Hospital Cardiac Arrest Research Articles

Improving access to extracorporeal membrane oxygenation for out of hospital cardiac arrest: pre-hospital ECPR and alternate delivery strategies

BackgroundThe use of extracorporeal membrane oxygenation (ECPR) in refractory out-of-hospital cardiac arrest (OHCA) patients is usually implemented in-hospital. As survival in ECPR patients is critically time-dependent, alternative models in ECPR delivery could improve equity of access.ObjectivesTo identify the best strategy of ECPR delivery to provide optimal patient access, to examine the time-sensitivity of ECPR on predicted survival and to model potential survival benefits from different delivery strategies of ECPR.MethodsWe used transport accessibility frameworks supported by comprehensive travel time data, population density data and empirical cardiac arrest time points to quantify the patient catchment areas of the existing in-hospital ECPR service and two alternative ECPR strategies: rendezvous strategy and pre-hospital ECPR in Sydney, Australia. Published survival rates at different time points to ECMO flow were applied to predict the potential survival benefit.ResultsWith an in-hospital ECPR strategy for refractory OHCA, five hospitals in Sydney (Australia) had an effective catchment of 811,091 potential patients. This increases to 2,175,096 under a rendezvous strategy and 3,851,727 under the optimal pre-hospital strategy. Assuming earlier provision of ECMO flow, expected survival for eligible arrests will increase by nearly 6% with the rendezvous strategy and approximately 26% with pre-hospital ECPR when compared to the existing in-hospital strategy.ConclusionIn-hospital ECPR provides the least equitable access to ECPR. Rendezvous and pre-hospital ECPR models substantially increased the catchment of eligible OHCA patients. Traffic and spatial modelling may provide a mechanism to design appropriate ECPR service delivery strategies and should be tested through clinical trials.

Sex difference in the association between type of bystander CPR and clinical outcomes in patients with out of hospital cardiac arrest

BackgroundA recent study suggested that women with out-of-hospital cardiac arrest have a smaller survival benefit with bystander cardiopulmonary resuscitation than men. We evaluated whether this weaker association between bystander cardiopulmonary resuscitation and survival in women is related to dispatcher-assisted vs unassisted bystander cardiopulmonary resuscitation. MethodsIn a national registry in the Republic of Korea, we identified adult patients with out-of-hospital cardiac arrest during 2013–2018. The main exposure was type of bystander cardiopulmonary resuscitation (categorized as none, dispatcher-assisted, and unassisted). The primary outcome was favourable neurological survival. Multivariable logistic regression evaluated for an interaction between sex and type of bystander cardiopulmonary resuscitation. ResultsOf 93,245 patients with out-of-hospital cardiac arrest, there were 31,578 (33.9%) women and 61,667 (66.1%) men. Overall, both types of bystander cardiopulmonary resuscitation were associated with favourable neurological survival (unassisted: adjusted OR, 1.81 [95% CI: 1.66–1.98]; dispatcher-assisted: adjusted OR, 1.44 [95% CI: 1.33–1.56]). When unassisted cardiopulmonary resuscitation was administered, the association between bystander cardiopulmonary resuscitation and favourable neurological survival was similar between women and men: adjusted ORs of 1.59 (95% CI: 1.30–1.95) in women and 1.88 (95% CI: 1.71–2.08) in men; interaction p = 0.65). In contrast, when dispatcher-assisted cardiopulmonary resuscitation was administered, the association differed by sex: adjusted ORs of 1.08 (95% CI: 0.90–1.92) in women and 1.55 (95% CI: 1.42–1.69) in men; interaction p < 0.0002). ConclusionsDispatcher-assisted cardiopulmonary resuscitation was associated with favourable neurological survival in men but not in women whereas unassisted bystander cardiopulmonary resuscitation was associated with favourable neurological survival in women and men.

