Cardiac Arrest Patients Research Articles

Hydrocortisone improves post-resuscitation myocardial dysfunction by inhibiting the NF-κB pathway.

Myocardial dysfunction is a major cause of early mortality after successful cardiopulmonary resuscitation (CPR) following cardiac arrest (CA). Following the return of spontaneous circulation, myocardial ischemia-reperfusion injury can activate the NF-κB pathway, leading to the transcription of inflammatory genes that impair myocardial function. While clinical studies show hydrocortisone (HC) improves outcomes in CA patients during CPR, its specific role in modulating the NF-κB pathway is unclear. In this study, we established an in vitro model by inducing hypoxia/reoxygenation (H/R) injury in H9C2 cardiomyocytes using Na2S2O4, followed by HC treatment. The results showed that HC treatment of H/R-injured cardiomyocytes promoted proliferation, inhibited apoptosis, and suppressed the NF-κB pathway, thereby reducing IL-6, IL-8, and TNF-α levels. Moreover, inhibition of the NF-κB pathway enhanced the proliferative capacity of H/R cardiomyocytes, decreased apoptosis rates, and reduced IL-6, IL-8, and TNF-α expression levels, with these effects being further amplified by HC treatment. These findings were further supported by in vivo experiments. In conclusion, our study suggests that HC may promote H/R cardiomyocyte proliferation, inhibit apoptosis, and alleviate inflammatory responses by suppressing the NF-κB pathway, providing new evidence to support its potential clinical application in CA management.

Abstract Su403: Iterative Simulation to Optimize Mechanical CPR Device Application

Mechanical chest compression devices (MCDs) are commonly used for in-hospital and emergency department (ED) cardiac arrest resuscitation. Manufacturer guidelines and educational materials demonstrate that in the prehospital setting, MCDs can be deployed with an interruption in CPR of less than 15 seconds. No similar materials exist for the in-hospital environment, where observational studies have noted median CPR interruptions of up to 40 seconds for MCD deployment. With the integration of extracorporeal CPR (eCPR) into OHCA systems of care, the need to transfer patients with ongoing CPR to MCDs in the ED is growing. To develop a hospital-specific procedure for receiving a patient in cardiac arrest and deploying the MCD with minimal no-flow time. We used an iterative participatory design process to develop a procedure for receiving patients in cardiac arrest from Emergency Medical Services (EMS). Tasks included transferring a patient, replacing defibrillator pads, and deploying the hospital MCD with minimal no-flow time. Participants including ED physicians, nurses, and respiratory therapists performed a series of simulations using a high-fidelity manikin, resuscitation equipment, and an MCD. Simulations were followed by focused debriefings, participant-directed modification of the working procedure, and repeat simulation until participants expressed satisfaction with the procedure. Participant roles were shuffled after each round. The primary outcome was the duration of CPR interruption required to deploy the MCD; change in this time over successive iterations was assessed using a Wilcoxon signed-rank test. The final procedure described a sequence of steps and responsibilities that participants deemed efficient and reproducible. Through seven simulation-debriefing cycles, CPR interruption associated with MCD deployment decreased from 19 to 10 seconds (p = 0.033). The most common failure modes that participants corrected during modifications involved needed equipment that was out of reach, obstructed provider positioning, and poorly defined roles. On subsequent days, two additional groups of on-shift ED providers deployed the MCD in less than 15 seconds following the developed procedure. Using an iterative design process, we created an MCD deployment procedure that minimized CPR interruptions and was acceptable to hospital staff. This represents an effective, low-cost methodology to design a process for transfer of care during CPR and MCD deployment.

