Cardiopulmonary Resuscitation Research Articles

Abstract Su506: A Comparison of Synchronized Versus Unsynchronized Mechanical Chest Compressions in a Swine Model

Background: The proportion of cardiac arrest presenting with pulseless electrical activity (PEA), which includes pseudo-PEA, is increasing and survival remains dismal. We hypothesized that mechanical chest compressions synchronized to native cardiac contractions improve coronary perfusion pressure (CPP) during resuscitation of pseudo-PEA. Methods: We developed a model of pseudo-PEA by infusing high dose esmolol intravenously into anaesthetized, intubated, and central arterial and venous catheterized swine to a goal of 45 mm Hg mean arterial blood pressure (MAP). We then provided alternating synchronized and unsynchronized chest compressions for 52 seconds preceded by 8 second breaks consecutively four times. We repeated the protocol two to three times with one minute breaks after each four minute block. Synchronized compressions were provided 1:1 with native contractions during systole and unsynchronized compressions were provided at 100 beats per minute (BPM). We measured average CPP, MAP, and heartrate (HR) for 5 beats immediately preceding the onset of chest compressions and for 30 seconds 10 seconds after the onset of compressions. We computed the difference in continuous CPP during compressions compared to the immediately preceding baseline for each interval. We developed a mixed linear model with outcome variable average CPP during compressions minus baseline, fixed variable compression type, and random variable animal. Results: We included four animals. Mean baseline HR was 78.9 BPM, MAP 55.2, and CPP 44.0. Chest compressions increased CPP from baseline an average 4.0 mm Hg when unsynchronized and 6.4 mm Hg synchronized. The adjusted difference was 2.5 mm Hg (95% CI 0.3 – 4.6). Conclusions: Synchronized chest compressions significantly increased CPP 2.5 mm Hg (62%) more than unsynchronized chest compressions despite a lower compression rate in a medication-induced swine model of pseudo-PEA. Further refinement and application to patients suffering pseudo-PEA cardiac arrest appear warranted.

Abstract Su405: Effect Of A Visual Feedback Device On The Acquisition Of Cardiopulmonary Resuscitation Skills In Training Certified By The American Heart Association: Randomized Clinical Trial

Background: High-quality cardiopulmonary resuscitation (CPR) is fundamental for the success in the care of cardiorespiratory arrest. In CPR skills training, manequins with feedback on quality parameters have been employed and received varied evaluative results. The American Heart Association (AHA) encourages the use of feedback devices in CPR training; however, its effects have not been evaluated in courses certified by it. Research Questions: Training with visual feedback devices alters the learning of students in acquiring psychomotor skills in CPR? Goals: To evaluate the effect of a visual feedback device on CPR training, in AHA certified courses. Methods: A randomized clinical trial was conducted to estimate the intervention of a visual feedback device in practical CPR training for nurses, medical students and physicians in the Advanced Cardiovascular Life Support (ACLS) courses. For that, having as parameters the quality criteria determined by the AHA, we tried to compare the performance results of the trained students with objective feedback from the device and the trained students with subjective feedback from the instructor. Statistical analysis included chi-square test, Student's t test, Mann-Whitney u test, Spearman’s-rho correlation coefficient. Significance level considered was 0.05. A survey was registered with ClinicalTrials®, under resgistration NCT 04338490. Results: The sample consisted of 209 students; of these 119 (56.9%) were women, and 148 (70.8%) were physicians. The control group had 98 students, and the intervention group 111 students. The performance of students from both groups reached the criteria of quality in CPR. The group trained with a feedback device achieved, according to guidelines, better results in the rate of chest compressions, 78 (70.3%) versus 48 (49.0%), p <0.01, and in return of the chest 100 (91; 100) versus 99 (78.25; 100), p <0.03. As for the recommended compression fraction, 60% to 80%, both groups were above 60%; however, no student in the study reached 80%. Conclusions: The visual feedback device was effective in CPR training, improving students’ performance in the criteria of compression rates between 100 and 120/min and total return of the chest between compressions.

Abstract Su806: Enhancing Cardiac Arrest Registries and Research – A Framework for Handling Defibrillator Data

Background: Cardiac arrest is the most time-sensitive medical condition, and survival probability is highly dependent on early, high-quality cardiopulmonary resuscitation (CPR) measures. Resuscitation registries are established tools for continuous quality improvement and serve as a source for research. Yet they lack comprehensive information on the quality of CPR measures themselves—such as the depth, rate, and release of chest compressions—and are limited in the temporal resolution of these measures. However, data on both are contained in the recordings of defibrillators. Aims: To develop a framework for healthcare providers to gain immediate case-specific feedback, reduce documentation efforts and make fine-grained information accessible for research. Approach: An open-source Python module named CPRDAT (Kern et al. Zenodo, https://doi.org/10.5281/zenodo.10057964) was designed. This module is capable of importing and extracting data from various defibrillators as well as data recorded by VitalRecorder ( VitalDB , Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul, Korea) into a uniform data object. Methods were implemented to automatically process, analyze, and aggregate these time-series of physiological signals, with particular attention to CPR. To reduce manual annotation workload, classification algorithms were developed. Plotting routines were developed to display the signals interactively in web applications, allowing healthcare providers to interact with the data through zooming, scaling, shifting, concatenating, merging and labelling. Results: The module was implemented into the German Resuscitation Registry, offering users a manufacturer-agnostic, data-driven, case-specific debriefing tool. Extracted information on CPR measures is stored in the registry. The framework, able to manage multiple time-series data sources, was further implemented in other settings, such as the analysis of laboratory data of a CPR swine model. Conclusions: The new module dramatically enhances the accessibility of physiologic time-series recordings. More fine-grained data will provide deeper insights into processes and CPR physiology. Finally, the open-source Python module abolishes barriers in research.

