bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 516: Electromagnetic Properties of Blood-flow for Screening of Peripheral Artery Disease
Authors: Rogers Jerad , Jayakumar Balakumar , Patterson Jeremy , Cluff Kim
Published: June 2021

Peripheral artery disease (PAD) is a slowly progressive vascular disease characterized by abnormal narrowing of peripheral arteries through atherosclerosis. PAD often goes unnoticed and is heavily under diagnosed due to its initially asymptomatic features and if not detected early enough can lead to critical limb ischemia or limb amputation. Current PAD screening options are limited to the clinical setting and require specialized equipment, specialized training in operation, specialized training for interpretation of the results, and lack the ability to screen for PAD in a simple, cost effective point-of-care manner. In this study, our objective was to create a novel, non-invasive, point-of-care screening patch for the early detection of PAD. To attain our objective, we tested our hypothesis that electromagnetic changes in the permittivity and permeability of blood can be used to detect blood-flow abnormalities of PAD with a simple wireless biosensor - applied like a small adhesive bandage. When activated by an external RF wave, the skin patch developed an electromagnetic field that penetrates into its surroundings. Using a Vector Network Analyzer (VNA), we were able to quantify the skin patch’s electromagnetic field interactions with its surroundings. Using a human arm phantom with vascular network, synthetic blood, and heart pump the skin patch was able to measure pulsatile blood flow as shifts in the sensor’s resonant frequency. The results were validated using an ultrasound pulse wave Doppler which detected 50 bpm on the arm phantom. The smart skin patch was able to detect pulsatile flow with 100% accuracy when compared to ultrasound. These results strongly suggest that the patch may be capable of measuring pulsating blood-flow in a point-of-care fashion which does not require specialized training or expensive equipment. What’s more, is that this biosensor does not have batteries, no electrical components, and has wireless communication.
Abstract 656: In Vivo Plaque Inflammation and Endothelial Permeability Independently Predict Atherosclerosis Progression: A Serial Multimodality Imaging Study
Authors: Osborn Eric A , Ughi Giovanni J , Verjans Johan W , Gerbaud Edouard , Takx Richard A , Tawakol Ahmed , Tearney Guillermo J , Jaffer Farouc A
Published: June 2021

Background:
Atheroma inflammation impairs plaque stability and promotes plaque progression and complications. However, it is unknown how measures of plaque biology relate to changes in plaque burden, and whether plaque biology can independently predict plaque progression in coronary-sized arteries. This study evaluated the ability of intravascular near-infrared fluorescence (NIRF) biological imaging to inform experimental atheroma progression in vivo.

Methods:
Atherosclerosis was induced by balloon-injury in the aorta of 14 cholesterol-fed rabbits. Serial intravascular ultrasound (IVUS) and dual-modality intravascular NIRF - optical coherence tomography (OCT) imaging was performed following injection of a NIRF molecular imaging agent of plaque inflammatory protease activity (ProSense VM110; n=7), or impaired plaque endothelial permeability (indocyanine green (ICG); n=7). Plaque progression was further assessed by IVUS change in plaque burden. Regression analysis was used to evaluate the association of NIRF with plaque progression. In vivo imaging results were corroborated by ex vivo fluorescence reflectance imaging, fluorescence microscopy, and histopathology.

Results:
Quantitative analysis of 1,811 axial images spanning individual plaques, the change in NIRF plaque biological signals from 8 to 12 weeks strongly correlated with IVUS plaque burden from 8 to 12 weeks (ProSense VM110: r=0.774; ICG: r=0.572; p<0.0001). This finding remained significant on multivariate analysis adjusted for IVUS plaque burden, lumen area, and remodeling index (p<0.001). In additional multivariate analyses, the baseline NIRF signal at 8 weeks further predicted the magnitude of plaque progression even after adjustment for baseline plaque burden (p<0.001 for Prosense VM110; p=0.004 for ICG). Histology demonstrated NIRF agent uptake in inflamed, lipid-rich plaques.

Conclusion:
Plaque pathobiology and plaque burden progress in concert as assessed by translatable intravascular NIRF imaging technology. The baseline NIRF inflammation and impaired plaque permeability signals independently predict plaque progression. Integrated biological-microstructural imaging may enhance the ability to detect high-risk plaques at risk of progression.
Abstract 01: The Importance of Time to Cooling in Out-Of-Hospital Cardiac Arrest Patients to Influence Neurologically Intact Survival: A Sub-Analysis of the Princess Trial
Authors: Awad Akil , Taccone Fabio Silvio , Jonsson Martin , Forsberg Sune , Hollenberg Jacob , Ringh Mattias , Abella Benjamin , Becker Lance B , Svensson LeiF G , Nordberg Per
Published: June 2021

Background:
Early initiation of hypothermia has shown to be important to reduce brain injuries in experimental cardiac arrest models. The aim of this study was to investigate the association between time to initiate cooling and neurological intact survival in patients with out-of-hospital cardiac arrest (OHCA).

Methods:
A secondary analysis of prospectively collected data from the PRINCESS trial (NCT01400373) including 677 OHCA patients randomized to transnasal evaporative intra-arrest cooling or standard advanced life support and cooling started subsequent to hospital arrival. Time to randomization was used a proxy measurement for time to initiate cooling. An early treatment group was defined as patients randomized by the EMS <20 minutes from the time of the cardiac arrest. Propensity scores were used to find matching patients in the control group. Patients with initial shockable rhythms were analyzed as a predefined subgroup. The primary outcome was good neurologic outcome, Cerebral Performance Category (CPC) 1-2 at 90 days. Secondary outcome was complete recovery (CPC 1).

