bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 117: Chronic Efficacy of Liposome-Encapsulated Hemoglobin (HbV) on Rat’s Lethal 85% Hemorrhage: Intraosseus HbV Transfusion Acutely Rescues Through Anti-Arrhythmogenic Effects on Myocardium That Continues in Chronic Phase
Authors: Takase Bonpei , Higashimura Yuko , Hashimoto Kenichi
Published: June 2021

Introduction:
Liposome-encapsulated hemoglobin vesicles (HbVs) can serve as a blood substitute with human blood.

Method:
To investigate the resuscitation effect of HbVs on lethal hemorrhage and their efficacy for decreasing myocardial arrhythmogenesis, optical mapping analysis (OMP) and an electrophysiological study (EPS) were performed in graded 85% hemorrhage in rats in both acute and chronic phase. Six rats were resuscitated by intraosseous infusion of 5% albumin solution (ALB group), while 6 rats by washed rat erythrocytes (wRBC group) and 6 rats by HbVs (HbV group). Survival effects over 24 hours were examined in > 10 rats in each group. After excising the heart, OMP and an EPS were performed.

Results:
All rats died in ALB group, whereas all survived subsequent 24 hours in wRBC group and HbV group. In acute phase, OMP showed impaired (prolonged) action potential duration dispersion (APDd) in left ventricle in ALB group. In contrast, myocardial APDds in left ventricle were substantially attenuated in HbV group and wRBC group. Lethal arrhythmias (ventricular tachycardia [VT] or ventricular fibrillation [VF], VT/VF) were provoked by EPS in ALB group. No VT/VF was induced in both wRBC group and HbV group. In chronic phase of two weeks after the resuscitation, OMP and an EPS were performed again in excising the heart. Anti-arrhythmic effects were confirmed by normal OMP findings (Normal APDd) and No VT/VF induced as shown in Figure.

Conclusions:
Lethal hemorrhage causes VT/VF in the presence of impaired APDd. Intraosseous HbVs infusion acutely rescues lethal hemorrhage through preventing lethal arrhythmias with preserved APDd. These effects were preserved in chronic phase.
Abstract 128: Assessing the Temporal Trend in Survival to Hospital Admission Following Out-Of-Hospital Cardiac Arrest: Analysis From a Public Access Defibrillator Registry
Authors: Torney Hannah , McAlister Olibhear , Harvey Adam , Bond Raymond , Finlay Dewar , Magee Justin , McEneaney David , Adgey Jennifer
Published: June 2021

Introduction:
The AHA Get With the Guidelines Resuscitation Investigators recently identified that in-hospital cardiac arrest patients admitted during nights and weekends are less likely to survive to discharge. Our analysis aimed to determine if a similar relationship applied to out-of-hospital cardiac arrest (OHCA) patients.

Methods:
Worldwide data collection began in Oct 2012. Users of HeartSine SAM PAD public access defibrillators submitted electronic event data (comprising time/date of event and electrocardiogram traces) and an event report form (comprising patient demographics, location of arrest and survival to hospital outcome). First shock success was defined as termination of shockable rhythm for 5 seconds post-shock. Data was analysed using R.

Results:
A total of 3400 OHCA cases were collected. Median (IQR) age was 63 (50, 75) and males accounted for 72.4% of the dataset. A total of 1127 first shocks were delivered, and first shock success was 87.2% (983 shocks). Survival outcomes were reported in 2942 cases, and 783 (26.6%) patients survived to hospital admission. First shock success as a response to day of the week (weekday versus weekend [12am Saturday-11.59pm Sunday]) adjusted for patient age, gender and location of arrest, was assessed and there was no association found. When the same model was fitted with survival to hospital admission as a response to day of the week, it was determined that patients are approximately 20% less likely to survive to hospital admission at the weekend (OR=0.81, 95%CI [0.68, 0.95], p=0.01). There was a negative association between survival and OHCA occurring at home (OR=0.32, 95%CI [0.10, 0.94], p=0.03) and increasing age (per 1-year increase, OR=0.99, 95%CI [0.98, 1.00], p<0.001). Adjusting the model for time of day (morning [6am-11.59am], afternoon [12pm-5.59pm], evening [6pm-11.59pm] and night [12am-5.59am]) did not highlight an association with any particular time of day.

Conclusions:
OHCA patients are significantly less likely to survive to hospital admission at weekends compared to weekdays. Further analysis on the availability of PADs at professional and recreational locations and availability of trained medical rescuers at the weekend versus weekdays could account for the differences observed.
Abstract 132: Predictive Value of Inflammation Markers With Stroke Recurrence and Cardiovascular Mortality
Authors: Yunyun Yang
Published: June 2021

Background:
Inflammation markers are associated with the risk of cardiovascular events, however, the relationships of inflammation markers with risk of post-stroke remain controversial.
Objects:
To investigated association of two clinical recorded inflammation markers, white blood cell count (WBC) and platelet count (PLTC) with first-onset stroke and long-term prognosis of stroke.

Methods:
A Chinese case-control study was conducted, comprising 2002 stroke cased (885 atherothrombosis, 565 lacunar stroke, 552 hemorrhagic stroke) and 1996 controls. Stroke patients were prospectively followed-up for a median of 4.5 years (range, 0.1-6.0).

Results:
The WBC and PLTS were higher in stroke patients than controls, however, the ratio of PLTS to WBC was lower in stroke patients than controls. During the follow-up, 369 recurrent strokes and 343 cardiovascular mortality were documented. Adjusted for cardiovascular disease, the increased ration of PLTC to WBC was negatively correlated with stroke recurrence (HR, 0.60, 95%CI 0.44 to 0.81,
P
=0.001), with no associations for PLTC and WBC. Compared with stroke patients with WBC in the first quartile (2.1-5.6х10
9
/L) , subjects in the fourth quartile (7.8-19.8х10
9
/L) had 2.10-fold risk for cardiovascular mortality (hazard ration [HR],2.10, 95% confidence interval [CI], 1.20 to 2.48,
P
=0.004), with no associations for PLTC. However, the increased ratio of PLTC to WBC decreased risk of cardiovascular mortality HR was 0.61 in the second quartile (2.09-17.60х10
9
/L), HR was 0.58 in the third quartile (17.61-24.04х10
9
/L) and HR was 0.48 in the fourth quartile (24.05-34.54х10
9
/L) (all
P
<0.01).