A new method to predict return of spontaneous circulation by peripheral intravenous analysis during cardiopulmonary resuscitation: a rat model pilot study.

Enhancing venous return during cardiopulmonary resuscitation (CPR) can lead to better hemodynamics and improved outcome after cardiac arrest (CA). Peripheral Intravenous Analysis (PIVA) provides feedback on venous flow changes and may indicate an increase in venous return and cardiac output during CPR. We hypothesize PIVA can serve as an early indicator of increased venous return, preceding end-tidal CO2 (etCO2) increase, before the return of spontaneous circulation (ROSC) in a rat model of CA and CPR. Eight male Wistar rats were intubated and ventilated, and etCO2 was measured. Vessels were cannulated in the tail vein, femoral vein, femoral artery, and central venous and connected to pressure transducers. Ventilation was discontinued to achieve asphyxial CA. After 8min, CPR began with ventilation, epinephrine, and automated chest compressions 200 times per minute until mean arterial pressure increased to 120mmHg. Waveforms were recorded and analyzed. PIVA was calculated using a Fourier transformation of venous waveforms. Data are mean ± SE. Maximum PIVA values occurred in the tail vein 34.7 ± 2.9s before ROSC, with subsequent PIVA peaks in femoral vein and centrally at 30.9 ± 5.4 and 25.1 ± 5.0s, respectively. All PIVA peaks preceded etCO2 increase (21.5 ± 3.2s before ROSC). PIVA consistently detected venous pressure changes prior to changes in etCO2. This suggests that PIVA has the potential to serve as an important indicator of venous return and cardiac output during CPR, and also as a predictor of ROSC.

Abstract Su402: Comprehensive Assessment of Chest Compression Quality Across All Phases of Prehospital Care Using a Manikin

Background: High-quality cardiopulmonary resuscitation (CPR) is crucial for improving the prognosis of out-of-hospital cardiac arrest (OHCA) patients. The quality of chest compressions may vary during different phases of prehospital care. Objectives: To investigate changes in chest compression quality during prehospital activities and identify the causes. Methods: Eleven emergency medical teams of three members each participated. Using a manikin (Laerdal QCPR), we measured achievement rates of compression depth (≥5 cm) and recoil, compression rate, and chest compression fraction (CCF). The process from the scene to the hospital bed was divided into four phases: 1) on-site, 2) transport from the scene to the ambulance (canvas stretcher), 3) in the ambulance, 4) transport from the ambulance to the hospital bed (wheeled stretcher). We analyzed the quality changes in chest compressions and the causes of degradation or interruptions. Each team performed both manual CPR (Man-CPR) and mechanical CPR (Mech-CPR) using the LUCAS3 device. The scenario assumed cardiac arrest on the second floor, transport down stairs to the ambulance, and a 15-minute drive to the hospital. ACLS was established in Phase 1 and continued until hospital arrival. In Mech-CPR, a mechanical CPR device was applied in Phase 1 and used throughout all phases. Results: Man-CPR showed lower compression depth achievement in Phases 2 and 4 compared to Phases 1 and 3, mainly due to transport transitions (Fig. 1). CCF was high in Phases 1 and 3 but decreased in Phases 2 and 4 due to these transitions. Interruptions in Phases 1 and 3 were due to checking ECG rhythm, securing an airway, and confirming ventilation. Recoil achievement was low across all phases. Mech-CPR showed high achievement rates for compression depth and recoil across all phases and maintained high CCF. However, Man-CPR had a higher CCF in Phase 1 than Mech-CPR due to interruptions for device application. Mech-CPR had no degradation due to dual work, but improper application caused long degradations and interruptions. The longest interruption times were 69 seconds (transport) for Man-CPR and 25 seconds (device application) for Mech-CPR. Both Man-CPR and Mech-CPR maintained compression rates within the guideline range of 100-120/min, with Man-CPR tending to be faster. Conclusion: Chest compression quality varies from the scene to hospital arrival. Man-CPR and Mech-CPR have different causes of quality changes and interruptions.