Results:
In total 406 patients were randomized <20 minutes from the cardiac arrest and were propensity score matched (1:1). In the propensity score matched analysis the proportion of patients with CPC 1-2 was 21.7% in the intervention and 17.2% in the control group, odds ratio (OR) 1.33, 95% confidence interval (CI) 0.80-2.21, p=0.273. In patients with initial shockable rhythm (79 intervention, 79 control) the difference in CPC 1-2 was 48.1% versus 32.0%, OR 2.05, 95%CI 1.00-4.21, p=0.0498. The proportion of patients with complete neurologic recovery, CPC 1, was 19.7% in the intervention and 13.3% in the control group, OR 1.60, 95% CI 0.92-2.79, p=0.097. In patients with initial shockable rhythm the proportion with CPC 1 was 45.6% versus 24.6%, OR 2.81, 95% CI 1.23-6.42, p=0.014.

Conclusions:
In this ancillary study of OHCA patients receiving intra-arrest cooling, there were differences in survival with good neurologic outcome and in complete neurological recovery in favor of early intra-arrest cooling patient group compared to standard care. These differences were statistically significant in the subgroup of patients with initial shockable rhythms.
Abstract 04: Diagnostic Accuracy of Coronary CT in Survivors of Out-Of-Hospital Circulatory Arrest: Can CT Serve as a Gatekeeper for Invasive Coronary Angiography?
Authors: Branch Kelley R , Hira Ravi , Brusen Robin M , Maynard Charles , Gatewood Medley , Fly Deborah L , Petek Bradley J , Kudenchuk Peter , Strote Justin A , Olsufka Michelle , Sayre Michael R , Carlbom David , Gunn Martin
Published: June 2021

Introduction:
Out-of-hospital circulatory arrest (OHCA) is commonly assumed to be from a cardiac cause although routine early invasive coronary angiography (ICA) remains controversial and has a relatively high proportion of studies without obstructive coronary artery disease (CAD). The ability of coronary CT angiography (CCTA) to detect significant CAD in OHCA survivors has not been evaluated.

Methods:
The prospective CT-FIRST trial enrolled 104 OHCA survivors who had an early (<6 hours from hospital arrival) head-to-pelvis CT scan that included an ECG-gated CCTA (FORCE CT, Siemens). The CCTA scanned 0-90% of the cardiac cycle without routine use of beta blockers or nitroglycerin. Treating physicians were blinded to the CCTA analysis. ICA was ordered at the discretion of treating physicians. Readers blinded to corresponding studies analyzed CCTA and ICA for coronary stenoses using a 20 segment coronary model. Obstructive CAD was assumed for >50% stenosis. Patient-level diagnostic accuracy calculations for CCTA to identify obstructive CAD used ICA as the standard.

Results:
Of the 104 enrolled patients, 28 (27%) had both CT and ICA. All CCTA studies were evaluable. Diagnostic accuracy data are shown in the Table. Overall, diagnostic accuracy measures were excellent between CCTA and ICA at the patient level.

Conclusions:
Early CCTA in OHCA survivors has high diagnostic accuracy for obstructive coronary artery disease and could be used as a gatekeeper to ICA.
Abstract 10: Early Neuroprognostication After Refractory VF/VT Cardiac Arrest Requiring ECPR
Authors: Bartos Jason A , Nutting Lindsay , Carlson Claire , Raveendran Ganesh , Aufderheide Tom P , Yannopoulos Demetris
Published: June 2021

Background:
Extracorporeal cardiopulmonary resuscitation (ECPR) can improve survival for refractory ventricular fibrillation (VF) cardiac arrest. Early prognostication will be critical to focus this resource-intensive care to patients likely to benefit.

Objectives:
The aim of this study is to examine the efficacy of current neuroprognostication tools early in the setting of ECPR for refractory VF.

Methods:
Consecutive patients transported for the University of Minnesota ECPR program and surviving to hospital admission between December 2015 and May 2019 were assessed. All patients received neurologic assessment with head CT, continuous EEG, cerebral near-infrared spectroscopy (NIRS), biomarkers including S100B and neuron specific enolase (NSE), and neurologic exam. All patients were considered viable unless they developed refractory shock, devastating brain injury, or family requested cessation of efforts. For this analysis, patients were divided into two groups: 1) neurologically favorable survival (CPC 1-2) and 2) those who died or had CPC 3-4. Data from the first 24 hours of hospital admission were used.

Results:
Of 168 patients, 130 patients survived to hospital admission. Of these, 42% (54/130) survived neurologically favorable. Abnormalities on admission head CT were predictive of poor outcomes; cerebral edema was 100% specific and 30% sensitive for poor outcomes while anoxic injury provided 98% specificity and 39% sensitivity. Admission NSE levels greater than three times the upper limit of normal were predictive with 98% specificity and 26% sensitivity for poor outcome. Admission S100B was highly variable failing to discriminate patient outcome. Absence of brainstem reflexes at 24 hours had 100% specificity and 32% sensitivity. An isoelectric EEG at 24 hours had 100% specificity and 20% sensitivity. NIRS did not predict poor outcomes. When combined, ≥ 1 of the following: anoxic injury on CT, edema on CT, NSE, absence of brainstem reflexes, isoelectric EEG have a specificity of 96% and sensitivity of 67% for poor outcome.

Conclusions:
Neuroprognostication after 24 hours of hospital admission may be possible in the refractory VF population requiring ECPR. High specificity is possible but sensitivity is limited. Further study is needed.
Abstract 101: Effect of Extracorporeal Membrane Oxygenation for Accidental Hypothermia With Absent Vital Signs: A Nationwide Observational Study
Authors: Ohbe Hiroyuki , Yasunaga Hideo
Published: June 2021

Introduction:
Patients with accidental hypothermia and absent vital signs are increasingly receiving venoarterial extracorporeal membrane oxygenation (VA-ECMO). However, there is limited knowledge on the efficacy of this advanced rewarming method. Despite the limited evidence, the resuscitation guidelines from the European Resuscitation Council and the American Heart Association both recommended the use of extracorporeal life support in patients with accidental hypothermia and absent vital signs.

