Initial Arrest Rhythm Research Articles

1743 Frailty is associated with poor cardiopulmonary resuscitation outcomes in the COVID-19 pandemic

Abstract Background This study aims to investigate the relationship between frailty and in-hospital cardiopulmonary resuscitation (CPR) outcomes in the COVID-19 pandemic. Methods The study was carried out in a tertiary hospital in Scotland and included all patients over the age of 18 who had an in-hospital CPR attempt between April 2020 and March 2022. Patients were identified via the pre-existing National Cardiac Arrest Audit Database which was collected prospectively. Data collected from this included age, sex, initial arrest rhythm, return of spontaneous circulation (ROSC) and in-hospital mortality. The electronic and paper patient notes were retrospectively reviewed to calculate a Rockwood clinical frailty scale (CFS) and Charlson comorbidity index (CCI). The data was stratified in to frail (CFS ≥5) and non-frail (CFS <5) groups. Results 65 patients were included in the study. In univariate analysis, there was a significant difference between the frail and non-frail groups in age (p=0.006), ROSC (p=0.02) and survival to discharge (p=0.004). Only 10 out of 34 (29.4%) frail patients had ROSC and of those only 3 (8.8%) survived to discharge compared to 12 out of 31 (35.3%) of non-frail patients. In a binary logistic regression, there was a significant association between frailty and both ROSC (adjusted OR 3.31 [95% CI: 1.12-9.78}) and survival to discharge (adjusted OR 6.33 [95% CI: 1.48-27.13]) and no significant association with age, CCI or sex. Conclusion The findings support the relationship between frailty and poor CPR outcomes independent of age and co-morbidity during the COVID-19 pandemic.

Outcome of Extracorporeal Cardiopulmonary Resuscitation in Pediatric Patients Without Congenital Cardiac Disease: Extracorporeal Life Support Organization Registry Study.

To describe the use of extracorporeal cardiopulmonary resuscitation (ECPR) in pediatric patients without congenital heart disease (CHD) and identify associations with in-hospital mortality, with a specific focus on initial arrest rhythm. Retrospective cohort study using data from pediatric patients enrolled in Extracorporeal Life Support Organization (ELSO) registry between January 1, 2017, and December 31, 2019. International, multicenter. We included ECPR patients under 18 years old, and excluded those with CHD. Subgroup analysis of patients with initial arrest rhythm. None. We identified 567 patients: neonates (12%), infants (27%), children between 1 and 5 years old (25%), and children over 5 years old (36%). The patient cohort included 51% males, 43% of White race, and 89% not obese. Most suffered respiratory disease (26%), followed by acquired cardiac disease (25%) and sepsis (12%). In-hospital mortality was 59%. We found that obesity (adjusted odds ratio [aOR], 2.28; 95% CI, 1.21-4.31) and traumatic injury (aOR, 6.94; 95% CI, 1.55-30.88) were associated with greater odds of in-hospital mortality. We also identified lower odds of death associated with White race (aOR, 0.64; 95% CI, 0.45-0.91), ventricular tachycardia (VT) as an initial arrest rhythm (aOR, 0.36; 95% CI, 0.16-0.78), return of spontaneous circulation before cannulation (aOR, 0.56; 95% CI, 0.35-0.9), and acquired cardiac disease (aOR, 0.43; 95% CI, 0.29-0.64). Respiratory disease was associated with greater odds of severe neurologic complications (aOR, 1.64; 95% CI, 1.06-2.54). In children without CHD undergoing ECPR, we found greater odds of in-hospital mortality were associated with either obesity or trauma. The ELSO dataset also showed that other variables were associated with lesser odds of mortality, including VT as an initial arrest rhythm. Prospective studies are needed to elucidate the reasons for these survival differences.

Outcomes after cardiac arrest in Medical Intensive Care Unit: A propensity score matching analysis of COVID-19 MICU vs non COVID-19 MICU cardiac arrest

AimTo assess whether there were differences in resuscitation efforts and outcomes for medical intensive care unit (MICU) in-hospital cardiac arrest (IHCA) during the COVID-19 pandemic when compared to pre-pandemic. MethodsComparing COVID-19 MICU-IHCA patients (03/2020 to 10/2020) to non-COVID-19 MICU IHCA (01/2014 to 12/2018) at Clevleand Clinic Health System (CCHS) of NE Ohio. Propensity score matching analysis (PSMA) was used to create comparable groups. ResultsThere were a total of 516 patients, 51 in COVID-19 MICU IHCA cohort and 465 in the non-COVID-19 MICU IHCA cohort. The mean (SD) age of the study population was 60.9 (16) years and 56% were males. In 92.1% (n = 475) patients, initial arrest rhythm was non-shockable. At the time of ICU admission, compared to the non-COVID-19 MICU-IHCA cohort, the COVID-19 MICU IHCA cohort had a lower mean APACHE III score (70 [32.9] vs 101.3 [39.6], P = <0.01). The COVID-19 cohort had a higher rate of survival to hospital discharge (12 [23.5%] vs 59 [12.7%], P = 0.03). Upon PSMA, the algorithm selected 40 COVID-19 patients and 200 non-COVID-19 patients. Imbalances in baseline characteristics, comorbidities, and APACHE III were well-balanced after matching. Survival rate after matching became non-significant; (10 [25%] vs 42 [21%], P = 0.67). Further, there were no significant differences in ICU or hospital length-of-stay or neurological outcomes at discharge for survivors in the two matched cohorts. ConclusionIt is imperative that COVID-19 patients receive unbiased and unrestricted resuscitation measures, without any discouragement.

