Non-shockable Rhythm Research Articles

Abstract 13013: Survival After In-Hospital Cardiopulmonary Resuscitation for Cardiac Arrest in Patients With COVID-19: An Updated Meta-Analysis

Introduction: Several small studies have reported variable outcomes following in-hospital cardiac arrest (IHCA) in patients with COVID-19. A clear estimate is important in prognostication and guiding resuscitation efforts and policies for these patients. Methods: A search of PubMed, Embase, and Scopus databases was conducted to identify studies reporting outcomes after IHCA in adult patients with confirmed COVID-19. The cumulative characteristics of the patients were described. The primary outcome studied was survival at 30 days or at hospital discharge (short term survival). Additional outcomes of interest were proportional prevalence of the initial rhythm at arrest, return of spontaneous circulation (ROSC), and neurological recovery (defined as Cerebral Performance Category Score of 1-2 ). Metanalysis of proportions was performed utilizing the Metaprop command. A random effects model was chosen to account for interstudy variance. Results: A total of 13 eligible studies were identified and included in the analyses. Out of all the hospitalized patients with COVID-19, 1,618 underwent advanced cardiac resuscitation after an IHCA. Patients who had a cardiac arrest had a median age between 50-69 years. IHCA occurred predominantly in men, and in the ICU setting. Shockable rhythms were identified in 8% (95% CI 5-10%, I2; 56%) and non-shockable rhythms in 89% (95% CI 85-94% I2; 84%) of patients (Fig. 1a). ROSC was achieved in 40% (95% CI 31-48% I2; 90%) (Fig. 1b). Only 7 % ( 95% CI 3-12% I2; 86%) of patients survived at 30 days/hospital discharge (Fig. 1c). Neurological recovery was seen in 5% (95% CI 3-9% I2; 67%) of patients who suffered a IHCA (Fig. 1d). Conclusions: Our meta-analysis demonstrates the majority of the cardiac arrests in patients with COVID-19 have non-shockable rhythms. Survival rate in these patients is low, and neurological recovery is unfavorable. This study provides further insight in guiding resuscitation efforts in these patients.

Abstract 12792: Enhancing the Accuracy of Cardiac Rhythm Analysis in Automated External Defibrillators During Ongoing Cardiopulmonary Resuscitation by Applying a Deep Encoder-Decoder Filtering Model

Survival from out-of-hospital cardiac arrests depends on an accurate defibrillatory shock decision during cardiopulmonary resuscitation (CPR). Since chest compressions induce severe motion artifact in the electrocardiogram (ECG), current automatic external defibrillators (AEDs) do not perform CPR during the rhythm analysis period. However, performing continuous CPR is vital and dramatically increases the chance of survival. Hence, we demonstrate a novel application of a deep convolutional neural network encoder-decoder (CNNED) method in suppressing CPR artifact in near real-time using only ECG data. The encoder portion of the CNNED uses the frequency and phase contents derived via time-varying spectral analysis to learn distinct features that are representative of both the ECG signal and CPR artifact. The decoder portion takes the results from the encoder and reconstructs what is perceived as the motion artifact removed ECG data. These procedures are done via multitude of training of CNNED using many different arrhythmia contaminated with CPR. In this study, CPR-contaminated ECGs were generated by combining clean ECG with CPR artifacts from 52 different performers. ECG data from CUDB, VFDB, and SDDB datasets which belong to the Physionet’s Physiobank archive were used to create the training set containing 89,984 14-second ECG segments. The performance of the proposed CNNED was evaluated on a separate test set comprising of 23,816 CPR-contaminated 14-second ECG segments from 458 subjects. The results were evaluated by two metrics: signal-to-noise ratio (SNR), and Defibtech’s AED rhythm analysis algorithm. CNNED resulted in the increase of the mean SNR value from -3 dB to 5.63 dB and 6.3 dB for shockable and non-shockable rhythms, respectively. Comparing Defibtech’s AED rhythm classifier before and after applying CNNED on the CPR-contaminated ECG, the specificity improved from 96.57% to 99.31% for normal sinus rhythm, and from 91.5% to 96.57% for other non-shockable rhythms. The sensitivity of shockable detection also increased from 67.68% to 87.76% for ventricular fibrillation, and from 62.71% to 81.27% for ventricular tachycardia. These results indicate continuous and accurate AED rhythm analysis without stoppage of CPR using only ECG data.

