bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 153: Non-invasive Measurement of Cerebral Tissue Oxygen Extraction Fraction is Correlated with Microdialysis Brain Injury Biomarkers During Extracorporeal Cardiopulmonary Resuscitation
Authors: Ko Tiffany S , Slovis Julia , Volk Lindsay , Mavroudis Constantine D , Morgan Ryan W , Breimann Jake , Starr Jonathan P , Landis William P , Benson Emilie , Hallowell Thomas , Delso Nile , Andersen Kristen , Roberts Anna , Jahnavi Jharna , Padawer Curry Jonah , Lin Yuxi , Graham Kathryn , Berg Robert A , Baker Wesley B , Licht Daniel J , Kilbaugh Todd J
Published: November 2020

Introduction:
Extracorporeal membrane oxygenation (ECMO) assisted CPR (ECPR) can improve outcomes after prolonged or unsuccessful resuscitative efforts, but neurological injury remains common in survivors. The lack of routine neuromonitoring during ECPR and ECMO prohibits brain-targeted management to help improve neurological outcomes. In this study, we examine the association of non-invasive, frequency-domain diffuse optical spectroscopy (FD-DOS) measurements of cerebral tissue oxygen extraction fraction (OEF), an indicator of metabolic stress, with invasively collected brain injury biomarkers to explore the utility of this monitoring modality during ECPR.

Hypothesis:
FD-DOS measurement of cerebral OEF is positively correlated with biomarkers of brain injury (lactate-pyruvate ratio, LPR; glycerol).

Methods:
Cerebral OEF was continuously monitored by FD-DOS in nine pediatric swine (8-11 kg) who underwent 30-60 minutes of manual CPR, were cannulated for ECMO, and remained on ECMO for 22-24 hours. Cerebral pyruvate, lactate, glycerol and glucose content were measured from cerebral microdialysate samples collected hourly. The correlation between OEF and microdialysis parameters were assessed using a linear mixed-effects model incorporating subject-specific random slope and intercept effects. Significance was determined at p<0.05.

Results:
Microdialysis parameters from 192 samples were compared against non-invasive OEF values. OEF was significantly correlated with LPR (p=0.001), and relative change in glycerol (p=0.005) and glucose (p=0.020) concentrations from baseline.

Conclusions:
Non-invasive FD-DOS neuromonitoring of OEF demonstrated significant correlations with invasive brain injury biomarkers; increasing OEF was associated with elevated LPR and glycerol, and diminished glucose. FD-DOS detection of critical neurometabolic stress at the bedside may facilitate brain-targeted ECMO management after cardiac arrest.
Abstract 154: Hyperoxemia is Associated with Poor Neurological Outcomes in Patients with Out-of-hospital Cardiac Arrest Rescued by Extracorporeal Cardiopulmonary Resuscitation: Insight From the Nationwide Multicenter Observational JAAM-OHCA (Japan Association for Acute Medicine) Registry
Authors: Nishihara Masaaki , Hiasa Ken-ichi , Enzan Nobuyuki , Ichimura Kenzo , Iyonaga Takeshi , Shono Yuji , Kitazono Takanari , Tsutsui Hiroyuki
Published: November 2020

Introduction:
Previous studies have shown an association between hyperoxemia and mortality in out-of-hospital cardiac arrest (OHCA) patients after cardiopulmonary resuscitation (CPR); however, the evidence is lacking in patients receiving extracorporeal CPR (ECPR).

Hypothesis:
To test the hypothesis that hyperoxemia is associated with poor neurological outcome in patients treated by ECPR.

Methods:
The Japanese Association for Acute Medicine - OHCA (JAAM-OHCA) Registry is a multicenter, prospective, observational registry including 34,754 OHCA patients between 2014 and 2017. Patients who had been resuscitated and survived 24 hours after OHCA and had a PaO
2
levels above 60 mmHg were included. Eligible patients were divided into 2 groups by each 2 definition according to the PaO
2
levels measured from arterial blood gas analysis 24-h after the ECPR, (1) High-level of PaO
2
(H-PaO
2
, n=242) as PaO
2
≥ 157 mmHg (median) and control (n=211) as 60 < PaO
2
< 157 mmHg, (2) hyperoxemia (HO, n=80) as PaO
2
≥ 300 mmHg and control (n=373) as 60 < PaO
2
< 300 mmHg. The primary and secondary outcomes were the favorable neurological outcome, defined as Cerebral Performance Categories (CPC) Scale 1-2, and survival at 30 days after OHCA, respectively.

Results:
Out of 34,754 patients with OHCA, 453 patients with ECPR were included. The number of CPC 1-2 was significantly lower in the H-PaO
2
and HO group compared with each control group (H-PaO
2
: 17.4% vs. 33.2%; Odds ratio [OR] 0.42; 95% confidence interval [CI] 0.27-0.66; P<0.0001, HO: 8.8% vs. 28.2%; OR 0.24; 95% CI 0.11-0.55; P<0.001). The 30-day survival was lower in these high oxygen groups (H-PaO
2
: 39.3% vs. 57.4%; OR 0.48; 95% CI 0.33-0.70; P<0.0001, HO: 25.0% vs. 52.6%; OR 0.30; 95% CI 0.17-0.52; P<0.0001). After adjusting for potential confounders, the H-PaO
2
and HO were associated with unfavorable neurological outcomes (adjusted OR, H-PaO
2
; 2.71; 95% CI 1.16-6.30; P=0.021, HO; 5.76; 95% CI 1.30-25.4; P=0.021). The H-PaO
2
and HO were also associated with poor 30-day survival (adjusted OR, H-PaO
2
; 2.28; 95% CI 1.13-4.60; P=0.021, HO; 3.75; 95% CI 1.28-11.0; P=0.016).

