bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 173: The Neuroprotective Effect Of JZL184 is Comparable With Therapeutic Hypothermia in a Rat Model of Cardiac Arrest
Authors: Xu Jing , Zheng Guanghui , Hu Juntao , Ge Weiwei , Bradley Jennifer , Peberdy Mary Ann A , Ornato Joseph P , Tang Wanchun
Published: June 2021

Introduction:
JZL184 is a synthetic monoacylglycerol lipase inhibitor that reduces brain edema, infarct size and alleviates inflammation following cerebral ischemia in experimental studies. In this study, we compared its cerebral protective effects with therapeutic hypothermia following cardiopulmonary resuscitation (CPR) in a rat model.

Hypothesis:
JZL184 will have similar neuroprotective effects to therapeutic hypothermia after cardiac arrest (CA) by reducing brain and blood brain barrier (BBB) injury and preserving cerebral microcirculation following CPR.

Methods:
Thirty six male Sprague-Dawley rats weighing between 450-550 g were randomized: 1) control 2) hypothermia 3) JZL184. Ventricular fibrillation was induced and untreated for 6 min for all rats. Resuscitation was attempted with a 4 Joule defibrillation after 8 min of CPR. Immediately following resuscitation, either hypothermia (33+0.5
o
C) or JZL184 (16 mg/k, IP) was administered. Cerebral microcirculation, S-100β, NSE and Evan’s Blue (EB) concentrations were analyzed at 6hrs after resuscitation.

Results:
NSE and S-100β levels were higher in control compared to hypothermia and JZL18 at 6hr post ROSC (p < 0.001) (Fig. 1). Compared with control, there was a significant decrease in brain permeability to EB in Hypothermia and JZL184 after 6hr post ROSC (p<0.001) (Fig. 2). Microvascular flow index (MFI) was reduced in control compared with hypothermia and JZL184 6hr post ROSC (p <0.01).

Conclusions:
JZL184 administered following resuscitation reduced brain and BBB injury and preserved cerebral microcirculation at 6 hr post arrest to the same extent as hypothermia in a rat model of cardiac arrest.
Abstract 177: A Multimodal Neuroprotection Strategy Using Ketamine, Melatonin, and Limited Initial Reoxygenation Following Cardiac Arrest Does Not Improve MRI Cytotoxic Injury in a Swine Model: A Pilot Study
Authors: Peckham Miriam , DeHavenon Adam , Alexander Matthew D , McNally Scott , Anderson Jeffrey , McKellar Stephen H , Tonna Joseph , Steenblik Jacob , Wong Ka-ho , Youngquist Scott T
Published: June 2021

Introduction:
Reperfusion/ischemic brain injury following arrest is a major cause of death/disability among patients surviving to admission. Aside from targeted temperature management, no proven neuroprotective strategies exist. Melatonin (anti-epileptic/antioxidant) and ketamine (glutamate inhibitor), along with controlled reintroduction of oxygenated blood have been proposed to reduce secondary injury.

Hypothesis:
We hypothesized that a combination of above therapies would reduce the ischemic burden measured on MRI following cardiac arrest if administered upon initial reperfusion.

Methods:
6 swine underwent isoflurane anesthesia and control MRI (DTI b2000/20 directions, DSC). Swine were randomized to fixed periods of cardiac arrest (2 swine to 20 min and 1 to 30 min in both control and treated groups), and ECMO catheters placed in the distal aorta and right atrium, then ventricular fibrillation induced by a bipolar pacing catheter. Following ischemia, swine were reperfused at 2.8-3.5 L/min with either unblended oxygenated blood in the control group, or 21% oxygenated blood increased to 30% after 4 minutes and then titrated to maintain PaO2 of 80-100 mm Hg, melatonin 5 mg/kg bolus then 5 mg/kg/hr and ketamine 4 mg/kg/hr for 2 hours in the treated group. After 4 min swine were defibrillated until return of heartbeat. Animals were weaned from pump, decannulated, and epinephrine and fluid boluses administered for hemodynamic support, then re-imaged within 2 hours post-resuscitation using same protocol. Whole brain ADC measurements were performed on gray and white matter. Frontal lobe regions of interest drawn for DSC perfusion parameters.

Results:
Baseline hemodynamic parameters: BP, Heart Rate, End-Tidal CO2, and SpO2 were similar between animals. There was no difference in percent change ADC in gray or white matter between treated and untreated swine (p=0.9), or difference in CBV (p=0.67). CBF showed an upward trend in treated animals (p=0.17).

Conclusions:
A multimodal neuroprotective strategy of melatonin, ketamine, and controlled reoxygenation failed to demonstrate measurable impact on MRI markers of ischemia-reperfusion injury in this pilot study. The translation of promising neuroprotectants might be triaged using the employed model.
Abstract 178: Evaluating Effects of Lysophosphatidic Acid on Neurological Function in a Rodent Model of Cardiac Arrest
Authors: Nishikimi Mitsuaki , Yagi Tsukasa , Shoaib Muhammad , Okuma Yu , Yin Tai , Becker Lance B , Kim Junhwan
Published: June 2021

Introduction:
Lysophosphatidic acid (LPA) has been shown to increase blood brain barrier permeability for a short periods of time, which may be utilized as a potential drug delivery mechanism to the brain in cardiac arrest. In addition, prior studies have suggested a potential neuroprotective role of LPA administration. However, no study has investigated the effects of LPA in cardiac arrest.

Objective:
The aim of this study is to evaluate the effects of intravenously administered LPA on neurological function and survival outcomes of rats after cardiac arrest.

Methods:
Adult maleSprague-Dawley rats were subjected to 8 min of asphyxial cardiac arrestand resuscitated using chest compressions. After achieving return of spontaneous circulation (ROSC), rats were treated with either LPA or vehicle. Survival was followed for up to 24 hours after cardiac arrest. For all surviving rats, neurological outcome was examined using a modified Neurological Deficit Score (mNDS) in a blinded manner.