Conclusion:
Higher WBC and PLTC are associated with poorer prognosis of stroke, and the ration of WBC to PLTC improved the predictive value for cardiovascular mortality and stroke recurrence.
Abstract 14: Echocardiographic Evaluation of Left Ventricular Recovery After Refractory Out-Of-Hospital Cardiac Arrest
Authors: Kalra Rajat , Bartos Jason , Kosmopoulos Marinos , Carlson Claire , John Ranjit , Shaffer Andrew , Martin Cindy M , Raveendran Ganesh , Yannopoulos Demetris
Published: June 2021

Introduction:
Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly used to treat cardiogenic shock and refractory cardiac arrest. However, the degree and mechanisms of myocardial recovery remain unclear.

Methods:
We retrospectively evaluated myocardial recovery and parameters of myocardial loading with decreasing VA-ECMO support in patients with refractory ventricular tachycardia/ventricular fibrillation (VT/VF) out-of-hospital cardiac arrest treated with the Minnesota Resuscitation Consortium protocol.

Results:
Of 158 consecutive patients, 58 had interpretable echocardiographic images on
>
1 echocardiographic evaluations (age, 54.7±19.3 years). Decannulation was successful in 50 patients (86%); 8 patients (14%) could not be decannulated. Left ventricular ejection fraction (LVEF) was 43.4±14.0% at 10.5±18.0 days after admission in successfully decannulated patients vs 18.1±22.4% at 4.1±2.9 days in patients who were not decannulated (
P
<0.001). Echocardiographic turndown studies showed significantly higher LVEF values in decannulated patients vs those who were not decannulated at the initial turndown (P=), during the final turndown (P<0.001), and at the last echocardiogram of the hospital stay (
P
<0.001). As VA-ECMO support decreased during the final turndown echocardiogram, LV end-diastolic diameter increased by 0.8±4.4 mm in patients who were subsequently decannulated and decreased by 3.1±4.7 mm in patients who could not be decannulated (
P
=0.04). Differences regarding change in LVEF, LV end-systolic diameter, and fractional shortening were not significant (Figure).

Conclusion:
Patients with refractory VT/VF cardiac arrest who are treated with VA-ECMO experience significant recovery of ventricular function. Changes in myocardial loading patterns suggest that this may occur via decreased transpulmonary flow and left ventricular preload, with little echocardiographic evidence of change in afterload.
Abstract 165: Impact of Prehospital Epinephrine for Patients Treated With Extracorporeal Cardiopulmonary Resuscitation After Refractory Out-Of-Hospital Shockable Cardiac Arrest
Authors: Nagao Ken , Tahara Yoshio , Nonogi Hiroshi , Yonemoto Naohiro , Gaieski David , Ito Noritoshi , Yagi Tsukasa , Nobutaka Chiba , Tachibana Eizo , Ikeda Takanori , Sato Naoki
Published: June 2021

Background:
The 2015 CoSTR recommended that standard-dose epinephrine (SDE) was reasonable for patients with out-of-hospital cardiac arrest (OHCA) and extracorporeal cardiopulmonary resuscitation (ECPR) was reasonable rescue therapy for selected patients with ongoing cardiac arrest when initial conventional CPR was unsuccessful. We investigated the effect of prehospital SDE for patients who met the criteria of ECPR.

Methods:
From the All-Japan OHCA Utstein Registry between 2007 and 2015, we included 22,552 patients who met the criteria of ECPR of the SAVE-J study (age between 20 and 75, witnessed shockable OHCA, cardiac arrest on hospital arrival, cardiac etiology, and collapse-to-ECPR interval within 60 minutes). Study patients were divided into two groups according to prehospital SDE or not. Primary endpoint was favorable 30-day neurological outcome after OHCA.

Results:
Of the 22,552 study patients, 5,659 (25%) received prehospital SDE and 16,893 (75%) did not. The SDE group resulted in lower proportion of favorable 30-day neurological outcome than the no-SDE group (5.6% versus 8.4%, p<0.001) with longer collapse-to-hospital-arrival interval (36.7±9.8 min vs. 29.6±11.3 min, p<0.001). After adjustment for independent predictors of resuscitation, prehospital SDE did not impact on neurological benifit (adjusted OR,1.13; 95%CI,0.98-1.29), but the collapse-to-hospital-arrival interval was associated with neurological benefit (adjusted OR, 0.94; 95% CI, 0.93-0.95). In curve estimation of the SDE group, when collapse-to-hospital-arrival interval was delayed, proportion of the favorable neurological outcome decreased to about 25% at 1 minute and about 0% at 54 minutes (R=0.14). In the 274 patients undergoing ECPR of the SAVE-J study, however, it was about 43% at 1 minute and about 0% at 96 minutes (R=0.17).

Conclusions:
Prehospital SDE did not improve likelihood of favorable neurological outcome for patients who met the criteria of ECPR (age between 20 and 75, witnessed shockable OHCA, cardiac arrest on hospital arrival, cardiac etiology and collapse-to-ECPR interval within 60 minutes), because SED administration delayed the collapse-to-hospital-arrival interval which was closely related to the neurologically intact survival on ECPR.
Abstract 174: Effects of Melatonin (N-Acetyl-5-Methoxytryptamine) on Inflammation and Cerebral Microcirculation After Cardiopulmonary Resuscitation in a Rat Model of Cardiac Arrest
Authors: Hu Juntao , Zheng Guanghui , He Fenglian , Ge Weiwei , Xu Jing , Ji Xianfei , Bradley Jennifer , Peberdy Mary Ann A , Ornato Joseph P , Tang Wanchun
Published: June 2021

Introduction:
Cerebral ischemia-reperfusion injury produces inflammation and cerebral microcirculatory dysfunction after cardiopulmonary resuscitation (CPR). Melatonin (N-acetyl-5-methoxytryptamine) has both anti-inflammatory and anti-oxidative properties. In this study, we investigated the effects of melatonin on inflammation and cerebral microcirculation after cardiopulmonary resuscitation in a rat model of cardiac arrest.

