Comatose Survivors Of Out-of-hospital Cardiac Arrest Research Articles

Oxygen targets following immediate percutaneous coronary intervention in comatose survivors of out-of-hospital cardiac arrest - a BOX sub-study

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): The Novo Nordisk Foundation The Lundbeck Foundation. Background Treatment with supplemental oxygen in patients with acute myocardial infarction (AMI) has previously been associated with poorer outcomes. However, in patients with AMI resuscitated from out-of-hospital cardiac arrest (OHCA) and undergoing immediate revascularization, evidence regarding specific oxygen targets is sparse. Purpose To assess the impact of a restrictive versus a liberal oxygen target on infarct size in OHCA patients undergoing immediate percutaneous coronary intervention (PCI). Methods The current study is a sub-study of the BOX trial, a randomized trial with a 2-by-2 factorial design, in which comatose OHCA patients with a presumed cardiac cause of arrest were randomly assigned to either a restrictive oxygen target (partial pressure of arterial oxygen (Pao2) of 9 to 10 kPa) or a liberal oxygen target (Pao2 of 13 to 14 kPa). In this sub-study we included patients who underwent immediate revascularization with PCI. The primary outcome was myocardial infarct size as assessed by the cardiac enzyme troponin-T (TnT). TnT was measured repeatedly during the first 72 hours and analyzed with a repeated measures variance component model with baseline adjustment. Secondary outcome was one-year all-cause mortality assessed by Kaplan-Meier and Cox proportional hazards analyses. Results A total of 329 patients underwent immediate PCI, whereof 172 patients were randomized to the restrictive oxygen target and 157 to the liberal oxygen target. The oxygen intervention was successful with a significantly higher PaO2 in the liberal oxygen target group during the first 72 hours (p<0.0001). Baseline characteristics and findings on coronary angiography (CAG) were similar in the two oxygen target groups. Thus, median age was 63 (interquartile range (IQR) 55–71), 81% were male, and estimated left ventricular ejection fraction on arrival to hospital was 35% (IQR 25–45%). Further, 74% of the patients had an initial postresuscitation electrocardiogram with ST-segment elevations, and the left anterior descending artery was deemed as culprit lesion in 49% of the patients. There was no difference in peak TnT between the restrictive and liberal oxygen target group (median 2540 (IQR 925–6420) versus 3410 (792–8630), ng/l, p=0.23), nor did TnT differ between the groups during the first 72 hours after admission (Figure 1, p=1.00). Within one year from admission, 120 patients (36.5%) had died. There was no difference in mortality between the restrictive (34%) and liberal (39%) oxygen target group (hazard ratio, 0.80; 95% CI, 0.56-1.14; p=0.21) (Figure 2). Conclusion Targeting a restrictive versus a liberal oxygen level in comatose survivors of OHCA who underwent immediate revascularization did not affect infarct size nor did it result in a significant difference in one-year mortality rate.Figure 1:Troponin-T levelsFigure 2:Kaplan-Meier curves

Grey-to-white matter ratio values in early head CT as a predictor of neurological outcomes in survivors of out-of-hospital cardiac arrest based on severity of hypoxic-ischemic brain injury

Background: Hypoxic-ischemic brain injury (HIBI) is a common complication of out-of-hospital cardiac arrest (OHCA). Objectives: We investigated whether grey-to-white matter ratio (GWR) values, measured using early head computed tomography (HCT), were associated with neurological outcomes based on the severity of HIBI in survivors of OHCA. Methods: This retrospective multicenter study included adult comatose OHCA survivors who underwent an HCT scan within 2 hours after the return of spontaneous circulation. HIBI severity was assessed using the revised post-Cardiac Arrest Syndrome for Therapeutic hypothermia (rCAST) scale (low, moderate, and severe). Poor neurological outcomes were defined as Cerebral Performance Categories 3–5 at 6 months after OHCA. Results: Among 354 patients, 27% were women and 224 (63.3%) had poor neurological outcomes. The distribution of severity was 19.5% low, 47.5% moderate, and 33.1% severe. The area under the receiver operating curves of the GWR values for predicting rCAST severity (low, moderate, and severe) were 0.52, 0.62, and 0.79, respectively. The severe group had significantly higher predictive performance than the moderate group (p=0.02). Multivariate logistic regression analysis revealed a significant association between GWR values and poor neurological outcomes in the moderate group (adjusted odds ratio=0.012, 95% CI 0.0–0.54, p=0.02). Conclusions: In this cohort study, GWR values measured using early HCT demonstrated variations in predicting neurological outcomes based on HIBI severity. Furthermore, GWR in the moderate group was associated with poor neurological outcomes.