Abstract 8883: Pre-hospital Physician’s Presence and Neurological Outcome Among Patients Performed Pre-hospital Advanced Airway Management: A Nationwide Multicenter Observational Study in Japan (the Japanese Association for Acute Medicine-out-of-Hospital Cardiac Arrest Registry)

Purpose: Using the out-of-hospital cardiac arrest (OHCA) registry in Japan, we evaluated the effectiveness of pre-hospital advanced airway management under physicians’ presence after adjusting in-hospital treatments. Methods: This was a multicenter cohort study. We registered all consecutive OHCA patients in Japan who, from 1 June 2014 through 31 December 2017, were transported to institutions participating in the Japanese Association for Acute Medicine OHCA Registry. We included OHCA patients performed pre-hospital advanced airway management, who were ≥18 years of age with medical etiology and who received resuscitation from emergency medical services (EMS) personnel and medical professionals in hospitals. The primary outcome was one-month favorable neurological survival.We estimated the propensity score by fitting a logistic regression model that was adjusted for several variables before the arrival of EMS personnel and/ or pre-hospital physician. A multivariable logistic regression analysis in propensity score-matched patients was used to adjust confounders including extracorporeal membrane oxygenation, percutaneous coronary intervention, intra-aortic balloon pumping, and targeted temperature management. Results: We analyzed 9,672 patients. Among them, 2.3% (N = 218) had a neurologically favorable outcome. The adjusted odds ratio (AOR) of pre-hospital advanced airway management under physicians’ presence compared with their absence for primary outcome was 0.96 (95% confidence interval (CI): 0.61-1.51). Among first documented non-shockable cardiac rhythm, the AOR was 3.10 (95% CI: 1.05-10.77). Among first documented shockable cardiac rhythm, the AOR was 0.90 (95% CI: 0.53-1.53). Conclusion: In Japan, pre-hospital advanced airway management under physicians’ presence was not associated with one-month favorable neurological survival among patients with first documented shockable cardiac rhythm, whereas it was associated with a neurologically favorable outcome among patients with first documented non-shockable cardiac rhythm.

Abstract 11372: A Risk-Adjustment Model for Patients Presenting to Hospitals with Out-of-Hospital Cardiac Arrest and ST-Elevation Myocardial Infarction

Background: Given the diversity of patients resuscitated from out-of-hospital cardiac arrest (OHCA) complicated by STEMI, adequate risk adjustment is needed to account for potential differences in case-mix to reflect the quality of percutaneous coronary intervention. Objectives: We sought to build a risk-adjustment model of in-hospital mortality outcomes for patients with OHCA and STEMI requiring emergent angiography. Methods: Within the Cardiac Arrest Registry to Enhance Survival, we included adult patients with OHCA and STEMI who underwent angiography within 2 hours from January 2013 to December 2019. Using pre-hospital patient and arrest characteristics, multivariable logistic regression models were developed for in-hospital mortality. We then described model calibration, discrimination, and variability in patients’ unadjusted and adjusted mortality rates. Results: Of 2,999 hospitalized patients with OHCA and STEMI who underwent emergent angiography (mean age 61.2 ±12.0, 23.1% female, 64.6% white), 996 (33.2%) died. The final risk-adjustment model for mortality included higher age, unwitnessed arrest, non-shockable rhythms, not having sustained return of spontaneous circulation upon hospital arrival, and higher total resuscitation time on scene ( C -statistic, 0.804 with excellent calibration). The risk-adjusted proportion of patients died varied substantially and ranged from 7.8% at the 10 th percentile to 74.5% at the 90 th percentile (Figure). Conclusions: Through leveraging data from a large, multi-site registry of OHCA patients, we identified several key factors for better risk-adjustment for mortality-based quality measures. We found that STEMI patients with OHCA have highly variable mortality risk and should not be considered as a single category in public reporting. These findings can lay the foundation to build quality measures to further optimize care for the patient with OHCA and STEMI.

Abstract 11666: Who Could Return To Their Former Lifestyle In Comatose Survivors Of Cardiac Arrest With Asystole?

Introduction: In patients with initial shockable rhythms had favor outcomes than those with non-shockable rhythms, and those of asystole had worst outcomes. Purpose: The purpose of the study is to investigate the predictors of favorable outcomes in specific in the asystole rhythms. Method: Patients who were resuscitated after out-of-hospital cardiac arrest and were underwent targeted temperature management were enrolled in this study. Patients were divided into 3 groups according to initial recorded rhythms after indexed cardiac arrest. Favorable outcomes were defined as cerebral performance category of 1 or 2 after 90 days of indexed cardiac arrest. The logistic regression analysis was performed to assesses independent predictor of favorable outcomes. Results: Among the 305 study patients, 57 (19%) patients had initially recorded asystole rhythms, 149 (49%) patients had shockable rhythms, and 99 (32%) patients had pulseless electrical activity (PEA). The patients of PEA were elder (median 62 y [interquartile range 49 y - 72 y], 65 [57 - 75], and 62 [49 - 74], P = 0.03 in the patients of shockable, PEA, and asystole), the rate of male was higher in the shockable (86%, 58%, and 72%, P < 0.001), the time interval from collapse to return of spontaneous circulation (ROSC) were longer in the asystole (28 min [17 - 48], 37 [24 - 53], and 46 [39 - 61], P < 0.001), and the lactate of hospital arrival were higher in the asystole (10.1 mmol/l [6.1 mmol/l - 13.6 mmol/l], 12.0 [8.6 - 15.4], and 13.3 [9.6 - 18.3], P = 0.002). The rate of acute coronary syndrome as the cause of arrest were similar between the groups (45%, 34%, and 28%, P = 0.06). The rate of favorable outcome was 53%, 21%, and 12% (P < 0.001), respectively. The time interval from collapse to ROSC were independently associated with favorable outcomes in the patients of all initial recorded rhythms. Conclusions: The cardiac arrest patients who were witnessed arrest or shorter interval from collapse to ROSC with initial recorded asystole rhythms had favor outcomes than those not. We could not find specific predictors in the patients with asystole.