Results:
Baseline characteristics, including body weight, surgical procedure time, vital signs before cardiac arrest, cardiac arrest duration, chest compression time, and time to achieve ROSC were similar between LPA-treated (n = 8) and vehicle-treated (n = 11) groups. There was no statistically significant difference in 24 hour survival between the two groups (LPA, 75.0% (6/8) vs. vehicle, 45.5% (5/11), p = 0.15). However, LPA-treated rats exhibited significantly improved neurological function at 24 hours examination (LPA, 89.3% ± 5.0 vs. vehicle, 75.6% ± 7.1, p = 0.01). This difference was most apparent in retention of coordination ability in the LPA group (LPA, 66.7% ± 18.6 vs vehicle, 20% ± 18.7, p < 0.01)

Conclusion:
LPA administration in post-cardiac arrest rats significantly improved neurological function at 24 hours after cardiac arrest. LPA has a potential to serve as a novel therapeutic in cardiac arrest.
Abstract 18: Trends in Median CPR Duration Over Time in Patients With and Without Return of Spontaneous Circulation
Authors: Berg Katherine M , Donnino Michael , Moskowitz Ari , Holmberg Mathias J , Wiberg Sebastian , Grossestreuer Anne V
Published: June 2021

Introduction:
Survival after in-hospital cardiac arrest (IHCA) is increasing. In the Get-With-The-Guidelines-Resuscitation (GWTG-R) registry, longer median CPR duration in patients not achieving ROSC is associated with higher survival rates at the hospital level. We analyzed trends over time in median CPR duration by hospital in patients who achieved ROSC and those who did not, and stratified this analysis by age, gender and race.

Methods:
We included adult IHCA cases in GWTG-R from 2001-2017, excluding data from a given hospital and year if fewer than 5 eligible arrests were recorded. A nonparametric test for trend was done to evaluate median CPR duration over time in those with and without ROSC, in all patients and in groups stratified by age (<60, 61-80 and >80 years), gender, and race (white and black). Linear regression was done to evaluate the amount of change per year. Association with survival was tested using Pearsons correlation.

Results:
Of 359,107 IHCA events, 31,189 were excluded, leaving 327,918 for analysis. Over time, there was a significant increase in median CPR duration in patients who did not achieve ROSC, and a decrease in those who did attain ROSC.(Fig.) These trends persisted when stratified by gender, race and age. Each year was associated with a decrease in median CPR duration of 0.37 min (95% CI -0.41 to -0.33 min) in those with ROSC and an increase of 0.29 min (95% CI 0.25 to 0.33 min) in those without. There was a small but significant correlation between median CPR duration in those without ROSC and adjusted survival by hospital over time (r=0.224, p<0.0001).

Conclusions:
In the GWTG-R registry, median duration of CPR is decreasing over time in patients achieving ROSC, but increasing in those not achieving ROSC. The increasing trend in CPR duration in those without ROSC correlates positively with the trend in survival. Whether the increase in median CPR duration in those without ROSC is contributing causally to improvements in survival warrants further study.
Abstract 183: Association of Hospital-Level Factors With Variation in Survival After Out-Of-Hospital Cardiac Arrest Between Receiving Hospitals in Japan
Authors: Koyama Satoshi , Gibo Koichiro , Yamaguchi Yutaka , Okubo Masashi
Published: June 2021

Background:
Patient outcomes after out-of-hospital cardiac arrest (OHCA) varies at multiple levels (geographic regions, emergency medical service agencies, and receiving hospitals). However, the contribution of hospital-level factors to the outcome variation is unclear. We aimed to investigate the association between hospital-level factors and variation in outcomes after OHCA between hospitals.

Methods:
We performed secondary analysis of the Japanese Association for Acute Medicine OHCA Registry, a prospective multi-center registry. We included adults (≥18 years) with OHCA of medical origin between June 2014 and December 2015. The primary outcome was 1-month survival and secondary outcome was 1-month survival with favorable functional status, defined as Cerebral Performance Category scale 1 or 2. We constructed two multivariable hierarchical logistic regression models for each outcome: (1) patient-level factors and (2) patient- and hospital-level factors. Hospital-level factors included the number of medical staff involved in resuscitation, proportion of patients who received targeted temperature management among those with return of spontaneous circulation, and proportion of patients who received extracorporeal cardiopulmonary resuscitation among those with shockable rhythm. We calculated adjusted outcomes for each hospital and median odds ratios (MORs) to evaluate the effects of hospital-level factors on between-hospital variation in outcomes.

Results:
We analyzed the data of 9,303 adults with OHCA of medical origin treated at 67 hospitals. After adjustment for patient-level factors, 1-month survival was 0.02-0.14 (adjusted MOR, 1.36; 95% credible interval (CI), 1.17-1.77). After adjustment for patient- and hospital-level factors, the adjusted MOR was 1.14 (95% CI, 1.05-1.33). Similarly, the adjusted MORs for favorable functional outcomes were 1.48 (95% CI 1.18-2.12) with adjustment for patient-level factors and 1.30 (95% CI 1.07-1.80) with adjustment for patient- and hospital-level factors.

Conclusions:
With adjustment for hospital-level factors, we noted attenuation of variation in patient outcomes after OHCA across hospitals, suggesting that hospital-level factors may partly explain outcome variations.
Abstract 186: Sex Differences in Outcomes for Out-Of-Hospital Cardiac Arrest
Authors: Kotini-Shah Pavitra , Pugach Oksana , Chen Ruizhe , Del Rios Marina , Vellano Kimberly , McNally Bryan F , Vanden Hoek Terry L , Chan Paul
Published: June 2021

Introduction:
Approximately 1,000 out-of-hospital cardiac arrest (OHCA) occur per day in the United States. Although survival rates remains low, the extent to which OHCA neurological outcomes differ between men and women remains poorly characterized.