1140: COOLING DEVICE USE AND FEVER AVOIDANCE IN POST-CARDIAC ARREST PATIENTS

Introduction: In the wake of TTM2 many clinicians have replaced therapeutic hypothermia using a cooling device with fever avoidance (sometimes without a cooling device) in post-cardiac arrest patients. Given this and the adverse effects of fever, we aimed to establish the incidence of post arrest fever (Tmax ≥38oC) when a cooling device was not used and impact on outcome. Methods: A retrospective chart review of adult cardiac arrest survivors admitted to the ICUs in the Mount Sinai Health System in 2021 was conducted. Patients who had traumatic arrests, extracorporeal cardiopulmonary resuscitation (ECPR), hypo- or hyperthermia prior to arrest, death within 72 hours, and those aged ≥90 years were excluded. Patients were stratified by cooling device vs no cooling device. Univariate and multivariable statistics were computed, and endpoints examined included Tmax of ≥38oC within 48h of admission and discharged alive (vs deceased). Results: 364 patients were screened, 170 excluded, and 194 analyzed. In univariate analysis, patients who were younger (median (IQR) 60 (53-67) vs 66 (56-75) years, p=0.014), status-post out-of-hospital arrest (77.1% vs 39.2%, p< 0.001), and with a longer ROSC time (16.5 (10-34.5) vs 8 (3-15) min, p< 0.0001) were more likely to receive a cooling device. Patients without a cooling device were more likely to reach Tmax ≥38oC (37.1% vs 13.5%, p< 0.001); however, those with a cooling device were less likely to be discharged alive (28.7% vs 55.3%, p< 0.001). In multivariable analyses controlling for variables such as age, arrest location, initial arrest rhythm, and ROSC time, lack of cooling device was consistently an independent predictor of Tmax ≥38oC. Further, lower peak temperature at 48h emerged in some multivariable models as an independent predictor of being discharged alive. At the same time, however, lack of cooling device was a consistent independent predictor of being discharged alive. Lower ROSC time and greater GCS were associated with being discharged alive in some models. Conclusions: Cooling devices appeared to be associated with fever prevention but used in patients who ultimately did poorly. Moreso than use of a cooling device, achieving fever avoidance (however that may be obtained) may be more important for prognosis.

The impact of a high-performance cardiopulmonary resuscitation protocol on survival from out-of-hospital cardiac arrests witnessed by paramedics

AimIn this study, we examine the effect of a high-performance cardiopulmonary resuscitation (HP-CPR) protocol on patient outcomes following out-of-hospital cardiac arrests (OHCA) witnessed by emergency medical services (EMS) personnel. MethodsWe performed a retrospective cohort study of adult, EMS witnessed OHCA patients of medical aetiology in Victoria, Australia. Patients treated after the introduction of a HP-CPR protocol and training programme between February 2019 and January 2020 were compared to historical controls between January 2015 and January 2019. The effect of a HP-CPR protocol on survival to hospital discharge was examined using logistic regression models adjusted for arrest factors. ResultsA total of 1,561 and 420 EMS witnessed OHCA patients were treated in the control and intervention periods, respectively. Baseline characteristics were mostly balanced across study periods, except for an initial arrest rhythm of asystole which was more frequent during the intervention period (20.2% vs 15.9%; p-value = 0.04). Unadjusted survival to hospital discharge was similar across control and intervention periods for the overall population (32.1% vs 29.4%, p-value = 0.27), but significantly higher during the intervention period for initial shockable arrests (76.9% vs 66.6%; p-value = 0.03). After adjustment for confounders, cases in the intervention period were associated with an improvement in the adjusted odds of survival to hospital discharge for overall arrests (adjusted odds ratio [AOR] 1.37, 95% CI: 1.00–1.88) and initial shockable arrests (AOR 1.70, 95% CI: 1.03–2.82). ConclusionThe implementation of a HP-CPR protocol was associated with a significant improvement in survival from EMS witnessed OHCA. Efforts to improve CPR performance could yield further improvements in patient outcomes.