Abstract 13761: Does Targeted Temperature Management Modify the Association Between Increasing Epinephrine Dose and Survival Outcomes Following Out-of-Hospital Cardiac Arrest?

Introduction: Epinephrine (EPI) improves return of circulation after out of hospital cardiac arrest (OHCA). These beneficial cardiac effects are not accompanied by improved neurological survival possibly due to EPI induced microvascular effects and critical brain ischemia. We hypothesized that these dose-dependent adverse EPI effects may be mitigated by targeted temperature management (TTM) such that the relative benefit of TTM is greater at higher EPI doses. Methods: This was a retrospective cohort study of adult non-traumatic OHCA patients in Seattle and King County, Washington from 2008-2018, who were unconscious at hospital admission. We used logistic regression to assess the relationship among EPI dose, TTM, and survival to hospital discharge, and survival with favorable neurological status (Cerebral Performance Category (CPC) 1 or 2). The model evaluated whether TTM modified the association of increasing EPI dose using an interaction term between TTM and EPI dose. Results were stratified by initial shockable vs non-shockable rhythm. Results: Of 5254 eligible patients, the median EPI dose was 2.0 mg (IQR 1.0 - 3.0); 3052 (58%) received TTM. In all, 2177 (41%) survived to discharge, and 1889 (36%) survived with CPC 1-2. Increasing dose of EPI was associated with a decreasing likelihood of survival (OR 0.58, [95% CI 0.55-0.61] for each additional mg of EPI) and CPC 1-2 (OR 0.56, [0.53-0.59]). The dose-dependent EPI association was modified by TTM. After adjustment for Utstein covariates, for each additional mg of EPI, TTM was associated with a relative stepwise improvement in odds of survival (interaction OR 1.35, [1.23, 1.49]) and CPC 1-2 (OR 1.34, [1.21, 1.50]) (Figure). This interaction was consistent among shockable and non-shockable OHCA (Figure). Conclusions: We observed an interaction between TTM and EPI dose such that the beneficial association of TTM increased with increasing EPI dose, suggesting TTM may attenuate the adverse effects of higher dose EPI.

Abstract 10611: Variation in Out-of-Hospital Cardiac Arrest Survival Across EMS Agencies

Background: Although some studies have reported variation in out-of-hospital cardiac arrest (OHCA) survival by neighborhood and geographic region, little is known about variation in OHCA survival at the level of EMS agencies—which, unlike neighborhoods and regions, may have modifiable resuscitation practices. Methods: Within the national Cardiac Arrest Registry to Enhance Survival, we identified 258,320 non-traumatic OHCAs from 764 EMS agencies with ≥10 OHCAs annually between 2015-2019. Using multivariable hierarchical logistic regression, we computed risk-adjusted rates of survival to hospital admission for each EMS agency. We quantified the extent of variation in survival with the median odds ratios (MOR) and assessed the extent to which variation in survival was explained by two EMS agency resuscitation practices: time from 911 call to EMS arrival and the proportion of OHCAs at each EMS agency with termination of resuscitation (TOR) without meeting TOR futility criteria. Results: Of 258,320 persons with OHCA, mean age was 62.2 ± 17.0 years and 36.1% were female. Overall, 85.0% were of presumed cardiac etiology, 82.3% occurred at home, 44.0% were witnessed by a bystander, and ~75% were due to a non-shockable initial rhythm. Across the 764 EMS agencies, the median risk-adjusted rate of survival to hospital admission was 27.4% (IQR, 24.5% - 30.2%). The adjusted MOR was 1.35 (95% CI: 1.32, 1.39), suggesting that the odds of survival to hospital admission after an OHCA varied by 35% in two identical patients in one randomly selected EMS agency vs. another. EMS agencies in the lowest quartile of risk-adjusted survival had a mean EMS response time of 12.0 ± 3.4 minutes, whereas those in the highest quartile had a mean EMS response time of 9.0 ± 2.6 minutes ( P <0.001). The mean proportion of OHCA cases where CPR was terminated in the field without meeting TOR futility criteria was 27.9% ±16.1% in quartile 1 and 18.9% ±11.4% in quartile 4 ( P <0.001). Adjustment for the EMS-level variation in both resuscitation practices attenuated the MOR to 1.30 (95% CI: 1.27, 1.33). Conclusions: Rates of survival to hospital admission for OHCA vary significantly by EMS agency, and some of this variation in survival is explained by differences in EMS arrival time and TOR practice patterns.