Methods:
Within the national Cardiac Arrest Registry to Enhance Survival (CARES) registry, we identified 195,722 adult individuals with an OHCA between 2013-2017. Using multi-variable logistic regression models, we evaluated for sex differences in rates of survival to hospital discharge and favorable neurological outcome (survival with discharge CPC score of 1 or 2), adjusted for cardiac arrest characteristics, race, location, year of arrest, age, and use of targeted temperature management (TTM) and coronary angiography.

Results:
Overall, 70,767 (31%) patients were women. Median age was 64 and 62 years for women and men, respectively. An initial shockable rhythm (14.9% vs. 25.7%) and a witnessed arrest (40.9% vs. 45.6%) was more common in men. Bystander CPR was provided to 37% of women and 39% of men. Men were less likely to survive to hospital discharge than women (8.7% vs. 10.9%; adjusted OR 0.75, 95% CI 0.73, 0.78). Similarly, men were less likely to have favorable neurological outcome (6.6% vs. 9.2% for women; adjusted OR 0.78, 95% CI 0.74, 0.82). Further interaction analysis for the pre-hospital elements found small, but statistically significant sex differences in favorable neurological survival for witnessed status (among female OR 2.29, 95% CI 2.10, 2.49; among males OR 2.07, 95% CI 1.92, 2.23, p= 0.04) and for bystander CPR (among females OR 1.20, 95% CI 1.11, 1.29; among males OR 1.34, 95% CI 1.27, 1.42, p= 0.01). Interaction of sex with the hospital level variables of TTM and coronary angiography, for the subset of patients that survived to hospital admission, had no sex differences in favorable neurological outcome.

Conclusion:
Our analysis shows that for OHCA in the United States, women have better survival outcomes than men. There was a sex differences in the pre-hospital variable of BCPR, but not in the other modifiable variables of TTM and coronary angiography. Further study is needed to better understand sex differences in overall survival and neurological outcomes.
Abstract 188: Racial Disparities in Survival Outcomes Following Pediatric In-Hospital Cardiac Arrest
Authors: Haskell Sarah E , Girotra Saket , Zhou Yunshu , Del Rios Marina , Merchant Raina M , Atkins Dianne L
Published: June 2021

Introduction:
Among adults with in-hospital cardiac arrest (IHCA), overall survival is lower in black patients compared to white patients. Data regarding racial differences in survival for pediatric IHCA remain unknown.

Methods:
Using data from the American Heart Association Get With the Guidelines-Resuscitation registry, we identified children >24 hours and < 18 years of age with IHCA due to an initial pulseless rhythm. We used generalized estimation equation to examine the association of black race with survival to hospital discharge and return of spontaneous circulation (ROSC).

Results:
Overall, 2940 pediatric patients (898 black, 2042 white) with IHCA were included. The mean age was 6 years, 57% were male and 16% had an initial shockable rhythm. Baseline demographics, cardiac arrest characteristics including initial rhythm did not differ significantly by race. Although black race was associated with lower rates of ROSC compared to white patients (69.5% in blacks vs. 74.6% in whites; adjusted OR 0.8012, 95% CI 0.6749 - 0.9512, P= 0.0113), it was not associated with survival to discharge (34.7% in blacks vs. 37.8% in whites; adjusted OR 0.9705, 95% CI 0.8086 – 1.1648, P=0.7476). A lower rate of ROSC in black patients was not explained by longer delays in epinephrine administration for patients with a non-shockable rhythm, or defibrillation in patients with a shockable rhythm.

Conclusion:
In contrast to adults, no statistically significant racial differences in survival were present in pediatric IHCA.
Abstract 189: Time to Awakening in Women Compared to Men After Out-Of-Hospital Cardiac Arrest
Authors: Perman Sarah M , Shelton Shelby , Daugherty Stacie L , Havranek Edward
Published: June 2021

Background:
Previous studies have shown that comatose survivors of cardiac arrest awaken approximately 3 days after return of spontaneous circulation (ROSC) however, variability in time to awakening is frequently observed. Recent data has shown that women metabolize drugs (sedatives and paralytics) differently than men. It is unknown if there are sex based differences in time to awakening for comatose survivors of cardiac arrest, and if this phenomenon might be affected by differences in withdrawal of life sustaining therapy (WLST).

Objective:
To determine if comatose women have different times to awakening after resuscitation from cardiac arrest.

Methods:
We analyzed 327 consecutive charts from a single center registry of all out of hospital cardiac arrest patients who had return of spontaneous circulation but remained comatose, cared for at an urban academic tertiary care hospital. Patient demographic and arrest characteristics were abstracted. We identified day of awakening for comatose survivors by abstracting day when Glasgow coma motor score was 6 as documented in nursing flowsheets. Time to withdrawal of life sustaining therapy was also abstracted for the cohort that did not awaken. Patients were excluded from analysis if they did not awaken or if they died for reasons other than WLST.

Results:
Twenty-eight percent of patients woke prior to hospital discharge and 43.4% underwent withdrawal of life sustaining therapy. Women made up 39.5% of the total cohort, 40% of the awakened cohort and 41% of the WLST cohort. Women had earlier day of awakening in comparison to men (day 2 (2, 4) vs. day 4 (2,5), p=0.0036), and also earlier time to WLST after ROSC than men (59 hours (26, 131) vs. 64 hours (22, 135), p=NS).

Conclusion:
In this single center cohort, there was a difference in time to awakening between men and women. How time to awakening might differ between the sexes with guideline concordant time to WLST is unknown. Further research is necessary to explore the role of therapeutic interventions and differing physiology between men and women as it applies to time to awakening.
Abstract 190: Does Gender Matter? Addressing the Question of Gender Superiority in Resuscitation Leadership
Authors: Rosenman Elizabeth D , Misisco Anthony , Olenick Jeffrey , Chipman Anne K , Vrablik Marie C , Brolliar Sarah M , Kalynych Colleen , Grand James , Chao Georgia T , Kozlowski Steve W , Fernandez Rosemarie
Published: June 2021

Introduction:
Effective team leadership is linked to better patient care during resuscitations. Several studies suggest a relationship between team leader gender and the quality of resuscitation leadership and clinical care. However, these studies have been either (1) retrospective investigations that do not capture clinical care processes or (2) simulation-based research involving novice medical student subjects. The objective of this study is to compare the quality of team leadership and clinical care between male- and female-led trauma resuscitation teams.