Hypothesis:
We hypothesized that VA-ECMO is associated with lower in-hospital mortality compared with cardiopulmonary resuscitation (CPR) only in patients with accidental hypothermia and absent vital signs.

Methods:
Using the Japanese Diagnosis Procedure Combination inpatient database from July 2010 to March 2017, we identified patients diagnosed with accidental hypothermia (International Classification of Diseases Tenth Revision code T68) who received closed-chest cardiac massage in hospital on admission day. Patients who received VA-ECMO on admission day were allocated to the VA-ECMO group, and those who received CPR only were allocated to the conventional CPR group. The primary outcome was in-hospital mortality. The secondary outcome was alert consciousness for Japan Coma Scale status at discharge. Propensity score analyses were performed to compare the outcomes between the two groups.

Results:
We identified 1,624 eligible patients during the 81-month study period. Of these, 19% (314 of 1,624) received VA-ECMO on admission day. Crude in-hospital mortality was 65.3% (205 of 314) and 84.1% (1,102 of 1,310) in the VA-ECMO and conventional CPR groups, respectively. Propensity score-matching analyses demonstrated significantly lower in-hospital mortality (risk difference, –14.1%; 95% confidence interval, –21.9% to –6.3%) and higher proportion of alert consciousness at discharge (risk difference, 8.5%; 95% confidence interval, 2.1% to 15.0%) in the VA-ECMO group compared with the conventional CPR group.

Conclusions:
VA-ECMO was significantly associated with decreased in-hospital mortality and favorable neurologic outcome compared with conventional CPR in patients with accidental hypothermia and absent vital signs.
Abstract 103: Rewarming Speed Affects Cardiopulmonary and Neurological Functions After Deep Hypothermic Cardiac Arrest
Authors: Linardi Daniele , Walpoth Beat H , Mani Romel , Tessari Maddalena M , Decimo Ilaria , Dolci Sissi , Cavada Annalisa , Luciani Giovanni , Faggian Giuseppe , Rungatscher Alessio
Published: June 2021

Introduction:
The optimal rewarming rate from accidental or induced deep hypothermia is still unknown. Fast extracorporeal rewarming by extracorporeal circulation has been associated with cardiac dysfunction, pulmonary edema and poor neurologic outcome.

Hypothesis:
This study investigates whether the speed of rewarming after deep hypothermic cardiac arrest has neurological and cardiopulmonary effects.

Methods:
Thirty male Sprague-Dawley adult rats (450-550g) were rapidly cooled (ice packs) until 15°C core body temperature. Deep hypothermic cardiac arrest was maintained for 60 min. Thereafter rats were randomised to receive slow (90 minutes) or fast (30 minutes) rewarming by cardiopulmonary bypass to a target temperature of 35°C. After 90 minutes of reperfusion all animals underwent hemodynamic assessment by biventricular pressure-volume analysis, brain MRI and heart, lungs and brain were collected.

Results:
Slow rewarming preserved cardiac systolic and diastolic functions, ventricular arterial coupling and endothelium dependent relaxation. Lung edema was attenuated after slow rewarming. Cardimyocytes pro-survival kinases ERK and Akt activation were significantly higher in the slow rewarming group. MRI demonstrated enhancement of cerebral blood flow and reduction of cerebral edema after slow rewarming. Neurologic inflammatory response measured by IL-6, ICAM-1, CCL5 and TNF-α expression was significantly decreased in the slow rewarming group. Oxidative stress assessed by malondialdehyde was significantly reduced after slow rewarming.

Conclusion:
Slow rewarming by extracorporeal circulation after deep hypothermic cardiac arrest might improve systolic and diastolic function, preserve ventricular-arterial coupling, attenuate cerebral perfusion impairment and reduce neuronal damage.
Abstract 113: Readmission Rates and Causes for In-Hospital Cardiac Arrest Survivors at 30 and 180 Days: Insights from Nationwide Readmission Database
Authors: Elkaryoni Ahmed , Chan Paul
Published: June 2021

Introduction:
Rates of survival to discharge for patients with in-hospital cardiac arrest (IHCA) have improved over the past 2 decades from 13% in 2000 to 25% in 2016. Yet, little is known about rates and causes of readmissions among those survivors. We sought to investigate early and late rates and causes of readmission for IHCA survivors at 30 and 180 days after discharge.

Methods:
Within the Nationwide Readmission Database (NRD), we identified patients 18 years of age or older who survived to hospital discharge after an IHCA between 2010 and 2016. IHCA was defined by an ICD-9 or ICD-10 diagnosis code (cardiac arrest, ventricular fibrillation or flutter) combined with a procedure code (defibrillation or external chest compression). We evaluated rates and causes of 30 and 180 days readmission and examined whether these have changed over time.

Results:
A total of 86,140 patients had an IHCA and survived to hospital discharge. Overall, mean age was 64.3 ± 14.9, women were 40.1%, and the mean length of stay was 15.1 ±17.9 days. All-cause readmission rates at 30 and 180 days were 22.7% and 69.9%, respectively. Readmission rates decreased over time. Thirty-day readmission rates decreased from 23.8% in 2010 to 21.1% in 2016, and 180-day readmission rates decreased from 76.1% to 63.6%. (Figure) Among readmitted patients, 13.5% were readmitted more than once at 30 days and 44.9% were readmitted more than once at 180 days. The most common cause of 30-day readmissions were congestive heart failure (11.7%), infection/septicemia (11.4%), and cardiac dysrhythmias (5.3%),whereas the top causes of 180-day readmissions were congestive heart failure (11.9%), infection/septicemia (11.3%), and respiratory insufficiency, or device complications (4.6%).