Hypothesis:
Melatonin decreases the systemic inflammatory response after cardiopulmonary resuscitation and will preserve cerebral microcirculation in a rat model of cardiac arrest.

Method:
Eighteen male Sprague Dawley rats weighing between 450-550 g were randomized into three groups: 1) sham: no ventricular fibrillation (VF) and CPR; 2) CPR control: untreated VF for 6 min followed by 8 min CPR; 3) CPR+melatonin: untreated VF for 6 min followed by 8 min CPR. Melatonin (10 mg/kg) was administered intraperitoneal (IP) in line with hypoxia-ischemia animal studies after return of spontaneous circulation (ROSC). Serum TNF- α, IL-1 β and cerebral microcirculation were measured at baseline and 6 h following ROSC.

Result:
Serum TNF-α and IL-1β were significantly lower in the CPR+melatonin group at 6h after ROSC compared to CPR controls (
p
<0.01, Fig. 1). Animals treated with melatonin had improved cerebral microcirculation including perfused vessel density (PVD), proportion of perfused vessels (PPV) and microvascular flow index (MFI) compared to control animals (
p
<0.05, Fig. 2).

Conclusion:
In a rat model of cardiac arrest, melatonin reduced systemic inflammation and preserved cerebral microcirculation following resuscitation.
Abstract 187: Cardiac Arrest Incidence, Bystander Cardiopulmonary Resuscitation Rates, and Community Characteristics Differ by High and Low Risk Areas
Authors: Cash Rebecca , Rivard Madison K , Cortez Eric , Keseg David , Panchal Ashish
Published: June 2021

Introduction:
Survival from out-of-hospital cardiac arrest (OHCA) has significant variation which may be due to differing rates of bystander cardiopulmonary resuscitation (BCPR). Defining and understanding the community characteristics of high-risk areas (census tracts with low BCPR rates and high OHCA incidence) can help inform novel interventions to improve outcomes. Our objectives were to identify high and low risk census tracts in Franklin County, Ohio and to compare the OHCA incidence, BCPR rates, and community characteristics.

Methods:
This was a cross-sectional analysis of OHCA events treated by Columbus Division of Fire in Franklin County, Ohio from the Cardiac Arrest Registry to Enhance Survival between 1/1/2010-12/31/2017. Included cases were 18 and older, with a cardiac etiology OHCA in a non-healthcare setting, with EMS resuscitation attempted. After geocoding to census tracts, Local Moran’s I and quartiles were used to determine clustering in high risk areas based on spatial Empirical Bayes smoothed rates. Community characteristics, from the 2014 American Community Survey, were compared between high and low risk areas.

Results:
From the 3,841 included OHCA cases, the mean adjusted OHCA incidence per census tract was 0.67 per 1,000 with a mean adjusted BCPR rate of 31% and mean adjusted survival to discharge of 9.4%. In the 25 census tracts identified as high-risk areas, there were significant differences in characteristics compared to low-risk areas, including a higher proportion of African Americans (64% vs. 21%, p<0.001), lower median household income ($30,948 vs. $54,388, p<0.001), and a higher proportion living below the poverty level (36% vs. 20%, p<0.001). There was a 3-fold increase in the adjusted OHCA incidence between high and low risk areas (1.68 vs. 0.57 per 1,000, p<0.001) with BCPR rates of 27% and 31% (p=0.31), respectively. Compared to a previous analysis, 9 (36%) census tracts persisted as high-risk but an additional 16 were newly identified.

Conclusions:
Neighborhood-level variations in OHCA incidence are dramatic with marked disparities in characteristics between high and low risk areas. It is possible that improving OHCA outcomes requires multifaceted interventions to address social determinants of health.
Abstract 20: Peripheral Intravenous Analysis Detects Return of Spontaneous Circulation Without Interruption of Chest Compressions in a Rat Model of Cardiopulmonary Resuscitation
Authors: Balzer Claudius , Baudenbacher Franz J , Hernandez Antonio , Salzman Michele M , Riess Matthias L , Eagle Susan S
Published: June 2021

Introduction:
A higher chest compression fraction (CCF) or percentage of time providing chest compressions is associated with improved survival after cardiac arrest (CA). Pauses in chest compression duration during cardiopulmonary resuscitation (CPR) to palpate a pulse can reduce the CCF. Peripheral Intravenous Analysis (PIVA) is a novel method for determining cardiac and volume status using waveforms from a standard peripheral intravenous (IV) line. We
hypothesize
that PIVA will demonstrate the onset of return of spontaneous circulation (ROSC) without interruption of CPR.

Methods:
Eight Zucker Diabetic Fatty (ZDF) rats (4 lean, 4 diabetic) were intubated, ventilated, and cannulated with a 24g IV in the tail vein and a 22g IV in the femoral artery, each connected to a TruWave pressure transducer. Mechanical ventilation was discontinued to achieve CA. After 8 minutes, CPR began with mechanical ventilation, IV epinephrine, and chest compressions using 1.5 cm at 200 times per minute until mean arterial pressure (MAP) increased to 120 mmHg per arterial line. All waveforms were recorded and analyzed in LabChart. PIVA was measured using a Fourier transform of the peripheral venous waveform. Data are mean ± SD. Statistics: Unpaired student’s t-test (two-tailed), α = 05.