Hypothesis:
We hypothesize that team leader gender is not associated with differences in trauma team leadership and clinical care

Methods:
We performed a secondary analysis of prospectively acquired data by analyzing video recordings of trauma resuscitations at a Level 1 trauma center. Subjects (n=60) included 2
nd
and 3
rd
year emergency medicine and surgery residents functioning in the team leader role. Two video recorded observations for each participant (n=120) were coded for team leadership and clinical care by two sets of raters balanced with regard to gender and blinded to study hypothesis. Duplicate coding was performed on 10% of the observations. We analyzed data using random coefficient modeling (RCM), controlling for patient injury severity score and subject postgraduate training year.

Results:
We found no significant difference between men and women on team leadership behavior (p=.43; Men: M=7.63, SE = 0.54; Women: M = 8.67, SE = 0.74) nor on clinical care (p=.39; Men: M = 62.32, SE = 1.50; Women: M = 64.87, SE = 2.57). Effect sizes were modest in favor of women and nonsignificant for both team leadership behavior (
d
= .26) and clinical care (
d
=.21).

Conclusion:
Our prospective evaluation of team leadership quality and clinical care during trauma resuscitations does not support a male performance advantage, contradicting previous simulation-based work. Focusing on effective team leadership behaviors, not inherent traits and leadership styles, will allow resuscitation leaders to optimize their individual and team performance, irrespective of gender. Further work is needed to develop training and cognitive aids capable of supporting team leadership during complex resuscitative care.
Abstract 199: TNF-Alpha Response After Experimental Cardiac Arrest in Rats is Not Attenuated by Thalidomide
Authors: Drabek Tomas , Stezoski Jason , Janesko-Feldman Keri , Kochanek Patrick
Published: June 2021

Background:
Resuscitation from cardiac arrest (CA) results in systemic cytokines response, and neuroinflammation. Thalidomide has been reported to selectively decrease tumor necrosis factor alpha (TNFa) and shown to be neuroprotective.

Hypothesis:
Thalidomide would decrease systemic and organ-specific cytokine response and biomarkers of injury after CA in rats.

Methods:
Adult male rats were subjected to 10 min ventricular fibrillation CA. Three groups were studied (n=4-6 per group): naives, CA treated with vehicle and CA treated with thalidomide (CA+T, 50 mg/kg i.p.). TNFa was assessed at 3 h in the cortex, hippocampus, striatum, cerebellum, plasma, heart and lung (Luminex). NSE and S100b were used to assess neuronal and glial injury, cardiac troponin I (cTnI) cardiac ichemia and IFABP to assess intestinal damage (ELISA).

Results:
CA resulted in a robust increase of TNFa in plasma (Figure 1) and tissues (Figure 2) with no differences between CA and CA+T groups in any region. NSE, S100b, cTnI and IFABP were increased after CA or CA+T vs. naives (all p<0.05) without differences between CA vs. CA+T.

Conclusions:
CA resulted in an early massive TNFa response systemically and in target organs, with increased biomarkers of organ injury. Thalidomide in a dose reported previously to improve outcome of
in vivo
models of brain ischemia did not decrease TNFa levels in plasma, brain or extracerebral organs, or biomarkers of injury in our model of experimental CA. Cytokine response to CA was identified as a therapeutic target for future interventions on systemic and end-organ levels. Other promising anti-TNFa strategies incl. anti-TNFa antibodies are currently being evaluated in CA models.
Abstract 211: Enteral Feeding Shortly After Cardiac Arrest Treated With Veno-Arterial Extra Corporeal Membrane Oxygenation and Therapeutic Hypothermia is Safe and Feasible
Authors: Gutierrez Alejandra , Carlson Claire , Yannopoulos Demetris , Bartos Jason A
Published: June 2021

Introduction:
Literature regarding the timing and safety of enteral feeding after cardiac arrest treated with therapeutic hypothermia and veno-arterial extra corporeal membrane oxygenation (VA-ECMO) is lacking.

Aim:
To describe the safety and feasibility of early enteral feeding in adult patients presenting with refractory out-of-hospital cardiac arrest treated with VA ECMO and therapeutic hypothermia.

Methods:
We performed a retrospective analysis of the enteral feeding patterns for patients admitted through the University of Minnesota ECPR program for refractory ventricular tachycardia or fibrillation (VT/VF). Outcomes were compared in patients with early enteral feeding initiation (within 2 days of admission) versus those with delayed enteral feeding (>2 days after admission).

Results:
The study included 108 consecutive patients (age 56.3+/-12.2 years, 78% male) admitted to the CICU between December 2015 and February 2019. Average CPR duration was 62.8+/-15.3min. Enteral feeding was initiated in 68(62.9%) of the sample. Enteral feeding was not started in patients expected to die within 48 hours of ICU admission. All patients underwent therapeutic hypothermia and 97.2% received neuromuscular blockade. Time to enteral feeding initiation ranged from 1 to 11 days post admission. Patients who had enteral feeding started within the first two days (43%) had similar rates of feeding interruption, (with 40% of cases in the setting of a surgical procedure or family request), gut ischemia, ileus and ventilator associated pneumonia (Table 1). Mortality and neurologic outcomes were not affected by timing of enteral feeding initiation.