Conclusion:
All-cause readmission rates for IHCA survivors at 30 and 180 days have decreased over time, Congestive heart failure is the most common cause of readmissions but accounts for only 11.7% and 11.9% of readmissions at 30 and 180 days.
Abstract 118: Resuscitative Transfusion With Hemoglobin Vesicles in the Management of Post-Partum Hemorrhage
Authors: Hagisawa Kohsuke , Kinoshita Manabu , Ishibashi Hiroki , Sakai Hiromi
Published: June 2021

Background:
We developed a Hemoglobin vesicles (HbV), which are artificial substitute for Red blood cells (RBCs).

Objective:
To evaluate the efficacy of HbV for alternative treatment instead of RBCs transfusion in rabbits with hemorrhagic shock due to post-partum hemorrhage.

Methods:
New Zealand white rabbits at late gestation underwent uncontrolled hemorrhagic shock by transecting a right mid-artery in the myometrium, after cesarean section of right side uterus. Initially, in the simulated ordinal treatment of bleeding, rabbits received colloid fluids (Voluven®) through an femoral vein with equivalent volume of the bleeding every 5 minutes. Once blood loss achieved 100ml, animals subsequently faced on critical hemorrhagic situation, where mean arterial pressure (MAP) reduced to approximately 48mmHg. They were randomly divided into three isovolemic resuscitation regimens: continuing colloid fluid resuscitation (n=4); transfusion of autologous washed RBCs with plasma (n=4); HbV infusion combining 5% human serum albumin (n=4). After 60 minutes of bleeding, all animals underwent surgical control of bleeding and cesarean section of left side uterus.

Results:
At the point of critical hemorrhagic situation, Hb concentration reduced to 4.8 g/dl. At the end of resuscitation, HbV infusion regained MAP and restored Hb concentration as well as RBCs transfusion, besides colloid fluid resuscitation exaggerated the severe hemorrhagic shock as shown in the table.

Conclusions:
HbV treatment may be effective in the management of post-partum hemorrhagic shock.
Abstract 119: Influence of Anesthetics on the Hemodynamic Response in a Rat Model of Hemorrhagic Shock
Authors: Balzer Claudius , Baudenbacher Franz J , Eagle Susan S , Salzman Michele M , Cleveland William J , Riess Matthias L
Published: June 2021

Introduction:
Experimental models of hemorrhagic shock (HS) in rats are important to test new treatments that may improve outcomes in humans, and general anesthesia is required during these experiments. The volatile anesthetic Isoflurane is known for its beneficial effects in rat HS models. Focusing on cardiovascular compensatory mechanisms, we wanted to evaluate Isoflurane versus the injectable anesthetic Pentobarbital in our rat model of mild HS (class 2). We hypothesize that Isoflurane during development of HS improves hemodynamics compared to Pentobarbital.

Methods:
Twelve Sprague-Dawley rats were initially anesthetized with an intraperitoneal (IP) injection of Pentobarbital (45 mg/kg) and intubated (1 L/min, FiO
2
0.25); heart rate (HR) was monitored by subcutaneous ECG needles. Femoral artery and vein were cannulated for continuous blood pressure measurement and delivery of fluids, respectively. In one group (n=7), anesthesia was continued with repeated IP injections of Pentobarbital (dose mg/kg), the other group (n=5) received continuous Isoflurane (1%). After 30 min of stabilization and administration of Heparin (100 IU/kg), HS was induced by removal of 1 ml of blood over 1 min via the femoral vein, repeated every 3 min until a volume of 5 ml of blood was removed. Mean arterial blood pressure (MAP) and HR were recorded and analyzed in LabChart.

Results:
During baseline, rats showed no significant differences in HR and MAP between both groups. After 5 ml of hemorrhage, both groups showed significant changes compared to baseline, with significantly higher MAP and HR in rats given only Pentobarbital.

Conclusions:
In our rat model of HS, Isoflurane dampens the physiologic response to compensate for mild hemorrhage. The cardiovascular response of rats in the Isoflurane group was a decrease of HR and MAP to every ml of hemorrhage, while rats given only Pentobarbital were able to maintain their MAP by raising their HR until decompensation.
Abstract 13: Adenosine Receptor Activation During Extracorporeal Cardiopulmonary Resuscitation Improves Survival After Cardiac Arrest in Swine
Authors: Chancellor William Z , Money Dustin , Beller Jared P , Byler Matthew R , Zhang Aimee , Charlton Jennifer R , Levin Daniel E , Lunardi Nadia , Yang Zequan , Laubach Victor , Mehaffey James , Kron Irving , Roeser Mark E
Published: June 2021

Introduction:
Despite advances in resuscitation protocols, including the addition of Extracorporeal Cardiopulmonary Resuscitation (ECPR), survival after cardiac arrest remains less than 40% and novel methods are needed to attenuate global injury and improve outcomes. ATL1223, an adenosine 2A receptor (A2AR) agonist has been shown to attenuate organ specific reperfusion injury by modulating the interaction of inflammatory cells.

Hypothesis:
A2AR activation during ECPR will improve survival and decrease the burden of injury in a large animal model of cardiac arrest.