Abstract 13076: Refractory Out-of-Hospital Cardiac Arrest in Patients With Pulmonary Embolism and Use of Extracorporeal Membrane Oxygenation: Prague OHCA Study Subanalysis

Introduction: Refractory out-of-hospital cardiac arrest (r-OHCA) in patients with pulmonary embolism (PE) has poor outcome. Data about use of extracorporeal membrane oxygenation (ECMO) in PE are heterogenous and there is minimal evidence for its use in patients presenting with r-OHCA. Hypothesis: To describe in detail profile, initial settings of cardiac arrest (CA) and clinical course of patients with PE presenting with r-OHCA and its specifics in comparison to patients with r-OHCA of other cause. The special attention was paid to the use of ECMO and its potential benefit for patient prognosis. Methods: We reanalyzed subgroup of patients with PE from Prague OHCA study - a randomized control trial evaluating the effect of hyperinvasive approach including the use of ECMO in r-OHCA. Patients characteristics, the specifics of CA settings and the outcome were compared to the patients with other cause of r-OHCA. The neurologically favorable survival was then compared between PE patients randomized to Hyperinvasive and Standard arm of the study. Results: The PE was identified as a cause of CA in 24 (9.4 %) patients in Prague OHCA study. PE patients were more likely women (12 [50 %] vs 32 [13.8 %]) with non-shockable initial rhythm (23 [95.8 %] vs 77 [33.2 %]; P < 0.0001). The CA occurs more frequently after arrival of emergency medical service (14 [58.3 %], vs 22 [9.5 %]; P < 0.0001), had shorter time to hospital admission (median in minutes [IQR], 40 [34.5-57.8] vs 54 [46-64]; P = 0.01) with more severe acidosis at admission (median pH [IQR]; 6.83 [6.75-6.88] vs 6.98 [6.82-7.14] P = 0.0008). The primary outcome of patients with PE - CPC 1 or 2 at 180 days - was significantly worse (2 [8.3 %] vs 66 [28.4 %]; P = 0.049). There was non-significant difference in primary outcome - CPC 1 or 2 at 180 days - between PE patients in Hyperinvasive (12 [50%]) and Standard arm of the study (2 [16.7 %] vs 0; P = 0.24). Conclusion: The initial profile of patients and the settings of CA in patients with r-OHCA and PE differs from patients with other CA cause and their prognosis is significantly worse. The Hyperinvasive approach did not improved outcome in this subgroup of patients.

Abstract 13407: Validation of the MIRACLE2 Score for Prognostication After Out of Hospital Cardiac Arrest

Background: Early prediction of long-term outcomes after out-of-hospital cardiac arrest (OOHCA) remains a diagnostic challenge. MIRACLE2 is a points-based risk score that has been derived as a simple tool to aid clinicians in prognosticating those at high risk of poor neurological outcomes. To date, the score has been validated in two independent cohorts in the MIRACLE2 study. The aim of this study was to validate the MIRACLE2 score in a further independent cohort, with the primary outcome poor neurological outcome at 6 months (Cerebral Performance Category (CPC) 3-5). Methods: We retrospectively identified all patients treated at the Bristol Royal Infirmary from January 2019 to July 2020 with a primary or secondary ICD-10 diagnosis code for cardiac arrest. Patients were screened against the inclusion and exclusion criteria used in the MIRACLE2 study and the data required to calculate the MIRACLE2 and CPC scores were extracted from medical records. Results: 198 patients met the OOHCA inclusion criteria and were included for analysis. Multivariable logistical regression confirmed 6 out of the 7 MIRACLE2 components as independent predictors of poor neurological outcome at 6 months: age category (60-80 years, OR 6.4, p=0.005; >80 years, OR 148.1, p<0.001), initial non-shockable rhythm (OR 36.9, p<0.001), non-reactivity of pupils (OR 13.7, p=0.002), low pH <7.20 (OR 5.1, p=0.014), adrenaline administration (OR 4.1, p=0.024), changing intra-arrest rhythms (OR 3.4, p=0.048). The MIRACLE2 score had an area under the curve of 0.89. The risk of poor neurological outcome in this cohort, across the previously described MIRACLE2 score risk groups (low <=2, intermediate 3-4, and high >=5), was comparable to that in the MIRACLE2 study (low: 15% vs. 6%; intermediate: 54% vs. 55%; and high: 93% vs. 92%, respectively). Conclusion: The MIRACLE2 score has been externally validated in an independent cohort as an accurate predictor of poor neurological outcome following OOHCA.

Abstract 9502: Prehospital Variables Associated With Neurologically Intact Survival in Elderly Survivors After Out-of-Hospital Cardiac Arrest: Evidence from a Japanese Nationwide Population-based Cohort Study