Conclusions:
Hyperoxemia was associated with worse neurological outcomes in OHCA patients with ECPR.
Abstract 156: Capnographic Differences in Out-of-hospital Overdose-related, Respiratory, and Cardiac Arrests
Authors: McDannold Robyn , Hu Chengcheng , Spaite Daniel W , Silver Annemarie E , Mullins Margaret , Mullins Terry , Chikani Vatsal , Bradley Gail , Gaither Joshua B , Rice Amber D , Bobrow Bentley J , Glenn Melody , Keim Samuel M , Barnhart Bruce J
Published: November 2020

Background:
Little is known about the ventilatory aspects of overdose-related OHCA (OD-OHCA). We compared maximum ETCO2 (mETCO2; each patient’s highest CO2 level) and mean for each recorded minute of CPR in OD-OHCA to that of respiratory (R-OHCA) and cardiac (C-OHCA) arrests.

Methods:
Continuous CO2 data (Zoll E/X series monitors) were obtained from 3 Arizona EMS agencies. Cases had at least 3 min of recorded CO2 during CPR. Arrests were classified as OD-OHCA by EMS and/or hospital documentation. Any drug OD was included (e.g., opioids, mixed). C-OHCA and R-OHCA cases were randomly chosen for comparison. The groups were compared using Fisher’s exact test or Chi-squared for categorical and Kruskal-Wallis for continuous variables.

Results:
Included were 263 subjects (37 OD-OHCA, 157 C-OHCA and 69 R-OHCA; median age 61, 64% male, 1/10-12/18) with 10,271 min of data [median resuscitation interval 37 min (IQR 29, 47)]. Mean ETCO2 (SD): OD-OHCA [41 mmHg (24)]; R-OHCA [40 (23)], C-OHCA [30 (13); p<0.01]. Median mETCO2: OD-OHCA [57 mmHg (95CI: 50, 77)]; R-OHCA [61 (50, 73)], C-OHCA [48 (44, 50); p<0.001; Fig 1]. While mean ETCO2 and mETCO2 were similar for OD-OHCA and R-OHCA, they were both significantly higher than C-OHCA (p<0.01 for all comparisons). ETCO2 waveforms in OD-OHCA resembled the very high, full waveforms typical of R-OHCA while those in C-OHCA tended to be low and blunted.

Conclusions:
We believe this is the first report of continuous capnography during resuscitation of OD-OHCA. The mean ETCO2 and median of mETCO2 of OD-OHCA and R-OHCA imply similar physiology (hypoventilation and hypercapnia leading to arrest). Both etiologies had much higher ETCO2 values compared to C-OHCA, where low blood flow delivers minimal CO2 to the lungs and yields low, and morphologically different, waveforms. Future studies assessing OD arrest physiology and various approaches to resuscitation and pharmacological reversal are needed.
Abstract 157: Multicenter Evaluation of Etiology and Observed Transition Intensities Between Pulseless Electrical Activity and Return of Spontaneous Circulation
Authors: Unneland Eirik , Norvik Anders , McGovern Shaun K. , Buckler David G. , Irusta Unai , Bhardwaj Abhishek , Aramendi Elisabete , Nordseth Trond , Abella Benjamin S. , Edelson Dana P , Kvaløy Jan Terje , Skogvoll Eirik
Published: November 2020

Background:
Cardiac arrest presents with one of three clinical states; Cardiac standstill (asystole), Pulseless Electrical Activity (PEA), or ventricular fibrillation/tachycardia (VF/VT). PEA results from multiple etiologies and accounts for most in-hospital cardiac arrests. We quantified the dynamic nature of transitions in and out of PEA, in terms of hospital sites and presumed etiology.

Methods:
We analyzed 538 episodes of cardiac arrest at one Norwegian hospital and three U.S. hospitals. ECG, chest compressions and ventilations were recorded by defibrillators during CPR. Each event was assessed using a graphical application. We quantified the transition intensity, i.e. the immediate probability of a transition given the current state, between PEA and ROSC using Aalen’s additive model for time-to-event data.

Results:
The overall transition intensity from PEA to ROSC was about 0.10 min
-1
, so an average patient in PEA has about 10 % chance to gain ROSC the following 1 minute. The intensity peaked at 7 minutes of CPR (Figure), with some heterogeneity between hospitals (0.07 to 0.11 min
-1
). The reverse transition intensity from ROSC to PEA was rather constant at 0.10 min
-1
(range 0.05-0.11). Information regarding assumed cardiac or non-cardiac etiology was available in 208 episodes (123 cardiac). Patients with a cardiac etiology had a marginally smaller (-0.03 min
-1
) chance of making the transition from PEA to ROSC (p=0.049), but etiology did not impact on the ROSC to PEA transition (p=0.39).

Discussion:
For transitions between PEA and ROSC we observed an overall intensity of 0.1 min
-1
, with some hospital heterogeneity. This may be due to heterogeneity in the underlying patient populations. We found the probability of transitioning from PEA to ROSC to increase from the start event recording until an average peak intensity at 7 minutes. This information may increase the clinicians’ understanding of the process from PEA to ROSC.
Abstract 202: Video Laryngoscopy for Out of Hospital Cardiac Arrest
Authors: Huebinger Ryan M , Stilgenbauer Hutch , Jarvis Jeffrey L , Ostermayer Daniel , Schulz Kevin , Wang Henry E
Published: November 2020

Introduction:
Intubation is an essential component of cardiac arrest resuscitation. While prior studies have evaluated video laryngoscopy (VL) to assist intubation for in hospital cardiac arrest, there is a paucity of research evaluating VL for out of hospital cardiac arrest (OHCA). We sought to evaluate the association of video laryngoscopy with first pass success and ROSC.