Abstract Su203: Development of Bioimpedance for the Measurement of Ventilation During Cardiopulmonary Resuscitation

Introduction: Previous studies have shown that ventilation during cardiopulmonary resuscitation (CPR) produces better patient outcomes. However, research regarding ventilation during the early stages of basic life support CPR is limited. Prior studies showed that thoracic bioimpedance, recorded by the LifePak 12 defibrillator device, can be used to count ventilations with a tidal volume at least 250 mL during CPR. However, the relationship between thoracic bioimpedance and tidal volume has yet to be studied for the Phillips MRx device, excluding a large data set from ventilation studies. Hypothesis: Bioimpedance, measured by the Phillips MRx device has a linear relationship with tidal volume. Aims: To determine the relationship between bioimpedance measured by the Phillips MRx device and tidal volume in males and females. Methods: We conducted the study in a respiratory laboratory at a University Hospital. We asked 27 volunteers to breathe fixed volumes (250 mL, 300 mL, 400 mL, 600 mL, and 800 mL) delivered by a mechanical ventilator while recording bioimpedance simultaneously with the Philips MRx monitor-defibrillator through electrode pads placed on the chest. Six measurements of bioimpedance waveform amplitudes (Ohms) were taken at each tidal volume. Results: Of 27 volunteers, 11 were female and 16 were male. In the female sample set, a linear equation of y=0.003x + 0.837 with an R^2 value of 0.9995 was calculated. In the male sample set, a linear equation of Y=0.0016x +0.1039 with a R^2 value of 0.995 was calculated. Females had a higher median bioimpedance amplitude than men at each tidal volume, and a steeper linear regression slope. At the minimum threshold tidal volume used for counting ventilations (250 mL), the median bioimpedance amplitude was 0.5 (0.4, 0.6) ohm for males and the median bioimpedance amplitude was 0.8 (0.6, 1) ohm for females. Conclusion: As measured and recorded with the Philips MRx monitor-defibrillator, there is a linear relationship between tidal volume and thoracic bioimpedance. The linear models created in this study can be used in future studies to count ventilations during CPR using the Philips MRx device.

Abstract 4144566: Building CPR/AED Confidence through Community Volunteer Prevention Screening Sessions: The Impact of the Eric Paredes Save A Life Foundation

Introduction: Sudden cardiac arrest (SCA) remains a leading cause of death among young individuals, often occurring without prior symptoms. Public confidence in recognizing SCA warning signs, understanding risk factors, and using cardiopulmonary resuscitation (CPR) and Automated External Defibrillators (AEDs) is generally low. The Eric Paredes Save A Life Foundation addresses this gap by offering free cardiac screenings and educational sessions. This abstract evaluates the foundation's impact on participants' confidence in these critical areas. Goals: The primary objectives were to enhance participants' confidence in identifying SCA warning signs and risk factors, performing CPR, using AEDs during cardiac emergencies, and communicating youth heart health concerns to healthcare providers. Methods: Volunteer-led prevention screening sessions were conducted, incorporating educational components on SCA warning signs, risk factors, and hands-only CPR and AED training. Post-session surveys were administered to 1,123 participants to assess their confidence levels in these areas. Results: The screening sessions significantly increased participants' confidence. Specifically, 96% of participants reported heightened confidence in recognizing SCA warning signs and understanding risk factors. Additionally, 94% felt more assured in discussing youth heart health with providers. Confidence in performing CPR during a cardiac emergency rose to 92%, while confidence in using an AED reached 89%. These results demonstrate the effectiveness of the sessions in empowering individuals with essential life-saving skills. Conclusions: The Eric Paredes Save A Life Foundation's prevention screening sessions are highly effective in improving participants' confidence in recognizing SCA warning signs, understanding risk factors, and using CPR and AEDs. The substantial increase in confidence levels underscores the importance of community-based education and training programs in reducing SCA-related fatalities among youth. These findings support the need for ongoing and expanded initiatives to further enhance public health outcomes and preparedness for cardiac emergencies.

Abstract Su502: Is 80% a Reasonable Minimal Goal for Defibrillation Efficacy of Out-of-Hospital Cardiac Arrest ?

Introduction: There is no clear goal defined by standards or learned societies on clinical performance related to defibrillation efficacy. In literature, monophasic shocks defibrillation efficacy is mainly >70% whereas biphasic is >80%. Resuscitation guidelines define efficient defibrillation as cessation of shockable rhythm at 5s post-shock and proceed to state that beyond 5s, shock outcomes are biased by known confounders (call to AED connection time (CallAEDTime), bystander, cardio-pulmonary resuscitation (CPR), drugs…). Thus, it is consistent that automated external defibrillator (AED) performance should be assessed in terms of defibrillation efficacy right after the shock rather than in terms of restoration of a spontaneous circulation or survival to hospital discharge. This study aimed to define an acceptable goal for validation of defibrillation efficacy. Method: In this observational retrospective study, we included AED tracings of adult non-traumatic out-of-hospital cardiac arrest (OHCA) patients with initial ventricular fibrillation (VF) rescued by basic life support teams (Paris Fire Brigade) from 01/2017 to 02/2022. Cardiac rhythm was examined during the 10 first minutes of connection of the AED (DGT7, Schiller Médical, France). Shockable rhythm is defined as coarse-VF with at least 200µV peak-to-peak amplitude (ptpA). Efficient defibrillation was defined as cessation of shockable rhythm at 5s post-shock. We fitted a linear mixed model to predict defibrillation efficacy using the 4s ptpA of pre-shock VF. The model included the patient as random effect and a p-value <0.05 was considered statistically significant. Results: We analyzed 1333 shocks from 547 patients, with: median age of 59 (interquartile range, IQR[49-71]), 78% male, 36% in public places, 72% with bystander CPR and median[IQR] CallAEDTime of 13min [10-15]min. The effect of the pre-shock ptpA of VF on the defibrillation efficacy is statistically significant: OR=1.023, 95% Confidence Interval (CI) [1.010,1.036], p<0.001. That means that for each 100µv increment in VF amplitude pre-shock, the probability of success at 5s post-shock increases by 2.3%. Adjusting for age, sex, location, CPR and CallAEDTime does not change the results. The logistic regression of Figure1, shows a defibrillation efficacy at 200µV ptpA of 79%, CI [75,82]%. Conclusion: Based on 1333 OHCA biphasic shocks, this study suggests defining 80% as a reasonable minimal goal for validation of the AED defibrillation efficacy.