Introduction: Prehospital variables associated with neurologically intact survival in elderly survivors after out-of-hospital cardiac arrest (OHCA) are unclear and could differ according to age. Methods: We evaluated 6,349 elderly patients with OHCA (age ≥ 65 years) of cardiac origin who achieved prehospital return of spontaneous circulation (ROSC) and survived for at least 1-month after OHCA. Data were obtained from the prospectively recorded All-Japan Utstein Registry between 2011 and 2016. Patients witnessed by emergency medical service providers were excluded. The primary outcome was 1-month neurologically intact survival, defined as a cerebral performance category (CPC) score of 1-2. Patients were divided into three groups by age (65-74, 75-89, or ≥ 90 years). The time from call receipt to ROSC was calculated. Results: The rates of 1-month CPC 1-2 in patients aged 65-74, 75-89, and ≥ 90 years were 66.5% (2,079/3,125), 52.9% (1,557/2,943), and 42.7% (120/281), respectively (p for trend < 0.001). In multivariate logistic regression analysis, initial shockable rhythm and witnessed arrest were significantly associated with 1-month CPC 1-2 for all age groups (Table). However, the presence of bystander cardiopulmonary resuscitation (CPR) was significantly associated with 1-month CPC 1-2 only for patients aged 65-74 years. Time from call receipt to ROSC was not associated with 1-month CPC 1-2 for patients aged ≥ 90 years. In recursive partitioning analysis, the best single predictor for 1-month CPC 1-2 was initial shockable rhythm for all age groups. The next predictor for patients aged 65-74 years with initial shockable rhythm was the presence of bystander CPR, whereas the witnessed arrest was the next predictor for patients aged 65-74 years with initial non-shockable rhythm and other age groups regardless of the initial rhythm. Conclusions: Prehospital variables associated with neurologically intact survival in elderly survivors after OHCA varied with age.

Abstract 13292: Comparison of Outcomes Between Pulseless Electrical Activity by Electrocardiography and Pulseless Myocardial Activity by Echocardiography in Out-of-Hospital Cardiac Arrest

Objective: To measure prevalence of discordance between electrical activity recorded by electrocardiography (ECG) and myocardial activity visualized by echocardiography (echo) in patients presenting after cardiac arrest and to compare survival outcomes in cohorts defined by ECG and echo. Methods: This is a secondary analysis of a previously published prospective study at twenty hospitals. Patients presenting after out-of-hospital arrest were included. The cardiac electrical activity was defined by ECG and contemporaneous myocardial activity was defined by bedside echo. Myocardial activity by echo was classified as myocardial asystole- -the absence of myocardial movement, pulseless myocardial activity (PMA)--visible myocardial movement but no pulse, and myocardial fibrillation- -visualized fibrillation. Primary outcome was the prevalence of discordance between electrical activity and myocardial activity. Secondary outcome was survival to hospital discharge. Results: 793 patients and 1943 pauses in CPR were included. 28.6% of CPR pauses demonstrated a difference in electrical activity (ECG) and myocardial activity (echo), 5.0% with asystole (ECG) and PMA (echo), and 22.1% with PEA (ECG) and myocardial asystole (echo). Survival to hospital admission for patients with PMA (echo) was 29.1% (95%CI-23.9-34.9) compared to those with PEA (ECG) (21.4%, 95%CI-17.7-25.6). Twenty-five percent of the 32 pauses in CPR with a shockable rhythm by echo demonstrated a non-shockable rhythm by ECG and were not defibrillated. One of these patients survived, a patient with asystole on ECG and vfib by echo survived because vfib was identified on ECG during a subsequent pause and was defibrillated. Conclusion: Patients in cardiac arrest commonly demonstrate different electrical (ECG) and myocardial activity (echo). Further research is needed to better define cardiac activity during cardiac arrest and to explore outcome between groups defined by electrical and myocardial activity.

Abstract 11532: Variation in Coronary Angiography Use in Out-of-Hospital Cardiac Arrest

Introduction: Current patterns of use of coronary angiography (CAG) among out-of-hospital cardiac arrest (OHCA) patients based on ST segment elevation (STE) on post-resuscitation ECG are not well described. Methods: Using data from the Continuous Chest Compressions trial between 2011 and 2016, we identified OHCA patients who survived to hospitalization. We examined rates of CAG across different trial clusters in the overall cohort and among pre-specified subgroups with presumed cardiac etiology of arrest e.g. initial shockable rhythm and STE on presenting ECG. Results: Of 26,148 OHCA patients across 49 trial clusters, 5608 survived to hospital admission. The mean age of patients was 64 years, with 65% men and 43% with initial shockable rhythm. Among patients with initial shockable rhythm 44% had STE on initial ECG compared with 18% of patients with initial non-shockable rhythm. Use of CAG was significantly higher in patients presenting with STE compared with no STE on initial ECG irrespective of initial rhythm: 70% vs. 31%, p<0.001 for initial shockable rhythm and 28% vs. 5%, p<0.001 for initial non-shockable rhythm. In the overall cohort, there was significant variation in CAG use across trial clusters ranging from 4% - 41% of patients within a trial cluster receiving CAG ( Figure ). This variation persisted among pre-specified subgroups with the proportion of patients within a trial cluster receiving CAG ranged from 11% - 75% for patients with initial shockable rhythm, 0% to 19% with initial non-shockable rhythm, 16% - 82% with STE, 2% - 28% without STE and 0% - 63% in patients with initial shockable rhythm and no STE on presenting ECG ( Figure ). Conclusion: There is a higher use of CAG in STE and shockable cardiac arrest, consistent with presumed cardiac etiology of arrest; however, there is large variation in the use of CAG across sites, even among patients with a presumed cardiac etiology of cardiac arrest suggesting challenges with interpretation of current guidelines.