Abstract 210: Norepinephrine Versus Epinephrine For Post-Cardiac Arrest Shock In The Prehospital Setting: A Retrospective Analysis

Introduction: Shock after out-of-hospital cardiac arrest (OHCA) is common and often treated with vasopressors. Compared with norepinephrine (NOR), infusion of epinephrine (EPI) is associated with higher mortality and morbidity among hospitalized patients; but the optimal prehospital approach is unknown. We sought to examine whether infusion of EPI versus NOR is associated with neurologically-intact survival among OHCA patients. Methods: This retrospective cohort study included transported OHCA cases in Seattle, WA from 2014-2021 who received advanced life support. Our primary exposure was infusion of EPI or NOR. Our primary outcome was neurologically-favorable survival (Cerebral Performance Category score of 1 or 2) to hospital discharge. Key secondary outcomes were prehospital rearrest, survival to hospital admission, and hospital mortality. We conducted multivariable logistic regression adjusting for baseline patient and OHCA characteristics. Results: Of 1784 OHCA patients, 263 (15%) received NOR and 201 (11%) received EPI infusions, 18 received both, and 1298 received neither. Those who received EPI were older (median 65 [IQR 52-78] vs 62 [IQR 47-75] years), but otherwise had similar baseline characteristics, including initial arrest rhythm (Table 1). Patients who received EPI were over twice as likely to have rearrested in the prehospital setting (53% vs 24%). After adjustment, there was no difference in neurologically-favorable survival (OR 0.91, 95% CI 0.47-1.78). We found no difference in survival to hospital admission or discharge. Conclusion: Neurologically-favorable survival was similar among patients who received NOR or EPI infusions for post-OHCA shock, though patients who received EPI had prehospital rearrests more often. Future trials should examine the optimal approach to hemodynamic management for post-OHCA shock.

Abstract 13: Myocardial Metabolic And Electrolyte Derangements Linked To PEA Rearrest

Background: Cardiac rearrest after return of spontaneous circulation (ROSC) is a significant barrier to successful resuscitation, making it a high priority for emergency care research. Regardless of initial arrest rhythm, rearrest is commonly due to pulseless electrical activity (PEA). However, mechanisms underlying PEA rearrest are poorly understood. Previously, myocardial contractile function during ischemia-reperfusion has been tied to alterations in extracellular sodium (Na+) and calcium (Ca2+) concentrations. Objective: To determine physiological predictors and explore potential mechanisms underlying susceptibility to PEA rearrest. Methods: Acute myocardial infarction (AMI) induced by left anterior descending artery (LAD) occlusion was followed by 8 min of VF, then pigs were resuscitated (defibrillation, CPR, epinephrine) to ROSC and the LAD was reperfused. Pigs were instrumented to measure metabolic variables from arterial and coronary sinus venous blood gases, electrolytes, and hemodynamics. Subjects that had PEA rearrest (n=7) were compared to those that did not rearrest (n=4). Results: Hemodynamic and primary arrest characteristics were similar between PEA and no rearrest groups, including ischemia duration, time to ROSC, CPR events, and epinephrine administration. At ROSC, hemodynamic and metabolic variables including pH, myocardial lactate consumption, myocardial arterial/venous oxygen difference were also similar between groups. Importantly, post-ROSC myocardial lactate consumption was significantly increased in the PEA group (3.9 vs. 0.5 mmol, p&lt;0.03) as was coronary sinus Na+ (147 vs. 135 mEq/L, p&lt;.03); however, coronary sinus Ca2+ was significantly reduced (1.9 vs. 2.3 mEq/L, p&lt;.01 ). Taken together, these data suggest that metabolic substrate depletion may promote local electrolyte shifts contributing to mechanical dysfunction underlying PEA. Conclusion: PEA rearrest was associated with increased myocardial lactate consumption and derangements in cardiac Na+ and Ca2+ in a translational model with well controlled arrest characteristics. Improved understanding of mechanisms underlying post-ROSC electrolyte shifts may identify novel mechanisms and therapeutic approaches to prevent and treat PEA.

Variation in coronary angiography use in Out-of-Hospital cardiac arrest

IntroductionMultiple studies have examined the association of early coronary angiography (CAG) among out-of-hospital cardiac arrest (OHCA) patients with conflicting results. However, patterns of use of CAG among OHCA patients in real-world settings are not well-described. MethodsUtilizing data from the Resuscitation Outcomes Consortium’s Continuous Chest Compressions trial for our analysis, we stratified patients based on initial arrest rhythm and ST-elevation on initial post-resuscitation electrocardiogram (ECG) and examined the rates of CAG in resuscitated patients. We also examined the rates of CAG across different trial clusters in the overall study population as well as in pre-specified patient subgroups ResultsOf 26,148 patients in the CCC trial, 5,608 survived to hospital admission and were enrolled in the study. Among them, 26 % underwent CAG. Patients with ST-elevation underwent CAG at a significantly higher rate than patients presenting without ST-elevation (70 % vs 31 %, p < 0.001). Similarly, patients presenting with shockable rhythms underwent CAG more frequently compared with patients with non-shockable rhythms (28 % vs 5 %, p < 0.001). There was marked variation in CAG frequency across different trial clusters with the proportion of patients within a trial cluster receiving CAG ranging from 4 % − 41 %. The proportion varied more among patients with ST-elevation (16 % − 82 %) or initial shockable rhythm (11 % − 75 %) compared with no ST-elevation (2 % − 28 %) or initial non-shockable rhythm (0 % − 19 %). ConclusionAmong a national cohort of OHCA patients, large variation in the use of CAG exists, highlighting the existing uncertainty regarding perceived benefit from early CAG in OHCA.