Abstract Su605: Return of Spontaneous Circulation after Transport with Ongoing Cardiopulmonary Resuscitation: Is Transport Always Futile?

Introduction: Despite validated Termination of Resuscitation (TOR) rules for Out of Hospital Cardiac Arrest (OHCA) some OHCA patients are transported prior to Return of Spontaneous Circulation (ROSC), sometimes with long transport times. There are certain therapies unavailable in the prehospital setting which could make transport prior to ROSC beneficial for some OHCA patients. Hypothesis: We hypothesized that longer transport times for patients with ongoing Cardiopulmonary Resuscitation (CPR) would be associated with progressively lower probability of achieving ROSC. Aims: To determine if there is a transport time interval beyond which ROSC becomes so unlikely that transport time could be determinant factor for TOR. Methods: We performed a retrospective study of the 2020-2022 NEMSIS national prehospital dataset. We included adult OHCA patients that did not have ROSC prehospital, were transported to the hospital, and had outcome and timestamp data available. We calculated transport time for each encounter and stratified encounters into 5-minute transport time intervals. We defined our outcome as ROSC after transport. We used multivariable logistic regression evaluating the association between 5-minute increases in transport time and ROSC. We performed a secondary analysis of patients that met termination of resuscitation (TOR) criteria (unwitnessed OHCA with no CPR or AED placement prior to EMS arrival). Results: Of 1,409,692 OHCAs, we included 137,957 OHCAs that were transported without prehospital ROSC. The median transport time was 8.9 minutes (IQR 5.4-13.8), and 17,957 (13.1%) had ROSC after hospital arrival. In 5-minute intervals from 0-30 minutes, ROSC rates were 13.5%, 13.1%, 12.0%, 11.1%, 12.1%, and 13.9%. Odds of ROSC per 5-minute increase in transport time was 1.00 (95% CI 1.00-1.00). For patients that met field TOR criteria, rates of ROSC for each 5-minute interval from 0-30 minutes were 9.2%, 8.7%, 7.6%, 5.9%, 6.1%, 4.2%, 7.5%. Odds of ROSC per 5-minute increase in transport time was 0.93 (95% CI 0.88-0.98). Conclusion: In this dataset we were unable to identify a transport time interval up to 30 mins beyond which transport is futile, even in patients who were transported despite meeting the universal TOR rule. Decision to transport based on case-by-case OHCA characteristics could have influenced results. Further research is needed to identify the subset of patient in whom transport prior to ROSC may be beneficial.

Abstract Su907: Post-Cardiac Arrest Potassium Abnormalities Associated With Unfavorable Functional Outcome

Background: Abnormal potassium levels are common findings in the intensive care unit (ICU) population. We aimed to determine the incidence of dyskalemias at ICU admission and their association with functional outcome in comatose patients resuscitated from cardiac arrest. Hypothesis: We hypothesized that both hypokalemia and hyperkalemia are associated with unfavorable functional outcome. Methods: Pooled data from four randomized clinical trials in comatose post-cardiac arrest patients admitted to ICU after return of spontaneous circulation (ROSC). Reference potassium levels were defined as between 3 and 4.9 mmol/L, as proposed in the Simplified Acute Physiology Score II. Favorable functional outcome was defined as a Cerebral Performance Category of 1 or 2 at 180 days. Results: We included 1133 patients (557 from HYPERION, 346 from TTH48, 120 from COMACARE and 110 from Xe-HYPOTHECA) with a median age of 64 (IQR: 55-72) years and a predominance of males (72%). Overall, 421 (36%) patients had favorable functional outcome. On admission, 221 (19.5%) patients experienced hyperkalemia and 35 (3.1%) patients experienced hypokalemia. More patients in the normokalemia group (364/877, 41.5%) had a favorable functional outcome, as compared to the hypokalemia (11/35, 31.4%) and hyperkalemia (41/221, 18.6%) groups p<0.001). In a mixed-effects logistic regression model including initial rhythm, delay from collapse to ROSC, bystander cardiopulmonary resuscitation, lactate, and urea and with normokalemia as reference group, hyperkalemia was associated with higher odds for unfavorable functional outcome (OR 1.85, 95% CI 1.10-3.12, p=0.02) whereas hypokalemia was not (OR 1.36 95% CI 0.51-3.60, p=0.53). Conclusions: One fifth of unconscious cardiac arrest patients experienced dyskalemia on ICU admission. Hyperkalemia was associated with unfavorable functional outcome at 180 days compared to normokalemia, whereas hypokalemia was not an independent predictor of outcome.