Abstract 4135211: Children with the D801N Variant of the ATP1A3- Encoded Sodium-Potassium ATPase Alpha-3 Subunit Demonstrate Paradoxical QT Response to Bradycardia and Increased Ventricular Arrhythmia Risk

Introduction: Alternating hemiplegia of childhood (AHC) is a rare condition most frequently caused by mutations in ATP1A3, encoding for the alpha-3 subunit of Na + /K + -ATPase, and D801N is the most common variant. Individuals with ATP1A3-D801N have shorter corrected QT (QTc) than those with other variants and can experience ventricular arrhythmias following bradycardia; however, the mechanism of why this occurs is unknown. Goals: To analyze how QT and QTc change with heart rate in ATP1A3-D801N compared to healthy individuals. Hypothesis: Individuals with ATP1A3-D801N have increased shortening of QT and QTc at lower heart rate. Methods: In this retrospective observational study, patients seen for evaluation of AHC at Duke University Medical Center were categorized by genotype: ATP1A3-D801N, ATP1A3 non-D801N single nucleotide variant, ATP1A3 loss-of-function variant, and genotype negative. A cohort of matched healthy children was also compiled. We collected average heart rate, QT, and QTc measurements over 5-minute intervals from Holter recordings using HScribe TM software and conducted manual blinded validation to ensure accuracy. We then used linear regression to investigate the relationship between heart rate, QT, and QTc. Results: The cohort consisted of 44 patients with ATP1A3 -related phenotypes with 81 total Holter recordings (52.27% female; mean age at first Holter 8.04 years), compared to 36 healthy individuals with 57 total Holter recordings (52.78% female; mean age at first Holter 9.84 years). Patients with ATP1A3-D801N showed diminished prolongation of QT with decreasing heart rate, manifested as a reduced mean slope for heart rate vs QT compared to healthy (-0.85 ± 0.46 vs -1.52 ± 0.42, p<0.0001). This blunted QT response resulted in paradoxical shortening of QTc at lower heart rate, demonstrated by an increased mean slope for heart rate vs QTc compared to healthy (0.80 ± 0.51 vs 0.22 ± 0.43, p<0.0001). Further, patients with ATP1A3- related phenotypes and very short baseline QTc showed increased shortening of QT and QTc at lower heart rate compared to those with normal QTc (p=0.0025 and p=0.0013, respectively). Conclusions: Children with AHC and ATP1A3-D801N demonstrate a paradoxical shortening of QT and QTc with slowing of heart rate. The impaired prolongation of QT and resultant further shortening of QTc increase the risk of arrhythmia. We put this forward as a novel mechanism of sudden cardiac arrest in patients with ATP1A3 mutations.

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.

Abstract Su1202: The utility of post cardiac arrest temperature control protocol according to the severity of hypoxic encephalopathy based on amplitude-integrated electroencephalography findings

Introduction: The TTM2 trial showed that active fever prevention below 37.5°C and hypothermia at 33°C had similar outcomes in out-of-hospital post cardiac arrest patients. However, the patients in the trial had mild hypoxic encephalopathy, and the effects of hypothermia may vary with its severity. We previously reported that amplitude-integrated electroencephalography (aEEG) findings after the return of spontaneous circulation can be used to categorize the severity of hypoxic encephalopathy (Crit Care. 2018;22:226). In September 2022, we adopted a new temperature control protocol wherein the target temperature was set based on aEEG findings. This study examined changes in outcomes before and after implementing this new protocol. Methods: We assessed out-of-hospital cardiac arrest patients who received post cardiac arrest care in our emergency intensive care unit between March 2021 and February 2024. We divided the patients into two groups: before (B) and after (A) the introduction of the new protocol. We classified the patients into categories 1 (C1) to 4 (C4) based on the severity of hypoxic encephalopathy (Figure 1). All patients in group B were treated with hypothermia at 34°C. In group A, patients in C1 were treated with active fever prevention, and those in C2–C4 received hypothermia at 34°C (Figure 2). Primary outcome was favorable neurological outcomes (cerebral performance categories of 1 or 2) at hospital discharge. Secondary outcome was the duration of mechanical ventilation. Results: A total of 160 patients were included. The median age was 62 years and 105 (66%) patients had cardiac etiology. Fifty-five (34%) patients underwent extracorporeal cardiopulmonary resuscitation. The median cardiac arrest time was 29 min. Groups B and A comprised 57 and 103 patients, respectively. C1 category comprised 20 and 28 patients in groups B and A, respectively. The rate of favorable neurological outcomes was 35% in both B and A groups (p=1.00). Regarding C1 patients, the rates were 90% and 86% in B and A groups (p=1.00). Median duration of mechanical ventilation was 5 and 3 days in group B and A, respectively (p=0.11). Conclusion: Neurological outcomes before and after introducing the new protocol were similar. Management of patients with mild hypoxic encephalopathy can be simplified with active fever prevention. A temperature control protocol based on the severity of hypoxic encephalopathy using aEEG findings is feasible for emergency physicians.