Association between quantitative analysis of cerebral edema using CT imaging and neurological outcomes in cardiac arrest survivors

BackgroundTo determine if the density distribution proportion of Hounsfield unit (HUdp) in head computed tomography (HCT) images can be used to quantitatively measure cerebral edema in survivors of out-of-hospital cardiac arrest (OHCA). MethodsThis retrospective observational study included adult comatose OHCA survivors who underwent HCT within 6 h (first) and 72–96 h (second), all performed using the same CT scanner. Semi-automated quantitative analysis was used to identify differences in HUdp at specific HU ranges across the intracranial component based on neurological outcome. Cerebral edema was defined as the increased displacement of the sum of HUdp values (ΔHUdp) at a specific range between two HCT scans. Poor neurological outcome was defined as cerebral performance categories 3–5 at 6 months after OHCA. ResultsTwenty-three (42%) out of 55 patients had poor neurological outcome. Significant HUdp differences were observed between good and poor neurological outcomes in the second HCT scan at HU = 1–14, 23–35, and 39–56 (all P < 0.05). Only the ΔHUdp = 23–35 range showed a significant increase and correlation in the poor neurological outcome group (4.90 vs. -0.72, P < 0.001) with the sum of decreases in the other two ranges (r = 0.97, P < 0.001). Multivariate logistic regression analysis demonstrated a significant association between ΔHUdp = 23–35 range and poor neurological outcomes (adjusted OR, 1.12; 95% CI: 1.02–1.24; P = 0.02). ConclusionIn this cohort study, the increased displacement in ΔHUdp = 23–35 range is independently associated with poor neurological outcome and provides a quantitative assessment of cerebral edema formation in OHCA survivors.

Abstract 256: Quantitative Assessment and Visualization of Hypoxic Ischemic Brain Injury in Survivors of Cardiac Arrest Using Unenhanced Computed Tomography Images

Aim: This study aimed to investigate whether the distribution of Hounsfield units (HU) values in head computed tomography (HCT) images can serve as an effective tool for assessing the severity of hypoxic ischemic brain injury (HIBI) in survivors of out-of-hospital cardiac arrest (OHCA). Methods: This retrospective study included adult comatose OHCA survivors who underwent first HCT scans within 6 hours and second HCT scans between 72-96 hours on the same CT machine after the return of spontaneous circulation. Automated quantitative analysis was used on CT images to eliminate artifacts and identify differences in the proportion of HU values (HUp) at specific intervals across the intracranial area based on neurological outcome. Additionally, correlation analysis was conducted between serum levels of neuron-specific enolase (NSE) at 48 hours post-ROSC and the sum of HUp values in the aforementioned intervals. Poor outcome was defined as cerebral performance categories 3-5 at 6 months post-ROSC. Results: Of the 55 included patients (84% male), 23 (42%) had poor outcome. Significant differences in HU values were observed between outcomes in the second HCT scan at HU=1-14, 23-35, and 39-56 (P&lt;0.05). Within the same HU interval, the poor outcome group showed a greater change between the first and second HCT scans compared to the good outcome group (Figure). The correlations between the sum of HUp and NSE levels within the range of HU=1-14, 23-35, and 39-56 in the second HCT were 0.34, 0.60, and 0.49, respectively (Figure). The second HCT scans demonstrated better prognostic performance than the first HCT scan for HU=1-14 (area under the curve 0.75 vs. 0.60), 23-35 (0.85 vs. 0.62), and 39-56 (0.75 vs. 0.59), while no significant difference was observed compared to GWR (0.78) (all P≥0.05). Conclusions: The proportional sum of HU values within specific intervals in the entire cerebral area on CT images can effectively assess and visualize the extent of HIBI in survivors of OHCA.

Abstract 188: Association Between Mean Arterial Pressure and Neurological Outcomes in Comatose Cardiac Arrest Patients: A Multicenter Observational Study

Aim: The target blood pressure has not been determined in comatose cardiac arrest patients. Therefore, we aimed to investigate the association between mean arterial pressure (MAP) and six-month neurological outcomes in out-of-hospital cardiac arrest (OHCA) survivors who underwent targeted temperature management (TTM). Methods: We analyzed the prospective registry of comatose OHCA survivors who underwent TTM. The arterial blood pressure measured every 1 hr in a 48-hour period after return of spontaneous circulation (ROSC) was recorded between January 2019 and May 2021 in the registry. We calculated the MAP during 48 hr and at every 6 hr. Patients with an MAP &lt; 65 mmHg or missing MAP data for more than 6 hr were excluded. We conducted a multivariable logistic regression analysis to determine the association between MAP and neurological outcomes and conducted a linear mixed models analysis to reveal the interaction between MAP over time and neurological outcomes. The primary outcome was six-month neurological outcomes with Cerebral Performance Category (CPC), which was dichotomized into good (CPC 1 or 2) and poor (CPC 3-5) neurological outcomes. Results: Of the 394 included patients, 255 patients (64.7%) had poor neurological outcomes. MAP did not differ between the neurological outcome groups (poor [89 mmHg, 82-97 mmHg] vs. good [89 mmHg, 84-95 mmHg]; p = 0.498). MAP was not independently associated with poor neurological outcomes (odds ratio, 1.010 [95% confidence intervals, 0.978-1.042]) adjusted with age, sex, body mass index, pre-existing illness (coronary artery disease, diabetes, pulmonary disease, renal impairment), witnessed collapse, first-monitored rhythm, cardiac etiology, downtime, lactate level after ROSC, and sequential organ failure assessment score. Repeated MAP measurements every 6 hr did not differ between the neurological outcome groups (p = 0.403), and the interaction between MAP every 6hr and neurological outcomes was not significant (p = 0.136). Conclusions: MAP during 48 hr after ROSC was not associated with the six-month neurological outcomes. MAP measurements every 6 hr during 48 hr after ROSC did not differ between neurological outcome groups, and the changes in MAP over time were not associated with neurological outcomes.