Long term survival in patients who sustained in-hospital cardiac arrest

Introduction: Cardiopulmonary resuscitation can be termed successful only if the victim survives to hospital discharge and returns to a reasonable quality of life. Aim: The aim of this study was to determine long term survival and quality of life of patients who sustained in-hospital cardiac arrest. Patients and Methods: This was a prospective interventional study of 1955 patients who sustained in- hospital cardiac arrest at a tertiary hospital in India. Adult patients who sustained cardiac arrest in the hospital were included in the study and patients who were &lt; 18 years of age, cardiac arrest in operation theatre and patients who were brought in ‘near death’ state to the hospital were excluded. Parameters were collected during two periods, before and after introduction of Modified Early Warning Score (MEWS). Results: In the PreMEWS period, 228 out of 1135 (20%) patients had return of spontaneous circulation (ROSC), of whom 59 survived to discharge (5.19%), 51 patients (4.49%) were alive at 6 months and 45 patients (3.96%) were independent at activities of daily living (ADL). In the PostMEWS period, 202 out of 820 patients (24.6%) had ROSC, of whom 138 patients (16.82%) survived to discharge, 110 were alive at 6 months (13.41%) and 99 (12.07%) were independent at ADL. Conclusion: The rate of return of spontaneous circulation, survival to discharge rate, 6 month survival and independence at activities of daily living are all better with the use of modified early warning score.

Extracorporeal Cardiopulmonary Resuscitation: A Narrative Review and Establishment of a Sustainable Program.

The rates of survival with functional recovery for out of hospital cardiac arrest remain unacceptably low. Extracorporeal cardiopulmonary resuscitation (ECPR) quickly resolves the low-flow state of conventional cardiopulmonary resuscitation (CCPR) providing valuable perfusion to end organs. Observational studies have shown an association with the use of ECPR and improved survivability. Two recent randomized controlled studies have demonstrated improved survival with functional neurologic recovery when compared to CCPR. Substantial resources and coordination amongst different specialties and departments are crucial for the successful implementation of ECPR. Standardized protocols, simulation based training, and constant communication are invaluable to the sustainability of a program. Currently there is no standardized protocol for the post-cannulation management of these ECPR patients and, ideally, upcoming studies should aim to evaluate these protocols.

Prehospital monitoring of cerebral circulation during out of hospital cardiac arrest ? A feasibility study

BackgroundAbout two-thirds of the in-hospital deaths after out-of-hospital cardiac arrests (OHCA) are a consequence of anoxic brain injuries, which are due to hypoperfusion of the brain during the cardiac arrests. Being able to monitor cerebral perfusion during cardiopulmonary resuscitation (CPR) is desirable to evaluate the effectiveness of the CPR and to guide further decision making and prognostication.MethodsTwo different devices were used to measure regional cerebral oxygen saturation (rSO2): INVOS™ 5100 (Medtronic, Minneapolis, MN, USA) and Root® O3 (Masimo Corporation, Irvine, CA, USA). At the scene of the OHCA, advanced life support (ALS) was immediately initiated by the Emergency Medical Services (EMS) personnel. Sensors for measuring rSO2 were applied at the scene or during transportation to the hospital. rSO2 values were documented manually together with ETCO2 (end tidal carbon dioxide) on a worksheet specially designed for this study. The study worksheet also included a questionnaire for the EMS personnel with one statement on usability regarding potential interference with ALS.ResultsTwenty-seven patients were included in the statistical analyses. In the INVOS™5100 group (n = 13), the mean rSO2 was 54% (95% CI 40.3–67.7) for patients achieving a return of spontaneous circulation (ROSC) and 28% (95% CI 12.3–43.7) for patients not achieving ROSC (p = 0.04). In the Root® O3 group (n = 14), the mean rSO2 was 50% (95% CI 46.5–53.5) and 41% (95% CI 36.3–45.7) (p = 0.02) for ROSC and no ROSC, respectively. ETCO2 values were not statistically different between the groups. The EMS personnel graded the statement of interference with ALS to a median of 2 (IQR 1–6) on a 10-point Numerical Rating Scale.ConclusionOur results suggest that both INVOS™5100 and ROOT® O3 can distinguish between ROSC and no ROSC in OHCA, and both could be used in the pre-hospital setting and during transport with minimal interference with ALS.