Abstract Su1204: Impact of Hypothermia vs. Normothermia Temperature Management Based on Body Temperature at Hospital Arrival on 30-Day Neurological Outcomes in Out-of-Hospital Cardiac Arrest Patients: A Nationwide, Retrospective Study in Japan

Introduction: Temperature management (TM) to prevent fever is crucial to mitigate neurological deterioration post-cardiac arrest. Whether hypothermic TM (h-TM) is superior or equal to normothermic TM (n-TM) after out-of-hospital cardiac arrest (OHCA) is debatable, prompting ongoing effects to identify patients who might benefit more from h-TM. We hypothesized that effect of TM would differ based on body temperature at hospital arrival. Aim: Explore which post-cardiac arrest patient subsets might benefit from h-TM by stratifying them based on body temperature at hospital arrival. Methods: This retrospective, observational study used data from the OHCA registry in Japan. Patients 18 years and older who experienced OHCA due to medical cause and received TM in the intensive care unit were included. Primary outcome measure was 30-day favorable neurological outcomes, defined as a Cerebral Performance Category score of 1 or 2. Patients were stratified into groups based on body temperature at hospital arrival: normothermia (36.0-38.0°C), hypothermia (<36.0°C), and hyperthermia (>38.0°C). Effect of TM post-cardiac arrest (h-TM [32-34°C] or n-TM [35-36°C]) was evaluated in each stratified group. Univariable and multivariable logistic regression analysis was used for comparison. Adjusted odds ratio (OR) for favorable neurological outcome with h-TM was calculated using n-TM as a reference. Hyperthermia was excluded from multivariable analyses due to small sample size. Results: We analyzed 3,044 patients, 1,273 in the normothermia group, 1,747 in the hypothermia group, and 24 in the hyperthermia group. Numbers of patients with favorable neurological outcomes were as follows: 530/1,273 (41.6%) in the normothermia group, 584/1,747 (33.4%) in the hypothermia group, and 4/24 (16.7%) in the hyperthermia group. There were no differences in favorable 30-day neurological outcomes between h-TM and n-TM in any stratified group in the univariable analysis: normothermia (h-TM 323/785 [41.2%] vs. n-TM 207/488 [42.4%], p=0.66); hypothermia (411/1,185 [34.7%] vs. 173/562 [30.8%], p=0.11); hyperthermia (3/13 [23.1%] vs. 1/11 [9.1%], p=0.59). Multivariable analysis also showed no differences: normothermia (OR: 0.96, 95% CI: 0.72-1.26), hypothermia (OR: 1.10, 95% CI: 0.85-1.42). Conclusion: TM (h-TM vs. n-TM) did not significantly affect 30-day neurological outcomes, regardless of initial temperature at hospital arrival.

Abstract Su1201: Alteration in cerebrospinal fluid flow in out-of-hospital cardiac arrest patients who underwent target temperature management.