Hypothesis:
Video laryngoscopy improves first pass success rate and improves the rate of ROSC

Methods:
We analyzed the 2018 data from ESO Inc. (Austin, TX), a national prehospital electronic health record used by 1289 EMS agencies in the US. We included all adult (age >18 years), non-traumatic cardiac arrests that were intubated with an endotracheal device. We applied a chi2 test to evaluate the first pass success rate for VL vs direct laryngoscopy (DL). We then created a mixed model, fitting agency as a random intercept and adjusting for age, gender, race, location of arrest, witnessed arrest, initial shockable rhythm, and bystander CPR. We applied the mixed model to analyze the association between VL and first pass success rate, ROSC, and sustained ROSC (survival to ED or ROSC for greater than 20 minutes).

Results:
We included 22,097 patients cared for by 914 agencies. 5,674 (25.7%) patients were intubated with video laryngoscopy. The median age was 66 (IQR 55-77). 61.9% of patients were male and 73.0% were white. 71.9% of cardiac arrest happened at home, 56.8% of were witnessed, 37.4% had bystander CPR, and 20.6% had a shockable rhythm. Compared to DL, VL had a lower rate of bystander CPR (41.4% v 36.1%, p<.001), but other characteristics were similar between the groups. We found that VL had a higher first pass success rate than DL (75.1% v 69.5%, p<.001). Using a mixed model analysis, VL was associated with a higher rate of first pass success (OR 1.5, CI 1.3-1.6), but VL was not associated with improvement in ROSC (OR 1.1, CI 0.97-1.2) or sustained ROSC (OR 1.1, CI 0.9-1.2).

Conclusion:
VL had a higher first pass success rate than DL, and on adjusted, mixed-model analysis, VL use was associated with increased rate of first pass success. However, VL was not associated with increased rate of ROSC
Abstract 229: Cardiopulmonary Resuscitation Compliance of Clinical Nurses Using Feedback Technology from the Zoll R Series Defibrillator
Authors: Boudreau Martha A
Published: November 2020

Use of technology driven devices aimed at providing audio-visual feedback during CPR have been developed, however research is limited to their usefulness effecting chest compression quality of clinical nurses who are often first to respond and begin chest compression on patients experiencing cardiac arrest. This study aimed to examine CPR chest compression compliance of nurses with and without feedback from the Zoll R Series® defibrillator on a manikin.

Hypothesis:
Audio-visual feedback technology use from the Zoll R Series defibrillator improves the percentage of appropriate chest compression depth and rate of nurses during a CPR manikin demonstration exercise.

Methods:
Thirty-four nurses participated using an AHA approved manikin. Each nurse performed two minutes of uninterrupted chest compressions without feedback, followed by a rest period and two minutes of uninterrupted chest compressions using feedback technology from the defibrillator. Compression data for rate and depth and total compressions in target within AHA 2015 ECC Guidelines were recorded by the defibrillator and entered into Zoll RescueNet® software. Demographics obtained for years of BLS and ACLS certification.

Results:
Of the 34 nurses, mean years of ACLS certification was 3.4 years and 11.7 certified years of BLS. Compressions performed with feedback showed a higher percentage of compressions in target (M = 87.37,
SD=
15.95) including rate (M= 86.33,
SD
=15.13) and depth (M= 97.12,
SD
= 5.63) of compressions compared to percent compressions in target without feedback (M= 64.42,
SD
= 30.54) including rate (M= 65.73,
SD
= 32.44) and depth (M=93.34,
SD
= 19.99) of compressions. Twenty nine or 85% of the 34 nurses improved chest compression performance using feedback. No significant correlation found between years of BLS and ACLS certification and pre and post feedback compliance.

Conclusions:
Defibrillators offering verbal encouragement and a visual display allow for adjustments in rate and depth of compressions to maintain chest compressions compliance within ECC Guidelines. Further studies should investigate whether the incorporation of feedback technology use in mock code and CPR training sessions could improve CPR performance of healthcare providers including nurses.
Abstract 236: Gender Disparities in Bystander CPR and Defibrillation Persist in Black and Hispanic Neighborhoods in the US
Authors: Blewer Audrey L , Starks Monique A , Malta Hansen Carolina , Ong Marcus E , Viera Anthony J , Al-Araji Rabab , McNally Bryan F , Granger Christopher B
Published: November 2020

Introduction:
Bystander CPR (B-CPR) and defibrillation for sudden cardiac arrest (SCA) vary by gender with females being less likely to receive these interventions. Despite known differences by race and ethnicity, it is unknown whether gender disparities in B-CPR and defibrillation persist by neighborhood race and ethnicity.

Objectives:
We examined the likelihood of receiving B-CPR and defibrillation by gender stratified by public location and neighborhood racial/ethnic composition. We hypothesized that in public locations within Black neighborhoods, females will have a lower likelihood of receiving B-CPR compared to males.

Methods:
We conducted a retrospective cohort study using data from the US Cardiac Arrest Registry to Enhance Survival (CARES) registry. Neighborhoods were classified by census tract based on percent of Black or Hispanic residents using the threshold in the definition of “White flight” where Whites leave a neighborhood when it exceeds >30% of a minority population. We independently modeled the likelihood of receipt of B-CPR and defibrillation by gender stratified by public location and neighborhood racial/ethnic composition controlling for confounding variables.

Results:
From 2013-2018, CARES collected 350,722 US arrests; after excluding pediatric arrests, those witnessed by EMS, or those that occurred in a healthcare facility, 214,464 were included. Mean age was 64±16 and 65% were male; 39% received B-CPR, 9% received bystander defibrillation prior to 9-1-1 responders arrival, and 18% occurred in the public. In Black neighborhoods, females who had SCA in public locations were 22% less likely to receive B-CPR (OR: 0.78 (0.64-0.95), p=0.01) and 42% less likely to receive defibrillation (OR: 0.58 (0.45-0.74), p<0.01) compared to males. In Hispanic neighborhoods, females who had SCA in public locations were also less likely to receive B-CPR (OR: 0.72 (0.59-0.87), p<0.01) and less likely to receive defibrillation (OR: 0.62 (0.48-0.80), p<0.01) compared to males.