Abstract 146: Advanced Age and Neurological Recovery in Elderly Patients With Out-of-Hospital Cardiac Arrest Treated With Targeted Temperature Management: A Nationwide Population-Based Registry Study

Objectives: The chance of neurological recovery after out-of-hospital cardiac arrest (OHCA) can be influenced by advanced age, however further recent evidence will be need in elderly population. The purpose of this study is to evaluate the impact of advanced age on the neurological recovery in elderly OHCA survivors treated with targeted temperature management (TTM). Methods: This retrospective observational study, using a nationwide population-based OHCA registry, was conducted from January 2016 to December 2020. Non-traumatic elderly (≥ 65 years) comatose OHCA survivors treated with TTM were enrolled. The elderly patients were divided into four groups (65-69 years, 70-74 years, 75-79 years, and ≥ 80 years). The primary outcome was good neurological outcome, defined as Cerebral Performance Categories (CPC) of 1 or 2 at hospital discharge. Results: Among 23,336 OHCA patients who admitted to the hospital, 3,398 patients treated with TTM. Excluding 2,033 non-elderly patients, 1,365 patients were analyzed. In four elderly group, the rate of good neurological outcomes were decreased by advanced age (24.2%, 16.1%, 11.4%, and 5.9%). This was also observed after subgroup analysis based on the initial shockable (40.6%, 31.5%, 28.6%, and 14.9%) and non-shockable rhythm (10.6%, 7.2%, 4.1%, and 3.4%). Multivariate analysis showed the adjusted odds ratio (aOR) for good neurological outcome decreased as advanced age (65-69 years: reference, 70-74 years: aOR 0.70, 75-79 years: aOR 0.49, and ≥ 80: aOR 0.25). The optimal age cutoffs for good outcome in elderly OHCA survivors with shockable and non-shockable rhythm were 77 years and 72 years respectively. Conclusions: The neurologic recovery rate in OHCA survivors treated with TTM was gradually decreased with advanced age. However even with ≥ 80 years with shockable rhythm, had a good neurologic outcome of 14.9%, which is higher than 65-69 years of 10.6% in non-shockable rhythm.

Blood-pressure targets in comatose survivors of cardiac arrest with ST-elevation myocardial infarction treated with primary percutaneous coronary intervention - a BOX sub-study

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Novo Nordisk Foundation. Background After successful resuscitation from out-of-hospital cardiac arrest (OHCA), patients who remain comatose often need hemodynamic support with vasoactive drugs in order to secure an adequate perfusion pressure to vital organs. However, evidence regarding specific blood-pressure targets is sparse, and patients with concomitant heart disease such as acute ST-elevation myocardial infarction (STEMI) might benefit from a lower afterload and lower doses of vasoactive drugs. Purpose To assess the impact of blood-pressure on biochemical infarct size in comatose survivors of OHCA with STEMI and, further, to investigate whether a high or low mean arterial blood-pressure target is superior in preventing death or severe brain injury. Methods The BOX study (n=789) is a randomized trial with a 2-by-2 factorial design which evaluated a double-blind intervention of a high (77 mmHg) versus a low (63 mmHg) mean arterial blood-pressure target in comatose survivors of OHCA of presumed cardiac cause. In this pre-specified sub-study we included patients who had an initial electrocardiogram with STEMI recorded after return of spontaneous circulation (ROSC). The primary outcome was creatine kinase (CK), creatine kinase MB (CKMB), and troponin T (TnT) levels measured at 48 hours as surrogate markers of infarct size. A secondary outcome was a composite of all-cause death within one year from admission or discharge from the hospital with a Cerebral Performance Category (CPC) of 3 to 4, indicating severe neurological disability or a comatose or vegetative state. Results A total of 350 patients were included. Mean time to ROSC was 21±13 minutes. The mean age was 63±12 years and approximately 4 out of 5 were male. The prevalence of relevant prior medical history was as follows; hypertension 42%, diabetes 12%, chronic ischemic heart disease 20%, percutaneous coronary intervention 11%, coronary artery bypass grafting 4%, and congestive heart failure 10%. Mean CK, CKMB and TnT measured at 48 hours did not differ between the two blood-pressure target groups (p=0.42, p=0.14 and p=0.65, respectively). Within one year, 138 patients (39%) had died or been discharged with a CPC of 3 to 4 with no difference found between high or low blood pressure targets (hazard ratio, 1.02; 95% CI, 0.73-1.43; p=0.9). Conclusion Targeting a high versus a low mean arterial blood-pressure in comatose survivors of OHCA with STEMI did not affect infarct size estimated by coronary biomarkers at 48 hours nor did it result in a significant difference in death or severe neurologic disability. Although not evaluating side effects, this study thus suggests that the use of pharmacologic circulatory support in post-resuscitation care can be limited.