Background: Various parameters of cerebrospinal fluid (CSF) flow measured through magnetic resonance imaging (MRI) flowmetry are utilized to assess the progression of certain diseases. Our study evaluated changes in CSF flow using MRI flowmetry in survivors of out-of-hospital cardiac arrest (OHCA) who underwent target temperature management (TTM). Methods: This prospective observational cohort study was conducted from May 2023 to April 2024 at a single center. We performed Wilcoxon signed-rank tests to compare maximum velocity (V max ), stroke volume (SV), maximum flow (flow max ), and stroke distance measured immediately after return of spontaneous circulation (ROSC) with those measured at 72 h after ROSC. Results: Of the 20 patients enrolled, 7(35.0%), 1(5.0%), 2(10.0%), 5(25.0%) and 5(25.0%) patients had CPC scores of 1, 2, 3, 4, and 5, respectively. V max , SV, flow max , stroke distance measured immediately after ROSC were 3.41 (2.03~4.96), 14.00 (4.00~23.38), 0.09 (0.06~0.22), -0.07 (-0.17~0.05), respectively. V max , SV, flow max , stroke distance measured at 72h after ROSC were 5.26 (2.76~9.28), 24.00 (10.38~42.25), 0.14 (0.08~0.31), -0.07 (-0.18~0.03), respectively. Although V max , SV, and flow max measured at 72 h after ROSC were statistically significantly higher compared to those measured immediately after ROSC (p = 0.002, 0.02, 0.002), there was no significant difference between the stroke distances measured immediately after ROSC and at 72 h after ROSC (p = 0.43). Additionally, the caudocranial direction of CSF flow was observed in 13 (65.0%) patients immediately after ROSC, and in 14 (70.0%) patients 72h after ROSC. Conclusion: This study demonstrated that alterations in cerebrospinal fluid flow were observed in OHCA patients. However, Further studies are needed to determine whether there are differences in alteration in CSF flow based on neurological prognosis.

Abstract Su1207: Influence of Duration of Device-based Fever Prevention on Inflammation, Vasopressor Usage, and Oxygen Consumption after Cardiac Arrest - a Substudy of a Randomized Controlled Trial

Background: In the post-resuscitation phase, cardiac arrest patients develop a systemic inflammatory response and fever is likely if not actively treated. The Blood Pressure and Oxygenation Targets after Out-of-hospital Cardiac Arrest (BOX) trial, randomized patients to a total duration of device-based fever prevention for 36 or 72 hours. The trial found no differences in mortality or neurologic outcome. Use of device-based fever prevention for a shorter or longer duration could however result in clinically relevant differences in the magnitude of inflammation, vasopressor usage, and oxygen consumption. Aim: To assess the effect of a shorter or longer duration of device-based fever prevention on inflammation, vasopressor usage, and oxygen consumption in the intervention period from 36 to 72 hours. Methods: The BOX trail [NCT03141099] randomized comatose resuscitated out-of-hospital cardiac arrest (OHCA) patients to three different treatment targets in the post-resuscitation phase: mean arterial blood pressure target of 63 or 77mmHg; oxygenation targets of 68-75 or 98-105 mmHg; and duration of device-based fever prevention in comatose patients for a total of 36 or 72 hours. Endpoints at 48 and 72 hours: leukocytes; CRP; vasoactive-inotropic score (VIS); systemic oxygen consumption determined by use of Fick’s principle. Analyses were performed both on the total BOX population, and for a sensitivity analysis, selectively on patients still comatose at 72 hours (i.e., not awake or dead) as these had the most exposure to the intervention. Results: The total population consists of 789 patients, with 393 and 396 randomized to a total duration of device-based fever prevention for 36 and 72 hours respectively. For the analysis of patients still comatose at 72 hours, 122 and 148 were available for analysis in the 36-hour and 72-hour group respectively. There were no differences between the 36- and 72-hour group for leukocytes, CRP, VIS, or oxygen consumption during the intervention period from 36 until 72 hours, neither for the total population (Figure 1, all p>0.05) or the cohort of patients still comatose at 72 hours (Figure 2, all p>0.05). Conclusions: There were no group differences for patients randomized to device-based fever prevention for 36 or 72 hours with respect to the magnitude of inflammation, vasopressor usage, or oxygen consumption. These findings were consistent for the cohort as a whole, and when examining those with most exposure to the intervention.