Conclusion:
Females with public SCA have a decreased likelihood of receiving B-CPR and defibrillation, and these findings persist in Black and Hispanic neighborhoods. This has implications for strategies to reduce disparities around bystander response to SCA.
Abstract 238: A Deep Neural Network Approach for Continuous Electrocardiogram-based Shock Advisory System During Cardio Pulmonary Resuscitation
Authors: Hajeb Mohammadalipour Shirin , Cascella Alicia , Valentine Matt , Chon K.H.
Published: November 2020

The ability of an automatic external defibrillator (AED) to make a reliable shock decision during cardio pulmonary resuscitation (CPR) would improve the survival rate of patients with out-of-hospital cardiac arrest. Since chest compressions induce motion artifacts in the electrocardiogram (ECG), current AEDs instruct the user to stop CPR while an automated rhythm analysis is performed. It has been shown that minimizing interruptions in CPR increases the chance of survival. While deep learning approaches have been used successfully for arrhythmia classification, their performance has not been evaluated for creating an AED shock advisory system that can coexist with CPR. To this end, the objective of this study was to apply a deep-learning algorithm using convolutional layers and residual networks to classify shockable versus non-shockable rhythms in the presence and absence of CPR artifact using only the ECG data. The feasibility of the deep learning method was validated using 8-sec segments of ECG with and without CPR. Two separate databases were used: 1) 40 subjects’ data without CPR from Physionet with 1131 shockable and 2741 non-shockable classified recordings, and 2) CPR artifacts that were acquired from a commercial AED during asystole delivered by 43 different resuscitators. For each 8-second ECG segment, randomly chosen CPR data from 43 different types were added to it so that 5 non-shockable and 10 shockable CPR-contaminated ECG segments were created. We used 30 subjects’ and the remaining 10 for training and test datasets, respectively, for the database 1). For the database 2), we used 33 and 10 subjects’ data for training and testing, respectively. Using our deep neural network model, the sensitivity and specificity of the shock versus no-shock decision for both datasets using the four-fold cross-validation were found to be 95.21% and 86.03%, respectively. For shockable versus non-shockable classification of ECG without CPR artifact, the sensitivity was 99.04% and the specificity was 95.2%. A sensitivity of 94.21% and a specificity of 86.14% were obtained for ECG with CPR artifact. These results meet the AHA sensitivity requirement (>90%).
Abstract 240: Comparison of Hemodynamics Generated by Synchronized and Interposed Compressions During Treatment of Pseudo Electro-mechanical Dissociation
Authors: Lampe Joshua W , Badin Jill K , Clark Lyra , Gould Jeff R , Moodie Karen L , Paradis Norman A
Published: November 2020

Introduction:
Pseudo electro-mechanical dissociation (P-EMD) is a cardiac arrest variant characterized by a life-threatening reduction in cardiac output in the presence of organized electrical activity. Synchronization of chest compressions to the R-wave in the ECG may be preferable to the delivery of standard CPR. However, in the bradycardic P-EMD state, synchronization may result in inadequate blood flow due to the low compression/heart rate. This pilot study examined the hemodynamic effect of interposing additional chest compressions between synchronized chest compressions during bradycardic P-EMD to increase the compression rate.

Methods:
P-EMD was induced via hypoxia in three female swine (~30 kg) and treated with synchronized compressions until the onset of asystole (HR<12 BPM). Interposed compressions were added when the heart rate fell below 60 BPM. A chest compression was classified as synchronized or interposed depending on the presence or absence of a co-incident R-wave. Hemodynamic parameters were integrated or averaged over each compression interval.

Results:
Synchronized compressions tended to produce larger aortic pressures, larger carotid blood flows, and lower right atrial pressures than interposed compressions. Data from one experiment are shown in Figure 1. The relative hemodynamic benefit of a synchronized chest compression appears to depend on the effectiveness of the underlying heart contraction. The interposed chest compressions generated forward carotid blood flow and increased the compression rate during bradycardia.

Discussion:
During bradycardic P-EMD, synchronized compressions may generate better hemodynamics than interposed compressions, and the combination of synchronized and interposed compressions may result in more blood flow than the delivery of synchronized compressions alone.

Figure 1. Comparison of hemodynamics generated by synchronized compressions (blue) and interposed compressions (red).
Abstract 254: High Shock Efficacy and Algorithm Performance for a 150J Biphasic Waveform AED Used by Lay and BLS Responders During Out-of-hospital Cardiac Arrest
Authors: Gehman Stacy , Kompare Edward , Fink Barbara , Johnson Tim , Hufford Walter , Najarian Kevin , Jorgenson Dawn
Published: November 2020

Introduction:
Effective AED defibrillation of out of hospital cardiac arrest (OHCA) depends on the safe and effective identification of shockable rhythms, and on delivery of effective defibrillation energy. This report summarizes rhythm detection performance and shock efficacy during OHCA uses of Philips HeartStart Home and OnSite AEDs using non-escalating 150 J therapy.

Methods:
A convenience sample of 185 OHCA AED patient uses were reviewed by clinical experts. All analysis periods that resulted in AED rhythm advisories (Shock Advised or No Shock Advised) were annotated. Shockable rhythm categories include VF and polymorphic VT/flutter. Non-Shockable rhythm categories include normal sinus rhythm, other rhythms (e.g., atrial fibrillation/flutter, bradycardia, SVT, idioventricular, bundle branch block), and asystole. Intermediate rhythms (benefits of defibrillation are limited or uncertain) were not included. Post-shock rhythm was categorized as shockable, non-shockable, or undeterminable (rhythms corrupted by CPR artifact or pads removal within 5-s of shock delivery). Shock success was defined as conversion to a non-shockable rhythm within 5-s post-shock.

