at the start of decompression or an asynchronous (Async) breath. Cerebral perfusion pressure, coronary perfusion pressure, end-tidal CO2, intracranial pressure, esophageal intrathoracic pressure, peak airway pressure (PAP), inspiratory and expiratory TVs as well as arterial blood gases were continuously measured. Values (mean ± SD) were compared by paired and unpaired student’s t-tests with a Bonferroni correction.

Results:
Parameters during the last minute of MBV and ABV are summarized in the table. No significant differences were observed in hemodynamic and ventilatory parameters, except for PAP and pO2 values which were significantly lower with MBV. No significant differences were also observed between the Sync and Async ABV modes.

Conclusion:
Manual and mechanical ventilation resulted in overall similar physiological effects. The clinical relevance of the observed significant differences in PAP and pO2 is unclear. Additional studies are warranted to further assess the safety and effectiveness of mechanical ventilation during AHUP-CPR.
Abstract 325: Two-Year Outcomes of an Electronic Health Record Integrated Rapid Response Team Model
Authors: Tart Dustin , Kester Kelly , Dunn Catie , Glenn Adam , Santos Rosimeire , Granger Bradi B , O'Brien Cara L
Published: December 2023

Background:
Literature supports improved patient outcomes with dedicated resources for rapid response to patient deterioration in inpatient settings. However, studies of the association of centralized resource allocation and electronic health record (EHR) integration on patient outcomes are lacking.

Aim:
To improve early, centralized rapid response to patient deterioration and reduce unanticipated transfers to the ICU.

Methods:
Using a prospective longitudinal quality improvement design, we implemented a centralized, EHR supported patient response team (PRT) at an academic medical center in the southeastern United States. The model served 1,043 inpatient beds. Pre-intervention the PRT used episodic data capture and included 1 critical care RN, 1 physician, and 1 respiratory therapist; each expected to leave assigned patients to respond to non-ICU events. We implemented a dedicated PRT (4 critical care RNs and 1 hospitalist) to provide 24/7 response to code blue, RRT, and stroke code events. The team provided proactive rounding, preventive consultation, and assessment of patients from ICU or emergency within 24 hours. Standardized workflow and outcome documentation was integrated in the EHR. Improvement in processes and outcomes were analyzed using statistical process control charts with 25 data points over a 2-year period.

Results:
At baseline (FY 2020), the PRT responded to 1739 rapid response calls and 166 code blue events. Unanticipated transfer to ICU occurred in 935 (53.8%) patients. Post-implementation of the integrated PRT model, the rate of early rapid response calls improved (FY 2021 n=2099; FY 2022 n=2239), code blue events decreased (FY 2021 n=151; FY 2022 n=115), and unanticipated ICU transfers also decreased (25%; Figure 1).

Conclusions:
A centralized PRT model using technology-supported EHR integration, pre-defined workflows, and a dedicated team can reduce non-ICU cardiac arrests and decrease unanticipated transfers to ICU.
Abstract 331: Whether the Compliance of Target Temperature Management Protocol Affects Outcomes in Cardiac Arrest Survivors?
Authors: LEE HSIN YU , Tsai Min-Shan , Chen Wen-Jone , HUANG CHIEN-HUA , Ma Matthew , Chiang Wen-chu , Lu Kuan-Ting (Chris)
Published: December 2023

Background:
Targeted temperature management (TTM) improves neurological recovery in cardiac arrest survivors and protocols have been established during the implementation of high quality TTM with recommended about cooling rate, duration of maintenance, and rewarming speed.
Research question
Whether fitting TTM protocols results in better survival and neurological recovery remains un-investigated.

Aim:
To evaluate the benefit of TTM protocol compliance on the outcomes in cardiac arrest survivors.

Methods:
The retrospective cohort study enrolled 1141 non-traumatic adult cardiac arrest survivors and pre-arrest Cerebral Performance Category (CPC) score=1-2 during 2015-2020 at a tertiary medical center. Patients who underwent TTM (n=305) were further selected. Patients with spontaneous hypothermia (<35°C) at ROSC (n=107) and those without TTM completion (n=21) were excluded. A total of 202 patients were finally enrolled in the study. As the protocol was divided into three categories: cooling rate, duration of maintenance, and rewarming speed, there were 110 patients in the protocol-fit group and 92 patients in the protocol non-fit group. The favorable neurological recovery was considered as CPC=1-2 at hospital discharge.