In-hospital extracorporeal cardiopulmonary resuscitation for patients with an out-of-hospital cardiac arrest in a semi-rural setting: An observational study on the implementation of a helicopter emergency medical services pathway

AimIn this study, we aimed to investigate the efficacy of a helicopter emergency medical service (HEMS) facilitated pathway for in-hospital extracorporeal cardiopulmonary resuscitation (ECPR) for patients with an out of hospital cardiac arrest (OHCA) in a semi-rural setting. MethodsWe retrospectively reviewed all patients with an OHCA attended by a UK HEMS service between 1 January 2018 and 20 September 2021, when a dedicated ECPR pathway was in effect to facilitate transport of eligible patients to the nearest ECLS centre. The primary endpoint was the number of patients meeting ECPR eligibility criteria at three pre-defined time points: at HEMS dispatch, during on-scene evaluation and upon arrival in hospital. ResultsDuring the study period, 162 patients attended met ECPR pathway dispatch criteria. After on-scene evaluation, 74 patients (45%) had a return of spontaneously circulation before arrival of HEMS, 60 (37%) did not meet eligibility criteria regarding initial rhythm or etiology of the OHCA, and 15 (9%) had deteriorated (mainly into asystole) and were no longer suitable candidates upon arrival of HEMS. Eleven patients were eligible for ECPR and transported to hospital in arrest, and a further two patients were transported for post-ROSC ECLS. Nine patients deteriorated during transport and were no longer suitable ECPR candidates upon arrival. ECLS was successfully initiated in two patients (one intra-arrest, and one post-ROSC). ConclusionIn-hospital ECPR is of limited value for patients with refractory OHCA in a semi-rural setting, even when a dedicated pathway is in place. Potentially eligible patients often cannot be transported within an appropriate timeframe and/or deteriorate before arrival in hospital.

Coronary angiography after resuscitation without ST‐Elevation: Indication remains elusive

Key Points Survivors of out of hospital cardiac arrest without ST‐segment elevations present uncertain indications and timing for coronary angiography. Patients without ST‐elevations who undergo angiography tend to be younger, with better neurologic status, and more rapid resuscitation. Outcomes between patients whether they had angiography early, later, or never, were similar suggesting further work on discriminating the best care pathway for these patients is needed.

Speed of cooling after cardiac arrest in relation to the intervention effect: a sub-study from the TTM2-trial

BackgroundTargeted temperature management (TTM) is recommended following cardiac arrest; however, time to target temperature varies in clinical practice. We hypothesised the effects of a target temperature of 33 °C when compared to normothermia would differ based on average time to hypothermia and those patients achieving hypothermia fastest would have more favorable outcomes.MethodsIn this post-hoc analysis of the TTM-2 trial, patients after out of hospital cardiac arrest were randomized to targeted hypothermia (33 °C), followed by controlled re-warming, or normothermia with early treatment of fever (body temperature, ≥ 37.8 °C). The average temperature at 4 h (240 min) after return of spontaneous circulation (ROSC) was calculated for participating sites. Primary outcome was death from any cause at 6 months. Secondary outcome was poor functional outcome at 6 months (score of 4–6 on modified Rankin scale).ResultsA total of 1592 participants were evaluated for the primary outcome. We found no evidence of heterogeneity of intervention effect based on the average time to target temperature on mortality (p = 0.17). Of patients allocated to hypothermia at the fastest sites, 71 of 145 (49%) had died compared to 68 of 148 (46%) of the normothermia group (relative risk with hypothermia, 1.07; 95% confidence interval 0.84–1.36). Poor functional outcome was reported in 74/144 (51%) patients in the hypothermia group, and 75/147 (51%) patients in the normothermia group (relative risk with hypothermia 1.01 (95% CI 0.80–1.26).ConclusionsUsing a hospital’s average time to hypothermia did not significantly alter the effect of TTM of 33 °C compared to normothermia and early treatment of fever.

Science, Medicine, and the Anesthesiologist

Science, Medicine, and the Anesthesiologist

Abstract 233: Chest Compression Release Velocity In Pediatric In Hospital Cardiac Arrest: A Descriptive Study