Conclusion:
Initiation of enteral feeding within the first two days of presentation was not associated with adverse outcomes in patients with refractory cardiac arrest treated with prolonged CPR, VA ECMO, and therapeutic hypothermia.
Abstract 227: Sudden Cardiac Arrest During Exercise Occurs Infrequently and With Few Warning Symptoms
Authors: Allan Katherine S , Grunau Brian E , Haines Morgan , Nowroozpoor Armin , Christenson James , Besserer Floyd , Fordyce Christopher , Dorian Paul , Lin Steve
Published: June 2021

Introduction:
The incidence and details of sudden cardiac arrest (SCA) during exercise in the general population are not well described. We describe a cohort ages 2-85 who experienced an SCA within ≤ 1 hour of moderate to vigorous activity in 4 metropolitan areas of British Columbia, Canada.

Methods:
We reviewed prehospital records of consecutive out-of-hospital cardiac arrests (OHCAs) in the provincial BC OHCA Registry from June 17 2017 to August 16 2018. We included non-traumatic OHCAs treated by EMS occurring within ≤ 1 hour of exercise. We defined SCA as an OHCA of no obvious cause, witnessed/unwitnessed, survived/died. We assigned an estimated metabolic equivalent (MET) score to each type of physical activity. We defined moderate exercise as a MET score of 3-5.9 and vigorous as ≥6.

Results:
A total of 2674 OHCAs occurred during the study period of which 56 SCAs (2.1%) occurred within ≤1 hour of participation in 23 types of exercise (Figure 1). The incidence of SCA during exercise was 1.45 (95% CI 1.10-1.88) per 100,000 population. The median age was 56.5 [IQR 45-69] and 87.5% (49/56) were male. Most exercise related SCAs occurred in public (49/56 87.5%), 83.3% (45/54) were bystander witnessed and 85% (46/54) received bystander CPR. Over 70% (40/56) had a shockable rhythm. The survival rate was 55.4% (31/56). Half of the SCAs collapsed during exercise (49.1%; 26/53) while the other half collapsed within ≤1 hour after exercising (51%; 27/53). Symptom data were available in 46% of patients (23/50) with most experiencing chest pain, dizziness, feeling unwell or seizure just prior to collapse.

Conclusions:
SCAs during exercise are rare and frequently occur in a public location. Survival is high and may be related to witnessed and public location status. Equal numbers of SCAs collapsed during or ≤ 1 hour of exercising and symptoms were present in almost half. Future research is needed to determine what factors could predict those at highest risk for SCA in order to prevent future events.
Abstract 23: The Usefulness of Neuron-Specific Enolase in Cerebrospinal Fluid to Predict Neurological Prognosis in Cardiac Arrest Survivors Who Underwent Target Temperature Management: A Prospective Observational Study
Authors: Park Jung Soo
Published: June 2021

Aim:
We aimed to investigate the prognostic performance between serum NSE and cerebrospinal fluid (CSF) NSE for 6-month neurologic outcome in OHCA survivors underwent target temperature management (TTM).

Hypothesis:
We hypothesized that the NSE levels measured in the CSF would affect the change, earlier and more sensitively than serum, according to severity of hypoxic brain damage.

Methods:
This single-centre prospective observational study included out-of-hospital cardiac arrest (OHCA) patients underwent TTM. NSE levels were assessed in blood and CSF samples obtained immediately (Day 0), and 24 h (Day 1), 48 h (Day 2), and 72 h (Day 3) after return of spontaneous circulation (ROSC). The primary outcome was the 6-month neurological outcome.

Results:
We enrolled 34 patients (males, 24; 70.6%), 16 (47.1%) had a poor neurologic outcome. CSF NSE and serum NSE values were significantly higher in the poor outcome group compared to the good outcome group at each time point, except for serum Day 0. CSF NSE and serum NSE had area under curve (AUC) of 0.819-0.972 and 0.648-0.920, respectively. CSF NSE prognostic performances were significant higher than serum NSE at Day 1 and showed excellent AUC values (0.969; 95% Confidential Interval [CI] 0.844-0.999) and high sensitivity (93.8%; 95% CI 69.8-99.8) at 100% specificity.

Conclusion:
We found CSF NSE values were highly predictive and sensitive markers of 6-month poor neurological outcome in OHCA survivors treated with TTM at Day 1 after ROSC. Thus, CSF NSE level at day 1 after ROSC can be a useful early prognosticator in OHCA survivors.
Abstract 230: Opioid-Related Cardiac Arrest Incidence and Epidemiology in Maine
Authors: MAY Teresa , Gagnon David , Seder David B , West Bailey , Lerwick Patricia , Sholl Matthew , Lucas Lee , Riker Richard R
Published: June 2021

Introduction:
The frequency of opioid-related cardiac arrest (ORCA) is increasing across several geographic regions in the United States. Understanding how Maine’s urban and rural areas are affected by ORCA is necessary to improving prevention and treatment of this public health threat.

Hypothesis:
Patient demographics, clinical features, rurality and survival to emergency department (ED) admission vary significantly between ORCA and non-ORCA.

Methods:
We evaluated the National Emergency Medical Services Information System data from 2016-2017 for all emergency 911 responses in which emergency medical services (EMS) reported non-traumatic out of hospital cardiac arrest (OOHCA). We defined ORCA as EMS suspected opioid overdose as the primary etiology, or an overdose without established etiology and naloxone administered during cardiopulmonary resuscitation (CPR). Rurality was assigned using Rural-Urban Commuting Area Codes (RUCA). Demographics and arrest-specific factors were compared between ORCA and non-ORCA, followed by logistic regression to evaluate how ORCA was associated with survival to ED admission.

Results:
There were 3131 EMS responses for OOHCA during the study period. One hundred sixty-eight (5%) patients met the definition of ORCA. These patients were younger (35 ± 9 years vs 62 ± 17 years, p<0.001), less likely to have the reported diagnosis or treatment for chronic medical conditions (p<0.001-0.02), an initial shockable rhythm (12% vs 28%, p<0.001), occur in a public place (13% vs 23%, p=0.02), or be witnessed (38% vs 60%, p<0.001), but more likely to receive bystander CPR (27% vs 16%, p<0.001) and report illicit drug use (19% vs 2%, p<0.001). ORCA was more likely to occur in metropolitan or large rural areas compared to small rural or isolated rural areas (75% vs 25%, p<0.001). After adjusting for age, gender, initial shockable rhythm, witnessed arrest, bystander CPR, and rurality, patients with ORCA had an increased odds of surviving to ED admission (OR 1.83 [CI 1.11-2.95]).