Abstract Su205: Using Emergency Medical Services Monitors for Cardiac Arrest Patients in the Emergency Department is Associated with Faster Initial Rhythm Analysis and Defibrillation

Introduction: The 2020 American Heart Association guidelines for Cardiopulmonary Resuscitation (CPR) emphasizes the importance of high-quality CPR and early defibrillation in improving cardiac arrest (CA) survival. Using our emergency department (ED) CA video review registry, we can capture metrics to reliably assess the effectiveness of different approaches to CA management. Goals/Hypothesis: We propose that emergency medical services (EMS) pads and defibrillators should be used to initially analyze cardiac rhythm in the ED. We hypothesize that this “EMS Equipment” approach is associated with shorter time to first ED rhythm detection and defibrillation, higher chest compression fraction (CCF), and improved return of spontaneous circulation (ROSC) rates. Methods: This is a single center, retrospective cohort study using our CA video review registry between 10/03/2018 – 2/20/2024. Atraumatic, out-of-hospital CA patients ≥18 years were included while patients arriving to the ED with ROSC were excluded. The “EMS Equipment” group utilized EMS pads and defibrillators while the “ED Equipment” group utilized ED pads and defibrillators for the first ED rhythm analysis. Wilcoxon rank sum tests were used to assess differences in time to first rhythm check and first defibrillation among the two groups. Chi-square tests were used to assess whether the proportions of patients achieving above median CCF, ROSC, survival to admission and discharge in the two groups were different. Results: A total of 247 patients were included in the analysis with 69 patients in the EMS Equipment group (27.9%) and 178 patients in the ED Equipment group (72.1%). The EMS Equipment group had a shorter median time to first ED rhythm detection (96 vs. 255 seconds, p <0.00001). Among the 63 patients defibrillated in the ED, the EMS Equipment group had a shorter median time to first ED defibrillation (103 vs. 413 seconds, p = 0.0024). There was no significant difference in CCF, ROSC rates, survival to admission or discharge. ROSC was achieved in 36% of cases. Conclusion: In conclusion, initial rhythm analysis with EMS pads and defibrillators was associated with shorter time to initial ED rhythm detection and defibrillation, but not improved CCF, ROSC rates, and survival. Larger studies are needed to verify these exploratory results in more diverse settings.

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 Su304: The Effect of Time to DC Shock on Return of Spontaneous Circulation in Out-of-Hospital Cardiac Arrest with Recurrent Shockable Rhythm

Objective: The optimal timing for defibrillation attempts in out-of-hospital cardiac arrest (OHCA) patients with recurrent shockable rhythms [ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT)] is uncertain. This study examined the association between "time to DC shock" and the return of spontaneous circulation (ROSC) in OHCA patients with recurrent shockable rhythms. Methods: This was a retrospective analysis of data from the Salt Lake City Fire Department (SLCFD) from 2012 to 2023. Rhythm-filtering technology, used since 2012, enabled real-time and accurate interpretation of cardiac rhythms during CPR, with local protocols allowing early defibrillation for recurrent VF/ pulseless VT cases. Patients who experienced four or five episodes of shockable rhythms and received defibrillation were included. Generalized estimating equation (GEE) analysis was used to evaluate the association between time to shock preceding recurrent defibrillation and ROSC. Results: A total of 142 patients were included, with a mean age of 59.7 ± 15 years; 105 (73.9%) were male, 63 (44.4%) arrested in public locations, and 101 (71.1%) had witnessed arrests. Adjusted GEE analysis revealed that longer time to shock was associated with lower odds of achieving ROSC (OR: 0.81, 95% CI: 0.72–0.93, p = 0.005). Every one-minute delay in defibrillation is predicted to decrease the likelihood of achieving ROSC by 19%. Conclusion: In patients with recurrent shockable rhythms, every one-minute delay in delivering a shock was associated with a statistically significant 19% reduction in the chance of achieving ROSC. This finding highlights the importance of reducing the time to defibrillation in managing recurrent shockable rhythms and suggests reevaluating the current recommendation of two-minute intervals for rhythm check and shock delivery.