Outcomes of cardiopulmonary resuscitation in patients with pulmonary arterial hypertension.

Over the past 20 years, despite significant advancements in pulmonary arterial hypertension (PAH) medical therapy, many patients require admission to the hospital and are at risk for in‐hospital cardiac arrest (IHCA). Prior data found poor survival in PAH patients after cardiac arrest. The purpose of this study was to explore post‐IHCA outcomes in PAH patients receiving advanced medical therapies. This is a single‐center retrospective study of PAH patients who underwent cardiopulmonary resuscitation for IHCA between July 2005 and May 2021. Patients were identified through an internal cardiac arrest database. Twenty six patients were included. Half of the cohort had idiopathic PAH, with 54% of patients on combination therapy, 27% on monotherapy, and 19% of patients on no therapy. Mean right atrial pressure, mean pulmonary artery pressure, cardiac index, and pulmonary vascular resistance were 13 ± 6 mmHg, 57 ± 13 mmHg, 2.0 ± 0.7 L/min/m2, and 14.5 ± 7.6 Wood units, respectively. Most common etiology of cardiac arrest was circulatory collapse. Initial arrest rhythm in all but one patient was pulseless electrical activity. Six patients (23%) achieved return of spontaneous circulation (ROSC) and one patient (4%) survived to hospital discharge. Rates of ROSC and survival to discharge after IHCA are poor in patients with PAH. Even patients with mild hemodynamics had low likelihood of survival. In patients who are lung transplant candidates, there should be early consideration of extracorporeal support before cardiac arrest.

A retrospective multi-centre cohort study: Pre-hospital survival factors of out-of-hospital cardiac arrest (OHCA) patients in Thailand

ObjectiveThis study aimed to explore significant pre-hospital factors affecting the survivability of Out-of-Hospital Cardiac Arrest (OHCA) patients in countries with developing EMS systems. MethodA retrospective cohort study was conducted examining data from January 1, 2017 to December 31, 2020 from Utstein Registry databases in Thailand, collected through Pan-Asian Resuscitation Outcomes Study (PAROS). Data were collected from three centres, including regional, suburban-capital, and urban-capital hospitals. The primary endpoint of this study was 30-day survival or discharged alive after an OHCA event. The multivariable risk regression was done by modified Poisson regression with robust error variance to explore the association between 30-day survival and pre-hospital factors with potential confounders adjustments. FindingsOf 1,240 OHCA cases transferred by Emergency Medical Services (EMS), 42 patients (3.4%) were discharged alive after 30 days, including 22 (8.6%), 8 (3.0%), and 12 (1.7%) from regional, suburban-capital, and urban-capital centres, respectively. The initial arrest rhythm was 89.7% unshockable, with no significant variations across the three centres. Overall, bystander Cardiopulmonary Resuscitation (CPR) was 40.4%. However, bystander CPR with Automated External Defibrillator (AED) application was 0.8%. Bystander CPR significantly increased 30-day survival probability (aRR 1.88, 95% CI 1.01 to 3.51; p 0.049). Additionally, reducing the EMS response time by one minute significantly increased OHCA survivability (aRR 1.12, 95% CI 1.04 to 1.20; p 0.001). ConclusionsResponse time and bystander CPR are the factors that improve the 30-day survival outcomes of OHCA patients. In contrast, scene time, transport time, and pre-hospital advanced airway management didn’t improve 30-day OHCA survival.

Abstract 12933: Myocardial Dysfunction After In-Hospital Cardiac Arrest in COVID-19 Patients