Sex differences in acute hemodynamic response in comatose survivors of OHCA

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Novo Nordisk Fonden Background In critically ill patients with cardiogenic shock, neurohormonal activation is higher in females compared with males. Whether this is the case in patients resuscitated from out of hospital cardiac arrest (OHCA) is not known and whether sex-based differences relate to achieving mean-arterial-pressure (MAP)-target has not previously been described. Methods This was an investigator-initiated, randomized, controlled study of targeted MAP (63 vs 77 mmHg) and PaO2 (9-10 vs 13-14 kPa) interventions in 789 comatose OHCA (of presumed cardiac origin) patients. Patients underwent serial hemodynamic assessments with pulmonary artery catheter at time of insertion, 6 h, 12 h, 24 h, 36 h and 48 h. Among parameters recorded were heart rate (HR), cardiac output (CO) and central venous pressure (CVP), from which cardiac index (CI) and systemic vascular resistance index (SVRI) were derived. Patient characteristics included sex for stratification, age, time to return of spontaneous circulation (ROSC) and initial electrocardiographic (ECG) rhythm. Results Hemodynamic parameters from 729 patients were analysed, of which 138 (19%) were female and 591 (81%) were male. Both groups had a median age of 64 years, with median time-to-ROSC of 19 minutes in females versus 18 minutes in males. In females versus in males, SVRI and HR were higher (fig.1,2). There were no differences among sexes with regards to CI, MAP, or dose of noradrenaline. At 12 hours, median SVRI in females was 755 dyn·s/cm5·m2 (inter-quartile ratio, IQR 569-931) versus 554 dyn·s/cm5·m2 (IQR 441-684) in males (P&amp;lt;0.0001). At the same point in time, median HR was 71 beats/minute (bpm) in females (IQR 59-82) versus 62 bpm (IQR 54-74) in males (P&amp;lt;0.0001). Lastly, 12-hour median CI was 1.82 L/min/m2 (IQR 1.54-2.40) in females versus 1.95 L/min/m2 (IQR 1.63-2.43) in males (P=0.1303). Conclusions Female comatose OHCA patients had higher SVRI and HR during the first 48 hours of ICU admission, without difference in MAP or vasopressor requirement. Sex specific physiological mechanisms may be involved in maintaining vascular resistance.

Influence of blood-pressure and oxygen levels on the prognostic value of quantitative pupillometry for comatose cardiac arrest patients - a BOX-trial substudy

Abstract Funding Acknowledgements Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Novo Nordisk Foundation Background Quantitative pupillometry has been implemented in resuscitation guidelines as part of multimodal prognostication in comatose out-of-hospital cardiac arrest (OHCA) patients. Post-resuscitation intensive care allows for different blood-pressure and oxygen targets, but evidence on the implication of these targets on prognostication is limited. Purpose To assess the impact of different blood-pressure and oxygen targets in resuscitated OHCA patients on the prognostic ability of the quantitatively assessed percentage reduction of pupillary size (qPLR, %) and the neurological pupil index (NPi, 0-5). Methods The BOX-trial is a multicenter, double-blind, randomized trial, comparing low (63 mm Hg) versus high (77 mm Hg) mean arterial blood-pressure targets and restrictive (9 to 10 kPa) versus liberal (13 to 14 kPa) partial pressure of arterial oxygen targets in comatose survivors of OHCA. In this predefined, prospective substudy, quantitative pupillometry measurements were obtained from consecutively enrolled patients at 0, 24, 48, 72, 96, and 120 hours after OHCA (t0-t120). The prognostic performance of qPLR and NPi for high and low blood-pressure groups, and liberal and restrictive oxygen target groups were illustrated through the area under the receiver operating characteristic (ROC) curves (AUC). The time point achieving the highest AUC was used for further analyses. AUCs were compared with DeLong’s test. Results The highest AUC for qPLR and NPi were achieved for measurements made 48 hours after OHCA. qPLR produced AUC at 0.79 [95%CI 0.73-0.85] and 0.81 [95%CI 0.75-0.86] for high and low blood-pressure groups, and 0.79 [95%CI 0.73-0.85] and 0.80 [95%CI 0.74-0.86] for liberal and restrictive oxygen target groups, respectively (Fig 1). For NPi AUC were 0.79 [95%CI 0.73-0.85] and 0.78 [95%CI 0.72-0.84] in high and low blood-pressure groups, and 0.77 [95%CI 0.71-0.83] and 0.80 [95%CI 0.75-0.86] in liberal and restrictive oxygen target groups, respectively (Fig 2). No significant difference between any groups, for either blood-pressure or oxygen targets, was found. Conclusion Prognostic value of quantitative pupillometry for predicting outcome in resuscitated OHCA patients was high and consistent across different blood-pressure and oxygen level targets.