Results:
There were 42 patients (38.2%) in the protocol-fit group had favorable neurological recovery, while 32 patients (34.8%) in the protocol non-fit group. After adjusting age, initial shockable rhythm, witnessed collapse and CPR duration, the protocol non-fit group was associated to the poor neurological outcome (adjusted odds ratio [aOR] 2.44, 95% confidence interval [CI]= 2.23-5.35) but not the in-hospital mortality (aOR 2.31, 95% CI= 0.70-2.47). In the protocol non-fit group, the most common non-fitting reason was the prolong time-to-target temperature (n=33, 58.7%). Twenty-four patients who failed to fit the 2 categories. The number of non-fitting category was not significantly associated with in-hospital mortality and poor neurological recovery due to limited sample number.

Conclusion:
Among cardiac arrest survivors undergoing TTM, patients who did not fit the TTM protocols were associated with poor neurological recovery than those who completely fit the protocols.
Abstract 337: Bystander Defibrillation in High Risk Neighborhoods
Authors: Uzendu Anezi , Garcia Raul A , El-Zein Rayan , Nguyen Dan , Chan Paul S
Published: December 2023

Background:
Whether public health efforts successfully prioritize bystander automated external defibrillator (AED) application in areas with highest of hospital cardiac arrest (OHCA) burden is unknown.

Methods:
Within the Cardiac Arrest Registry to Enhance Survival, we identified all adult, public OHCAs linked to a census tract between 2013- 2021. We ranked all census tracts by annual public OHCA volume to ascertain relative burden, then assessed the association of census tract OHCA burden and bystander AED application rate (application prior to emergency personnel arrival), using a hierarchical modified poisson regression model, to account for clustering within tracts, and arrest characteristics.

Results:
Among 25,787 tracts with 90,898 public OHCAs, the mean (SD) age was 57.1 (16.0) years, with 70,900 (78.0%) male and 45,388 (49.9%) White victims. Overall, bystander AED application rates were low (10.9%). There was a modest association between neighborhood OHCA burden and bystander AED application rates (ρ=0.243). After adjustment, neighborhoods with the highest OHCA burden (>2/ year) had a higher relative risk of bystander AED application than those with lowest burden (<1/ every other year) (RR 2.07; 95% CI 1.95, 2.20, p<.0001). However, this was due to a small proportion of high performing communities, as 700/1145 (61.1%) of highest OHCA burden communities had a bystander AED application rate less than the overall mean, 10.9%.

Conclusion:
High OHCA burdened areas have increased odds of bystander AED application, however this is driven by a few high performing neighborhoods. Targeted, context informed strategies are necessary to improve application rates and survival for the majority of high-risk neighborhoods.
Abstract 342: Willingness to Participate in an Active Pediatric Critical Care Interventional Trial Using Exception From Informed Consent
Authors: Ross Catherine E , Asad Muhammad , Berg Robert A , Kleinman Monica E , Donnino Michael
Published: December 2023

Introduction:
Emergency interventional trials using Exception From Informed Consent (EFIC) are rare, but pooled survey data preceding 27 EFIC studies show that 73% of respondents were willing to be enrolled in the associated trial. However, given the hypothetical nature of these surveys, the actual rate of willingness to participate in an active EFIC trial and any associations with demographic characteristics are unknown.

Aims:
To 1) compare the actual rate of willingness to participate in an EFIC trial with that from previously published hypothetical surveys for the same trial; and 2) describe demographic characteristics associated with actual willingness rates.

Hypothesis:
We hypothesized that the actual rate of willingness to participate in an EFIC trial would be lower than the hypothetical survey rate.