Abstract 4146302: NETosis Attenuating Nanoprobe Improves Survival after Cardiac Arrest

NETosis, the process of neutrophil cell death due to the formation and release of neutrophil extracellular traps (NETs) has been implicated in the pathogenesis of heart disease. NETs are composed of immunogenic DNA fragments and citrullinated histones. The role of NETosis in the context of cardiac arrest and resuscitation (CA/R) is however unknown. We previously reported the development of a Dextran-Thiazole Orange (DTO) nanoprobe, with nanomolar affinity for nucleic acids, that exerts acute anti-inflammatory effects and reduces ischemia-reperfusion injury in mice. We aimed here to determine whether the DTO nanoprobe would also bind to the nucleic acid in NETS, whether DTO could attenuate the intensity of NETosis, and whether this would improve outcomes and survival after cardiac arrest. C57Bl6 mice were arrested for 8 minutes before resuscitation. DTO or unmodified dextran (vehicle control) was injected at the time of resuscitation, and again 4 hours later (n=38 mice). Survival and neurological function were scored daily. Time-domain resolved (lifetime) and conventional fluorescence imaging was performed at 4 hours after resuscitation in 6 additional mice injected with DTO. NETosis was evaluated by protein blot in the hearts of cardiac arrest mice injected with DTO or control. DTO significantly (p<0.05) improved 10-day survival (Fig. A), mean survival (from 4 to 7 days, Fig. B), and neurological function (Fig. C) following CA/R. Lifetime imaging (Fig. D), but not conventional fluorescence imaging (Fig. E) revealed the presence of DTO in the injured heart, liver and kidneys. In the heart, DTO signal was significantly increased in CA/R compared to sham mice injected with DTO or CA/R mice injected with control dextran (Fig. F). Citrullinated H3 and HMGB-1 (High mobility group box 1, a chromatin protein) were both upregulated in CA/R, and were significantly attenuated by DTO injection (Fig. G-I). We show for the first time that NETosis plays a key role in cardiac arrest and resuscitation. DTO is capable of detecting NETosis as well as attenuating it, likely via a reduction in HMGB-1 activity. The modulation of NETosis may provide a new avenue to improve survival after cardiac arrest.

Abstract 4118415: Device Dislodgement and Embolization associated with a New Leadless Pacemaker

Background: Leadless pacemakers (LP) avoid the pocket and lead-related complications of transvenous pacing. A potential complication of LPs is dislodgement and/or embolization (D/E) during or after implant. No D/E occurred in the original 725-patient Micra™ VR clinical trial. However, in the 526-patient LEADLESS II-phase 2 trial, the rate of dislodgement for 200 Aveir™ VR LPs was 1.5%. Thus, there appears to be a significant difference in D/E rates between these LPs that have different fixation mechanisms and insertion tools. Aims: We aimed to determine if the Aveir VR LP has continued to exhibit D/E since it was approved by the Food and Drug Administration (FDA) in April 2022. Methods: We queried the FDA's Manufacturers and User Facility Device Experience (MAUDE) database for Aveir D/E that occurred in the U.S. and were reported by the manufacturer from April 2022-December 2023. The number of Aveir VR implants in the U. S. was obtained from the manufacturer's publicly available product performance report. D/E outside the U.S. were excluded. Results: During the 21 months, 55 of 3,139 (1.75%) Aveir VR implants exhibited D/E. More D/E (34;61.8%) occurred during implant, with 18 (52.9%) of these happening after release of the device from the tether mode. Fourteen (41.2%) of the intra-procedural D/E occurred when the device prematurely released from the delivery catheter, and two dislodged during cardiopulmonary resuscitation (CPR). D/E occurred in 21 patients (38.2%) after implant and were signified by loss of pacing or inability to interrogate the device. Four (19%) out of those 21 patients presented with symptomatic bradycardia. The dislodged devices commonly embolized to the pulmonary artery and right atrium/vena cava. LP retrieval was successful in 49 (89%) cases. Thirty-two patients (58.1%) received a new LP, 5 patients were transitioned to a transvenous system, and a replacement device was not specified for 17 (31%) patients. One patient died during implantation due to ventricular fibrillation (VF) not related to D/E. Conclusions: Fixation issues and premature separation of the device from the delivery catheter appear to be responsible for most of these D/E. Studies are needed to determine if impedance or another metric is associated with adequate Aveir fixation. The manufacturer should address the premature separation problem with Aveir. Success of D/E retrieval may be related to tools specific for Aveir. Further studies are needed to compare between the two LPs.