Abstract 177: Optimal Selection Of Predictors To Enhance Prognostic Performance In Post-resuscitation Care: A Single Center Experience

Objectives: The aim of this study was to investigate the optimal combinations that would enhance prognostic accuracy in post-resuscitation care after out-of-hospital cardiac arrest (OHCA). Methods: Prospectively registry data collected between May 2018 and January 2022 were analyzed. We analyzed the prognostic performance of all single predictors suggested from current guidelines: no ocular reflexes (OR) at 72 h, highly malignant pattern in electroencephalography at ≥ 24 h, neuron-specific enolase (NSE) at 72 h, and diffuse anoxic injury at 72 h on image studies of computed tomography (CT) and diffusion-weighted image (DWI). Gray-to-white matter ratio and high-signal intensity on CT and DWI, respectively, were used as a tool to estimate abnormal findings. We also analyzed the prognostic accuracy of combining strategies using 2 to 3 abnormal results from predictors. All prognostic accuracies were analyzed as sensitivities with false positive ratios (FPR) of &lt; 2%. The primary outcome was poor neurological outcome after 3 months from OHCA. Results: We assessed 119 comatose adult survivors of OHCA, of whom 62 (52.1%) had poor neurological outcomes. The highest sensitivity among single prognostic modalities was found in abnormal DWI, with an FPR of &lt; 2% (86.3%, 95% confidence interval [CI] 73.7 - 94.3). In multimodal assessments, combining NSE and DWI (87.8%, 95% CI 75.2 - 95.4) and combining NSE, OR, and DWI (87.8%, 95% CI 75.2 - 95.4) showed the highest sensitivities in dual and triple combining prognostic strategies, respectively. Combining strategies with image study at 72 h, regardless of whether CT or DWI, improved the sensitivities of every non-imaging study modality. Conclusions: This study emphasizes that combining prognostic strategies for multimodal assessment can enhance prognostic reliability. In particular, this combining strategy, along with the image study at 72 h, can be valuable to ensure the reliability of prognostication in post-resusciation care. 1

Abstract 316: Ultra-early Diffusion-weighted Magnetic Resonance Imaging For Assessment Of Prognosis In Out-of-hospital Cardiac Arrest Survivors

Aim: We investigated the association of poor neurological outcomes with ultra-early diffusion-weighted magnetic resonance imaging (DW-MRI) of the brain in out-of-hospital cardiac arrest (OHCA) survivors and how to complement for false-negative findings (FNF). Methods: This registry-based observational study included adult comatose OHCA survivors who underwent DW-MRI scans within 6 h after the return of spontaneous circulation (ROSC). This study was divided into four groups: Group A (poor outcome with high-signal intensity (HSI) on DW-MRI), Group B (poor outcome without HSI [FNF]), Group C (good outcome without HSI), and Group D (good outcome with HSI). We analyzed serum and CSF neuron-specific enolase (NSE), albumin quotient (albumin CSF /albumin serum ) (Qa), apparent diffusion coefficient (ADC) value, and low flow time, among others, obtained within 6 h after ROSC. The primary outcome was the 3-month poor (CPC 3-5) outcome. Results: Of the 110 patients, 62 (56.4%) had poor outcomes, time from ROSC to MRI was 2.8 h (IQR, 2.0-4.0 h), and HSI on DW-MRI was observed in 46 (41.8%). The composition of Groups A, B, C, and D was 46 (41.8%), 16 (14.5%), 48 (43.6%), and 0 (0%) patients, respectively. Group B had significantly lower serum NSE, 650 ADC value, Qa, and low flow time than Group A; however, CSF NSE was higher than in Group C (Fig. 1). DW-MRI and CSF NSE identified patients with poor outcomes with 74.2% sensitivity (95% CI 61.5-84.5) and 100% specificity (95% CI 92.6-100), and 67.9% sensitivity (95% CI 53.7-80.1) and 100% specificity (95% CI 90.3-100), respectively. Combining the two tools increased identification to 87.1% sensitivity (95% CI 76.1-94.3) at 0% false positive rate (FPR). Conclusions: The HSI on ultra-early DW-MRI in OHCA survivors was significantly associated with poor outcomes. The CSF NSE is a complementary tool showing higher sensitivity at 0% FPR than DW-MRI alone. Multicenter prospective studies are required to determine the results’ generalizability.

Abstract 314: Changes In The Hounsfield Unit Proportion Of Head Computed Tomography With Time And Neurological Outcomes In Out-of-hospital Cardiac Arrest Survivors

Changes in the Hounsfield Unit proportion of head computed tomography with time and neurological outcomes in out-of-hospital cardiac arrest survivors Aim: We compared changes in Hounsfield Unit proportion (HUp) with neurological outcomes using head computed tomography (HCT) obtained before and after targeted temperature management of out-of-hospital cardiac arrest (OHCA) survivors. Methods: This retrospective observational study included adult comatose OHCA survivors who underwent HCT scans within 6 h (first HCT) and 72-96 h (second HCT) after the return of spontaneous circulation (ROSC). Automated quantitative analysis using non-enhanced HCT images was applied to identify the difference in HU value distribution across the intracranial area between neurological outcomes. Each pixel in an HCT image has a certain HU level, λ, which is between 1 and 79 in this study. The proportion (%) of λ in a CT image is 0 to 100, with the sum of every λp as 100, as per the definition of λp. The primary outcome was the 6-month poor (CPC 3-5) outcome. Results: Of the 41 included patients (30 males; 73%), 14 (34%) had poor outcomes. In the first HCT, only HU = 29-30 showed a difference according to the neurological outcome; however, in the second HCT, HU = 1-12, 22-33, 39-50 showed a difference ( P &lt; 0.05) (Fig. 1). Among them, the greatest difference between the good and poor neurological outcome groups was the proportion of pixels with HU = 22-33, and the average values were 36.0 ± 6.0 and 43.6 ± 8.1, respectively ( P &lt; 0.01). In addition, receiver operating characteristic analysis showed that the of the second HCT was predictive of prognostic performance from poor neurological outcomes six months after ROSC to moderate to good (0.76; 95% confidence interval, 0.60-0.88). Conclusions: The proportion of in total cerebral regions in HCT scans obtained between 72-96 hours after ROSC in OHCA survivors was associated with poor neurological outcomes six months after ROSC.