Results:
CA and ROSC were achieved in all 8 rats. Within 1 minute of CPR, there was a 70 ± 35 fold increase/decrease in PIVA during CPR that was temporally associated with ROSC. Within 8 ± 13 seconds of a reduction in PIVA, there was a rapid increase in end-tidal CO
2
. In all rats, ROSC occurred within 38 ± 9 seconds of the maximum PIVA value. Peripheral venous pressure decreased by 1.2 ± 0.9 mmHg during resuscitation and ROSC, which was not significant different at p=0.05.

Conclusion:
In this pilot study, PIVA detected ROSC without interrupting CPR. Use of PIVA may obviate the need pause CPR for pulse checks, and may result in a higher CCF and survival. Future studies will focus on PIVA and CPR efficacy.
Abstract 215: Hemodynamics of Absolute, Proportional, and Adaptive Mechanical Chest Compression Strategies in a Swine Model of Pediatric Out-Of-Hospital Cardiac Arrest
Authors: Salcido David D , Koller Allison C , Genbrugge Cornelia , Kern Caelie , Menegazzi James J
Published: June 2021

Background:
Guidelines for pediatric resuscitation recommend a depth of 1.5in or 1/3 anterior-posterior chest diameter for chest compressions (CC) despite little supporting evidence.

Objective:
To evaluate the hemodynamic effects of the two recommended depths and an adaptive strategy.

Methods:
Thirty-eight animals (mass ~25kg) were sedated, anesthetized, intubated, and ventilated. Micromanometer pressure sensors were installed in the aorta and right atrium via the right femoral artery and vein. Coronary perfusion pressure (CPP) was calculated as aortic minus right atrial pressure. An ultrasonic flow probe was secured around the right common carotid. Biosignals were recorded at 1000Hz. Animals were then re-paralyzed, followed by a fentanyl bolus, and the endotracheal tube was occluded for 9min. Each was randomized to absolute (Group 1: 1.5in & 100/min), proportional (Group 2: 1/3 AP diameter & 100/min), or stepwise adaptive (Group 3: 1.5in & 100/min, adding 0.25in or 5/min q25s until CPP > 25mmHg) CC using a robotic compressor. Epinephrine (0.1mg/kg) and sodium bicarbonate (1mEq/kg) were given after 4min, followed by epinephrine (0.15mg/kg) q3min. Defibrillation (150J) was attempted after 5min; CPR discontinued after 20min. Mean arterial pressure (MAP), CPP and carotid blood flow (CBF) were calculated for the first 10 minutes of CPR and compared between groups with generalized estimating equations (GEE).

Results:
In GEE models, MAP, CBF and CPP did not differ between groups over the first 10 minutes of resuscitation. Each measure differed significantly over time (p<0.05). When considering only the first 5 minutes (early phase including first pressor), hemodynamic variables also did not differ.

Conclusion:
In a swine model of asphyxial cardiac arrest, CC methods based on current guidelines and an additional adaptive approach did not differ hemodynamically.
Abstract 219: Supplement Oxygen Dependence of Dissociated Oxygen Metabolism From Carbon Dioxide and Oxidative Toxic Stress in Post-Cardiac Arrest
Authors: Okuma Yu , Shinozaki Koichiro , Nishikimi Mitsuaki , Saeki Kota , Yin Tai , Kim Junhwan , Becker Lance B
Published: June 2021

Objective:
We recently reported a dissociation of oxygen metabolism in post-cardiac arrest rodents, which was represented by an increase in oxygen consumption (VO
2
) without a concomitant increase in carbon dioxide generation (VCO
2
) resulting in a lowered respiratory quotient (RQ) outside of the normally cited range of 0.7-1.0. We hypothesize that high supplemental O
2
is associated with both increased dissociation of oxygen metabolism and oxidative toxic stress after cardiac arrest (CA).

Methods:
Rats were resuscitated from 10 minutes of asphyxial CA and stratified into 2 groups: those that inhaled 100% supplemental O
2
(CA-FIO2 1.0) and those that inhaled 30% supplemental O
2
(CA-FIO2 0.3). We prepared a sham surgery group for comparison (sham-FIO2 0.3). Our newly developed method enabled measurements of VO
2
and VCO
2
from low to high inspiratory supplemental O
2
levels. RQ was calculated as VCO
2
/VO
2
. After 2 hours, we collected urine and tissue samples to determine the degree of reactive oxygen species (ROS) generation.

Results:
CA increased VO
2
(28.5±8.1 mL/kg/min at FIO2 1.0 and 19.1±3.0 at FIO2 0.3, p<0.05) compared with the sham group (15.0±1.4), whereas no differences in VCO
2
were found among the three groups. RQ of CA-FIO2 1.0 animals persistently decreased to 0.57±0.03 (0.84 ±0.10 at CA-FIO2 0.3 and 0.96±0.14 at sham-FIO2 0.3). Regarding ROS generation, urinary 8-hydroxydeoxyguanosine (8-OHdG) and brain carbonyl protein of CA-FIO2 1.0 animals was significantly higher than the CA-FIO2 0.3 or sham groups.

Conclusions:
100% supplemental oxygen increased VO
2
but not VCO
2
. 8-OHdG is produced during the repair of cellular DNA damaged from oxidative toxic stress and excreted into the urine. Our findings suggest that the high supplemental oxygen aggravate both dissociation of oxygen metabolism and oxidative toxic stress in post-CA rodents.
Abstract 228: Epidemiology and Outcome of Out-Of-Hospital Cardiac Arrests in Kunming, Yunnan, China
Authors: Yu Tao , Zhou Tianen , Wen Cai
Published: June 2021

Objective:
The purpose of this study was to better understand the epidemiological features and outcomes of emergency medical service(EMS)-assessed out-of-hospital cardiac arrests(OHCAs) in Kunming,Yunnan,China.