Abstract 4135335: A randomized trial of expedited intra-arrest transfer versus more extended on-scene resuscitation for refractory out of hospital cardiac arrest: the EVIDENCE Study

Background: Refractory out-of-hospital cardiac arrest (OHCA) has poor outcomes. The benefit of expedited intra-arrest transport with ongoing resuscitation versus more extended on-scene resuscitation for refractory OHCA is not clear. Methods: In this Phase III, multi-center (15 hospitals), randomized, controlled trial conducted in Sydney, Australia, we assigned patients with refractory out-of-hospital cardiac arrest to receive either expedited intra-arrest transport, with mechanical cardiopulmonary resuscitation, to a cardiac catherization-capable hospital for coronary angiography and, where available, extracorporeal membrane oxygenation (ECMO) cardiopulmonary resuscitation (ECPR) or more extended on-scene conventional CPR (advanced cardiac life support). Eligible patients were between 18 and 70 years of age, had received bystander CPR, initial rhythm VT/VF/PEA, and did not have a return of spontaneous circulation after 15 minutes of CPR, or three rounds of resuscitation. The primary outcome was survival with a favorable neurologic outcome, defined as a Cerebral Performance Category score of 1 or 2 at hospital discharge. Analyses were performed on an intention-to-treat basis. Results: One hundred and ninety-seven (197) eligible patients were randomized (median age, 57.0 years; 77 [81%] men), 149 VT/VF (76%). Ninety-five were assigned to receive expedited transfer and 102 to receive conventional CPR. Ten patients in the expedited arms and 6 patients in the conventional arm received ECPR at hospital. At hospital discharge, 15 patients (14.7%) in the expedited transfer group (median on scene time 26 mins) were alive with a favorable neurologic outcome, as compared with 15 patients (15.8%) (median on-scene time 36 minutes). This treatment difference was small and statistically insignificant (risk difference -1.1% [95% CI: -12.2% to 10.0%]), adjusted relative risk 0.95 [p=0.87, 95% CI: 0.50 to 1.8]. Conclusions: Among patients with refractory out-of-hospital cardiac arrest, expedited intra-arrest transport did not significantly improve survival with neurologically favorable outcome at discharge compared with more extended on-scene resuscitation. However, clinically relevant differences could still be consistent with our results.

Abstract 4120573: Abrupt cardiac rupture of the patient with ATTR amyloidosis

A Japanese male in his 80s was admitted to our emergency department with chest pain. His prior history was syncope and ventricular tachycardia. Transthoracic echocardiography (TTE) revealed thickening of the basal part of the antero-septal wall and thinning of the basal part of the inferior wall. Coronary angiography (CAG), cardiac MRI and blood test revealed no specific abnormalities. The day before his emergency admission, he visited the cardiology outpatient department for a periodic examination of cardiac hypertrophy. ECG, chest X-ray, and TTE were unchanged from his prior examination. However, that night, he experienced chest pain and was transferred to our hospital. On arrival, his vital signs were critical, with a blood pressure of 70/59 mmHg. ECG indicated ST elevation in antero-lateral leads. TTE detected pericardial effusion, and contrast-enhanced CT identified two focal areas of non-enhancement in the myocardium and pericardial effusion without signs of aortic dissection. CAG revealed no significant stenosis or obstructive lesion. During coronary angiography, the patient deteriorated to asystole. Cardiopulmonary resuscitation and percutaneous pericardial drainage were initiated. Hemorrhagic pericardial effusion was aspirated. Immediate surgical hemostasis was undergone, revealing about 2 cm lacerations and hematoma in the anterior and inferior wall. After surgery, he complained of abdominal discomfort. Esophageal gastrointestinal endoscopy was undergone to investigate the abdominal discomfort, and he was diagnosed with early gastric cancer. Endoscopic submucosal dissection (ESD) was undergone, and histopathological examination revealed adenocarcinoma and eosinophilic amorphous materials deposited in the submucosal vessels. Congo red staining of the submucosal vessels revealed orange-red areas. A technetium-99m pyrophosphatase scintigraphy showed Grade 2 uptake in the heart. Transthyretin (TTR) staining was positive in the specimen from ESD, leading to a diagnosis of TTR amyloidosis. Genetic test for TTR was negative, which led to a diagnosis of wild-type TTR amyloidosis and tafamidis was started. In cases of acute pericardial effusion and/or cardiac rupture, it is imperative to consider cardiac amyloidosis as a potential etiology, in addition to myocardial infarction and aortic dissection, especially in patients with left ventricular wall thickening, neuropathy, or abnormal ECG, also known as “red flag”.

Abstract 4135726: Prospective validation and implementation pilot study of an emergency department heart failure risk stratification tool: STRIDE-HF