Methods:
Adult swine underwent 20 minutes of circulatory arrest followed by defibrillation and 6 hours of ECPR. Animals were randomized to receive saline control (n=5) or the A2AR agonist Regadenoson (0.144 and 14.4mcg/kg/hr, n=5/group). Animals were subsequently weaned from ECPR and monitored for 24 hours. Clinical and biochemical endpoints were compared between groups.

Results:
The administration of Regadenoson increased survival after cardiac arrest compared to saline controls (10/10, 100% vs 2/5, 40%, p=0.02, Figure 1). Anesthetic administration (p=0.41), fluid resuscitation (p=0.54), and epinephrine required to maintain target arterial pressure (p=0.08) were similar for all subjects. Biochemical markers of organ damage, including creatinine (p=0.87), aspartate aminotransferase (p=0.89), and troponin I (p=0.38), were similar among groups (Figure 2).

Conclusions:
In a clinically relevant model of cardiac arrest treated with ECPR, selective A2AR agonism increased survival from 40% to 100% at 24 hours. These results suggest A2AR activation is a promising therapeutic target after cardiac arrest.
Abstract 135: N-Terminal Pro-B-Type Natriuretic Peptide May Serve as a Prognostic Indicator for 30-Day Mortality Following Out-Of-Hospital Cardiac Arrest, Whereas Both High-Sensitivity Cardiac Troponin-T and Copeptin Did Not Yield Prognostic Information
Authors: Aarsetoey Reidun , Omland Torbjorn , Rosjo Helge , Strand Heidi , Aarsetoey Hildegunn , Staines Harry , Nilsen Dennis W
Published: June 2021

Introduction:
Sudden cardiac arrest (SCA) may be due to different underlying conditions. Prior heart disease is a major risk factor, and coronary artery disease is the most common underlying cause. Hs-cTnT and copeptin are used for early diagnosis of acute myocardial infarction, and may also serve as prognostic indicators following an acute coronary syndrome. NT-proBNP is a marker of heart failure and may act as a predictor of mortality in SCA patients. These three biomarkers in relation to ventricular fibrillation (VF) and asystole on scene during resuscitation has not, to our knowledge, been evaluated.

Hypothesis:
We hypothesized that early-on levels of hs-cTnT, copeptin and NT-proBNP may relate to prognosis.

Methods:
From February 2007 until November 2010 blood samples were collected from patients aged > 18 years with out-of-hospital cardiac arrest of assumed cardiac origin. EDTA-blood was drawn during or immediately after termination of cardiopulmonary resuscitation or at hospital admission. Hs-cTnT, copeptin and NT-proBNP were all measured by standardized methods. Patients were classified according to first recorded heart rhythm. Both univariate and multivariate analyses, adjusted for age and gender, were performed using a Cox Proportional-Hazards model.

Results:
A total of 115 patients were included, 77 patients with VF and 38 patients with asystole as first recorded heart rhythm. Forty-four patients (38,3%) survived to 30-day follow-up. There was no significant difference in hs-cTnT (p = 0.71) or copeptin (p = 0.43) between non-survivors and survivors. The mean NT-proBNP level was significantly elevated in non-survivors compared to survivors, p = 0.001. The hazard ratio (HR) in the univariate analysis for patients with NT-proBNP in the highest quartile (Q4) compared to the lowest quartile (Q1) was 4.68 (95% CI 2.05-10.68), p = < 0.001, and in the multivariate analysis HR was 2.52 (95% CI 0.97-6.53), p = 0.058. All patients in the asystole group died. Only NT-proBNP differed between the two groups, with significantly higher values in the asystole group, p = < 0.001.

Conclusion:
Applying hs-cTnT, copeptin and NT-proBNP for assessment of prognosis in SCA patients with either VF or asystole, only NT-proBNP was found to yield prognostic information.
Abstract 136: Activated Factor IX - Antithrombin Complex Predicts Outcome After Out-Of-Hospital Cardiac Arrest
Authors: Aarsetoey Reidun , ten Cate Hugo , Spronk Henri M , van Oerle Rene , Aarsetoey Hildegunn , Lindner Thomas W , Staines Harry , Nilsen Dennis W
Published: June 2021

Introduction:
Sudden cardiac arrest (SCA) and cardiopulmonary resuscitation (CPR) are associated with activated coagulation and impairment of end-organ perfusion. Activated factor IX (FIXa) is part of the intrinsic coagulation system. FIX may also be activated by extrinsic tenase (tissue factor/activated factor VII), as well as through the intrinsic pathway, which may include thrombin-induced activation of factor XI, by which thrombin generation is sustained.

Hypothesis:
We hypothesized that the level of activated factor IX -antithrombin (FIXa-AT) complex, as a measure of coagulation activation, would be of prognostic value in SCA patients.

Methods:
From February 2007 until December 2010 blood samples in EDTA tubes were collected during or closely after termination of CPR from patients aged > 18 years with out-of-hospital cardiac arrest (OHCA) of assumed cardiac origin. Survivors had follow-up samples drawn 8-12 hours and 24-48 hours after admission. FIXa-AT was determined by ELISA. Patients were divided into quartiles (Q1-4) by FIXa-AT levels. Cox regression was used for analysis of death within 30 days.

Results:
A total of 115 OHCA patients were included. Of these, 71 patients (61,7%) died, of whom 35 died on scene and 36 in-hospital. Early-on FIXa-AT complex levels in the higher quartiles as compared to the lowest were significantly associated with increased risk of death (Figure 1). The hazard ratio (HR) for Q4 patients compared to Q1 was 6.79, (95% CI 2.04-22.61); p = 0.002, for Q3 4.48 (95% CI 1.33-15.16); p = 0,016, and for Q2 3.48 (95% CI 1.01-11.95); p = 0.048. Mean log
e
(FIXa-AT) in hospitalized non-survivors were higher than in survivors; 8-12 hours (p = 0.002) and 24-48 hours (p = 0.008). There was a positive correlation between the duration of advanced CPR and log
e
(FIXa-AT), r = 0.24, p = 0.012.