Results:
A total of 487 analysis periods resulted in AED rhythm advisories, with 175 annotated as Shockable and 312 Non-shockable. Sensitivity and specificity (n/N, Exact 95% CI) were 97.7% (171/175, 94.3%, 99.4%) and 100% (312/312, 98.8%, 100.0%) respectively. A total of 165 shocks were delivered to 100 patients with 5 undeterminable post-shock rhythms. The remaining 160 shocks were delivered to 156 Shockable rhythm episodes. All shock efficacy was 96.9% (155/160, 92.9%, 99.0%): 150 episodes converted to non-shockable rhythms after one shock (96.2% (150/156, 91.8%, 98.6%)); 154 after two shocks (98.7% (154/156, 95.4%, 99.8%)); and 155 after three shocks, the first two of which were undeterminable (99.4% (155/156, 96.5%, 100.0%)). The remaining episode had a failed first shock, followed by an undeterminable second shock, which was the last shock of the use.

Conclusion:
For these 150J fixed-energy AEDs, OHCA defibrillation is safe (100% specificity), and effective (97.7% sensitivity; 96.2% single shock effectiveness; 98.7% after two shocks; 99.4% after three shocks).
Abstract 258: Adherence to the Transport Recommendations in the Universal Termination of Resuscitation Rule and Survival After Out-of-Hospital Cardiac Arrest
Authors: Okubo Masashi , Wallace David J , Grunau Brian E , Daya Mohamud R , Callaway Clifton W
Published: November 2020

Introduction:
Survival after out-of-hospital cardiac arrest (OHCA) varies across emergency medical services (EMS) systems. The contribution of EMS practices variation on the outcome disparities is unclear. We evaluated the association between EMS agency variation in adherence to the transport recommendations in the Universal Termination of Resuscitation (TOR) Rule and survival after OHCA.

Methods:
We conducted a secondary analysis of the Resuscitation Outcomes Consortium Epistry. We included adults (≥ 18 years) with OHCA for whom EMS providers attempted resuscitation from 2011 through 2015. The main exposure was the proportion of patients for whom the Universal TOR Rule recommended transport (i.e., meeting any one of the following criteria, EMS-witnessed arrest; return of spontaneous circulation prior to transport;
or
shock delivery prior to transport) among those transported to hospitals, at the level of EMS agency. We then categorized EMS agencies into quartiles. Our primary outcome was survival to hospital discharge. We used multilevel modified Poisson regression model, including patient-level and EMS-level covariates with patients nested within EMS agencies.

Results:
We included 42,584 EMS-treated OHCAs from 112 EMS agencies. The median proportion of patients for whom the TOR rule recommended transport among those transported was 88.2% (interquartile range [IQR] 76.1-96.7) across EMS agencies. Compared with the patients treated at EMS agencies in the quartile of the lowest proportion (the median proportion 66.7%[ IQR 50.9-71.7]), survival to hospital discharge was associated with treatment at EMS agencies in the second quartile (the median proportion 83.0% [IQR 79.8-85.3]) (adjusted risk ratio [aRR] 1.12, 95% confidence interval [CI] 0.96-1.31), the third quartile (the median proportion 93.0% [IQR 89.7-95.6]) (aRR 1.58, 95% CI 1.32-1.87), and the fourth quartile (the median proportion 100% [IQR 98.5-100]) (aRR 1.86, 95% CI 1.59-2.19).

Conclusions:
In this large cohort study of adult patients with OHCA, treatment at EMS agencies with higher proportion of patients who met transport criteria of the Universal TOR rule among transported patients was associated with survival to hospital discharge.
Abstract 261: Acute Lung Injury and Recovery in Patients with Refractory Vf/vt Cardiac Arrest Treated with Prolonged Cpr and Veno Arterial Extracorporeal Membrane Oxygenation
Authors: Gutierrez Alejandra , Kalra Rajat , Yannopoulos Demetris , Bartos Jason
Published: November 2020

Background:
Post cardiac arrest syndrome includes significant pulmonary injury that is not clearly understood.

Objectives:
Describe the lung injury patterns among patients presenting with refractory ventricular tachycardia/ventricular fibrillation out-of-hospital cardiac arrest (VT/VF OHCA) patients who were treated with veno-arterial extracorporeal membrane oxygenation (VA-ECMO).

Methods:
OHCA characteristics, post-arrest computed tomography (CT) scans, ventilator parameters and complications were collected using a retrospective cohort design. Changes in lung compliance were compared over time between survivors, patients with acute brain death and those who had other modes of death with a two- way analysis of variance.

Results:
Among138 refractory VT/VF OHCA patients (81% were male with a median age of 59.0 years, mean CPR time of 64.3 ±16.1 min, a mean APACHE II score of 30.5 ± 4.6) 48/138 (34.8%) survived, acute brain death occurred in 48/138 (34.8%) and other modes of death in 56/138 (40.6%). The dependent posterior segments of the lung were the most commonly affected areas on the initial CT scan(Fig1A). There was no difference in the number of hyperattenuated areas between the survival groups.Compliance was borderline on day one (median 26.3(19.3,33.3)ml/cmH
2
0), but improved throughout the hospitalization (p=0.001) and was higher in survivors compared to those who died (p<0.001, Fig1B). VA-ECMO allowed the use of lung-protective ventilation in patients with borderline compliances maintaining safe PaO2 and PaCO2. Patients additionally treated with IABP/Impella had lower pulmonary compliance and more hyperattenuated areas on their initial CT scan compared to those treated exclusively with VA-ECMO.