Introduction: Chest compression release velocity (CCRV) during chest compression (CC) recoil is understudied in pediatrics. Our objective was to characterize CCRV during pediatric in hospital cardiac arrest (IHCA). Methods: Using the PediRES-Q multicenter prospective observational cohort from 2015 to 2021, we analyzed patients &lt;18 years who received ≥ 20 minutes of CPR with quantitative CPR metrics (ZOLL R Series) across 30 sites. Median and Interquartile Range (IQR) CCRV, measured by pad integrated accelerometers, was defined as maximum velocity during CC recoil. CCRV was calculated for each CC and compared between 3 age groups. Initial (min 0-3), early (min 5-8), and late (min 15-20) periods of CPR were compared when metrics were available for all stages. Wilcoxon rank sum was used for comparisons. Results: Of 308 events with CC metric data and ≥ 20 min duration there were 106 (34%) &lt;1 yo, 114 (37%) 1&lt;8 yo, and 88 (29%) 8&lt;18 yo. Median [IQR] duration was 43 [31, 58] min. Median CCRV for &lt;1 yo: 152 [125, 179] mm/s; 1&lt;8 yo: 213 [177, 261] mm/s; and 8&lt;18 yo: 397 [294, 388] mm/s. Difference in CCRV between age groups was significant (p&lt;0.0001) with CCRV increasing as age increased. 185 events had complete CC metric data during initial (min 0-3), early (min 5-8), and late (min 15-20) periods of CPR. There was no significant difference in CCRV over time: initial 222 [159, 329] mm/sec; early 218 [154, 322] mm/sec; late 219 [163, 321] mm/sec. Similar lack of difference over time was demonstrated between the 3 age groups: &lt;1 yo initial 151 [113, 191] mm/sec; early 149 [119, 191] mm/sec; late 160 [127, 213] mm/sec; 1&lt;8 yo initial 222 [177, 277] mm/sec; early 237 [186, 276] mm/sec; late: 220 [185, 256] mm/sec; and 8&lt;18 yo initial 376 [270, 524] mm/sec; early 395 [277, 441] mm/sec; late 381 [280, 468] mm/sec. Conclusions: We characterized CCRV during pediatric IHCA as a metric of CPR performance related to chest recoil. CCRV was significantly slower for &lt;1 yo, faster for 1 to &lt;8 yo, and fastest for 8 to &lt;18 yo. Surprisingly, CCRV was not different over time (initial, early, late CPR periods). These findings suggest differences in CCRV related to patient age but do not demonstrate changes in CCRV over time in the first 20 minutes of CPR.

Abstract 15047: Survival With Favorable Neurological Outcome and Quality of CPR Following In-Hospital Cardiac Arrest in Children With Cardiac Disease Compared to Non-Cardiac Disease

Introduction: Children with cardiac disease have higher rates of in hospital cardiac arrest (IHCA) compared to non-cardiac disease. We aimed to determine differences in survival in children with medical and surgical cardiac compared to non-cardiac disease following IHCA and to assess whether CPR quality was different between groups. Hypothesis: We hypothesized: 1) medical cardiac have worse and surgical cardiac have improved outcomes compared to non-cardiac patients, and 2) CPR quality is similar between groups. Methods: A secondary analysis of the ICU-RESUS citation project ( ICU-RESUS ; NCT02837497) was conducted. The primary outcome was survival to hospital discharge with favorable neurological outcome defined as a Pediatric Cerebral Performance Category score of 1 - 3 or no change from baseline. Secondary outcomes included physiologic measures of intra-arrest quality. Results: Of 1100 children with IHCA, 273 (25%) were medical cardiac, 383 (35%) were surgical cardiac, and 444 (40%) were non-cardiac. The medical cardiac group was less likely to survive with favorable outcome compared to the non-cardiac group (48% vs. 55%, aOR 0.59, CI 95 0.40, 0.88). There was no difference in outcome between the surgical cardiac (58%) and non-cardiac group. There were no differences in chest compression (CC) rate, CC fraction, ventilation rate, intra-arrest average target diastolic blood pressure or average target systolic blood pressure between medical cardiac vs. non-cardiac and surgical cardiac vs. non-cardiac groups. The surgical cardiac group was less likely to achieve target CC depth compared to non-cardiac group (OR 0.15, CI 95 0.02, 0.52). There was no difference in CC depth in medical cardiac vs. non-cardiac groups. Conclusions: In this large study of pediatric IHCA, medical cardiac patients had lower survival with favorable neurologic outcome compared to non-cardiac patients. Surgical cardiac patients had similar outcome to non-cardiac patients. CPR quality was similar in medical-cardiac and non-cardiac patients, however delivered CC depths were lower in surgical cardiac compared to non-cardiac patients.