Conclusions:
Patients in Maine with ORCA are distinctly different from patients with non-ORCA, are more likely to survive to ED admission and are seen more commonly in metropolitan and large rural areas.
Abstract 237: Using the Thoracic Impedance to Predict Measures From Invasive Arterial Blood Pressure in Out-Of-Hospital Cardiac Arrest
Authors: Elola Andoni , Aramendi Elisabete , Irusta Unai , Berve Per-Olav , Arnwald Fredrik K , Wik Lars , Chapman Fred W
Published: June 2021

Background:
During cardiopulmonary resuscitation (CPR), pulse detection can be challenging. Invasive blood pressure measurements (IBP) can help monitoring patient hemodynamics, but arterial catheter placement is difficult. Transthoracic impedance (TI) measured between the defibrillator pads can detect circulation activity. We hypothesized that TI changes can predict the corresponding IBP, and potentially be used to non-invasively detect pulse during CPR.

Materials and methods:
We included 28 out of hospital cardiac arrest patients receiving CPR by the Oslo Emergency Service who had concurrent recordings of IBP (radial artery, BD, 20G, US) and TI (via defibrillator pads, LP15, Stryker, US). 5-second segments with stable and CPR artefact free signals were extracted (Figure). The circulation component of the TI signal (Figure, red line) was extracted using a Kalman smoother. Ten waveform features were computed per segment and fed into a random forest regressor to predict systolic and diastolic arterial pressures (SAP, DAP), their difference (DifAP) and area of the IBP signal (ArAP). Pearson correlation coefficients between the regression model and the IBP metrics were computed. Data were divided by patient into training/test sets to fit and evaluate the model, respectively, and the process was repeated 500 times.

Results:
235 minutes (2261 segments) were extracted with median (Q1-Q3) values of 71.3(39.2-88.1) mmHg for SAP, 44.2(30.0-50.0) mmHg for DAP, 25.6(7.1-38.8) mmHg for DifAP and 63.4(17.0-85.9) mmHg*sec for ArAP. The correlation coefficients between TI-predicted and IBP-measured SAP, DAP, DifAP and ArAP were 0.62 (0.49-0.72), 0.36 (0.22-0.49), 0.69 (0.57-0.76) and 0.64 (0.50-0.73), respectively.

Conclusions:
Different hemodynamic phases can be observed in both TI and IBP (Figure). TI-based predictions showed good correlation with IBP measures. This could lead to new non-invasive methods to monitor different phases of circulation based on the TI.
Abstract 239: 911 Caller Description of Seizure-Like Symptoms and Delays to Starting Telecommunicator CPR
Authors: Kronemeyer Kara , Shee Kameron , Chikani Vatsal , Villa Normandy , Osborn Lesley , Panczyk Micah , Bobrow Bentley
Published: June 2021

Background:
Bystander cardiopulmonary resuscitation (BCPR) improves survival after out-of-hospital cardiac arrest (OHCA). Identifying delays to starting Telecommunicator CPR (TCPR) may improve outcomes. Identifying terms callers use to describe seizure-like symptoms may improve accuracy and expedite TCPR.

Methods:
A total of 586 confirmed OHCA calls from 3 regional 911 centers in Arizona were reviewed between 2013 to 2016. Frequency of terms callers use to describe seizure-like symptoms were assessed. Demographics and TCPR process measures were compared between the seizure and non-seizure cohorts using Chi-square analysis for categorical variables and Kruskal-Wallis test for continuous variables. Other data points were time to start of seizure description, time to end of description, and time to start of seizure intervention.

Results:
There were 545 calls after exclusions. Twenty-six (.05%) had seizure-like symptoms described. Of these, “seizure” or “seizing” were used in 22 (84.6%) calls, “shaking” in 6 (23.1%), “cramping up” in 2 (7.7%) and convulsing in 2 (7.7%). Descriptions were more common in witnessed arrests [65.4% (17/26) vs. 34.6% (9/26); p=0.045] and in younger patients [median age=57 (QI=45, Q3=68) vs. 66 (Q1=51, Q3=77); p=0.036.] In calls with descriptions, telecommunicators were less likely to recognize OHCA [56.0% (14/25) vs. 74.5% (382/513), .031% (17/545) missing; (p=0.041] but bystanders were not less likely to start compressions [42.3% (11/26) vs. 57.6% (289/501), .033% (18/545) missing; p=0.122]. Median time to recognition in calls with descriptions was delayed vs. calls without descriptions [142 s (Q1=74 s, Q3=194 s), n=13, vs. 63 s (Q1=40 s, Q3=112 s), n=336; p=0.005], as was time to first chest compression [262 s (Q1=182 s, Q3=291 s), n=6 vs. 154 s (Q1=110 s, Q3=206 s), n=155; p=0.011]. Median times to start of description, end of description, and start of intervention were respectively: 33 s (Q1=20 s, Q3=40 s; 54 s (Q1=37 s, Q3=138 s; and 50 s (Q1=38 s, Q3=162 s).