Conclusion:
Early-on FIXa-AT complex predicts 30-day mortality in OHCA-patients. Prolonged resuscitation seems to be associated with increased coagulation activation.
Abstract 138: Defining System of Care Best Practices for Out-Of-Hospital Cardiac Arrest Survival
Authors: Abir Mahshid , Guetterman Timothy C , Fouche Sydney , Iovan Samantha , Lehrich Jessica L , Nham Wilson , Mendel Peter J , Nelson Christopher , Fetters Michael D , Shields Teri , Neumar Robert W , Hsu Antony P , Forbush Bill , Swor Robert A , O’Neil Brian , Nallamothu Brahmajee K
Published: June 2021

Introduction:
EMS system factors key to improved survival for out-of-hospital cardiac arrest (OHCA) have not been well elucidated. This study explores factors associated with sustained return of spontaneous circulation (ROSC) in the field with pulse upon arrival to the ED-a measure of high quality of prehospital care-across the chain of survival.

Methods:
This sequential mixed methods study used data from the Michigan Cardiac Arrest Registry to Enhance Survival (MI-CARES) to evaluate variation in OHCA outcomes across EMS agencies. Sites were sampled based on geography, rurality, population density, and survival rate. We visited 1 low-, 1 middle-, and 3 high-survival EMS systems. At each site, we conducted key informant interviews with field staff, mid-level managers, and leadership from EMS, police, fire, and dispatch, as well as multidisciplinary focus groups. Transcripts were coded using a structured codebook and analyzed using thematic analysis.

Results:
An integrated multidisciplinary approach was critical for timely OHCA care coordination across the chain of survival. Themes that emerged across all stakeholders included: 1) OHCA education and multidisciplinary training; 2) shared awareness of roles in the chain of survival and system-wide response; 4) multidisciplinary QI; and 5) leadership and initiative (Table 1).

Conclusions:
Recognizing the critical role of each level in the chain of survival, this study identified specific practices from EMS system stakeholders that were associated with improved survival. The next phase of this work will include validating the factors associated with increased survival identified through a statewide survey of EMS agencies in Michigan. The final product of this work will include a toolkit of best practices and an implementation guide.
Abstract 139: Does Simplification of Guidelines Improve Retention of BLS Skills 3 Months After Training?
Authors: Nguyen Dung T , Lauridsen Kasper G , Johnsen Josephine , Krogh Kristian , Løfgren Bo
Published: June 2021

Background:
The European Resuscitation Council (ERC) 2015 basic life support (BLS) guidelines introduced a simplified algorithm compared to the ERC 2010 BLS guidelines. This was intended to improve adherence to guidelines and retention of skills. This study aimed to compare the retention of BLS skills 3 months after training using the ERC 2010 or 2015 guidelines.

Methods:
This was an observational study including video recordings of laypersons being skill tested 3 months after participation in a standardized ERC BLS/AED course using either the ERC 2010 guidelines or the simplified ERC 2015 guidelines. The endpoints were 1) remembering the correct sequence of BLS/AED algorithm, 2) remembering the correct sequence of the BLS/AED algorithm and performing all skills correctly, 3) time to: emergency medical service (EMS) call, first compression, and shock delivery.

Results:
We analyzed videos of 133 laypersons skill tested 3 months after initial training; 64 trained using the 2010 guidelines (mean ±standard deviation (SD) age: 40 ±11 years, male sex: 19 (30%)) and 69 trained using the 2015 guidelines (age: 44 ±10 years, male sex: 36 (52%)). Participants in the 2015 guidelines group improved the retention of the BLS/AED algorithm compared to the 2010 guidelines group (29 (42%) vs. 10 (16%), relative risk (RR): 2.7 (95% confidence interval (CI): 1.4 - 5.1) P=0.001). Both BLS/AED algorithm and all skills were correctly performed by 13 (19%) vs. 3 (5%) (RR: 4.0 (95% CI: 1.2 - 13.5) P=0.01) in the 2015 and 2010 groups respectively. No significant difference was found in time to EMS call (difference: 3 sec (95% CI: -2 - 9 sec) P=0.27), time to first compression (difference: 4 sec, (95% CI: -3 - 10 sec) P=0.28), and time to first shock (difference: 4 sec (95% CI: -5 - 14 sec) P=0.33) between the groups.

Conclusion:
BLS/AED training using ERC 2015 guidelines was associated with better skill retention compared to training using ERC 2010 guidelines. There was no difference in time to EMS call, first compression, or shock delivery.
Abstract 142: Partnering With Survivors and Families to Set Cardiac Arrest Research Priorities: Moving Towards More Patient-Oriented Resuscitation Research
Authors: Dainty Katie N , Morrison Laurie J , Vaillancourt Christian , Sinclair Doug , Laupacis Andreas , Goldstein Judah , Church Matthew , Christenson Jim , Seaton Bianca
Published: June 2021

Background:
“Priority setting” is something that we do in research in order to get a range of opinions on what research questions are the most important or timely in a particular field. This is typically done with a group of expert health care providers and researchers and has not involved patients, family or the public.

Methods:
With funding from the Canadian Institutes of Health Research we partnered with the James Lind Alliance (JLA) in the UK to use their proven consensus methodology to build a Public Priority Setting Partnerships (PSP) on out-of-hospital Cardiac Arrest (OHCA). We developed and administered two rounds of online surveys with survivors, family members and health care professionals to create the initial priority lists. From there we held a full-day in-person workshop to come to consensus on the top 10 priorities from a short list of 25. The workshop also included survivors, family members and health care professionals.