Abstract 10: Association Of Race And Medical Emergency Team Evaluations Prior To In Hospital Cardiac Arrest

Introduction: Racial disparities for in-hospital cardiac arrest (IHCA) outcomes exist. However, whether these are associated with medical emergency team (MET) activation prior to IHCA remain unknown. We aimed to evaluate the association between race and MET activation among patients with physiologic abnormalities (modified early warning score [MEWS] ≥3) prior to IHCA. We hypothesized that MET activation prior to IHCA would be less likely among Black as compared to white patients. In a secondary analysis, we hypothesized that among Black patients, MET activation would be associated with improved IHCA outcomes compared to events without MET activation. Methods: Retrospective cohort study of adults age ≥18 from the AHA Get With The Guidelines®-Resuscitation registry who had an IHCA outside an ICU between 2000 and 2021 with MEWS ≥3 prior to IHCA. A propensity-weighted cohort was constructed to balance confounders between Black and white patients. The association between race (Black vs. white) and MET activation (yes/no) was quantified with weighted multivariable logistic regression. A secondary analysis examined the association between any MET activation and IHCA outcomes among all Black patients. Results: Among 28,123 patients (average age: 68±15; 42% (42 of 100) female) with MEWS ≥3 (average 4±1), 2431 (9% (9 of 100)) had a documented MET activation prior to IHCA. Vitals were measured at a median time of 120 minutes (IQR 60, 210) prior to IHCA. Rates of MET activation were similar between Black and white patients with MEWS ≥3 prior to IHCA (aOR 1.04, CI 0.94-1.15, p=0.45). However, among Black patients, odds of ROSC were higher among patients with a MET activation prior to ICHA compared to those who did not have a MET activation (aOR 1.15, CI 1.03-1.28, p=0.02). Conclusions: Though racial disparities in IHCA outcomes exist, we failed to detect a significant association between race and MET activation for MEWS ≥3 as a potential mechanism for these disparities. Importantly, any MET activation improved IHCA outcomes among Black patients.

Abstract 261: Association Of Neighborhood Social Determinants Of Health With Adverse Out-of-hospital Cardiac Arrest (OHCA) Outcomes Among Medicare Beneficiaries

Introduction: Out-of-hospital cardiac arrest (OHCA) is a leading cause of death with prior studies demonstrated worse OHCA outcomes in neighborhoods with higher proportion of Blacks and lower socioeconomic status. The association between OHCA outcomes and other social determinants of health (SDOHs) like limited English proficiency (LEP) and education is not well studied. Hypothesis: We hypothesized patients living in neighborhoods with high proportion of LEP had worse OHCA outcomes. We chose survival to hospital admission as the primary outcome due to its proximity to reflect a neighborhood’s characteristics. Methods: We performed a two-level hierarchical logistic-regression model. Patient data were Medicare fee-for-service claims between January 1, 2013, and December 31, 2015 (level 1). Neighborhood characteristics for the area in which each OHCA occurred were derived from the 2014 American Community Survey at the ZCTA level (level 2). We identified six neighborhood SDOH predictors of interest including LEP, median household income, racial and ethnic-group composition, percent unemployment, less than high school education, and population density. Results: Among the 194,231 OHCA events identified, 60,760 (31.3%) survived to hospital admission. Contrary to our hypothesis, Patient who had a cardiac arrest in the highest proportion of LEP neighborhoods were more likely to survive to hospital admission as compared to those living in predominantly English-speaking neighborhoods (OR 1.16; 95% CI, 1.10 to 1.23). Household income, racial composition, and unemployment had no effect on the likelihood of survival to hospital admission in OHCA while education and population density appeared to be protective (Table) . Conclusions: In a large cohort study, we found that patients who had an out of hospital cardiac arrest were more likely to survive to hospital admission in higher LEP, higher education, and higher population density neighborhoods.

Abstract 293: Swedish Emergency Medical Dispatch Centres Ability To Answer And Manage Out Of Hospital Cardiac Arrest Calls In Accordance With The American Heart Association Performance Goals