Introduction: Post resuscitation myocardial dysfunction (PRMD) is common after out-of-hospital cardiac arrest. While PRMD is a known cause of post-resuscitation circulatory failure, few studies have reported associations between PRMD and neurologic outcome or survival. Further, little is known about PRMD after in-hospital cardiac arrest (IHCA) nor on the incidence and prognosis of PRMD in COVID-19 IHCA. We sought to evaluate the incidence of PRMD in a multicenter cohort of resuscitated COVID-19 IHCA patients. Study Population and Methods: We included adult patients (≥18 y) admitted to multiple hospitals of Cleveland Clinic Health System. Patients who attained ROSC with an initial echocardiogram (EC) in the 72 hours post-arrest were included. Data were extracted from a data registry and electronic medical records. Results: From 03/2020-10/2020, 58 patients with COVID-19 had IHCA. ROSC was noted in 35 patients (60.3%), 27 (46.6%) were alive at 24 h and 13 patients (22.4%) survived to hospital discharge. Of the 35 patients who had ROSC, 14 patients (40%) had an EC within 72 h. The median age of this cohort was 67 y (IQR 47 - 73); 71% were male, and median BMI of 28 (IQR 27 - 34), and admission APACHE II score was 13 (IQR 11 - 19). One third of the patients (36%) were mechanically ventilated before arrest and 43% were on vasopressors. Initial arrest rhythms were: PEA/Asystole, 79%; and VF/VT, 21%. Most patients (93%) received manual chest compression with median CPR duration of 5 min (IQR 2 - 10). The median time of obtaining first EC post-ROSC in these 14 patients was 22 hours (IQR 6 - 62). 7/14 (50%) of the patient had systolic dysfunction on initial EC (6 had global dysfunction, 1 with regional wall motion abnormality, and 4/7 had combined LV and RV systolic dysfunction). 5/14 patients had a follow up EC with a median time of 43 days. 2/5 had normal initial EC and 3 out of these 5 patients who initially had PMRD showed complete recovery in their LV and RV systolic function. Conclusion: We report a case series of PRMD in COVID-19 patients who experienced IHCA. We found that PMRD is seen in half of the patients. Most patients with PMRD recovered to normal RV and LV function, consistent with prior studies of non-COVID-19 arrest EC.

Complete Revascularisation is associated with Improved Survival after Out of Hospital Cardiac Arrest

Abstract Introduction Coronary artery disease (CAD) is common in patients with Out of Hospital Cardiac Arrest (OOHCA) but the clinical relevance of burden of CAD and evidence for revascularisation strategies in relation to outcomes and modes of death remains unclear. Purpose This study sought to assess the extent of CAD as defined by the SYNTAX score and prognostic value of complete compared with incomplete revascularisation by evaluating the SYNTAX revascularisation index (SRI) in patients with OOHCA. Methods 619 patients with OOHCA were admitted at our centre between 1st May 2012 and 31st December 2017. 237 were excluded for having a non-cardiac aetiology or prior neurological disability. 398 patients were included into the study and of these 272 (68.3%) had early coronary angiography (CAG) and were included in the final analysis. The baseline SYNTAX score (bSS) and residual SYNTAX score (rSS) were determined from the coronary angiograms by a cardiologist blinded to the outcome. Patients were subdivided into 4 subgroups according to quartiles of the baseline syntax score (bSS) of 0, Group A: 1–10, Group B: 11–20 and Group C: ≥21. Complete revascularisation (CR) was defined as SRI of 1 and incomplete (IR) as SRI &amp;lt;1 where the SRI=(1-[rSS/bSS]) ×100 (Figure 1). Results Patients with a bSS of 0 were younger, had less shockable initial arrest rhythms and worse lactate and pH on arrival.Patients with bSS&amp;gt;0 (i.e., those with coronary artery disease) had similar cardiac arrest circumstances in terms of rates of witnessed, bystander CPR and shockable rhythms. Admission metabolic status reflected by pH and lactate and rates of ST elevation/LBBB were also identical for all three groups. However, LVEF on admission decreased significantly as coronary complexity increased (P&amp;lt;0.0001). While early angiography was more preferentially performed in those with higher coronary complexity, paradoxically, those with bSS 1–4 had highest rates of culprit lesions which was reflected in higher rates of PCI (Figure 1). 124 (45.4%) had CR compared with 54.2% with IR. CR was most likely to be achieved as the coronary complexity reduced (Group A – 71.7%, Group B – 41.1%, Group C - 23.3%). There was no difference in rates of cardiogenic shock between both groups (CR 61.1% vs. IR 69% p=ns), but patients with complete revascularisation were younger (58.8 vs 67.8, p&amp;lt;0.0001), lower rates of hypertension and previous CABG (16.2% vs 3.2%, p≤0.0001) CR was associated with decreased mortality at 30 days (45.9% vs 34.6%, p=0.046) and 12 months (49.3% vs 35.4%, p=0.022). The lower mortality rate in CR appeared to partly be driven by lower cardiac deaths though this was not statistically significant (22% vs 7%, p=0.1) (Figure 2). Conclusions CR in a primary coronary aetiology OOHCA group is associated with reduced early and long-term mortality, which may be driven by a reduction in cardiac deaths. Prospective randomised trials in this population are warranted. Funding Acknowledgement Type of funding sources: None. Figure 1Figure 2

Functional outcomes following an in-hospital cardiac arrest: A retrospective cohort study