Results:
The initial survey yielded more than 425 responses and 1500 “questions”/comments from survivors, family members, lay responders, physicians, nurses, rehabilitation specialists, paramedics, etc. The second survey asked participants to rank a narrowed list of 125 questions. The final top 25 questions were brought to the in-person consensus meeting and a top 10 were selected. The results will be revealed publicly for the first time at the ReSS meeting.

Conclusions:
The JLA methodology is world-renowned for its rigor and we now have an official PSP on OHCA. This type of inclusive research priority setting provides crucial information for the AHA and the international resuscitation research community about where to invest our limited research resources. The results will also drive our community to include questions that matter to SCA survivors and their families in all of our work.
Abstract 147: AED on the Fly: A Drone Delivery Feasibility Study for Rural and Remote Out-Of-Hospital Cardiac Arrest
Authors: Cheskes Sheldon , Snobelen Paul , McLeod Shelley , Brooks Steven , Vaillancourt Christian , Chan Timothy , Dainty Katie N , Nolan Mike
Published: June 2021

Introduction:
Time-to-treatment plays a pivotal role in survival from sudden cardiac arrest (SCA). Every minute of delay in defibrillation results in a 7-10% reduction in survival. Time to defibrillation is particularly problematic in rural and remote regions, where traditional bystander and EMS response is often prolonged and automated external defibrillators (AED) are often not available. The objective of this study was to examine the feasibility of a novel AED drone delivery method for rural and remote SCA. A secondary objective was to compare times between AED drone delivery and ambulance response to various mock SCA resuscitations.

Methods:
We conducted four simulations to determine the feasibility of AED drone delivery to mock SCA resuscitations in a rural public setting in Ontario, Canada. During each simulation, a “mock” call was placed to 911 and a single AED drone and an ambulance were simultaneously dispatched from the same location to a pre-determined destination for a mock SCA. Once on scene, trained first responders retrieved the AED from the drone and initiated resuscitative efforts on a manikin until paramedics arrived.

Results:
The distance from dispatch location to scene varied from 6.6 kms to 8.8 kms. Mean (SD) response time from 911 call to arrive at mock code location was 11.2 (1.0) for EMS compared to 8.1 (0.1) minutes for AED drone delivery. In all four simulations, the AED drone arrived before EMS, ranging from 2.1 minutes to 4.4 minutes faster. Mean (SD) time from AED removal from drone to application to manikin by a trained responder was 35(5) sec. No difficulties were encountered in drone activation by dispatch, drone lift off, landing or removal of the AED from the drone by responders.

Conclusions:
This implementation study suggests AED drone delivery is feasible with improvements in response time during a simulated SCA scenario. These results suggest the potential for AED drone delivery to decrease time to first defibrillation in rural and remote communities. Further research is required to determine the appropriate distance for drone delivery of an AED in an integrated EMS system as well as optimal strategies to simplify bystander application of a drone delivered AED.
Abstract 149: Double Sequential External Defibrillation in Refractory Ventricular Fibrillation: The Dose VF Pilot Randomized Controlled Trial
Authors: Cheskes Sheldon , Dorian Paul , McLeod Shelley , Scales Damon , Pinto Ruxandra , Turner Linda , Morrison Laurie J , Drennan Ian R , Verbeek Richard
Published: June 2021

Background:
Despite significant advances in resuscitation efforts, there are some patients who remain in ventricular fibrillation (VF) after multiple defibrillation attempts during out-of-hospital cardiac arrest (OHCA). Double sequential external defibrillation (DSED) and vector change defibrillation (VC) have been proposed as alternate therapeutic strategies for OHCA patients in shock-refractory VF.

Objective:
To determine the feasibility, safety and sample size required for a larger, multicentered, 3-arm, cluster randomized controlled trial (RCT) with 2 crossovers comparing DSED or VC to standard defibrillation (control group) for OHCA patients presenting in shock-refractory VF.

Methods:
We conducted a pilot cluster randomized controlled trial with crossover including all consecutive treated adult OHCA patients who presented in VF and received a minimum of three successive shocks. In addition to standard cardiac arrest care, each EMS agency was randomly assigned to provide standard defibrillation (control), DSED, or VC, followed by crossover to an alternate defibrillation strategy after 6 months.

Results:
Prior to the launch of the trial, 2,500 paramedics received in-person training in the techniques of DSED and VC defibrillation using a combination of didactic, video and simulated scenarios. Between March 2018 and June 2019, 113 patients were enrolled in 4 Canadian EMS agencies, with zero missed cases. Monthly enrollment varied from 1 to 6 cases per agency. With respect to feasibility, 96% of cases were compliant with the study protocol, and only five (4.4%) cases received a defibrillation strategy that differed from the allocation schedule. There were no reported cases of defibrillator malfunction, no concerns expressed by paramedics, patients, families, or ED staff about the trial, and no reported cases of skin burns or difficulty with pad placement.

Conclusions:
Findings from our pilot implementation trial suggest the DOSE VF protocol is feasible and safe. The results of this internal pilot trial will allow us to calculate a sample size for a definitive multicenter cluster RCT with crossovers to determine if these alternate defibrillation strategies for OHCA shock refractory VF will impact patient-centered, clinical outcomes.
Abstract 151: Software Annotation of Defibrillator Files: Ready for Prime Time?
Authors: Gupta Vishal , Schmicker Robert , Owens Pamela , Aramendi Elizabete , Idris Ahamed
Published: June 2021

Introduction:
Defibrillators record important information about the quality of chest compressions during CPR. Software made for reviewing defibrillator files automatically annotate and measure chest compression metrics. However, evidence is limited regarding the accuracy of such measurements.