Background: We previously found the STRIDE-HF emergency department (ED) risk tool accurately predicted risk of a 30-day serious adverse event (SAE), including 30-day mortality, cardiopulmonary resuscitation, intra-aortic balloon pump insertion, intubation, new dialysis, myocardial infarction, or coronary revascularization. Research question: We sought to prospectively validate STRIDE-HF and describe safety of the deployed model in a clinical pilot. We hypothesized that performance would decrease slightly with prospective evaluation and that real-time risk display would contribute to safe disposition decisions. Goals: 1) To prospectively validate KPCARES-HF across 21 community EDs among ED patients with acute heart failure (AHF) from January 1, 2023 – December 31 st , 2023; and 2) to describe outcomes among patients predicted to be very low risk and discharged home in the clinical pilot. Methods: For prospective validation, we report 30-day mortality rates by risk strata. We assess model performance using area under the receiver operator curve (AUROC) and sensitivity at a key clinical threshold. We describe rates of 30-day SAE among patients predicted to be very low risk and discharged after ED or observation unit care in the clinical pilot. Results: There were 13,274 ED patients in the prospective validation; median age was 76, 50.8% were female, and 44.5% were non-White. We found 11.4%, 24.8%, 31.9%, and 31.9% of patients were very low, low, moderate, and high risk, respectively, while 21.6%, 15.2% and 63.0% were discharged, observed, and admitted, respectively. Among discharged patients, 29.2% and 13.3% were moderate or high risk, respectively, and 30-day mortality rates among these patients were 2.2% and 8.4%, respectively. Among 8,363 admitted patients, 27.7% were very low or low risk. Conclusions: STRIDE-HF maintained high predictive accuracy with prospective validation in this diverse, multi-center cohort. Our findings suggest that use of STRIDE-HF might help better align risk with admission decision and can be safely used to assist providers in identifying patients who may be stable for outpatient care.

Abstract Sa1108: The Aberrant Autophagy-Apoptosis regulation Mediates the Severe Neurological Dysfunction after Cardiac Arrest in Diabetic Mice

Background: Patients with diabetes have lower survival and worse neurological outcome after cardiopulmonary resuscitation (CPR) compared with non-diabetes. Previous studies have mentioned the aberrant autophagy in diabetic mice. However, whether this abnormal autophagy exacerbates neuronal apoptosis and neurological outcome in diabetic mice remains unclear. Methods: Patients were divided into non-diabetic cardiac arrest (CA) patients and diabetic CA patients, and the survival and neurological outcomes at discharge and day 28 after ROSC were compared between these two groups. Diabetic mice were fed with high fat diet (HFD), and CA model was established by inducing ventricular fibrillation electrically. The neurological prognosis was assessed by open field test (OPT), novel object recognition (NOR) and Y-maze. Neuronal apoptosis and autophagy were evaluated by immunofluorescence and western blotting, including TUNEL, cleaved caspase 3, LC3B, p62 and beclin1. Results: Compared with non-diabetic patients, the survival at discharge and at day 28 after ROSC are significantly lower in IHCA patients with diabetes. Meanwhile, the neurological deficits at discharge and at day 28 after ROSC are much severer in diabetic-CA patients. In addition, the lower survival and worse neurological function have been discovered, and the cognition impairment is more significant after ROSC in HFD mice. Neuronal apoptosis is severer in HFD mice. In ND mice, the activated autophagy has been revealed after CA-CPR-ROSC, however, autophagy can not be activated after ROSC in HFD mice since the baseline autophagy is at a higher level when compared with ND mice. Neuronal apoptosis is exacerbated after autophagy inhibition by 3-MA in ND mice, while after autophagy activation by rapamycin in HFD mice, apoptosis is attenuated after ROSC. Conclusion: Diabetes is the risk factor for neurological outcome in IHCA patients. The aberrant autophagy regulation in cortex neurons contributes to the severe apoptosis and neurological deficits after ROSC in diabetic mice.

Abstract Su407: Implementing An Effective Standardized Bystander CPR Protocol For US Golf Courses

Background: A golf course is the fifth most common public place for cardiac arrest (CA). Informal interviews with golfers and golf course personnel revealed striking incomplete and variable knowledge about what to do in the event of a CA on a golf course in accordance with most current bystander resuscitation guidelines. Hypothesis: We hypothesized that the development and implementation of a standardized protocol (called “911-CPR-AED”) for the three most critical first steps to assure aperson’s survival of an on-golf course CA will improve chances of surviving if playing partners, caddies and club staff are well prepared to respond urgently and appropriately to such an emergency. Aim: To successfully implement the standardized “911-CPR-AED” protocol for 4 different golf clubs. Approach: We achieved full support and involvement of the Club Boards, professional staff, club management, grounds crew and membership as well as coordination with local Emergency Medical Systems (EMS) and communications to all golfers and caddies. We created a specific four-panel laminated infographic customized for each club and designed to fit easily into every golfer’s bag and caddy vest, assuring a readily available “911-CPR-AED” guide for lay bystanders to notify EMS and Club staff, immediately initiate chest compressions, ensure rapid delivery of an AED and BLS certified persons to the arrest site, and safely guide EMS on their arrival. We also staged live “dry run’ simulations on the golf courses with all key team members and timed each and every step of the simulation from start to finish. All aspects of this process were shared with leaders of the closest EMS and hospital emergency departments (EDs). Results: Within the past 2 years, we have successfully implemented a standardized emergency resuscitation protocol we call “911-CPR-AED” at 4 different golf clubs for immediate initiation of bystander CPR in the event of full CA on a golf course. Since implementation, we have witnessed 3 CA events and achieved successful full “on course” resuscitations that deployed this protocol for all three survivors who are now back to playing golf. We intend to share the details and many lessons learned for these ongoing efforts. Conclusion: An effective, standard bystander CPR protocol now exists for use at any US golf course. We intend to expand Implementation to 3 new golf courses and will continue to raise awareness and encourage widespread local implementation across the US.