Background: In witnessed OHCA each minute of delay to CPR reduce the probability of survival. Thus, Emergency Medical Dispatch Centres (EMDC) ability to rapidly answer the emergency call and dispatch EMS is crucial. The American Heart Association (AHA) states that the goal of public safety answering points in a high performing system is to answer OHCA calls within 10 seconds (s) and dispatch the first EMS unit within 60 s. Aim: The aim of the study was to 1) describe the EMDC call answer delay and 2) time to dispatch of the first EMS unit in OHCA calls in the region of Stockholm, during 10 years in accordance with the AHA goals for OHCA call handling. We also aimed to 3) investigate the effect of “late responders” on 30-day survival. Method: This is an observational study based on OHCA data from the region of Stockholm, Sweden, between year 2012 to 2021. Data was collected from the Swedish Registry for Cardiopulmonary Resuscitation (SRCR) and SOS Alarm AB database. Results: During the 10-year period, the EMDC answered a total of 12 298 calls with a corresponding OHCA-record in the SRCR. Complete data was available in 11 484 calls (93%) which were included in the analysis. Of these, 62% (n=7127) of OHCA calls were answered within 10 s, 20% (n=2306) in 10-20 s and 18% (n=2051) above 20 s. The median delay was 7.3 s [IQR 3.3, 15.1]. Dispatch of the first EMS unit was performed within 60 s in 9% (1053 of 11470), 23% (2640 of 11470) between 60-90 s and 68% (7777 of 11470) above 90 s, with a median delay of 114.5 s [IQR 81.4, 168.6]. Differences in call answer delay and time to dispatch of the first EMS unit over the 10-years are presented in Figure 1. Survival at 30-days was 11% (109 of 990) when EMS was dispatched within 60 s, 8.7% (215 of 2459) in 60-90 s and 10.3% (746 of 7210) above 90 s. Conclusion: In the region Stockholm the majority of emergency calls concerning OHCA were answered within the high performance system goal of 10 seconds. Additional effort is needed to achieve the 60 second goal for dispatch of the first EMS unit.

Abstract 15267: LV Aneurysm Rupture - Dreaded Complication in an LVAD Patient

Introduction: Left ventricular (LV) aneurysm rupture is a highly fatal mechanical complication, usually seen following a myocardial infarction. We describe a unique case of a patient with a left ventricular assist device (LVAD) who presented with cardiac arrest due to an LV aneurysm rupture. Case: A 57-year-old male with history of ischemic cardiomyopathy status post HeartMate3 (HM3) LVAD presented as an out of hospital cardiac arrest. Following resuscitation, Computed Tomography Angiography (CTA) of the chest showed a large long-standing aneurysm along the inferior wall of the LV measuring 2.9 x 3.3 x 3.5 cm with rupture dissecting the pericardium and extending to cause hemo-peritoneum (Figure1), not amenable to intervention. He had presented earlier in the month with anemia that stabilized with transfusion. Abdominal imaging at the time showed a contained bleed with unknown source. He had likely suffered a progressive bleed from the rupture leading to his cardiac arrest. Decision Making: Pseudoaneurysm has been reported as a rare complication with earlier generation LVADs, but to our knowledge, this is the first reported case of an aneurysm formation with rupture with an HM3 LVAD. Conclusions: With the advent of advanced mechanical support devices, there is a heightened need for awareness and cognizance of diagnosing such mechanical complications in this patient population. An early diagnosis requires a high clinical index of suspicion and a multi-disciplinary approach. Multimodality imaging including CT scan can assist with this diagnosis.

Abstract 14701: Angiographic and Prognostic Difference of Acute Myocardial Infarction Patients With and Without Out of Hospital Cardiac Arrest Stratified by Killip Classification

Backgrounds: Although the mortality rates for AMI have declined, the mortality rate for AMI with out-of-hospital cardiac arrest (OHCA) remains high. It has been supposed that CTO (chronic total occlusion) in non-infarct related artery is associated with OHCA patients. However, the detailed angiographic and prognostic comparison between OHCA patients and non-OHCA patients stratified by Killip classification has not been well evaluated. Methods: Among 5662 AMI patients (5420 non-OHCA patients and 242 OHCA patient) who underwent emergency coronary angiography between 2013 and 2020 were enrolled from Mie ACS registry. Difference of culprit lesion and non-infarct related CTO lesion were analyzed between with and without OHCA. They were further stratified using Killip classification. Results: In-hospital mortality for AMI patients with OHCA was 31.4%, significantly higher than the 5.5% for AMI patients with non-OHCA (p&lt;0.001), and mortality rates tended to be increased with increasing Killip class in each group(P&lt;0.001). AMI patients with OHCA also had a significantly higher frequency of culprit artery with LMT and LAD and a higher frequency of CTO lesion in non-infarct related artery compared to the AMI patients with non-OHCA.(See Table) Multivariate analysis revealed that LAD CTO in non-infarct related artery(Odds ratio 2.3) culprit artery of LMT and LAD (Odds ratio 3.2 and 1.6), lower BMI(Odds ratio 0.96), younger age(Odds ratio 0.98) and male gender (Odds ratio 1.7)was significantly associated with OHCA(P&lt;0.05, respectively). However, non-LAD CTO lesion in non-infarct related artery was not associated with OHCA Conclusions: Patients with OHCA had a higher incidence of culprit artery with LMT and LAD, and non-infarct-related LAD CTO lesion, suggesting that extensive myocardial ischemia with LAD lesion was strongly associated with OHCA.