Conclusions:
Refractory VT/VF OHCA patients who are treated with VA-ECMO frequently have lung injury with borderline compliance soon after the index event. Lung compliance improves throughout hospitalization and is higher in survivors.
Abstract 264: Traumatic and Hemorrhagic Complications After Extracorporeal Cardiopulmonary Resuscitation for Out-of-hospital Cardiac Arrest
Authors: Nguyen My-Linh , Gause Emma , Mills Brianna , Tonna Joseph , Alvey Heidi , Saczkowski Richard , Grunau Brian E , Becker Lance B , Gaieski David F , Youngquist Scott T , Hamilton Jessica , Badulak Jenelle , Mandell Samuel , Bulger Eileen , Johnson Nicholas J
Published: November 2020

Introduction:
Extracorporeal cardiopulmonary resuscitation (ECPR) is a rescue therapy for treatment of refractory out-of-hospital cardiac arrests (OHCA). We describe the incidence of traumatic and hemorrhagic complications among patients undergoing ECPR for OHCA and the association between CPR duration and ECPR-related injuries or bleeding.

Methods:
We examined prospectively collected data from the Extracorporeal Resuscitation Outcomes Database (EROD), which includes ECPR-treated OHCAs from participating hospitals (Oct 2014 - Aug 2019). The primary outcome was traumatic or hemorrhagic complications, defined as injury to the chest, abdomen, or vasculature, or bleeding requiring transfusion or surgery. The primary exposure was the cardiac arrest to ECPR initiation interval (CA-ECPR interval), measured as the time from arrest to initiation of ECPR. Descriptive statistics were used to compare demographic, cardiac arrest, and ECPR characteristics among patients with and without CPR-related traumatic or bleeding complications. Multivariable logistic regression was used to examine the association between CPR duration and traumatic or bleeding complications.

Results:
A total of 68 patients from 4 hospitals received ECPR for OHCA were entered into EROD and met inclusion criteria. Median age was 51 (IQR 38-58), 81% were male, 40% had BMI > 30, and 70% had pre-existing medical comorbidities. A total of 65% had an initial shockable cardiac rhythm, mechanical CPR was utilized in at least 29% of patients, and 27% were discharged alive. A total of 37% experienced a traumatic or bleeding complication, with major bleeding (32%), vascular injury (18%), and cannula site bleeding (15%) being the most common. Compared to patients with shorter CPR times, patients with a 10 minute longer CA-ECPR interval had 18% (95% CI -2-42%) higher odds of suffering a mechanical or bleeding complication, but this did not reach statistical significance (p=0.08).

Conclusions:
Traumatic injuries and bleeding complications are common among patients undergoing ECPR. Further study is needed to investigate the relation between arrest duration and complications. Clinicians performing ECPR should anticipate and assess for injuries and bleeding in this high-risk population.
Abstract 288: Rapid Response Team Implementation Associated with Reductions in In-hospital Mortality Rate and Hospitalization Costs: A Retrospective Analysis
Authors: Sessim Filho Jacob , Azevedo Renato P , Assuncao Antonildes N , Sa Marcia M , Silva Felipe D , Pastore Laerte , Cardoso Luiz F , Ganem Fernando
Published: November 2020

Introduction:
Early recognition of clinical deterioration in inpatient subjects seems to be one of the main factors associated with prevention of in-hospital severe adverse events occurrence. Previous studies failed to demonstrate that the implementation of a rapid response team (RRT) could reduce in-hospital mortality rate.

Hypothesis:
Could a RRT implementation reduces in-hospital mortality and/or hospitalizations costs in a private general hospital in Brazil?

Methods:
This is a retrospective cohort built from data of electronic medical database of consecutive adult inpatients admitted to general wards who had to be transferred to an ICU after an acute clinical deterioration between May 1st, 2012 and June 30th, 2016. Subjects were divided into two groups as follows: group 1 (G1) with those admitted to ICU before RRT implementation on June 1st, 2014 and group 2 (G2) with the ones admitted to ICU after the implementation. All patients in G2 received care by the RRT before ICU admittance. In cases in which a patient had more than one hospital admission, only the first admittance was used for analyses.

Results:
Patients data are shown in table 1.Outcome data are shown in table 2.

Conclusions:
From these data, it is possible to infer that this RRT implementation at this hospital was associated with improvement in clinical outcomes of inpatients who needed an ICU admittance after an acute clinical deterioration, as well as a significant reduction of their hospitalization costs. These data reinforce the hypotheses that MERIT study was underpowered. Further multicenter randomized trials, with appropriate statistical power, shall be proposed to address these questions.
Abstract 290: The Association of Regional Intra-arrest Transport Practices for Out-of-hospital Cardiac Arrest with Survival and Neurological Status at Hospital Discharge
Authors: Grunau Brian E , Kawano Takahisa , Okubo Masashi , Reynolds Joshua , Heidet Matthieu , Scheuermeyer Frank , Cheskes Sheldon , Fordyce Chris , Drennan Ian R , Twaites Brian J , Christenson Jim
Published: November 2020

Background:
There is substantial regional variation in out-of-hospital cardiac arrest (OHCA) outcomes. We investigated whether regional-level intra-arrest transport practices were associated with patient outcomes.

Methods:
We performed a secondary analysis of the “CCC Trial” dataset, which included EMS-treated adult non-traumatic OHCA enrolled from 49 regional clusters. The exposure of interest was regional-level intra-arrest transport practices (RIATP), calculated as the proportion of cases within the enrolling cluster transported prior to return of spontaneous circulation (“intra-arrest transport”), divided into quartiles. We fit a multilevel mixed-effects logistic regression model to estimate the association of RIATP quartile and both survival and favorable neurologic status (mRS ≤ 3) at hospital discharge, adjusted for patient-level Utstein variables.