Methods:
From April 13 to June 5, 2023, we attempted to notify all eligible patients/families of an active EFIC trial enrolling in our PICU and gave them the option to opt out from enrollment. Responses were recorded, and patient demographics were abstracted from the medical record. Major exclusion criteria were age over 25 years and state custody. Surveys were performed prior to trial initiation with a similar screening process. Likert scale responses for willingness to participate were dichotomized.

Results:
Of 207 families contacted, 149 (72%) were willing to participate in the trial which was similar to our pre-trial survey data (43/58 [74%]; p = 0.87). Willingness rates varied by race category (Asian 5/5, 100%; Black 8/18, 44%; Hispanic 22/33, 67%; White 66/84, 79%; Other 12/20 60%; Unknown 36/47, 77%; p = 0.03) but not patient age (willing, median 5 years [IQR 1, 13] vs not willing, median 7 years [IQR 1,4]; p=0.84).

Conclusion:
The actual rate of willingness to participate in an EFIC trial in the PICU was similar to the hypothetical rate reported in pre-trial survey data, suggesting surveys may reasonably reflect attitudes of potential participants. Willingness rates varied by race, though a significant proportion of data was missing. Reasons for racial differences in research engagement should be explored to better understand the consequences of long-standing structural racism in the US and the impact on future trial participation for these groups.
Abstract 348: Machine Learning Approaches for Early Outcome Risk Stratification Within 6 Hours of Cardiac Arrest
Authors: Jin Qingchu , Riker Richard R , Williams Hunter , May Teresa , Seder David B , Winslow Raimond L
Published: December 2023

Background:
Formal prognostication should be delayed at least 72 hours after cardiac arrest, but early stratification of risk severity provides important information for medical decision making, research enrollment, and precision medicine.

Hypothesis:
EEG-derived indices are valid biomarkers of severity of injury after cardiac arrest and contribute to early identification of risk.

Aims:
To assess the relative impact of early clinical data and processed EEG indices in the first 6 hours after recovery of spontaneous circulation (ROSC).

Methods:
Data from the first 6 hours after ROSC in the International Cardiac Arrest Registry (INTCAR) from Maine Medical Center including demographics, cardiac arrest data, admission vital signs and laboratory results and processed EEG indices at 6 hours after ROSC (bispectral index or BIS6 and suppression ratio or SR6) were extracted. Cerebral Performance Category (CPC) scores at hospital discharge and 6-month follow-up were dichotomized into good (CPC = 1-2) and poor (CPC = 3-5) outcomes. Three models were trained, one with INTCAR data, a second with EEG data, and the third combining INTCAR and BIS6-SR6. Six machine learning algorithms were applied: Catboost, random forest, Xgboost, Adaboost, support vector machine and logistic regression. Variable importance was analyzed by the decrease of impurity of random forest.

Results:
Among 913 included patients, median age was 59 years (95%CI 23-85), 623 (68%) were male, initial rhythm was shockable in 405 (44%) patients, and average time to ROSC was 23 (95%CI 3 - 73) minutes. Survival to hospital discharge occurred in 41% (364/893), and poor outcome occurred in 72.7% at 6-month follow-up (607/835). For CPC at discharge, area-under-the curve (AUC) was 0.85 for the combined INTCAR and EEG data, greater than INTCAR (AUC = 0.80) or EEG (AUC = 0.77). For the CPC at follow-up, the AUC was 0.88 for the combined data, greater than INTCAR (AUC = 0.83) or EEG (AUC = 0.79). Variable ranking analysis showed that BIS6 and SR6 were the two most informative features for both outcomes.

Conclusions:
The processed EEG variables BIS6 and SR6 significantly contribute to risk identification in the first 6 hours after ROSC, and combined with early clinical data provide reliable risk stratification.
Abstract 372: Age-Dependent Effect of Trauma Center Transport on Survival Outcomes Among Severe Trauma Patients: Nationwide Observational Study
Authors: Kim Hakrim , Song Kyoung J , Hong Kijeong , Park Jeong Ho , Kim Tae Han H , Kim Ki Hong , LEE Stephen G , Ro Young Sun , Jeong Joo
Published: December 2023

Introduction:
Previous studies showed that the prognosis for severe trauma patients is better after transport to trauma centers compared to non-trauma centers. However, the benefit from transport to trauma centers may differ according to age group. This study aimed to evaluate the age-dependent effect of trauma center transport on survival outcomes among severe trauma patients.