Conclusion:
Description of seizure-like symptoms were uncommon and were associated with reduced and delayed OHCA recognition and delayed start of compressions.
Abstract 246: Development of a Reflex Work of Breathing Scale for Easy Implementation Outside Intensive Care Environments
Authors: Gazmuri Raul J , Apigo Mylene , Dhliwayo Nyembezi , Al Tameemi Mohammed , Schechtman Jeffrey
Published: June 2021

Introduction:
A common misconception is that increased work of breathing (WOB) in hospitalized patients can be ruled-out when arterial O
2
tension (or saturation) is adequate and arterial PCO
2
is not elevated. Unrecognized WOB increase leads to respiratory muscle fatigue, cessation of respiratory function, and cardiac arrest. We previously developed a WOB Scale for bedside use adding points (maximum 7) based on respiratory rate (1 to 20 bpm = 1 point; 21 to 25 bpm = 2 points; 26 to 30 bpm = 3 points; and > 30 bpm = 4 points), nasal flaring (No = 0 points; Yes = 1 point), activation of the sternocleidomastoid muscle (No = 0 points; Yes = 1 point), and activation of abdominal muscles (No = 0 points; Yes = 1 point). A WOB Scale > 3 points typical identifies a patient in need of intervention to reduce or support WOB increase. However, widespread application of our WOB Scale - especially outside intensive care environments - would likely benefit from a simplified approach. Thus, we investigated developing a “reflex” approach whereby measurement of all four components would be contingent on the respiratory rate level.

Methods:
We analyzed 110 WOB Scale measurements in a mixed population of ICU and General Ward patients and assessed WOB Scale levels hypothesizing that a respiratory rate of 1 point (1 to 20 bpm) would be predictive of a low WOB Scale (i.e., not exceeding 3 points); thus, obviating the need to perform a complete WOB Scale evaluation.

Results:
The WOB Scale distribution showed that most patients had normal WOB with only 14 patients (12.7%) having a WOB Scale > 3 points (i.e., 1 point = 60; 2 points = 24; 3 points = 12; 4 points = 6; 5 points = 7; 6 points = 1; 7 points = 0). A respiratory rate level of 1 point (i.e., 1 to 20 bpm), occurred in 68 patients and only 3 (1.5%) had a WOB Scale > 3 points. Yet, when the respiratory rate level was 2 points (i.e., 21 to 25 bpm), which occurred in 28 patients, 3 (10.7%) had a WOB Scale > 3 points. Respiratory rate levels of 3 or 4 points (> 26 bpm) were associated with activation of at least one accessory respiratory muscle examined in 64% of the patients.

Conclusions:
A respiratory rate of 20 bpm or less predicted low WOB in most patients supporting a Reflex WOB Scale whereby respiratory accessory muscle activation is assessed only when the respiratory rate exceeds 20 bpm.
Abstract 258: The Effect of Chest Compression Location on Cerebral Oxygenation
Authors: Gould Jeffrey R , Lampe Joshua W , Clark Lyra , Moodie Karen L , Elliott Jonathan T , Paradis Norman A
Published: June 2021

Introduction:
This study examined the effect of guideline-compliant compressions performed on two locations of the chest on changes in cerebral oxygenation as measured by NIRS. We hypothesized that compressions performed over the left ventricle (LV) would produce higher levels of cerebral oxygenation than over the left ventricular outflow tract (LVOT) despite both types of compressions being within recommended guidelines.

Methods:
LV and LVOT compression locations were identified on the chest using trans-esophageal ultrasound in 9 domestic swine. Following 6 minutes of untreated VF, 1-inch mechanical compressions were initiated at 100 cpm and depth was increased to 2 inches over the course of 1 min. Four 2-min periods of compressions were then performed alternating between the two chest locations, with periods separated by a 10 second pause. Animals were block randomized to start with either LV or LVOT locations. Following the fourth round of compressions, epinephrine was administered followed by up to three defibrillation attempts. Changes in cerebral oxygenation were quantified using the slope of the NIRS signal during each 2-min compression period. One animal was excluded from the analysis due to a ruptured right atrium during the first round of compressions.

Results:
The mean increase in the cerebral oxygenation signal was 1.8% units (95% CI: 0.9-2.7) during each 2-min period of LV compressions and 1.4% units (95% CI: 0.3 - 2.5) during LVOT compressions. Five out of nine animals achieved ROSC. The mean increase for animals that achieved ROSC was 2.4% units (95% CI: 1.2 - 3.6) during LV compressions and 2.1% units (95 CI: 0.64 - 3.6) during LVOT compressions. For those that did not achieve ROSC, the increase was 0.98% units (95% CI: -0.83 - 2.8) during LV compressions and -0.28 (95% CI: -1.6 - 1.1) during LVOT compressions.

Conclusions:
There does not appear to be an effect of chest compression location on cerebral oxygenation during mechanical CPR. However, increases in cerebral oxygenation appear to be greater in animals that achieved ROSC. Monitoring changes in cerebral oxygenation over a period of CPR may serve as an index of chest compression effectiveness.
Abstract 259: Controlled Sequential Elevation of the Head and Thorax Combined With Active Compression Decompression Cardiopulmonary Resuscitation and an Impedance Threshold Device Improves Neurological Survival in a Swine Model of Cardiac Arrest
Authors: Moore Johanna C , Salverda Bayert , Lick Michael , Rojas-Salvador Carolina , Debaty Guillaume , Lurie Keith
Published: June 2021

Introduction:
Survival rates after cardiac arrest with intact brain function remain poor and are not uniformly improved with a single intervention. A bundle of care approach to CPR that enhances cerebral and coronary circulation while simultaneously lowering intracranial pressure (ICP) provides new opportunity to improve neurological survival.

Hypothesis:
Active compression decompression (ACD) CPR and an impedance threshold device (ITD) to regulate intrathoracic pressure with controlled sequential elevation of the head and thorax (CSE) to lower ICP and increase cerebral and coronary (CoPP) perfusion pressures, will increase neurologically intact survival when compared to a conventional (C) CPR in the flat position in pigs.

Methods:
Female farm pigs were sedated, intubated, and anesthetized. Central arterial and venous access were continuously monitored. Regional brain tissue perfusion (CerO2) was also measured transcutaneously. Ventricular fibrillation was induced and untreated for 10 minutes. Pigs were randomized to 1) C-CPR flat or 2) CSE ACD+ITD CPR that included 2 min of ACD+ITD with the head and heart first elevated 10 and 8 cm, respectively, and then further elevation over 2 min to 22 and 9 cm, respectively. After 19 min of CPR, pigs were defibrillated and recovered. A veterinarian blinded to the intervention assessed cerebral performance category (CPC) at 24 hours. A neurologically intact outcome was defined as a CPC score of 1 or 2. Categorical outcomes were analyzed by Chi-Square and continuous outcomes with an unpaired student’s t-test. All p-values are unadjusted.