Comparison of outcomes between pulseless electrical activity by electrocardiography and pulseless myocardial activity by echocardiography in out-of-hospital cardiac arrest; secondary analysis from a large, prospective study

ObjectiveTo measure prevalence of discordance between electrical activity recorded by electrocardiography (ECG) and myocardial activity visualized by echocardiography (echo) in patients presenting after cardiac arrest and to compare survival outcomes in cohorts defined by ECG and echo. MethodsThis is a secondary analysis of a previously published prospective study at twenty hospitals. Patients presenting after out-of-hospital arrest were included. The cardiac electrical activity was defined by ECG and contemporaneous myocardial activity was defined by bedside echo. Myocardial activity by echo was classified as myocardial asystole--the absence of myocardial movement, pulseless myocardial activity (PMA)--visible myocardial movement but no pulse, and myocardial fibrillation--visualized fibrillation. Primary outcome was the prevalence of discordance between electrical activity and myocardial activity. Results793 patients and 1943 pauses in CPR were included. 28.6% of CPR pauses demonstrated a difference in electrical activity (ECG) and myocardial activity (echo), 5.0% with asystole (ECG) and PMA (echo), and 22.1% with PEA (ECG) and myocardial asystole (echo). Twenty-five percent of the 32 pauses in CPR with a shockable rhythm by echo demonstrated a non-shockable rhythm by ECG and were not defibrillated. Survival for patients with PMA (echo) was 29.1% (95%CI-23.9–34.9) compared to those with PEA (ECG) (21.4%, 95%CI–17.7–25.6). ConclusionPatients in cardiac arrest commonly demonstrate different electrical (ECG) and myocardial activity (echo). Further research is needed to better define cardiac activity during cardiac arrest and to explore outcome between groups defined by electrical and myocardial activity.

Abstract 11034: Extracorporeal Life-Support for Out-of-Hospital Cardiac Arrest: A Nationwide Multicenter Study

Introduction: Despite promising survival and favorable neurological results in IHCA, the outcomes of ECLS for OHCA are more heterogeneous. The clinical setting for the survival and favorable neurological outcomes of ECLS in OHCA may differ from that in IHCA. Hypothesis: This study aimed to determine whether ECLS is associated with improved survival to hospital discharge with favorable neurological outcome compared to conventional cardiopulmonary resuscitation and identify in which OHCA patients the implementation of ECLS would be beneficial. Methods: The clinical outcome of OHCA treated by ECLS or CCPR between 2015 and 2020 was retrospectively investigated using KoCARC, a nationwide multicenter OHCA registry of Korea. Differences in baseline clinical characteristics were adjusted by matching propensity for ECLS. Primary outcome was 30-day survival with neurologically favorable status of cerebral performance category of 1 or 2. Restricted mean survival time (RMST) was used to compare outcome between groups. Result: Of 12,006 patients (mean age=71, male gender=65%) included, ECLS was performed in 272 patients (2.2%). In unadjusted analysis, the frequency of survival with favorable neurological status was higher in ECLS compared to CCPR (15% versus 7%, RMST 9.4 versus 3.8 days, p<0.001). Subgroup analysis revealed that the benefit of ECLS was evident in high-risk groups including initial non-shockable rhythm or CPR duration≥20 min (p<0.05, all). In analysis of propensity score-matched 271 pairs, there was no difference in the clinical outcome between ECLS and CCPR (15% versus 16%, RMST 9.4 versus 9.0 days, p=0.33), but ECLS was still better than CCPR in initial non-shockable rhythm or CPR duration≥20 min (p<0.05, all). Conclusions: In this real-world data analysis, ECLS compared to CCPR did not result in better clinical outcome of OHCA in overall. However, ECLS might be beneficial for high-risk patients such as initial non-shockable rhythm or CPR duration≥20 min.

Abstract 12127: The Effect of Daylight Savings Time Transitions on the Incidence of Out-of-Hospital Cardiac Arrest: An Interrupted Time Series Analysis

Introduction: Many studies have reported increases in the risk of acute cardiovascular events following daylight savings time (DST) transitions. We sought to investigate the effect of DST transitions on the incidence of out-of-hospital cardiac arrest (OHCA) in Victoria, Australia. Methods: Between January 2000 and December 2020, we performed an interrupted time series analysis of the daily number of OHCA cases of medical etiology from the Victorian Ambulance Cardiac Arrest Registry. The effect of DST transition on OHCA incidence was estimated using negative binomial models and reported as either ‘immediate’ or ‘cumulative’ effects. Immediate effects were the average effects observed on the day of DST transition or each of the 6 days after DST transition. Cumulative effects were the sum of the average effects up to 6 days after the day of DST transition. Models were adjusted for population growth, temporal trends, and public holidays. Results: A total of 89,409 adult OHCA of medical etiology were included. Following the spring DST transition (i.e. shorter day), there was an immediate 13% (IRR 1.13, 95% CI: 1.02, 1.25; p=0.02) increased risk of OHCA on the day of transition (Sunday) and the cumulative risk of OHCA remained higher over the first 2 days (IRR 1.17, 95% CI: 1.02, 1.34; p=0.03) compared to non-transitional days. Following the autumn (fall) DST transition (i.e. longer day), there was a significant lagged effect on the Tuesday following transition, with a 12% (IRR 0.88, 95% CI: 0.77, 0.99; p=0.04) reduced risk of OHCA. The autumn (fall) DST transition also showed a cumulative effect on OHCA incidence, with a 30% (IRR 0.70, 95% CI: 0.51, 0.96; p=0.03) reduction in the incidence of OHCA by the end of the transitional week. Subgroups aged > 65 years and cases with initial non-shockable rhythms were most vulnerable to DST transitions. Conclusions: This study showed that there is a modest increased risk of OHCA in the 2 days following the spring DST transition and a decreased risk of OHCA in the week following the autumn DST transition. These findings should promote further research exploring strategies to reduce the risk of OHCA in vulnerable populations.