Methods:
A cross-sectional study using the Korean national emergency medical service (EMS) based on Severe Trauma Registry in 2018-2019 was conducted. EMS-treated trauma patients whose injury severity score was above or equal to 16, and who were not out-of-hospital cardiac arrest or death on arrival were included. Patients were classified into 3 groups: pediatrics (age <19), working age (age 19-65), and elderly (age>65). The primary outcome was in-hospital mortality. Multivariable logistic regression analysis was conducted to evaluate the effect of trauma center transport on outcome after adjusting age, sex, comorbidity, mechanism of injury, Revised Trauma Score, and Injury Severity Score. All analysis was stratified according to the age group, and subgroup analysis for traumatic brain injury was also conducted.

Results:
Overall, a total of 10,511 patients were included in the study, and the number of patients in each age group was 488 in pediatrics, 6,812 in working age, and 3,211 in elderly, respectively. The adjusted odds ratio (95% confidence interval [CI]) of trauma center transport on in-hospital mortality were 0.76 (95% CI, 0.43-1.32) in pediatrics, 0.78 (95% CI, 0.68-0.90) in working age, 0.71(95% CI, 0.60-0.85) in elderly, respectively. In the subgroup analysis of traumatic brain injury, the benefit from trauma center transport was observed only in elderly group.

Conclusion:
We found the age-dependent effect of trauma center transport in severe trauma patients. There was no beneficial effect of trauma center transport in pediatric group. Further research is warranted to evaluate and develop the response system for pediatric severe trauma patients in Korea.
Abstract 380: Prehospital Ground and Helicopter-Based Extracorporeal Cardiopulmonary Resuscitation (ECPR) Reduce Barriers to ECPR: A GIS Model
Authors: Gottula Adam , Qi Man , Lane Bennett , shaw Christopher , Gorder Kari , Powell Elizabeth , Danielson Kyle , Ciullo Anna , Johnson Nicholas J , Tonna Joseph , Hinckley William , Koshoffer Amy , Al-Araji Rabab , Bartos Jason , Benoit Justin , Hsu Cindy H
Published: December 2023

Introduction:
Evidence suggests that ECPR can improve survival rates for nontraumatic out-of-hospital cardiac arrest (OHCA). However, over 50% of potential ECPR candidates are unable to qualify in the current hospital-based system due to geographic limitations. This study employs a Geographic Information System (GIS) model to estimate the number of ECPR eligible patients within the U.S. in the current hospital-based system, a prehospital ECPR ground-based system, and a prehospital ECPR HEMS-based system (Figure 1).

Methods:
We constructed a GIS model to estimate ground and helicopter transport times. Time-dependent rates of ECPR eligibility were derived from the Resuscitation Outcome Consortium (ROC) database, while the Cardiac Arrest Registry to Enhance Survival (CARES) registry determined the number of OHCA patients meeting ECPR criteria within designated transportation times. EMS response time, ECPR candidacy determination time, and on-scene time were modeled based on data from the EROCA trial (Figure 1). The combined model was used to estimate the total ECPR candidates in each system.

Results:
The CARES registry recorded 736,066 OHCA patients from 2013 to 2021. After applying clinical eligibility criteria, 24,661 (3.4%) patients were eligible for ECPR. When considering overall ECPR eligibility within 45 minutes from OHCA to initiation, only 11.76% of clinically eligible patients qualified in the current hospital-based system. The prehospital ECPR HEMS-based system exhibited a four-fold increase in ECPR eligibility (49.3%), while the prehospital ground-based system showed a more than two-fold increase (28.4%).

Conclusions:
The study demonstrates a two-fold increase in ECPR eligibility for a field-deployable ground-based system and a four-fold increase for a prehospital ECPR HEMS-based system compared to the current hospital-based OHCA system. This novel GIS model can inform future ECPR implementation strategies, optimizing systems of care.