Abstract 320: Gray-white Matter Ratio Under 1.12 Could Predict Poor Neurological Outcomes, Even When Measured Within Two Hours After Return Of Spontaneous Circulation

Introduction: Literature on neuroprognostication suggests that gray-white matter ratio (GWR) measured from head computed tomography (CT) within two hours after return of spontaneous circulation (ROSC) can’t adequately predict neurological outcomes in out-of-hospital cardiac arrest (OHCA) patients. However, severe cerebral edema may predict poor outcomes within two hours after ROSC. Hypothesis: We evaluated if GWR measurements obtained early after OHCA (≤ 2 hours) indicated poor neurological outcomes in patients with severe cerebral edema. Methods: We conducted a multicenter, retrospective cohort study using data from five hospitals collected between 2007 and 2019 in Japan. Inclusion criteria: adult comatose OHCA survivors with head CT within two hours after ROSC. Exclusion criteria was trauma, stroke, or pre-existing neurological disorders. Primary outcome was poor neurological outcome, defined as Cerebral Performance Category (CPC) score ≥ 3 at one month after admission. GWR was measured at the levels of the basal ganglia (BG), corpus callosum (CC), and posterior internal capsule (PIC). The prognostic value of GWR for predicting poor outcome was assessed using a receiver operating characteristic (ROC) curve analysis, area under the curve (AUC) with sensitivity/specificity. Results: A total of 377 patients were included. Of those, 281 (74.6%) exhibited poor neurological outcome at one month after admission. GWR values did not alter by the time of obtaining head CT: 1.22 (0-30 min: n=194); 1.22 (31-60 min: n=127); 1.22 (61-120 min: n=56). Using a cut-off GWR value of &lt;1.2, ROC analysis demonstrated AUC for GWR-BG (0.69, 95% CI 0.65-0.73), GWR-CC (0.77, 95% CI 0.69-0.76), and GWR-PIC (0.76, 95% CI 0.72-0.79) with sensitivities/specificities of 45.5%/92.7%, 47.6%/97.9%, 55.8%/96.8%, and 46.2%/97.9%, respectively for poor outcomes. However, GWR values &lt;1.12 demonstrated 100% specificity for poor outcomes: GWR-BG (AUC 0.56, sensitivity/specificity 13.5%/100%), GWR-CC (AUC 0.56, sensitivity/specificity 13.5%/100%), and GWR-PIC (AUC 0.59, sensitivity/specificity 19.5%/100%). Conclusion: GWR (&lt;1.12) obtained even within two hours after ROSC could be used as a threshold for poor neurological outcome in OHCA patients.

Ion Shift Index at the Immediate Post-Cardiac Arrest Period as an Early Prognostic Marker in Out-of-Hospital Cardiac Arrest Survivors.

The ion shift index (ISI) is a suggested marker to reflect the magnitude of ischemic damage. This study aimed to investigate the prognostic value of the ISI for predicting poor neurological outcomes at 6 months in comatose out-of-hospital cardiac arrest (OHCA) survivors by comparing it with the OHCA and Cardiac Arrest Hospital Prognosis (CAHP) scores. This observational registry-based cohort study included adult comatose OHCA survivors admitted to a tertiary care hospital in Korea between 2015 and 2021. The ISI was calculated using the serum electrolyte levels obtained within one hour of resuscitation. The primary outcome was poor neurological function (Cerebral Performance Category score of 3–5) at 6 months. Of the 250 OHCA survivors, 164 (65.6%) had poor neurological outcomes. These patients had a higher median ISI than those with good neurological outcomes (4.95 vs. 3.26, p < 0.001). ISI (adjusted odds ratio, 2.107; 95% confidence interval, 1.350–3.288, p = 0.001) was associated with poor neurological outcomes. The prognostic performance of ISI (area under the curve [AUC], 0.859) was similar to that of the OHCA score (AUC, 0.858; p = 0.968) and the CAHP score (AUC, 0.894; p = 0.183). ISI would be a prognostic biomarker for comatose OHCA survivors that is available during the immediate post-cardiac arrest period.