2024 American Heart Association and American Academy of Pediatrics Focused Update on Special Circumstances: Resuscitation Following Drowning: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.

Drowning is the third leading cause of death from unintentional injury worldwide, accounting for 7% of all injury-related deaths. In the United States, drowning is the leading cause of death in children 1 to 4 years of age and second leading cause of death due to unintentional injury in those aged 5 to 14 years. Drowning generally progresses from initial respiratory arrest due to submersion-related hypoxia to cardiac arrest; thus, it can be challenging to distinguish respiratory arrest from cardiac arrest because pulses are difficult to accurately palpate within the recommended 10-second window. Therefore, resuscitation from cardiac arrest due to this specific circumstance must focus on restoring breathing as much as it does circulation. Resuscitation from drowning may begin with in-water rescue breathing when safely provided by rescuers trained in the technique and should continue with chest compressions, in keeping with basic life support guidelines, once the drowned individual and the rescuer are in a safe environment (eg, dry land, boat). This focused update incorporates systematic reviews from 2021 to 2023 performed by the International Liaison Committee on Resuscitation related to the resuscitation of drowning. These clinical guidelines are the product of a committee of experts representing the American Academy of Pediatrics and the American Heart Association. The writing group reviewed the recent International Liaison Committee on Resuscitation systematic reviews, including updated literature searches, prior guidelines related to resuscitation from cardiac arrest following drowning, and other drowning-related publications from the American Academy of Pediatrics and the American Heart Association. The writing group used these reviews to update its recommendations aimed at resuscitation from cardiac arrest following drowning in children.

Abstract Su507: Occurrence of Fibrillation in Out-of-hospital Cardiac Arrest Patients Presenting in a Non-shockable Rhythm when Treated with an Automated External Defibrillator

Background: Most out-of-hospital cardiac arrest (OHCA) patients who are initially treated with an automated external defibrillator (AED) and present in a non-shockable rhythm never receive a shock. This analysis reports on patients who presented in a non-shockable rhythm when the AED was initially applied and later transitioned into a shockable rhythm. Methods: Data from a convenience group of OHCA patients treated with a Philips HeartStart Home, Onsite or FRx AED were included. The AEDs were the first defibrillator on scene either in home, in public access or by a BLS team. Application of any medication during AED use was unlikely. Each patient’s heart rhythms were reviewed by an expert. All patients whose initial rhythm was non-shockable but later received at least one shock were identified and the rhythms were analyzed. Results: Out of 876 patients, 322 (36.8%) received at least one shock, of which five patients (1.6%) presented in a non-shockable rhythm and were later shocked. Three patients presented in an organized rhythm. The first patient degraded into Torsade de Pointe as shown in Figure 1; the post-shock rhythm was organized. The second patient received no CPR and A-V pacing was observed in the ECG recording. The pacing stopped when the rhythm transitioned into VF and restarted post shock. The third patient transitioned into VF during chest compressions and the post-shock rhythm was asystole. The remaining two patients presented in asystole and the rhythm evolved to fine VF after receiving chest compressions. After defibrillation, their rhythms returned to asystole. Conclusions: For OHCA patients treated with an AED, presenting in a non-shockable rhythm and later transitioning into a shockable rhythm is rare but possible. Lay-responder CPR may play a role in rhythm evolvement. The impact of rhythm changes on survivability of these patients is unknown.

2024 American Heart Association and American Academy of Pediatrics Focused Update on Special Circumstances: Resuscitation Following Drowning: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.

Drowning is the third leading cause of death from unintentional injury worldwide, accounting for 7% of all injury-related deaths. The World Health Organization estimates that there are ≈236 000 deaths due to drowning worldwide each year. Significant efforts have focused on creating systems to prevent drowning, but an average of 4000 fatal and 8000 nonfatal drownings still occur annually in the United States-likely an underestimate. Drowning generally progresses from initial respiratory arrest due to submersion-related hypoxia to cardiac arrest; thus, it can be challenging to distinguish respiratory arrest from cardiac arrest because pulses are difficult to accurately palpate within the recommended 10-second window. Therefore, resuscitation from cardiac arrest attributable to this specific circumstance must focus on restoring breathing as much as it does circulation. Resuscitation from drowning may begin with in-water rescue breathing when safely provided by rescuers trained in the technique and should continue with chest compressions, in keeping with basic life support guidelines, once the drowned individual and the rescuer are in a safe environment (eg, dry land, a boat). This focused update incorporates systematic reviews from 2021 to 2023 performed by the International Liaison Committee on Resuscitation related to the resuscitation of drowning. These clinical guidelines are the product of a committee of experts representing the American Heart Association and the American Academy of Pediatrics. The writing group reviewed the recent International Liaison Committee on Resuscitation systematic reviews, including updated literature searches, prior guidelines related to resuscitation from cardiac arrest following drowning, and other drowning-related publications from the American Heart Association and American Academy of Pediatrics. The writing group used these reviews to update its recommendations aimed at resuscitation of cardiac arrest following drowning in adults and children.