Background/PurposeWhilst much is known about the survival outcomes of patients that suffer an in-hospital cardiac arrest (IHCA) in Australia very little is known about the functional outcomes of survivors. This study aimed to describe the functional outcomes of a cohort of patients that suffered an in-hospital cardiac arrest (IHCA) and survived to hospital discharge in a regional Australian hospital. MethodsThis is a single-centre retrospective observational cohort study conducted in a regional Australian hospital. All adult patients that had an IHCA in the study hospital between 1 Jan 2017 and 31 Dec 2019 and survived to hospital discharge were included in the study. Functional outcomes were reported using the Modified Rankin Scale (mRS), a six-point scale for which increasing scores represent increasing disability. Scores were assigned through a retrospective review of medical notes. ResultsOverall, 102 adult patients had an IHCA during the study period, of whom 50 survived to hospital discharge. The median age of survivors was 68 years, and a third had a shockable initial arrest rhythm. Of survivors, 47 were able to be assigned both mRS scores. At discharge, 81% of patients achieved a favourable functional outcome (mRS 0–3 or equivalent function at discharge equal to admission). ConclusionsMost survivors to hospital discharge following an IHCA have a favourable functional outcome and are discharged home. Although these results are promising, larger studies across multiple hospitals are required to further inform what is known about functional outcomes in Australian IHCA survivors.

A Multicenter Evaluation of Survival After In-Hospital Cardiac Arrest in Coronavirus Disease 2019 Patients.

IMPORTANCE:In-hospital cardiac arrest survival among coronavirus disease 2019 patients has been reported to range from 0% to 12%. These numbers are significantly lower than reported prepandemic in-hospital cardiac arrest survival rates of approximately 20–25% in the United States for non–coronavirus disease 2019 patients.OBJECTIVE:To assess the incidence of in-hospital cardiac arrest survival of coronavirus disease 2019 patients.DESIGN:A retrospective cohort study of adult patients with coronavirus disease 2019 subsequently found to have in-hospital cardiac arrest and underwent cardiopulmonary resuscitation (cardiopulmonary resuscitation).SETTING:Multiple hospitals of the Cleveland Clinic Health System.PATIENTS:All adult patients (age ≥ 18 yr) admitted to Cleveland Clinic Health System with a diagnosis of coronavirus disease 2019 who experienced in-hospital cardiac arrest requiring cardiopulmonary resuscitation.MEASUREMENTS AND MAIN RESULTS:From March 01, 2020 to October 15, 2020, 3,555 patients with coronavirus disease 2019 were hospitalized; 1,372 were admitted to the ICU; 58 patients had in-hospital cardiac arrest. Median age of this cohort was 66.5 years (interquartile range, 55.0–76.0 yr). Patients were predominantly male (62.5%), White (53.4%), with a median body mass index of 29.7 (interquartile range, 25.8–34.6). Most in-hospital cardiac arrests were in critical care environments (ICU), 51 of 58 (87.9%); seven of 58 (12.1%) were on ward locations. Thirty-four of 58 patients (58.6%) were on mechanical ventilation prior to in-hospital cardiac arrest with a median duration of mechanical ventilation of 9 days (interquartile range, 2–18 d). Twenty-four of 58 patients (44%) were on vasopressors prior to arrest. Initial arrest rhythm was pulseless electrical activity at (63.8%), asystole (29.3%), and pulseless ventricular tachycardia/fibrillation (6.9%). Of the 58 patients, 35 (60.3%) attained return of spontaneous circulation, and 13 of 58 (22.4%) were discharged alive.CONCLUSIONS:We report a 22% survival to discharge after in-hospital cardiac arrest in coronavirus disease 2019 patients, a survival rate similar to before the coronavirus disease 2019 pandemic.

Long-term survival among OHCA patients who survive to 30 days: Does initial arrest rhythm remain a prognostic determinant?

ObjectiveTo determine whether initial cardiac arrest rhythm remains a prognostic determinant in longer term OHCA survival. MethodsThe St John Western Australian OHCA database was used to identify adults who survived for at least 30 days after an OHCA of presumed medical aetiology, in the Perth metropolitan area between 1998 and 2017. Associations between 8-year OHCA survival and variables of interest were analysed using a Multi-Resolution Hazard (MRH) estimator model with 1-year intervals. ResultsOf the 871 OHCA patients who survived 30 days, 718 (82%) presented with a shockable initial arrest rhythm and 153 (18%) presented with a non-shockable rhythm. Compared to patients with initial shockable arrests, patients with non-shockable arrests experienced increased mortality in the first (HR 3.33, 95% CI 2.12−5.32), second (HR 2.58, 95% CI 1.22−5.15), third (HR 2.21, 95% CI 1.02−4.42) and fourth (HR 2.21, 95% CI 1.02−4.42) year post arrest; however, in subsequent years the initial arrest rhythm ceased to be significantly associated with survival. The overall 8-year survival estimates after adjustment for peri-arrest factors (as potential confounders) were 87% (95% CI 77–93%) for shockable arrests and 73% (95% CI 55–86%) for non-shockable arrests. ConclusionsPatients with non-shockable (as opposed to shockable) initial arrest rhythms experienced higher mortality in the first 4-years following their OHCA; however, after four years the initial arrest rhythm ceased to be associated with survival.