Kinetics of 2 different high-sensitive troponins during targeted temperature management in out-of-hospital cardiac arrest patients with acute myocardial infarction: a post hoc sub-study of a randomised clinical trial

IntroductionShort term hypothermia has been suggested to have cardio protective properties in acute myocardial infarction (AMI) by reducing infarct size as assessed by troponins. There are limited data on the kinetics of these biomarkers in comatose out-of-hospital cardiac arrest (OHCA) patients, with and without AMI, undergoing targeted temperature management (TTM) in the ICU.PurposeThe aim of this post hoc analyses was to evaluate and compare the kinetics of two high-sensitivity cardiac troponins in OHCA survivors, with and without acute myocardial infarction (AMI), during TTM of different durations [24 h (standard) vs. 48 h (prolonged)].MethodsIn a sub-cohort (n = 114) of the international, multicentre, randomized controlled study “TTH48” we measured high-sensitive troponin T (hs-cTnT), high-sensitive troponin I (hs-cTnI) and CK-MB at the following time points: Arrival, 24 h, 48 h and 72 h from reaching the target temperature range of 33 ± 1 °C. All patients diagnosed with an AMI at the immediate coronary angiogram (CAG)—18 in the 24-h group and 25 in the 48-h group—underwent PCI with stent implantation. There were no stent thromboses.ResultsBoth the hs-cTnT and hs-cTnI changes over time were highly influenced by the cause of OHCA (AMI vs. non-AMI). In contrast to non-AMI patients, both troponins remained elevated at 72 h in AMI patients. There was no difference between the two time-differentiated TTM groups in the kinetics for the two troponins.ConclusionIn comatose OHCA survivors with an aetiology of AMI levels of both hs-cTnI and hs-cTnT remained elevated for 72 h, which is in contrast to the well-described kinetic profile of troponins in normotherm AMI patients. There was no difference in kinetic profile between the two high sensitive assays. Different duration of TTM did not influence the kinetics of the troponins.Trial registration: Clinicaltrials.gov Identifier: NCT01689077, 20/09/2012.

Immediate complete revascularization showed better outcome in out-of-hospital cardiac arrest survivors with left main or triple-vessel coronary diseases

This study aimed to evaluate the prevalence of left main or triple vessel coronary artery disease (CAD) in comatose out-of-hospital cardiac arrest (OHCA) survivors and assessed their outcome based on the revascularization strategy. This multicenter, retrospective, observational registry-based study was conducted at 9 Korean tertiary care hospitals. Adult comatose OHCA survivors with left main or triple vessel CAD documented by immediate (≤ 2 h) coronary angiography after return of spontaneous circulation between 2011 and 2019 were included. The primary outcome was neurologically intact survival at 1-month. Among 727 OHCA patients, 150 (25%) had left main or triple vessel CAD and underwent complete (N = 32), incomplete (N = 78), and no immediate (N = 40) revascularization, respectively. The rate of neurologically intact survival at 1 month was significantly different among the groups (53%, 32%, and 23% for complete, incomplete, and no immediate revascularization groups, respectively; P = 0.02). After adjustment using the inverse probability of treatment weighting, complete revascularization was associated with neurologically intact survival at 1 month (odds ratio, 2.635; P = 0.01). Left main or triple vessel CAD is not uncommon in OHCA patients. The complete revascularization was associated with better outcome. Further clinical trials to confirm the best revascularization strategy are needed.

Delayed head CT in out-of-hospital cardiac arrest survivors: Does this improve predictive performance of neurological outcome?

BackgroundWe compared the ability of head computed tomography (HCT) and MRI, respectively, obtained before or after target temperature management to predict neurologic outcomes in out-of-hospital cardiac arrest (OHCA) survivors. MethodsThis retrospective study included adult comatose OHCA survivors who underwent neuroimaging scans within 6 h (first HCT) or 72–96 h (second HCT and MRI) after the return of spontaneous circulation (ROSC). We calculated the gray-white matter ratio (GWR), hypoxic-ischemic brain injury presence (loss of boundary at the basal ganglia level [LOB at BG], sulcal effacement at the centrum semiovale [SE at CS], and pseudo-SAH sign), and the overall score based on MRI findings (a total score of 21 brain regions individually scored according to the degree of signal abnormality). ResultsOverall, 78 patients were included in this analysis, of whom 45 (58%) showed poor outcomes. The second HCT scan showed greater prognostic performance than the first HCT scan for GWR (area under curve 0.92 vs. 0.70), LOB at BG (0.93 vs. 0.65), SE at CS (0.89 vs. 0.64), and pseudo-SAH sign (0.75 vs. 0.51). The overall score on MRI (0.99) showed the highest prognostic performance. However, on the second HCT scan, the combination of GWR and LOB at BG showed prognostic performance (0.96) comparable to the overall score on MRI (P = 0.12); the corresponding sensitivity and specificity values were 85.7% and 100%. ConclusionsOverall score on MRI and the combination of GWR and LOB at BG findings on second HCT scans may help predict poor outcomes in OHCA survivors.