Results:
Return of spontaneous circulation rate was 8/8 (100%) with CSE and 2/8 (25%) for C-CPR (p = 0.002). For the primary outcome of neurologically intact survival, 6/8 (75%) pigs survived with CPC 1 or 2 with CSE versus 1/8 (12.5%) with C-CPR (p = 0.012). CoPP (mmHg, mean ± SD) was higher with CSE at 18 minutes (41 ± 24 vs 10 ± 5, p = 0.004). CerO2 (%, mean ± SD) and ETCO
2
(mmHg, mean ± SD) values were higher at 18 minutes with CSE (32.2 ± 8.5 vs 16.5 ± 2.1, p = 0.003, and 54.9 ± 8.6 vs 19.1 ± 7.0, p < 0.001), respectively.

Conclusions:
The novel bundled resuscitation approach of CSE with ACD+ITD CPR increased neurologically intact survival 6-fold versus C-CPR in a swine model of cardiac arrest.
Abstract 26: Prevalence and Pattern of Myocardial Injury in Patients With Cardiac vs Non-Cardiac Cause of Out-Of-Hospital Cardiac Arrest: A One-Year Multicenter Clinical Experience With the High-Sensitivity Troponin T Assay
Authors: Hamilton David E , Petek Bradley J , Panah Lindsay G , Mendez Sean R , Dormish Philip E , Silverman Michael G
Published: June 2021

Introduction:
Myocardial injury is common after out-of-hospital-cardiac arrest (OHCA). However, little is known about the role of early serial hs-TnT in patients with OHCA for identifying myocardial injury, and whether the prevalence and severity of injury differs according to cardiac (CV) vs noncardiac (non-CV) cause of OHCA.

Hypothesis:
Early hs-TnT will demonstrate high rates of myocardial injury after OHCA regardless of etiology. However, in the first 6 hours after OHCA the extent of hs-TnT elevation and rate of rise will be higher in patients with CV vs non-CV etiology.

Methods:
Multicenter retrospective study including OHCA patients presenting from 4/1/2018 to 4/1/2019. Hs-TnT was drawn as part of routine clinical care.

Results:
Baseline hs-TnT was measured in 120 patients after OHCA due to CV (n=51) and non-CV (n=69) etiologies, with subsequent serial hs-TnT values at 1hr, 3hrs, and 6hrs. Hs-TnT was greater than the 99
th
percentile in 97% (115/120) of patients and myocardial injury (hs-TnT> 52ng/L) was detected in 88% (105/120) of patients (no difference between CV vs non-CV etiology). Median hs-TnT values were compared between CV and non-CV etiologies of OHCA identifying no difference in hs-TnT at baseline (Figure: 54 [IQR 18-134] vs. 41 [IQR 19-100]; p=0.357) but significantly higher hs-TnT in patients with CV etiology at 1hr (159 [IQR 80-392] vs 93 [IQR 42-247]; p=0.049), 3hrs (400 [IQR 168-1005] vs 151 [IQR 75-401] p=0.009), and 6hrs (746 [IQR 248-1965] vs 251 [IQR 75-580]; p=0.001). Additionally, hs-TnT rise from baseline was present in both CV and non-CV etiologies but was significantly higher in patients with CV etiology (p = 0.005).

Conclusions:
As identified by hs-TnT, myocardial injury was prevalent in patients with both CV and non-CV cause of OHCA. Baseline hs-TnT was no different in patients with CV vs non-CV cause, however, over the first 6 hours both absolute value and rate of hs-TnT rise were significantly higher for patients with CV vs non-CV etiology of OHCA.
Abstract 265: Deterioration of Hemodynamic Support During Prolonged Mechanical CPR in a Porcine Model of Cardiac Arrest
Authors: Allen Shannon E , Ang Samantha , Smith Cody , Techiryan George , Canty John M , Weil Brian R
Published: June 2021

Introduction:
Although mechanical CPR devices provide automated delivery of fixed depth chest compressions, the consistency of hemodynamic support during prolonged resuscitation efforts is unclear, particularly in the absence of concomitant vasopressor treatment. In light of recent concerns regarding potentially harmful effects of epinephrine, we evaluated the hemodynamic support generated by 20 min of mechanical CPR without concurrent vasopressor administration in a porcine model of cardiac arrest (CA).

Methods:
Swine (n=10) were subjected to 7-8 min of CA following electrical induction of ventricular fibrillation. CPR was subsequently performed for 20 min using a mechanical compression system (LUCAS 3.1, Stryker) programmed to administer 102 compressions/min at a fixed depth of 2.1 inches. Aortic pressure (Ao), coronary perfusion pressure (CPP), and cerebral oxygen saturation (rSO
2
; near-infrared spectroscopy) were continuously recorded. Results were compared to a separate group of swine (n=11) that received manual CPR with a compression rate of 100/min and depth necessary to achieve peak Ao of 100 mmHg.

Results:
Initially, mechanical CPR generated significantly higher peak Ao and CPP vs. manual CPR (
Figure
). However, by 4 min CPR, peak Ao and CPP were no longer different between groups. Both parameters continued to decline in the mechanical CPR group but remained stable in animals receiving manual CPR. Cerebral rSO
2
values fell from 57±2 % at baseline to 42±4 % during CA (p<0.01) but were not significantly improved by mechanical or manual CPR.

Conclusion:
The superior hemodynamic support initially offered by mechanical CPR deteriorates during prolonged CPR when pharmacologic vasopressor support is absent. These results demonstrate that a fixed compression depth does not necessarily produce consistent hemodynamic support and suggest that concomitant vasopressor administration may be necessary to sustain Ao and CPP during prolonged mechanical CPR.