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 4137905: The association between prehospital epinephrine administration and short-term outcomes in patients with shockable out-of-hospital cardiac arrest and extracorporeal cardiopulmonary resuscitation: a propensity matched analysis

Background: In out-of-hospital cardiac arrest (OHCA) patients with an initial shockable rhythm, epinephrine increases the likelihood of return of spontaneous circulation (ROSC), but its effect on neurological outcome remains uncertain. Epinephrine administered before extracorporeal resuscitation (ECPR), which is a non-pharmacological method to obtain ROSC, may have worsened neurological outcome. Aim: To evaluate the impact of prehospital epinephrine administration on the prognosis of OHCA patients undergoing ECPR. Methods: This is a retrospective analysis of a cohort study from a multicenter, prospective registry of 81234 OHCA patients between 2014 and 2021. After the application of exclusion criteria, 1061 OHCA patients with an initial shockable rhythm and who underwent ECPR were eligible for this study. The primary outcome was favorable neurological outcome at 30 days after the OHCA and the secondary outcome was ROSC during transfer. Patients who did and did not receive prehospital epinephrine were propensity score-matched on the basis of age, gender, witness arrest, bystander-initiated CPR, dispatcher-assisted CPR, advanced airway management, call-to-defibrillation interval, year and district. Results: Among 1061 eligible patients, 442 patients received epinephrine and 619 patients did not. Matching was successful in achieving covariate balance as shown by a standardized difference of <10% for all variables (329 matched pairs). The proportion of patients with prehospital ROSC was significantly higher in those who received prehospital epinephrine than those who did not (36 [8%] vs 31 [5%]; adjusted odds ratio [OR] after propensity score-matching, 1.96 [95% CI 1.05-3.67], p=0.03). The proportion of patients with favorable neurological outcome at 30 days was not significantly lower in those who received prehospital epinephrine than those who did not (34 [8%] vs 78 [13%]; adjusted OR after propensity score-matching, 0.78 [95% CI 0.45-1.37], p=0.39). Conclusion: In patients with shockable OHCA and ECPR, prehospital epinephrine administration was significantly associated with increased ROSC before hospital arrival and not significantly with decreased favorable neurological outcome at 30 days.

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 Su1106: Evaluating Culturally Competent Cardiopulmonary Resuscitation (CPR) Training in Urban Minority Communities

Introduction: Timely resuscitation can triple the chance of survival for out-of-hospital cardiac arrest (OHCA) patients. Differences in bystander CPR rates between white and minority communities lead to significant racial and ethnic disparities in OHCA survival rates. Immigrant populations, in particular, face several educational barriers and are often excluded in community CPR trainings. Previous efforts have increased the inclusivity of CPR education for female and disabled citizens through targeted interventions. Significant opportunities exist to apply similar strategies and tackle community-level disparities. Aim: To examine the impact of culturally competent CPR instruction on confidence levels and acceptability of CPR skills among minority citizen groups. Methods: CPR cohorts were taught using a local emergency services syllabus. Through discussion with course site leaders, the syllabus was adapted in three categories: language variations, cultural adaptations, and/or consideration of cultural learning styles. A pre-post design was utilized to assess impact of culturally-tailored CPR training. Confidence and acceptability levels in performing CPR were measured using a digital survey. An unpaired t-test was used to analyze pre/post-course data. Trainings were held from November 2023 to May 2024. Results: All participants were 18 years or older (n=217). The response rate was 36.7% (n=80). Confidence levels increased by 121% for checking for breathing and responsiveness (p<0.0001), 63.9% for communicating with 911 (p<0.0001), 137% for administering chest compressions (p<0.0001), and 172% for connecting an AED (p<0.0001). CPR acceptability improved, with participants reporting a 47.8% reduction in perceived difficulty post-course (p<0.0001). Conclusions: Implementing culturally tailored CPR training significantly improved confidence in CPR skills and acceptability of CPR. Future experiments may compare outcomes between intervention and control CPR cohorts at more course sites.