Abstract 336: Data-driven Classification of Arrest Location for Emergency Department Cardiac Arrests

Introduction: Out-of-hospital cardiac arrest (OHCA), in-hospital cardiac arrest (IHCA), and emergency department (ED) cardiac arrests differ in epidemiology, etiology, and outcomes. Resuscitation research is inconsistent in how ED arrests are classified. We used unsupervised learning to compare ED arrests to non-ED OHCA and to non-ED IHCA. Hypothesis: Clinical features of ED cardiac arrest patients who achieve return of spontaneous circulation (ROSC) are more similar to IHCA than to OHCA. Methods: We performed a retrospective study including all patients resuscitated from cardiac arrest who were treated at a single academic medical center from January 2010 to December 2019. We abstracted clinical information from our prospective registry, including the details of arrest location (ED arrests, OHCA, or IHCA); age; sex; initial arrest rhythm; number of doses of epinephrine, bicarbonate and shocks given during the arrest; duration of arrest; most advanced airway placed intra-arrest; number of rearrests; early post-arrest illness severity (Pittsburgh Cardiac Arrest Category: PCAC); and survival to hospital discharge. We used unsupervised learning (K-prototypes) to identify clusters within the OHCA and IHCA cohorts. We determined the number of subgroups using Scree plots. Finally, we assigned individual ED arrest patients the nearest OHCA or IHCA cluster based on the shortest Gower distance from that patient to the nearest cluster center. Results: We included 2,723 patients: 1,709 (63%) OHCA, 642 (23%) IHCA, and 372 (14%) ED arrests. We identified 3 clusters in the OHCA cohort, and 4 clusters in the IHCA cohort. Of the total ED arrest cases, 292 (78%) most closely resembled an IHCA cluster and 80 (22%) most closely resembled an OHCA cluster. The large majority (64%) of ED arrests that were closest to an IHCA cluster survived to hospital discharge; 50% of this subset were awake post-arrest (PCAC I), and 16% were deeply comatose (PCAC IV). In contrast, only 13% of ED arrests that were closest to an OHCA cluster survived to hospital discharge; 65% of this subset were deeply comatose (PCAC IV) and only 5% were awake post arrest (PCAC I). Conclusion: Among cardiac arrest patients with ROSC, the large majority of ED arrests resemble IHCA more than OHCA.

Abstract 298: Predicting Pulse Status During Cardiopulmonary Resuscitation Using Dimensionality Reduction of Electrocardiogram Wavelet Transforms

Background: Current resuscitation protocols require pausing cardiopulmonary resuscitation (CPR) to check for a pulse. However, pausing CPR during a pulseless rhythm worsens patient outcome. We designed an ECG-based algorithm that predicts pulse status during uninterrupted CPR, and evaluated its performance both with and without CPR. Methods: We evaluated 383 patients who were treated for out-of-hospital cardiac arrest using defibrillators with real-time ECG, CPR, and audio recordings. We collected paired adjacent ECG segments with and without CPR during organized rhythms. Segments were collected during the 10-s CPR period just prior to pulse check, and 5-s segments without CPR during the pulse check. ECG segments with or without a pulse were identified by the audio annotation and recorded blood pressures. Patients were randomly divided into 60% (230/383) training and 40% (153/383) test groups. From training data, we developed an algorithm to predict clinical pulse status based on the wavelet transform of the bandpass-filtered ECG, applying principle component analysis (PCA). We then trained a linear discriminant model using 3 principle component modes as input features. Model performance was evaluated on test group segments with and without CPR using receiver operating curves overall and according to initial arrest rhythm. Results: There were 230 patients (540 pulse checks) in the training set and 153 patients (372 pulse checks) in the test set. In both of these sets, about 16% (37/230 and 25/153) of the patients presented with initial non-shockable rhythm . Overall 38% (351/912) of checks had a spontaneous pulse. The areas under the receiver operating characteristic curve (AUCs) for predicting pulse status with and without CPR on test data were 0.84 and 0.89, respectively. Conclusion: A novel ECG-based algorithm demonstrates potential to improve resuscitation by predicting presence of a spontaneous pulse without pausing CPR.

Mortality and Neurological Outcomes in Out-of-Hospital Cardiac Arrest Patients With and Without Targeted Temperature Management in a Multiethnic Asian Population