Objective:
To compare chest compression fraction (CCF) and rate measurements made with software annotation vs. manual annotation of defibrillator files.

Methods:
This is a retrospective, observational study from the Dallas Fort-Worth site of the Resuscitation Outcomes Consortium. We reviewed chest compression waveforms from the bioimpedance channel of defibrillator recordings (Physio-Control Lifepak 12 and 15, Redmond, WA) of 100 prehospital patients enrolled in the DFW Cardiac Arrest Registry from 9/8/2018 to 3/9/2019. Included cases were ≥18 years, had presumed cardiac cause of arrest, and continuous chest compressions. We assessed chest compression waveforms from the time of initial CPR until the time the defibrillator was removed. A trained reviewer revised the software annotations by marking the start and end of CPR and adding or removing chest compressions. Software annotated and manual reviewer annotated measurements were compared for CCF and rate using intraclass correlation coefficient (ICC) statistical analysis.

Results:
Mean patient age was 63 years with 59% male. The mean (±SD) duration of CPR was 30.4 ± 10.6 min. The overall mean CCF for files annotated by software vs. manual annotation was 0.64 ± 0.19 vs. 0.86 ± 0.07, respectively, and the ICC was 0.14. For software vs. manual annotation, the overall mean rate was 109 ± 10 vs. 108 ± 10, respectively, and ICC was 0.99. The software misidentified epochs before the start of chest compressions, failed to capture epochs after resuscitation ended, and after return of spontaneous circulation, resulting in low ICC for CCF. The ICC was excellent for compression rate because the software only counted epochs where chest compressions were actually given.

Conclusions:
Software annotation performed poorly for chest compression fraction and very well for chest compression rate. Defibrillator files must be reviewed and annotated manually before quality of chest compression measurements are calculated.
Abstract 16: Dispatched Citizen Responders Perform Three Out of Four of all Bystander Defibrillated Out-Of-Hospital Cardiac Arrests in Residential Areas
Authors: Andelius Linn , Malta Hansen Carolina , Lippert Freddy , Torp-pedersen Christian , Karlsson Lena , Gislason Gunnar H , Folke Fredrik
Published: June 2021

Introduction:
Bystander defibrillation has increased in public locations but remained stagnated around 2% in private homes, where most out-of-hospital cardiac arrests (OHCAs) occur.

Hypothesis:
Dispatching citizen responders through a smartphone application can increase bystander defibrillation in residential OHCAs.

Methods:
From September 2017-2018, a total of 23,117 (1,284/100,000) citizen responders and 5,225 (290/100,000) automated external defibrillators (AEDs) were registered in the Capital Region of Denmark (1.8 mil. inhabitants). In case of suspected OHCA, up to 20 citizen responders <1.8 km (1.1 miles) from the OHCA were alerted and dispatched to either start cardiopulmonary resuscitation (CPR) or to retrieve an AED. Activated citizen responders received a survey where they reported whether they arrived before Emergency Medical Services (EMS) and defibrillated the patient.

Results:
Of 433 consecutive OHCAs included, 354 (81.8%) were residential OHCAs. Compared with citizen responders in public locations, those in residential areas were a median of 100m further away from OHCAs but were equally likely to arrive before EMS (~40% of both residential and public OHCAs). A total of 9.3% (33 of 354) of all residential OHCAs were bystander defibrillated. Citizen responders were responsible for 75.8% (25 out of 33) of all bystander defibrillated OHCAs in residential areas compared to 50.0% (13 out of 26) of all bystander defibrillated OHCAs in public areas (Table 1).

Conclusions:
Dispatched citizen responders arrived before EMS in 40.1% (142 of 354) of all residential OHCAs and performed three out of four of all bystander defibrillated OHCAs in residential areas.
Abstract 166: Physiological Effects of Adrenaline in Human Cardiac Arrest With Pulseless Electrical Activity: A Pilot Study
Authors: Bakke Magnus , Borgen Alexander , Norvik Anders , Skjeflo Gunnar W , Irusta Unai , Dybos Tannvik Tomas , Bergum Daniel , Aramendi Elisabete , Eftestol Trygve , Skogvoll Eirik
Published: June 2021

Introduction:
During resuscitation from cardiac arrest with Pulseless Electrical Activity (PEA), studies show that adrenaline facilitates return of spontaneous circulation (ROSC) and possibly leads to an isolated increase in the heart rate (HR). In this study, we investigated the immediate effects of adrenaline on ECG characteristics; HR and QRS duration (duration of ventricle depolarization).

Method:
We studied 19 ECG segments of 300 s duration from emergency defibrillators in 10 adult patients during resuscitation from in-hospital cardiac arrest. Information on the exact timing of adrenaline administration (between 0.5 and 1 mg i.v.) was obtained from the defibrillators or the emergency personnel involved. HR (1/min) and QRS duration (ms) were annotated and registered using an ad-hoc Matlab (Mathworks, Natic, MA) graphical Data Annotator, and interpolated linearly between individual observations. Trends were identified with LOWESS.

Results:
The plots show the individual observations (red points) along with the trends (blue lines) of HR and QRS Duration during resuscitation, relative to the time of adrenaline administration. We observed a gradual increase in heart rate (peaking at 150 s after adrenaline administration) and a more pronounced narrowing of the QRS (levelling off also at about 150 s).

Discussion:
In this pilot study, administration of adrenaline was associated with narrowing of the QRS complex, while the relation to heart rate was less apparent. A limitation is that no adjustment for the individual patient’s trajectory was made. However, the results are fairly consistent with earlier studies on out-of-hospital resuscitation, when adrenaline was typically given much later.