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 Su901: Association of Hemoglobin and Partial Pressure of Oxygen in Arterial Blood on Survival and Neurologic Outcomes in In-Hospital Cardiac Arrest Patients

Background: Lower hemoglobin levels have been associated with poor outcomes in patients with out-of-hospital cardiac arrests. Pre-arrest hemoglobin (within 24 hours) and its association with outcomes and PaO2 in in-hospital cardiac arrest (IHCA) remains unknown. We aimed to evaluate the association of pre-arrest hemoglobin levels with survival and neurologic outcomes, and intra-arrest PaO2 levels in adults with IHCA. Methods: The study population included adults with IHCA undergoing resuscitation at an academic tertiary medical center from 2011-2019. Hemoglobin levels were obtained within 24 hours prior to arrest, and PaO2 levels were obtained intra-arrest via arterial blood gas samples. Patients were classified based upon three pre-arrest hemoglobin (Hgb) levels: Hgb < 8.5, Hgb 8.5-10.5, Hgb > 10.5. Return of spontaneous circulation (ROSC), survival to discharge, favorable neurological outcome (defined as a Glasgow Outcome Score of 4-5), and association with PaO2 served as outcomes of interest. Results: Of the 799 patients studied, 493 patients had pre-arrest hemoglobin data and 164 had intra-arrest PaO2 data. Of those patients that had pre-arrest hemoglobin data, 145 (29.4%) had Hgb < 8.5, 178 (36.1%) had Hgb 8.5-10.5, 170 (34.5%) had Hgb >10.5. Charlson Comorbidity Score was similar across each hemoglobin group. Most patients had PEA/Asystole as the initial rhythm at onset of cardiac arrest, and the number was similar across each hemoglobin group. Mean intra-arrest PaO2 was higher in the Hgb < 8.5 group. Compared to Hgb < 8.5, higher hemoglobin levels were associated with higher rates of ROSC in both univariate (Hgb < 8.5: 46.9% vs. Hgb 8.5-10.5: 59.6% vs. Hgb > 10.5: 62.9%, p = 0.012) and multivariate (Hgb 8.5-10.5: OR 1.51, 95% CI 0.96-2.39; Hgb > 10.5: OR 1.75, 95% CI 1.10-2.79) analyses. Higher hemoglobin levels were associated with higher rates of favorable neurologic outcome in the univariate analysis only (Hgb < 8.5: 10.5% vs. Hgb 8.5-10.5: 11.8% vs. Hgb > 10.5: 19.4%, p = 0.043). There was no significant correlation between pre-arrest hemoglobin and intra-arrest PaO2. Conclusions: In this contemporary registry of adults with IHCA, higher hemoglobin values were associated with higher rates of ROSC. There may be an association between higher hemoglobin levels and favorable neurologic outcome. There was no association between pre-arrest hemoglobin and intra-arrest PaO2.

Abstract Su301: Longer Chest Compression Intervals Between Pulse Checks in Patients with Non-Shockable Rhythms are Associated with Increased Subsequent Return of Spontaneous Circulation Events

Background: Chest compressions are a cornerstone of cardiopulmonary resuscitation (CPR), and evidence shows that fewer interruptions and higher chest compression fractions improve outcomes in cardiac arrest. Interruptions in chest compression are important in patients with shockable rhythms to assess the need for defibrillation; however, in pulseless electrical activity (PEA) or asystole, a pause in chest compressions every 2 minutes may be detrimental, as it decreases chest compression fraction and reduces myocardial, cerebral, and systemic perfusion. Hypothesis: We hypothesize that patients with non-shockable rhythms on whom chest compression intervals were greater than 2 minutes have better odds of achieving return of spontaneous circulation (ROSC). Objective: Our primary objective is to determine if longer chest compression intervals are associated with improved subsequent ROSC in patients with initial PEA or asystole rhythms. Methods: We conducted a retrospective cohort study of video-recorded adult atraumatic cardiac arrest resuscitations in a quaternary care Emergency Department from 1/30/2018 to 2/20/2024. We only examined patients in PEA or asystole and determined the duration of all chest compression intervals for each patient. We grouped the chest compression interval durations into 3 groups (<1min 45sec, 1min 45sec to 2 min 14sec, ≥2min 15 sec) and determined the odds of subsequent ROSC for each chest compression interval duration. We assessed the association between chest compression interval duration and ROSC episodes using a logistic regression model. Results: Out of 326 video-reviewed patients, 235 patients had an initial rhythm of PEA or asystole of which 44 (18.7%) survived to admission and 9 (3.8%) to hospital discharge. The 235 patients yielded 1724 chest compression intervals and 151 ROSC episodes. The ROSC rate for the chest compression intervals <1:45sec was 7.3% (49 out of 673) versus 8.1% (51 out of 632) for intervals 1:45 to 2:14 versus 12.2% (51 out of 419) for intervals ≥2 min 15sec. In a logistic regression model, using the 1min 45 sec to 2min 14 sec interval as the reference group, the <1min 45sec group had 10% lower odds of ROSC (OR: 0.90; 95% CI: 0.60, 1.35) and the ≥2min 15 sec group had 58% higher odds of ROSC (OR: 1.58; 95% CI: 1.05, 2.38). Conclusion: In cardiac arrest patients presenting with non-shockable rhythms, chest compression intervals ≥2 min15sec are associated with higher odds of achieving ROSC.