Methods:
In this prospective study,datas were collected according to the Utstein style on all cases of OHCAs from January 2010 to December 2014 in urban areas covered by Kunming EMS system.The outcomes were analysed at four time points of survival: no return of spontaneous circulation (no-ROSC),return of spontaneous circulation (ROSC),survival to hospital admission, and survival to hospital discharge.The adjusted odds ratios(ORs) and 95% confidence intervals(CIs) for survival were calculated and adjusted for potential risk factors using stratified multivariable logistic regression analysis.

Results:
There were 3387 EMS-assessed OHCAs with cardiac aetiology from 2010 to 2014. The incidence of EMS-assessed OHCA with cardiac aetiology was 20.7 per 100,000 inhabitants per year. Of the 3387 EMS-assessed OHCAs with cardiac aetiology,the rates of ROSC,survival to admission and survival to discharge were 12.4%,3.5% and 0.9% respectively. There were only 73(2.2%)patients with initial rhythm of ventricular fibrillation(VF) or pulseless ventricular tachycardia(VT) observed in the EMS-assessed OHCAs with cardiac aetiology.There was no statistical difference among the five years in outcomes of OHCAs with cardiac aetiology.Younger age, bystander CPR,witnessed by EMS, OHCA with initial rhythm of VF/pulseless VT,shorter medication interval,and shorter response interval were associated with a higher rate of survival to discharge respectively.

Conclusion:
In the urban areas of Kunming covered by EMS system, survival outcome of OHCA was unsatisfactory.Improvements are required in every link of the chain of survival.
Abstract 235: The Association Between No-Flow Interval and Neurological Outcomes in Out-Of-Hospital Cardiac Arrest: Implications for Rescuer Response, Initiating Resuscitation, and ECPR Candidacy Evaluation
Authors: Grunau Brian E , Guy Andrew , Kawano Takahisa , Scheuermeyer Frank , Besserer Floyd , Kanji Hussein , Christenson James
Published: June 2021

Introduction:
The benefits of early CPR are evident, however the relationship between the no-flow interval and neurological outcomes may assist clinicians with resuscitation management.

Methods:
We examined emergency medical system-treated non-traumatic out-of-hospital cardiac arrests from two clinical trials (PRIMED and CCC; 2006-2015), including only bystander witnessed cases without bystander resuscitation. We created a subgroup to simulate ECPR-treated cases (witnessed, age ≤65, non-asystole initial rhythm, and ROSC >30 minutes). We fit an adjusted logistic regression model to estimate the relationship between the “no-flow” interval (911 call-to-initiation of CPR) and favorable neurological outcome (MRS ≤3) at hospital discharge, and created a cubic spline curve.

Results:
Of 43,593 trial cases, 7299 were included; 616 (8.4%; 95% CI 7.8-9.1%) favourable neurological outcomes. The no-flow interval (per minute) was associated favorable neurological outcomes (adjusted OR 0.88, 95% CI 0.85-0.91). The adjusted probability of a favorable neurological outcome decreased by 0.52% (95% CI 0.39-0.65) per no-flow minute. No patients (0%; 1-sided 97.5% CI 0-0.051%) had both a no-flow duration >20 minutes and a favorable neurological outcome. In the ECPR group, 15 (9.9%; 95% CI 5.1-15%) had favourable neurological outcomes; 0/152 (0%; 1-sided 97.5% CI 0-2.4%) had both a no-flow interval >10 minutes and a favourable neurological outcome.

Conclusions:
The odds of a favorable neurological outcome decrease as the no-flow interval increases, highlighting the urgency of rescuer response. We found no favorable outcomes among cases with >20 minutes of no-flow duration, which may assist providers with decisions of starting or terminating resuscitation. Among ECPR-eligible cases with prolonged resuscitative efforts there were no favourable neurological outcomes among those with a no flow-interval >10 minutes, which may assist with ECPR candidacy assessment.
Abstract 238: Automating Medical Record Matching: A Key Component of an Automated Cardiac Arrest Registry
Authors: McDonald Samuel , Fowler Raymond , Owens Pamela , May Susanne , Herren Heather , Idris Ahamed H
Published: June 2021

Introduction:
An automated registry for out-of-hospital cardiac arrest can facilitate cardiac arrest research and emergency medical services (EMS) and community health quality improvement programs. A key element of a cardiac arrest registry is outcome, especially survival to hospital discharge, which is usually obtained from the hospital medical record. A crucial step in capturing survival data automatically is being able to reliably match EMS patient care reports with hospital medical records.

Objective:
To determine the accuracy of a probabilistic record-linkage approach to match EMS and hospital encounters and identify barriers of automation.

Methods:
This is a prospective feasibility study from the Dallas Fort-Worth Center for Resuscitation Research. Our cardiac arrest registry was part of the Resuscitation Outcomes Consortium (ROC) Epistry from 2006 to 2016. Since 2016, we maintained it separately from the ROC and have since enrolled over 20,000 cases. Record linkage was performed using demographic data of encounters from a single EMS agency within the registry and a community hospital in Dallas where these were transported from January 2017 to May 2018. An expectation maximization algorithm to aid in discerning matches and nonmatches was performed using the R package RecordLinkage identifying record pairs as a match, non-match, or possible match based on a pre-determined threshold. Match and Possible Match pairs were manually reviewed to assess the algorithm’s accuracy.

Results:
The EMS and hospital data sets had 67 and 6,050 unique encounters, respectively. The record linkage algorithm identified 40 EMS encounters as having a match (60%), 12 with a possible match (18%), and 15 with no identified match (22%). After manual review, the algorithm had a positive predictive value (PPV) of 100% (40/40) for the match group with a sensitivity of 60%.

Conclusions:
Applying probabilistic linkage to aid in automating a cardiac arrest registry was successful in linking over half of the EMS encounters with a PPV of 100%. When reviewing the unmatched encounters, many were adjacent to each other when sorted by time suggesting the poor sensitivity is more likely a reflection of the hospital’s data collection method as opposed to the linkage methodology.
Abstract 25: Prognostic Role of NT-ProBNP in Out-Of-Hospital Cardiac Arrest
Authors: Hamilton David E , Petek Bradley J , Panah Lindsay G , Mendez Sean R , Dormish Philip E , Silverman Michael G
Published: June 2021

Introduction:
The role of cardiac biomarkers in patients after out-of-hospital cardiac arrest (OHCA) has been subject to recent research due to myocardial stress and injury associated with cardiac arrest. However, it remains unclear to what extent NT-proBNP can be used as a prognostic tool after OHCA.