Results:
We included all 26,148 CCC-enrolled patients, 36% of whom were female, 97% were treated with prehospital ALS, and 23% had shockable initial rhythms. The median RIATP of the 49 clusters was 20% (IQR 6.2 - 30%). The figure shows outcomes stratified by RIATP quartile. Compared to the first quartile (<6.2%), increasing RIATP had the following adjusted associations with: (i) favourable neurological status: OR 0.87 (95% CI 0.60-1.26), 0.74 (95% CI 0.51-1.07), 0.36 (95% CI 0.25-0.53); and (ii) survival: 0.63 (95% CI 0.47-0.85), 0.60 (95% CI 0.45-0.79), 0.44 (95% CI 0.33-0.59).

Conclusion:
Treatment within a region that utilizes intra-arrest transport less frequently was associated with improved patient survival. These results may, in part, explain differences between regional OHCA survival outcomes.
Abstract 297: Identifying Optimization Targets in 911 Dispatch Workflows for Out-of-hospital Cardiac Arrest Management
Authors: Sams Woodrow , Dowker Stephen , Trumpower Brad , O'Leary Michael , Kamdar Neil , Smith Graham C , Hunt Nathaniel R , Coulter-thompson Emilee , Williams Michelle , Bloom Randy , Polydoras Cindy , Irwin Kevin , Swor Robert , Abir Mahshid , Domeier Robert , Friedman Charles , Neumar Robert W , Nallamothu Brahmajee K
Published: November 2020

Introduction:
Dispatch processes for prehospital management of out-of-hospital cardiac arrest (OHCA) vary greatly by region, and so do the barriers and facilitators of rapid time-to-first-treatment within those systems. In order to optimize local OHCA response, we sought to identify improvement targets by tracking time intervals during OHCA 911 calls and evaluating associated barriers and facilitators to timely OHCA prehospital care delivery.

Methods:
We developed a data abstraction tool to collect quantitative and qualitative data regarding key events in a random sample of 23 of emergency medical services (EMS)-confirmed, second-party, non-traumatic, non-overdose, non-facility adult OHCAs occurring prior to first responder arrival from November 2017 to November 2019 in Washtenaw County, Michigan. Trained abstractors double reviewed calls. We calculated descriptive statistics of key event times to summarize a timeline of care and evaluated qualitative data using thematic analysis to assess event intervals.

Results:
Based on quantitative and qualitative analyses, we created a timeline with summary data of dispatcher OHCA response based on an aggregate of 23 calls to 911 dispatch (see Figure 1). Data abstractors identified two intervals-of-interest as containing barriers to optimizing time-to-first treatment: 1) time between the first report of abnormal breathing and call taker statement of CPR need (Interval 1), and 2) time from patient positioning to the first compression instruction (Interval 2). Qualitative data suggested that these interval delays were a result of extensive efforts on the part of the call taker to reconfirm breathing status in particular. Additional barriers, such as the callers misunderstanding instruction, and on-scene physical limitations, were also identified.

Conclusions:
We identified two primary time intervals to target for improvement as well as barriers present in our local 911 system. These data may serve as a foundation to develop targeted interventions to optimize local systems of care for 911 dispatch workflows.

Figure 1
Abstract 300: Detection of Hemodynamic Status Using a Novel Analytic Based Solely on a Single Ecg Waveform
Authors: Bassin Benjamin S , Spino Catherine , Medlin Richard
Published: November 2020

Introduction:
Delayed identification of hemodynamic deterioration remains a persistent issue for in-hospital patient care. Unfortunately, no continuously measured non-invasive method of detecting hemodynamic deterioration currently exists. Clinicians rely on vital signs associated with tachycardia and hypotension to identify hemodynamically unstable patients. However, the collection of non-invasive vital signs remains labor-intensive, inconsistent, and error-prone in practice. In contrast, the Analytic for Hemodynamic Instability (AHI) depends only on the continuous ECG signal from a typical bedside monitor.

Hypothesis:
Continuous real-time hemodynamic status obtained from the analysis of existing ECG monitor data can accurately detect the combination of hypotension and tachycardia without the need for continuous direct measurement of blood pressure.

Methods:
28,348 5-minute windows of the analytic output were analyzed from 222 consecutive adult patients receiving continuous ECG and arterial line monitoring at an academic medical center. AHI outputs were compared to vital sign indication of tachycardia and hypotension in the same window.

Results:
The observed sensitivity and specificity of AHI compared to vital signs measurement were 95.6% and 84.9%, respectively, with an area under the curve (AUC) of 0.90 and an accuracy of 85.6%. The false-negative rate was 4.4%. The false-positive rate was 15.1%.

Conclusions:
The AHI derived hemodynamic status correlated well with vital sign derived hemodynamic status for both invasive and non-invasive methods. In patients who had their blood pressure monitored non-invasively, AHI provided continuous hemodynamic monitoring in patients who usually have vitals measured only every few hours.

Footnote:
The Analytic for Hemodynamic Instability is currently pending US FDA review and is not yet for sale in the US.
Abstract 306: Out-of-hospital Cardiac Arrest Response Characteristics Moderate the Effect of Response Time on Survival
Authors: Boutilier Justin J , Stoesser Clara , Sun Christopher L.F. , Brooks Steven , Cheskes Sheldon , Dainty Katie N , Feldman Michael , Ko Dennis T , Lin Steve , Morrison Laurie , Scales Damon , Chan Timothy C.Y.
Published: November 2020

Background:
Research has shown that each minute delay in response time reduces survival from OHCA. Although Utstein variables like public location, witnessed, bystander CPR, and bystander AED shock are known to independently improve survival, how they moderate the effect of response time delays on survival is unknown.