Neo Automatic Code to Improve Quality of Cardiopulmonary Resuscitation (CPR) in Society

Background: The quality of cardiopulmonary resuscitation (CPR) in Indonesian society is poor. One solution is to give society a metronome called the Neo Automatic Code (NAC) to guide CPR when cardiac arrest patients are present. This study aims to analyze the effect of NAC on the compression depth and compression rate during CPR. Methods: A quick experimental study with a control group design, where the population is chosen by simple random sampling to distinguish between odd and even. The population is health cadres and youth with an age range of 16-56 years. The intervention group gets training 2 times to do CPR with Neo Automatic Code, and the control group gets training in CPR using standard procedure. We use a CPR manikin to measure variables. Data analyzed used Mann Whitney. Results: The Mann-Whitney test shows p = 0.001, concluding that there is a difference in the accuracy of depth and compression speed in CPR between the intervention and control groups. This means the NAC metronome can improve CPR performance in compression depth and compression rate. CPR uses a neo-automatic code metronome to ensure the user breathes regularly and helps the rescuer to constantly give compression. Conclusion: Neo automatic code can improve the quality of CPR in Indonesian society. A study about how many times training must be given to society, considering age, level of education, and kinds of jobs, is needed.

Feasibility and Safety of Targeted Temperature Management During Interhospital Transport of Post-Cardiac Arrest Patients

Objectives Early initiation of targeted temperature management (TTM) is crucial for post-resuscitation care. Although TTM is initiated prior to transport and continued during interhospital transport (IHT), its feasibility and safety during IHT for cardiac arrest patients have not been thoroughly assessed. This study aims to evaluate the feasibility and safety of interhospital TTM for post-resuscitation patients. Methods A retrospective analysis of post-cardiac arrest patients transported by a dedicated critical care transport team between January 2016 and April 2023 was conducted. Adult patients resuscitated from cardiac arrest without mental recovery were enrolled. The study population was divided into those who received TTM during IHT (IHT-TTM group) and those who did not (non-IHT-TTM group). The primary outcome was body temperature drop during transport, with hypotension, or desaturation during transport considered as secondary outcomes. Multivariable conditional logistic regression analysis was performed after frequency matching. Results Among 593 post-cardiac arrest patients, 332 were included in the analysis after exclusions. Of these, 44 (13.3%) received TTM during IHT. Conditional logistic regression analysis showed significantly higher likelihood for a drop in body temperature during IHT for the IHT-TTM group, with an odds ratio (OR) of 12.91 (95%CI: 5.28–31.53). No significant association was found for hypotension (OR (95%CI): 0.72 (0.13–3.97)), or desaturation during IHT (0.65 (0.15–2.82)). Conclusions Administration of TTM during IHT for post-cardiac arrest patients appears to be feasible and safe. These findings support the implementation of dedicated critical care transport systems capable of providing TTM during IHT for post-cardiac arrest patients.