Hypothesis:
Baseline NT-proBNP is an independent predictor of mortality in patients after OHCA.

Methods:
Multicenter retrospective observational cohort study including non-traumatic OHCA patients presenting from 2/1/2017 to 4/1/2019. Relationship between NT-proBNP quartiles and mortality was assessed through unadjusted and adjusted (age, gender, presenting rhythm) analyses with logistic regression.

Results:
Baseline NT-proBNP values were obtained for 283 patients on presentation after OHCA with median 965 pg/mL (IQR 157-3550). Levels did not differ by arrest etiology (cardiac vs noncardiac) or presenting rhythm. NT-proBNP levels correlated with age (r = 0.44, p<0.0001), but not with lactate, CPR duration, or intra-arrest epinephrine. Overall in-hospital mortality was 68% (196/283). Mortality increased in a stepwise fashion among patients in increasing quartiles of NT-proBNP level (Figure). Mortality rate in Q1: 59% ( 42/71), Q2: 61% (43/70), Q3: 75% (54/72), Q4: 77% (54/70). Odds Ratios (OR) vs Q1 as reference: Q2 OR 1.10 [95% CI 0.56-2.17] p= 0.48; Q3 OR 2.08 [95% CI 1.01-4.17] p= 0.045; Q4 OR 2.33 [95% CI 1.11-4.76] p=0. 023. After adjusting for age, gender, and shockable rhythm there remained a stepwise relationship between higher mortality with increasing NT-proBNP quartile (Q2 OR 1.30 [95% CI 0.61-2.78] p= 0.78; Q3 OR 2.33 [95% CI 1.05-5.26] p= 0.038; Q4 OR 2.50 [95% CI 1.05-5.88] p= 0.039).

Conclusion:
In this multicenter cohort of patients with shockable and nonshockable OHCA, increased levels of NT-proBNP were predictive of an increased risk of in-hospital mortality even after adjustment for age, gender, and presenting rhythm.
Abstract 275: Oxygen Weaning is Slow and Highly Variable Among Mechanically Ventilated Patients After Out-Of-Hospital Cardiac Arrest
Authors: McGovern Shaun K , Laothamatas Kemarut , Bhardwaj Abhishek , Buckler David G , Abella Benjamin S
Published: June 2021

Introduction:
Arterial hyperoxia at 6 h following resuscitation from out-of-hospital cardiac arrest (OHCA) may be associated with worsened survival and neurologic outcome. While global resuscitation guidelines call for prompt weaning of inhaled oxygen fraction (FiO2) following return of spontaneous circulation, with titration to oxygen saturation (SaO2) >92%, the burden of hyperoxia (both FiO2 and duration) among OHCA patients in the emergency department (ED) and critical care setting is unknown.

Objectives:
We sought to characterize oxygen weaning behavior in a cohort of resuscitated and mechanically ventilated OHCA patients from two hospitals, with “hyperoxic exposure burden” defined as cumulative treatment hours with FiO2>0.6. We hypothesized that the majority of these patients receive at least 6 h of hyperoxic exposure despite concomitant SaO2>92% during and after weaning.

Methods:
A retrospective study of post-arrest care was performed at two academic hospitals from 1/2018-12/2018; both hospitals have well-developed post-arrest care protocols that include oxygen weaning instructions. Consecutive non-traumatic, adult (age>17 y) OHCA patients treated in the emergency department that achieved sustained ROSC and received mechanical ventilation were included. Demographic data, as well as data on FiO2, SaO2 and arterial blood gas results, were collected for the first 24 h of post-arrest care.

Results:
70 adult OHCA patients were included. Mean age was 61 y (SD 16.4), 51% were male, and 20% had initial shockable arrest rhythms. Survival to discharge was 21%. Median ED patient care time before ICU transfer was 2.7 h (IQR: 1.9-4.0). FiO2>=0.6 was administered to 52% of the cohort for at least 6 h; the median duration of hyperoxic exposure burden was 8.7 h (IQR: 3.9-15.0) with a wide range from 0.6-92 h. Among all patients with 6 h or more with FiO2>=0.6, median partial pressure of arterial oxygen was 136 mm Hg (IQR: 94-301) as measured during this period.

Conclusions:
Most resuscitated OHCA patients received substantial exposure to hyperoxia, and the timing of oxygen weaning was highly variable. Additional clinical investigation is required to understand the barriers to rapid weaning and to test the effect of improved weaning on clinical outcomes.
Abstract 277: Long-Term Daily Prophylactic Supplement With Melatonin as a Health Care Medicine Significantly Improved Survival and Neurological Outcome After Cardiac Arrest
Authors: Hu Yanan , Zhao Xuyan , Jin Mingxin , Jiang Ge , Sui Xin , Han Fei
Published: June 2021

Introduction:
Prophylactic pharmacotherapy for health care in reducing death after cardiac arrest (CA) is an elusive and less explored strategy. Melatonin, a natural health product contributing to sleep, was elevated upon arousal from torpor in hibernating mammals, which increased survival after blood return and reduced reperfusion injury. In this study, we sought to find the effects of long-term daily prophylactic supplement with melatonin as a health care medicine on the victim of CA.

Methods:
SD rats, 240-340 g, were used in this study. Sham, CA, and melatonin + CA (Mel + CA) groups were included. The rats in the Mel + CA group received daily IP injection of melatonin 100 mg/kg for 14 days. CA was induced by 8 mins asphyxia and followed by manual CPR. The endpoint was 24 h after resuscitation. Neurological outcome was assessed. Hippocampal mitochondrial integrity, dynamics and function were observed.