Different Stratification of Physiological Factors Affecting Cerebral Perfusion Pressure in Hypoxic-Ischemic Brain Injury after Cardiac Arrest According to Visible or Non-Visible Primary Brain Injury: A Retrospective Observational Study

We aimed to explore the stratification of physiological factors affecting cerebral perfusion pressure, including arterial oxygen tension, arterial carbon dioxide tension, mean arterial pressure, intracranial pressure (ICP), and blood-brain barrier (BBB) status, with respect to primary or secondary brain injury (PBI or SBI) after out-of-hospital cardiac arrest (OHCA). Among the retrospectively enrolled 97 comatose OHCA survivors undergoing post-cardiac arrest (PCA) care, 46 (47.4%) with already established PBI (high signal intensity (HSI) on diffusion-weighted imaging (DWI) had higher ICP (p = 0.02) and poorer BBB status (p < 0.01) than the non-HSI group. On subgroup analysis within the non-HSI group to exclude the confounding effect of already established PBI, 40 (78.4%) patients with good neurological outcomes had lower ICP at 24 h (11.0 vs. 16.0 mmHg, p < 0.01) and more stable BBB status (p = 0.17 in pairwise comparison) compared to those with poor neurological outcomes, despite the non-significant differences in other physiological factors. OHCA survivors with HSI on DWI showed significantly higher ICP and poorer BBB status at baseline before PCA care than those without HSI. Despite the negative DWI findings before PCA care, OHCA survivors have a cerebral penumbra at risk for potentially leading the poor neurological outcome from unsuppressed SBI, which may be associated with increased ICP and BBB permeability.

Background frequency can enhance the prognostication power of EEG patterns categories in comatose cardiac arrest survivors: a prospective, multicenter, observational cohort study

BackgroundWe assessed the prognostic accuracy of the standardized electroencephalography (EEG) patterns (“highly malignant,” “malignant,” and “benign”) according to the EEG timing (early vs. late) and investigated the EEG features to enhance the predictive power for poor neurologic outcome at 1 month after cardiac arrest.MethodsThis prospective, multicenter, observational, cohort study using data from Korean Hypothermia Network prospective registry included adult patients with out-of-hospital cardiac arrest (OHCA) treated with targeted temperature management (TTM) and underwent standard EEG within 7 days after cardiac arrest from 14 university-affiliated teaching hospitals in South Korea between October 2015 and December 2018. Early EEG was defined as EEG performed within 72 h after cardiac arrest. The primary outcome was poor neurological outcome (Cerebral Performance Category score 3–5) at 1 month.ResultsAmong 489 comatose OHCA survivors with a median EEG time of 46.6 h, the “highly malignant” pattern (40.7%) was most prevalent, followed by the “benign” (33.9%) and “malignant” (25.4%) patterns. All patients with the highly malignant EEG pattern had poor neurologic outcomes, with 100% specificity in both groups but 59.3% and 56.1% sensitivity in the early and late EEG groups, respectively. However, for patients with “malignant” patterns, 84.8% sensitivity, 77.0% specificity, and 89.5% positive predictive value for poor neurologic outcome were observed. Only 3.5% (9/256) of patients with background EEG frequency of predominant delta waves or undetermined had good neurologic survival. The combination of “highly malignant” or “malignant” EEG pattern with background frequency of delta waves or undetermined increased specificity and positive predictive value, respectively, to up to 98.0% and 98.7%.ConclusionsThe “highly malignant” patterns predicted poor neurologic outcome with a high specificity regardless of EEG measurement time. The assessment of predominant background frequency in addition to EEG patterns can increase the prognostic value of OHCA survivors.Trial registration KORHN-PRO, NCT02827422. Registered 11 September 2016—Retrospectively registered.

Abstract 10475: Heat Loss Augmented by Extracorporeal Circulation is Associated with Overcooling in Cardiac Arrest Survivors Who Underwent Targeted Temperature Management

Introduction: Extracorporeal circuit-based salvage therapy can affect targeted temperature management (TTM) in comatose out-of-hospital cardiac arrest (OHCA) survivors. We investigated the association of patients with extracorporeal device with TTM and neurological outcome. Methods: We performed a retrospective analysis using prospectively collected data from adult comatose OHCA survivors who underwent TTM between October 2015 and December 2020. We defined patients with ECMO and/or CRRT as the extracorporeal group. We calculated the cooling rate during the induction period; the minimum, maximum, and mean time-weighted core temperatures (TWCT), and the standard deviation (SD) of the core temperature and water temperature during the maintenance period based on the temperature measured every minute. We defined the sum of TWCT more and less than 33°C as positive and negative TWCT, respectively. The primary outcome was a poor neurological outcome, defined as cerebral performance category 3-5. We used propensity score (PS) matching to adjust the characteristics of patients who required an extracorporeal circuit device. Results: Of the 223 included patients, 140 (62.8%) patients had poor neurological outcome and 40 (17.9%) patients were categorized into the extracorporeal group. The extracorporeal group had a rapid cooling rate (2.08°C/h [1.13-3.73] vs. 1.24°C/h [0.77-1.79]; p &lt; 0.001). The extracorporeal group had lower mean core temperature; higher core temperature SD; lower positive TWCT; higher negative TWCT; and higher maximum, minimum, and mean water temperature than the no-extracorporeal group. In PS matched cohort, the extracorporeal group had a lower minimum core temperature, lower mean core temperature, higher core temperature SD, higher negative TWCT, higher maximum water temperature, and higher mean water temperature. The neurological outcomes were not different between the two groups, in either the whole or PS-matched cohort. Conclusions: The extracorporeal group achieved the target temperature earlier. The core temperature distribution during the maintenance period was further skewed below 33°C in the extracorporeal group. The extracorporeal group had similar neurological outcomes to the no-extracorporeal group.