Abstract 206: Easily Created Prediction Model Using Deep Learning For Termination Of Resuscitation (tor) In Out Of Hospital Cardiac Arrest (ohca) Cases: The All-japan Utstein Registry Experience.

Background: Correct identification of futile prehospital resuscitation in out-of-hospital cardiac arrest (OHCA) may reduce unnecessary transports. Reliable prediction variables are needed for 'termination of resuscitation' (TOR) rules in OHCA. However, making such prediction models requires a large number of samples and time-consuming statistical analysis. Deep learning (DL), a form of artificial intelligence (AI), is attractive for building such prediction models. We made a TOR prediction model using a DL software, Prediction One (Sony Network Communications Inc., Tokyo, Japan). The purpose of this study was to evaluate the efficacy of this predictive model using general purpose AI compared to the Universal TOR rule for out - of hospital cardiac arrest. Methods: A retrospective, population-based review of OHCA victims without prehospital ROSC from January 1, 2010 to December 31, 2017 in the All-Japan Utstein Registry. We divided half (2010-2014) as a training dataset and half (2015-2017) as an external validation dataset. Prediction one made the prediction model using the training dataset with internal cross-validation. We used both the created model and the Universal TOR rule to predict outcomes using the external validation set. Results: 989,929 OHCA cases, 18 years of age or older, were registered in the All-Japan Utstein Registry and 575,346 cases were of presumed cardiac origin. Of these, 354,356 cases were used as the training dataset and 220,990 cases were used as the external validation dataset. The model made by Prediction One using 11 variables had AUC of 0.969 and F value of 0.969, and its AUC for the validation cohort was 0.964 (95%CI 0.963-0.966) with 99.3% accuracy. The model made by Prediction One using three variables of universal TOR rule had AUC of 0.948 and F value 0.967, and its AUC for the validation cohort was 0.939 (95%CI 0.936-0.942) with 99.1% accuracy. Conclusions: The accuracy of prediction models using Prediction One was good. More research into the utility of using AI for TOR prediction is required.

Abstract 123: Bystander Cpr Usage In Out-of-hospital Cardiac Arrest During The Covid-19 Pandemic: Results From The Northeast Georgia Cardiac Arrest Registry

Background: During the COVID-19 pandemic, a higher incidence of out-of-hospital cardiac arrest (OHCA) has been reported but rates of bystander CPR usage have not been studied. Due to the COVID-19 pandemic, bystanders may be reluctant to perform CPR due to risk of infection and due to social isolation measures, there may be less bystanders present to perform CPR.Objective: The purpose of the study was to study rates of bystander CPR usage in out-of hospital cardiac arrest (OHCA) during the COVID-19 pandemic and to evaluate for any association between bystander CPR usage and increasing COVID-19 infection during 2020 and 2021. Methods: We performed a retrospective study of the Northeast Georgia Cardiac Arrest Registry to compare bystander CPR usage for all patients presenting to Northeast Georgia Medical Center in Gainesville, Georgia with OHCA from 14 surrounding counties of northeast Georgia from March 2019 to December 2021. Results: A total of 18,421 and 18,678 COVID-19 infections were reported in Hall County between Mar-Dec 2020 and Jan-Dec 2021, respectively. A total of 228 cardiac arrests occurred in 2019, 273 in 2020, and 268 in 2021. Overall bystander CPR usage was 44% in 2019, 43% in 2020, and 47% in 2021, p = .64. Before COVID-19 the bystander CPR usage was 43% and 46% during, p = 0.44. There was no significant correlation between bystander CPR usage and COVID-19 infections in Hall County (r = 0.06, p = 0.79). Multivariable logistic regression model demonstrated that initial shockable rhythm (p &lt; 0. 001) was the strongest predicator of bystander CPR (table 1). Conclusions: Bystander CPR usage in OHCA in the northeast Georgia region remained constant despite the COVID-19 pandemic. There were no significant differences in bystander CPR usage in OHCA prior to or during COVID-19 pandemic. Additional studies are needed to evaluate for possible variables which may be contributing to initial shockable rhythm as the strongest predicator of bystander CPR.