Results:
Survival in the Mel + CA group was significantly higher than in the CA group (78% vs. 44%,
P
= 0.036). NDS was better in the Mel + CA group than the CA group (
P
< 0.001). Neurons of CA1 were less damaged in the Mel + CA group than in the CA group (Figure). The mitochondria integrity in the CA group was severely damaged compared with the Mel + CA group. Sirt3 was highly expressed in the Mel + CA group than in the CA group (
P
< 0.05). Ac-CypD was lower in the Mel + CA group than in the CA group (
P
< 0.05). Drp1 was lower in the Mel + CA group than in the CA group (
P
< 0.05). LC3 was highly expressed in the Mel + CA group than in the CA group (
P
< 0.05). ΔΨm, mitochondria respiratory rate, and respiratory control rate were higher in the Mel + CA group than in the CA group (
P
< 0.05). ROS production was lower in the Mel + CA group (
P
< 0.05). Cleaved caspase-3 and caspase-9 were lower in the Mel + CA group (
P
< 0.05).

Conclusions:
Long-term daily prophylactic supplement with melatonin as a health care medicine significantly improved survival, neurological outcome and neuronal mitochondrial function after cardiac arrest.
Abstract 281: Cerebral Regional Oxygen Saturation (rSO
2
) is Useful as a Physiological Monitoring Tool During CPR in the Pre-Hospital Settings. An Analysis of 87 Cases in Osaka, Japan
Authors: Shigematsu Shinji , Sakai Tomohiko , Shiozaki Tadahiko , Ohnishi Mitsuo , Takegawa Ryosuke , Tachino Jotaro , Nakao Shunichiro , Muratsu Arisa , Hayashida Sumito , Shimazu Takeshi
Published: June 2021

Introduction:
The simplified monitoring of regional cerebral oxygen saturation (rSO
2
) is a non-invasive method of measuring cerebral perfusion, but continuous changes in the cerebral rSO
2
values among OHCA patients in the pre-hospital settings have not been sufficiently investigated. Our objective is to investigate the association between the change in rSO
2
pattern and patient outcome.

Methods:
We recently developed a very small portable rSO
2
monitoring system that can be used in the pre-hospital setting. The system can monitor cerebral rSO
2
immediately after attachment; monitoring is performed continuously during CPR. The system was used from June 2013 to May 2019 in Osaka City, Japan.The primary outcome measure was neurologically intact survival at 1 month.

Results:
We collected the continuous changes in the cerebral rSO
2
values of 87 OHCA patients during CPR by EMS personnel. The analyses of the continuous changes in the rSO
2
values of the 79 cases in which the rSO
2
value was measured before ROSC revealed two patterns of changes in the cerebral rSO
2
values. In type 1 (increasing rSO
2
type; n=38), the measured rSO
2
gradually increased during CPR or after ROSC. There were 3 patients of neurologically intact survival in type 1. In type 2 (non-increasing rSO
2
type; n=41), the measured rSO
2
did not increase during CPR. There was no patient of neurologically intact survival in type 2. We found an instructive phenomenon in the changes of the cerebral rSO
2
values. Measured rSO
2
dropped after confirmation of ROSC, which suggests that re-arrest had occurred during monitoring.

Conclusion:
We measured the continuous changes in cerebral rSO
2
values among 87 patients with OHCA in the pre-hospital setting and found 2 patterns and an instructive phenomenon in the continuous changes in rSO
2
values. Increasing type rSO
2
during CPR appeared to be associated with neurologically intact survival at 1 month.
Abstract 283: Cerebral Regional Oxygen Saturation (rSO
2
) Will Support to Evaluate an Oxygenation for Emergency Patients Who Can Not Measure SpO
2
at the Scene
Authors: Sakai Tomohiko , Shiozaki Tadahiko , Ohnishi Mitsuo , Takegawa Ryosuke , Tachino Jotaro , Muratsu Arisa , Nakao Shunichiro , Shimazu Takeshi
Published: June 2021

Introduction:
There are some critical ill patients who cannot measure oxygen saturation (SpO
2
) by pulse oximeter at the pre-hospital settings. For example, among emergency patients who were treated by emergency medical service (EMS) personnel of Osaka Municipal Fire Department in 2016, there were 3,571 patients who had urgent conditions judged by on-scene EMS personnel but did not have cardiopulmonary arrest (CPA), but the measurement of SpO
2
at the scene could not be measured for 395 patients. On the other hand, the measurement of cerebral regional oxygen saturation (rSO
2
) during resuscitation has been recently paid to attention.

Purpose:
To evaluate whether rSO
2
could be measured for these patients.Materials and

Methods:
We developed portable rSO
2
monitors and equipped them in nine ambulances (There are 63 ambulances in Osaka City). We measured serial changes in cerebral rSO
2
among emergency patients who had urgent conditions judged by on-scene EMS personnel and could not be measured SpO
2
at the scene from April 1st 2018 through March 31st 2019.

Results:
During the study period, there were 788 patients with incapable-measurement SpO
2
who had urgent conditions judged by on-scene EMS personnel but did not have CPA. We evaluated serial changes in cerebral rSO
2
among 12 patients at the pre-hospital settings. The values of many cases were lower than the normal rangemeasured from healthy adults (71.2 ± 3.9%, on room air). Some cases could not be measured at once during transport to a hospital in spite of any oxygenation. Three cases had > 60 mmHg of systolic blood pressure or an un-palpable radial artery. At some cases, rSO
2
value increased by oxygenation or ventilation.

Conclusions:
We could measure serial changes in cerebral rSO
2
among fourteen patients without the measurement of SpO
2
at the scene. Our data suggest that pre-hospital monitoring of cerebral rSO
2
might be a new physiological monitoring for urgent patients during transport.
Abstract 303: The Impact of Pediatric Resuscitation Events on Overall Emergency Department Flow
Authors: McBride Peter , Ainsley Matthew , Zhang Xuemei , Johnson Andrew , Donoghue Aaron , Myers Sage
Published: June 2021

Background:
Pediatric resuscitation events are infrequent but resource-intensive events which pull staff, leaving higher patient:provider ratios and less access to the resources in the emergency department (ED). There is a paucity of literature on the impact of these events on overall ED flow.