Insights from patients screened but not randomised in the HYPERION trial

BackgroundFew data are available about outcomes of patients screened for, but not enrolled in, randomised clinical trials.MethodsWe retrospectively reviewed patients who had non-inclusion criteria for the HYPERION trial comparing 33 °C to 37 °C in patients comatose after cardiac arrest in non-shockable rhythm, due to any cause. A good neurological outcome was defined as a day-90 Cerebral Performance Category score of 1 or 2.ResultsOf the 1144 patients with non-inclusion criteria, 1130 had day-90 information and, among these, 158 (14%) had good functional outcomes, compared to 7.9% overall in the HYPERION trial (10.2% with and 5.7% without hypothermia). Considerable centre-to-centre variability was found in the proportion of non-included patients who received hypothermia (0% to 83.8%) and who had good day-90 functional outcomes (0% to 31.3%). The proportion of patients with a good day-90 functional outcome was significantly higher with than without hypothermia (18.5% vs. 11.9%, P = 0.003).ConclusionOur finding of better functional outcomes without than with inclusion in the HYPERION trial, despite most non-inclusion criteria being of adverse prognostic significance (e.g., long no-flow and low-flow times and haemodynamic instability), raises important questions about the choice of patient selection criteria and the applicability of trial results to everyday practice. At present, reserving hypothermia for patients without predictors of poor prognosis seems open to criticism.

Incidence, clinical characteristics, and outcome after unexpected cardiac arrest among critically ill adults with COVID-19: insight from the multicenter prospective ACICOVID-19 registry

BackgroundInitial reports have described the poor outcome of unexpected cardiac arrest (CA) in intensive care unit (ICU) among COVID-19 patients in China and the USA. However, there are scarce data on characteristics and outcomes of such CA patients in Europe.MethodsProspective registry in 35 French ICUs, including all in-ICU CA in COVID-19 adult patients with cardiopulmonary resuscitation (CPR) attempt. Favorable outcome was defined as modified Rankin scale ranging from 0 to 3 at day 90 after CA.ResultsAmong the 2425 COVID-19 patients admitted to ICU from March to June 2020, 186 (8%) experienced in-ICU CA, of whom 146/186 (78%) received CPR. Among these 146 patients, 117 (80%) had sustained return of spontaneous circulation, 102 (70%) died in the ICU, including 48 dying within the first day after CA occurrence and 21 after withdrawal of life-sustaining therapy. Most of CA were non-shockable rhythm (90%). At CA occurrence, 132 patients (90%) were mechanically ventilated, 83 (57%) received vasopressors and 75 (51%) had almost three organ failures. Thirty patients (21%) had a favorable outcome. Sepsis-related organ failure assessment score > 9 before CA occurrence was the single parameter constantly associated with unfavorable outcome in multivariate analysis.ConclusionsIn-ICU CA incidence remains high among a large multicenter cohort of French critically ill adults with COVID-19. However, 21% of patients with CPR attempt remained alive at 3 months with good functional status. This contrasts with other recent reports showing poor outcome in such patients.Trial registration: This study was retrospectively registered in ClinicalTrials.gov (NTC04373759) in April 2020 (https://www.clinicaltrials.gov/ct2/show/NCT04373759?term=acicovid&draw=2&rank=1).

Association of subsequent treated shockable rhythm with outcomes after paediatric out-of-hospital cardiac arrests: A nationwide, population-based observational study