The use of targeted temperature management (TTM) is increasing although adoption is still variable. We describe our 6-year experience and compare the mortality and neurological outcomes of out-of-hospital cardiac arrest (OHCA) patients with and without the use of TTM in a multiethnic Asian population. We performed a retrospective observational study at a tertiary academic medical centre. OHCA survivors admitted to our hospital between April 2010‒December 2016 were included. Outcomes of interest were 30-day mortality postresuscitation, Cerebral Performance Category (CPC) and Overall Performance Category (OPC) scores. A total of 121 of 261 patients (46.3%) underwent TTM. TTM patients were younger (TTM 60.0 years old vs no TTM 63.7 years old, P = 0.047). There was no difference in the initial arrest rhythm of shockable origin between the 2 groups (P = 0.289). There was suggestion of lower 30-day mortality (TTM 24.3% vs no TTM 31.4%, P = 0.214), higher and good CPC/OPC scores (TTM 19.0% vs no TTM 15.7%, P = 0.514) with TTM although this did not reach statistical significance. On multivariable logistic regression analysis, TTM was not associated with 30-day mortality (P = 0.07). However, older age, initial non-shockable rhythm and increased duration from arrest to return of spontaneous circulation were associated with increased mortality. Malay ethnicity was associated with a poorer CPC/ OPC score. Adoption and outcomes of TTM postresuscitation is variable and there is still a need to optimise management of the identified predictors of survival and good neurological outcomes while TTM is being used.

The differential neurologic prognosis of low-flow time according to the initial rhythm in patients who undergo extracorporeal cardiopulmonary resuscitation

BackgroundLimited data is available on the association between low-flow time and neurologic outcome according to the initial arrest rhythm in patients underwent extracorporeal cardiopulmonary resuscitation (ECPR). MethodsBetween September 2004 and December 2018, 294 patients with in-hospital cardiac arrest (IHCA) were included in this analysis. We classified the patients into asystole (n = 42), pulseless electrical activity (PEA, n = 163) and shockable rhythm (n = 89) according to their initial rhythm. Primary outcome was poor neurologic outcome defined as Cerebral Performance Categories scores of 3, 4, and 5. ResultsOne-hundred ninety IHCA patients (64.6%) had poor neurologic outcomes. There was significantly worse neurologic outcomes among IHCA patients according to their initial rhythm (asystole [88.1%], PEA [66.3%], and shockable rhythm [50.6%], p < 0.001). The PEA group and the shockable rhythm group showed a significant association between low-flow time and neurologic outcomes while this relationship was not observed in the asystole group: PEA [ρ = 0.224, p = 0.005], shockable rhythm [ρ = 0.298, p = 0.006]), and asystole [ρ = −0.091, p = 0.590]. The best discriminative CPR to pump-on time for neurologic outcome was 22 min in the PEA group (area under the curve 0.687, 95% confidence interval [CI] 0.610–0.758, p < 0.001) and 46 min in the shockable rhythm group (area under the curve 0.671, 95% CI 0.593–0.743, p < 0.001). ConclusionsThe effect of interplay between arrest rhythm and low-flow time might be helpful for decisions about team activation and management for ECPR and could provide information for early neurologic prognosis.

Abstract 275: Oxygen Weaning is Slow and Highly Variable Among Mechanically Ventilated Patients After Out-Of-Hospital Cardiac Arrest

Introduction: Arterial hyperoxia at 6 h following resuscitation from out-of-hospital cardiac arrest (OHCA) may be associated with worsened survival and neurologic outcome. While global resuscitation guidelines call for prompt weaning of inhaled oxygen fraction (FiO2) following return of spontaneous circulation, with titration to oxygen saturation (SaO2) &gt;92%, the burden of hyperoxia (both FiO2 and duration) among OHCA patients in the emergency department (ED) and critical care setting is unknown. Objectives: We sought to characterize oxygen weaning behavior in a cohort of resuscitated and mechanically ventilated OHCA patients from two hospitals, with “hyperoxic exposure burden” defined as cumulative treatment hours with FiO2&gt;0.6. We hypothesized that the majority of these patients receive at least 6 h of hyperoxic exposure despite concomitant SaO2&gt;92% during and after weaning. Methods: A retrospective study of post-arrest care was performed at two academic hospitals from 1/2018-12/2018; both hospitals have well-developed post-arrest care protocols that include oxygen weaning instructions. Consecutive non-traumatic, adult (age&gt;17 y) OHCA patients treated in the emergency department that achieved sustained ROSC and received mechanical ventilation were included. Demographic data, as well as data on FiO2, SaO2 and arterial blood gas results, were collected for the first 24 h of post-arrest care. Results: 70 adult OHCA patients were included. Mean age was 61 y (SD 16.4), 51% were male, and 20% had initial shockable arrest rhythms. Survival to discharge was 21%. Median ED patient care time before ICU transfer was 2.7 h (IQR: 1.9-4.0). FiO2&gt;=0.6 was administered to 52% of the cohort for at least 6 h; the median duration of hyperoxic exposure burden was 8.7 h (IQR: 3.9-15.0) with a wide range from 0.6-92 h. Among all patients with 6 h or more with FiO2&gt;=0.6, median partial pressure of arterial oxygen was 136 mm Hg (IQR: 94-301) as measured during this period. Conclusions: Most resuscitated OHCA patients received substantial exposure to hyperoxia, and the timing of oxygen weaning was highly variable. Additional clinical investigation is required to understand the barriers to rapid weaning and to test the effect of improved weaning on clinical outcomes.