Objective:
Use novel, prospective, comprehensive data collection to evaluate the impact of resuscitation events on the time to physician evaluation (eval) for patients arriving to the ED after a resuscitation event.

Methods:
Data from all resuscitation events occurring in the ED are logged prospectively. Resuscitation dates were matched to 2 control dates by census within 2 weeks and with no resuscitation events within 3 hours of time zero. A difference-in-differences evaluation compared median time to physician eval for all ED patients arriving pre and post time zero between cases and controls. Multivariate linear mixed-effects models were used to compare time to physician eval post-resuscitation between cases and controls.

Results:
459 resuscitation dates were matched to 812 control dates. A higher median time to physician eval was found for cases, as compared to controls, which lasted for 2 hours after the time of the event (see Figure). A significant difference in time to physician eval post-resuscitation was found for cases (p=0.003) in multivariate models (see Table).

Conclusions:
Pediatric resuscitation events occurring in a large, high-resource, pediatric ED impact overall flow of the ED. Initiatives to redistribute care during resuscitation events, and evaluation of the impact of these interventions, could help ensure timely and appropriate care delivery to all ED patients.
Abstract 407: Utility of Abnormal Head Computed Tomography in Predicting Outcome in Out of Hospital Cardiac Arrest Victims Resuscitated and Subsequently Placed on Targeted Temperature Management
Authors: Bernett Michael , Swor Robert A
Published: June 2021

Introduction:
Head computed tomography (HCT) is often performed to assess for hypoxic-ischemic brain injury in resuscitated out of hospital cardiac arrest (OHCA) patients. Our primary objective was to assess whether cerebral edema (CE) on early HCT is associated with poor survival and neurologic outcome post OHCA.

Methods:
We included subjects from a prospectively collected cardiac arrest database of OHCA adult patients who received targeted temperature management (TTM) at two academic suburban hospitals from 2009-Sept-2018. Cases were included if a HCT was performed in the emergency department (ED). Patient demographics and cardiac arrest variables were collected. HCT results were abstracted by study authors from radiology reports. HCT findings were categorized as no acute disease, evidence of CE, or excluded (bleed, tumor, stroke). Outcomes were survival to discharge or cerebral performance scores (CPC) at discharge of three or four (poor neurologic outcome). Descriptive statistics, univariate, multivariate, survival, and interrater reliability analysis were performed.

Results:
During the study period, there were 425 OHCA, 277 cases had ED HCTs performed; 254 cases were included in the final survival analysis. Patients were predominately male, 189 (65.0%), average age 60.9 years, average BMI of 30.5. Of all cases, 44 (15.9%) showed CE on CT. Univariate analysis demonstrated that CE was associated with 9.2-fold greater odds of poor outcome (OR: 9.23; 95% CI 1.73, 49.2), and 9.1-fold greater odds of death (OR: 9.09: 95% CI 2.4 33.9). In adjusted analysis, CE was associated with 14.9-fold greater odds of poor CPC outcome (AOR: 14.9, 95% CI, 2.49, 88.4), and 13.7-fold greater odds of death (AOR: 13.7, 95% CI, 3.26, 57.4). Adjusted survival analysis demonstrated that patients with CE on HCT had 3.6-fold greater hazard of death than those without CE (HR: 3.56: 95% CI 2.34, 5.41). Interrater reliability demonstrated excellent agreement between reviewers for CE on HCT (κ = 0.86).

Conclusion:
The results identify that abnormal HCTs early in the post-arrest period in OHCA patients are associated with poor rates of survival and neurologic outcome. Prospective work is needed to confirm whether selection bias or other variables confound this association.
Abstract 415: Underlying Liver Disease and Survival Outcomes in Out-Of-Hospital Cardiac Arrest
Authors: Pak Jieun , Kim Ki Hong , Kim Jong Hwan , Lee Sun Young , Hong Ki Jeong , Shin Sang Do
Published: June 2021

Introduction:
It is unclear whether underlying liver disease can affect survival outcomes of out-of-hospital cardiac arrest (OHCA) patients. This study aims to evaluate the association between underlying liver disease and survival outcomes of OHCA patients.

Methods:
This study was a cross-sectional study using a nationwide OHCA registry in Korea. Adult OHCA patients with presumed cardiac etiology from 2013 to 2015 were included. The main exposure was underlying liver disease which was identified from medical record review. We categorized patients into 3 groups: chronic liver disease (CLD) with cirrhosis, CLD without cirrhosis and no CLD group. The primary outcome was discharge with good neurological recovery (cerebral performance category 1 or 2) and the secondary outcome was survival to discharge. Multivariable logistic regression was performed to calculate odds ratios (OR) with 95% confidence intervals (CIs) after adjusting for potential confounders.

Results:
A total of 8,844 patients, 1,323 (15%) patients had CLD with cirrhosis and 361 (4.1%) patients had CLD without cirrhosis. Good neurological recovery rate was 0.6% in CLD with cirrhosis group, 8.9% in CLD without cirrhosis group and 8.7% in no CLD group (P<0.0001). Compared to no CLD group, CLD with cirrhosis group was less likely to have favorable outcomes (adjusted OR [95% CI]: 0.28 [0.13-0.62] for good neurological recovery and 0.35 [0.21-0.59] for survival to discharge). There was no significant difference in favorable outcomes between no CLD group and CLD without cirrhosis group (adjusted OR [95% CI]: 1.64 [0.92-2.92] for good neurological recovery and 1.38 [0.87-2.19] for survival to discharge).

Conclusion:
Underlying CLD was associated with survival outcomes of OHCA patients. CLD with cirrhosis was associated with poor neurological recovery for OHCA patients.