Methods:
We included OHCAs from the Resuscitation Outcomes Consortium Epistry-Cardiac Arrest database from December 1, 2005 to June 30, 2015. We included all adult, non-traumatic, non-EMS witnessed, and EMS-treated OHCA episodes. We used a logistic regression model to estimate survival to hospital discharge as a function of response time. We adjusted for standard Utstein variables and included interaction terms between response time and public location, bystander witnessed, bystander CPR, and bystander AED shock. With four binary interacted variables, there were a total of sixteen subpopulations, each with a different effect of response time on survival.

Results:
83,275 patients were included (15% public, 45% witnessed, 47% CPR, 2% AED shock). Across the 10 subpopulations that comprise 99%+ of the data, a one-minute delay in response time reduced the odds of survival from 1.7% to 10.9%, depending on the arrest characteristics. All interaction tests for effect modification were significant. The reduction in odds of survival was largest for witnessed arrests (OR=0.961; 95% CI: 0.944-0.978), followed by arrests with bystander CPR (OR=0.965; 95% CI: 0.948-0.982) and in public locations (OR=0.978; 95% CI: 0.960-0.996). In contrast, a one-minute delay for arrests with bystander AED shock (OR=1.086; 95% CI: 1.058-1.114) increased the odds of survival.

Conclusions:
Utstein predictors significantly moderate the effect of response time on survival. Arrests that are witnessed, public location, and/or receive bystander CPR are negatively affected by slower response time. Arrests with a bystander AED shock are not sensitive to response time delays.
Abstract 318: Association Carbon Dioxide Level During Cardiopulmonary Resuscitation with Neurological Outcome After Out-of-hospital Cardiac Arrests
Authors: Matsuyama Tasuku , Kitamura Tetsuhisa , Iwami Taku , Ohta Bon
Published: November 2020

Background:
Little evidence exists to guide appropriate ventilation strategies during CPR. We aimed to investigate the association between carbon dioxide (CO2) pressure measured on hospital arrival from those who were receiving ongoing resuscitation and neurological outcome after out-of-hospital cardiac arrest (OHCA).

Method:
This nationwide hospital-based prospective observational study (The JAAM-OHCA registry) carried out between June, 2014 and December, 2017 in Japan. From this registry, we included adult OHCA patients aged ≥18 years with blood gas sampled on hospital arrival during CPR. The main exposure was CO2 level in blood gas analysis during CPR. Based on the CO2 level on hospital arrival, included patients were classified into four quartiles (Q1-Q4) defined as Q1 (<66.0 mmHg), Q2 (66.1-87.2 mmHg), Q3 (87.3-113.5 mmHg), and Q4 (≥113.6 mmHg). The primary outcome of this study was one-month survival with favorable neurological outcome defined by cerebral performance category 1 or 2. We adjusted for potential confounders with multivariable logistic regression analysis.

Results:
During the study period, a total of 21,137 patients were included in our analysis. The overall proportion of favorable neurological outcome was 1.0% (207/21137). The highest proportion of favorable neurological outcome was observed in the Q1 group (2.4% [140/5244]), followed by Q2 (0.7% [37/5284]), Q3 (0.4% [21/5296]), and Q4 (0.2% [9/5313]). In the multivariable logistic regression analysis, we found that the Q4 group had the significantly lower proportion of favorable neurological outcome than the Q1 group (adjusted odds ratio 0.25; 95% confidence interval 0.16-0.55). The adjusted probability of favorable neurological outcome decreased in a stepwise fashion across increasing quartiles (P<0.001).

Conclusion:
This study observed the association between lower CO2 level on hospital arrival and favorable neurological outcome after OHCA in a dose-dependent manner.
Abstract 331: Trajectories of Sequential Organ Failure Assessment (sofa) Scores After Cardiac Arrest
Authors: Flickinger Kate , Coppler Patrick J , Brown McKenzie , Elmer Jonathan
Published: November 2020

Cardiac arrest (CA) often results in multi-system organ failure (MSOF). The Sequential Organ Failure Assessment (SOFA) Score is a tool based on the assessment of 6 physiological systems and can quantify severity of MSOF. Understanding the epidemiology, temporal dynamics and anticipated course of MSOF after CA is critical to both clinical care and prognostication. We included patients treated at a single center after CA from 2010-2019, regardless of arrest location or etiology. We electronically extracted all medication, laboratory, ventilator, intake and output data. We calculated SOFA scores daily for up to five days (or until death or discharge). We used group-based trajectory modeling (GBTM, also known as growth curve mixture modeling) to identify groups of patients with distinct trajectories of SOFA over time. We started by fitting trajectories with third order polynomials then sequentially eliminated higher order terms with non-significant coefficients. We used AIC and BIC to determine the number of groups.

We included 2,740 patients, of whom most (1,633; 59%) were male, with mean (SD) age of 59 (16) years. Most arrests (2,106; 76%) occurred out-of-hospital and 837 (30%) had a shockable initial rhythm. Overall survival to discharge was 38%. Bilirubin was infrequently checked in this cohort, so we excluded the liver subscale of SOFA from total SOFA calculation making maximum SOFA 20. Mean presenting SOFA was 6 (3), and mean SOFA on day 2 was 6 (4). We identified 5 groups of patients with unique trajectories of SOFA over time. Baseline demographics and survival differed across trajectory groups. Despite showing delayed MOSF onset with rapidly rising SOFA from baseline to day 2, 26% of Group 4 still survived to discharge, while Group 3, which had an initially severe but rapidly improving MSOF had a 32% survival rate. Unique patterns of MSOF after CA can be identified using GBTM. Delayed onset of severe MSOF is less prognostically ominous than commonly believed by clinicians.