Abstract 172: Utility Of Cerebrospinal Fluid Lactate To Predict Neurological Prognosis In Patients With Out Of Hospital Cardiac Arrest Undergoing Target Temperature Management

Utility of cerebrospinal fluid lactate to predict neurological prognosis in patients with out of hospital cardiac arrest undergoing target temperature managementLactate is a predictor of poor neurological prognosis in patients with OHCA undergoing TTM.However, CSF lactate is independent on serum lactate, and has rapid turn around time. Therefore, we investigated the prognostic value of CSF lactate, measured every 2 h for 24 h after ROSC and the incidence of mitochondrial dysfunction (MD) and ischaemia with increased CSF lactate in the groups with good and poor neurological prognosis.This was a prospective observational study conducted from March 2021 to April 2022 (**** IRB 2020-04-051). All patients were monitored with aEEG. Serum and CSF were obtained using a radial arterial and a lumbar catheter. 22 patients were required through sample size calculation. The comparison of lactate between the two groups was evaluated using the generalized estimating equation. The AUROC was used to identify the prognostic values of lactate (Fig. 1, Table 1). Parameters measured immediately, and 24 h after ROSC were not different between the two groups (Table 2). CSF lactate level was higher in the group with poor neurological prognosis, and CSF lactate showed better performance in predicting poor neurological prognosis, even after 6 h post ROSC (Table 3, 4, Fig. 2). Additionally, the neurological prognosis was poor when MD or ischaemia in brain persisted more than 16 h after ROSC (Fig. 3).This study demonstrated that CSF lactate was a valuable tool in predicting poor neurological prognosis, and cases in which MD or ischaemia in the brain persisted more than 16 h after ROSC had poor outcome.

Abstract 15563: Analysis of the Ventricular Fibrillation Waveform Can Guide Resuscitation in Cardiac Arrest by Identifying the Precipitating Cause and Estimating the Underlying Hemodynamics

Background: Patients presenting with out of hospital cardiac arrest (OHCA) and prolonged (&gt;30 min) cardiopulmonary resuscitation (CPR) face nearly 100% mortality. In patients presenting with ventricular fibrillation (VF), coronary ischemia is thought to be the cause in up to 60%. As conventional CPR does not reverse a coronary ischemia, CPR often must be done until a patient can be brought to a cardiac catheterization laboratory (CCL) where the underlying cause (acute ischemia) can be treated. In a porcine model of cardiac arrest, we have previously demonstrated that machine learning (ML) targeting invasive hemodynamic monitoring, could significantly improve CPR quality. To advance the clinical relevance of the machine-controlled CPR methods, we developed ML algorithms that can diagnose coronary ischemia during VF, and infer the underlying hemodynamics while performing CPR. Methods: In a porcine model of cardiac arrest, VF was induced via high-grade coronary occlusion (ischemia) or electrical stimulation (dysrhythmia). The animals (n = 72) were left in VF for 3 minutes prior to intervention and the ECG waveform was collected. The VF signal was converted to the frequency domain using a fast-fourier transformation and an ensemble classifier was developed to detect underlying ischemia. CPR was then initiated and the VF waveform was continuously monitored along with the coronary perfusion pressure (CPP). We then developed a 20-layer convolutional neural network (CNN) to non-invasively infer the CPP from a 10-second VF waveform. Results: Animal studies were split into training and test sets. When using the developed ML technique to detect ischemia from the VF waveform, evaluation of the test set yielded an area under the curve (AUC) of 0.81 on a ROC. When we used the CNN to infer the underlying hemodynamics, we demonstrated a high correlation between measured and predicted CPP in the test set. The AUC for the ROC when predicting a CPP of &gt;15 mmHg was 0.85. Conclusion: Survival for patients with OHCA secondary to coronary ischemia will improve with rapid diagnosis and high quality CPR. Our results demonstrate the proof-of-concept that the VF waveform contains features that can guide resuscitation for cause identification and hemodynamic improvement.