AimAmong patients with paediatric out-of-hospital cardiac arrests (OHCAs), most have an initial non-shockable rhythm with poor outcomes. There is a subset who developed shockable rhythms. This study aimed to investigate the association between subsequent shock delivery and outcomes after paediatric OHCAs. MethodsWe analysed records of 19,095 children (aged <18 years) with OHCA and initial non-shockable rhythm. Data were obtained from a Japanese nationwide database for 13 years (2005–2017). The primary outcome measure was 1-month neurologically intact survival, defined as cerebral performance category 1–2. ResultsAmong patients with pulseless electrical activity (PEA, n = 3,326), there was no significant difference between those with subsequent treated shockable rhythm (10.0% [11/109]) and those with sustained non-shockable rhythm (6.0% [192/3,217], p = 0.10) with respect to the neurologically intact survival rate. Among asystole patients (n = 15,769), the neurologically intact survival rate was significantly higher in the subsequent treated shockable rhythm group (4.4% [10/227]) than in the sustained non-shockable rhythm group (0.7% [106/15,542], p < 0.0001). Subsequent treated shockable rhythm with a shock delivery time (time from emergency medical services [EMS]-initiated cardiopulmonary resuscitation [CPR] to shock delivery) ≤9 min was associated with increased odds of neurologically intact survival compared with sustained non-shockable rhythm (PEA, adjusted odds ratio, 2.45 [95% confidence interval, 1.16–5.16], p = 0.018; asystole, 9.77 [4.2–22.5], p < 0.0001). ConclusionAfter paediatric OHCAs, subsequent treated shockable rhythm was associated with increased odds of 1-month neurologically intact survival regardless of whether the initial rhythm was PEA or asystole, only when the shock was delivered ≤9 min of EMS-initiated CPR.

Women receive less targeted temperature management than men following out-of-hospital cardiac arrest due to early care limitations – A study from the CARES Investigators

BackgroundWomen experience worse neurological outcomes following out-of-hospital cardiac arrest (OHCA). It is unknown whether sex disparities exist in the use of targeted temperature management (TTM), a standard of care treatment to improve neurological outcomes. MethodsWe performed a retrospective study of prospectively collected patients who survived to hospital admission following OHCA from the Cardiac Arrest Registry to Enhance Survival from 2013 through 2019. We compared receipt of TTM by sex in a mixed-effects model adjusted for patient, arrest, neighborhood, and hospital factors, with the admitting hospital modeled as a random intercept. ResultsAmong 123,419 patients, women had lower rates of shockable rhythms (24.4 % vs. 39.2%, P < .001) and lower rates of presumed cardiac aetiologies for arrest (74.3% vs. 81.1%, P < .001). Despite receiving a similar rate of TTM in the field (12.1% vs. 12.6%, P = .02), women received less TTM than men upon admission to the hospital (41.6% vs. 46.4%, P < .001). In an adjusted mixed-effects model, women were less likely than men to receive TTM (Odds Ratio 0.91, 95% Confidence Interval 0.89 to 0.94). Among the 27,729 patients with data indicating the reason for not using TTM, a higher percentage of women did not receive TTM due to Do-Not-Resuscitate orders/family requests (15.1% vs. 11.4%, p < .001) and non-shockable rhythms (11.1% vs. 8.4%, p < .001). ConclusionsWe found that women received less TTM than men, likely due to early care limitations and a preponderance of non-shockable rhythms.

Cerebral autoregulation in anoxic brain injury patients treated with targeted temperature management

BackgroundLittle is known about the prevalence of altered CAR in anoxic brain injury and the association with patients’ outcome. We aimed at investigating CAR in cardiac arrest survivors treated by targeted temperature management and its association to outcome.MethodsRetrospective analysis of prospectively collected data. Inclusion criteria: adult cardiac arrest survivors treated by targeted temperature management (TTM). Exclusion criteria: trauma; sepsis, intoxication; acute intra-cranial disease; history of supra-aortic vascular disease; severe hemodynamic instability; cardiac output mechanical support; arterial carbon dioxide partial pressure (PaCO2) > 60 mmHg; arrhythmias; lack of acoustic window. Middle cerebral artery flow velocitiy (FV) was assessed by transcranial Doppler (TCD) once during hypothermia (HT) and once during normothermia (NT). FV and blood pressure (BP) were recorded simultaneously and Mxa calculated (MATLAB). Mxa is the Pearson correlation coefficient between FV and BP. Mxa > 0.3 defined altered CAR. Survival was assessed at hospital discharge. Cerebral Performance Category (CPC) 3–5 assessed 3 months after CA defined unfavorable neurological outcome (UO).ResultsWe included 50 patients (Jan 2015–Dec 2018). All patients had out-of-hospital cardiac arrest, 24 (48%) had initial shockable rhythm. Time to return of spontaneous circulation was 20 [10–35] min. HT (core body temperature 33.7 [33.2–34] °C) lasted for 24 [23–28] h, followed by rewarming and NT (core body temperature: 36.9 [36.6–37.4] °C). Thirty-one (62%) patients did not survive at hospital discharge and 36 (72%) had UO. Mxa was lower during HT than during NT (0.33 [0.11–0.58] vs. 0.58 [0.30–0.83]; p = 0.03). During HT, Mxa did not differ between outcome groups. During NT, Mxa was higher in patients with UO than others (0.63 [0.43–0.83] vs. 0.31 [− 0.01–0.67]; p = 0.03). Mxa differed among CPC values at NT (p = 0.03). Specifically, CPC 2 group had lower Mxa than CPC 3 and 5 groups. At multivariate analysis, initial non-shockable rhythm, high Mxa during NT and highly malignant electroencephalography pattern (HMp) were associated with in-hospital mortality; high Mxa during NT and HMp were associated with UO.ConclusionsCAR is frequently altered in cardiac arrest survivors treated by TTM. Altered CAR during normothermia was independently associated with poor outcome.