Post Arrest Patients Research Articles

Effect of hypercapnia on neurologic outcomes after cardiac arrest: A systematic review and meta-analysis.

Brain injury often occurs after cardiac arrest, and the regulation of PaCO2 plays a crucial role in mediating cerebral blood flow. The current guidelines recommend maintaining normocapnia through ventilation in post-arrest patients. However, the effects of hypercapnia on neurological outcomes remain controversial. To address this issue, we undertook a meta-analysis to compare the effects of hypercapnia and normocapnia on the neurological outcomes in patients with cardiac arrest. As of December 5, 2023, we conducted a search on eligible studies, including EMBASE, PubMed, and WOS databases. Our primary outcome of interest was a good neurological outcome, and two authors independently screened the studies and extracted relevant data. For analysis, a fixed effects model was used when the I2 values were less than 50%, whereas a random effects model was used for higher I2 values. From the 2137 studies initially identified, seven studies involving 2770 patients were ultimately included. Compared with normocapnia, hypercapnia significantly improved the neurological outcomes of patients with cardiac arrest (OR 0.73; 95% CI 0.56-0.96; P=0.02). According to the subgroup analysis, the hypercapnic group achieved better neurological outcomes in the short-term than did the normocapnia group (OR 0.61; 95% CI 0.42-0.88; P=0.008), whereas no significant difference was observed in long-term (OR 0.91; 95% CI 0.76-1.10; P=0.35). Moreover, there was no significant difference in mortality between the two groups (OR 1.03; 95% CI 0.65-1.63; P=0.91). Our results suggest that hypercapnia is associated with a good neurological prognosis, especially in the short-term setting. However, further well-powered randomized controlled trials are necessary to confirm the optimal PaCO2 targets. CRD42023457027. Registered 3 September 2023.

Abstract Su903: Prognostic Value of Early Grey-White Ratio in the presence of Hypercapnia after Cardiac Arrest

Background: Cerebral edema following cardiac arrest can be quantified by measuring the ratio of grey matter to white matter radiodensity (GWR). Decreased GWR may reflect edema from irrecoverable neuronal cell death or reversible hyperemia driven by hypercapnia. We tested for an interaction between GWR and partial pressure of carbon dioxide (PCO2) predicting outcomes. Methods: We identified comatose post-arrest patients treated at our single center between 2010 and 2023 who underwent brain computed tomography (CT) imaging within 24 hours and PCO2 measured within one hour of CT. We extracted demographics, GWR, and PCO2 from our prospective registry and electronic health record. We scaled and centered data, then fit a multivariate logistic model to quantify the interaction between GWR and PCO2 in predicting survival. Results: Of 901 included patients, 356 (40%) were female, median [IQR] age was 61 [51-70], and 221 (25%) survived to discharge. CTs were obtained 4.18 [2.8-5.7] hours post-arrest. PCO2 was sampled within 36 median [24-47] minutes of CT. The median PCO2 was 47 [39-59] mmHg. GWR predicted survival (coefficient estimate 1.16, 95% confidence interval [CI], 0.91-1.44, p < 0.001, but PCO2 (-0.11, 95% CI -0.32-0.09, p = 0.29) did not. There was no significant interaction between GWR and PCO2 (0.009, 95% CI -0.24-0.29, p = 0.95). Conclusion: There is no evidence of PCO2 modifying the association of early GWR with survival after resuscitation from cardiac arrest.

Carbon monoxide as a cellular protective agent in a swine model of cardiac arrest protocol.

Out-of-hospital cardiac arrest (OHCA) affects over 360,000 adults in the United States each year with a 50-80% mortality prior to reaching medical care. Despite aggressive supportive care and targeted temperature management (TTM), half of adults do not live to hospital discharge and nearly one-third of survivors have significant neurologic injury. The current treatment approach following cardiac arrest resuscitation consists primarily of supportive care and possible TTM. While these current treatments are commonly used, mortality remains high, and survivors often develop lasting neurologic and cardiac sequela well after resuscitation. Hence, there is a critical need for further therapeutic development of adjunctive therapies. While select therapeutics have been experimentally investigated, one promising agent that has shown benefit is CO. While CO has traditionally been thought of as a cellular poison, there is both experimental and clinical evidence that demonstrate benefit and safety in ischemia with lower doses related to improved cardiac/neurologic outcomes. While CO is well known for its poisonous effects, CO is a generated physiologically in cells through the breakdown of heme oxygenase (HO) enzymes and has potent antioxidant and anti-inflammatory activities. While CO has been studied in myocardial infarction itself, the role of CO in cardiac arrest and post-arrest care as a therapeutic is less defined. Currently, the standard of care for post-arrest patients consists primarily of supportive care and TTM. Despite current standard of care, the neurological prognosis following cardiac arrest and return of spontaneous circulation (ROSC) remains poor with patients often left with severe disability due to brain injury primarily affecting the cortex and hippocampus. Thus, investigations of novel therapies to mitigate post-arrest injury are clearly warranted. The primary objective of this proposed study is to combine our expertise in swine models of CO and cardiac arrest for future investigations on the cellular protective effects of low dose CO. We will combine our innovative multi-modal diagnostic platform to assess cerebral metabolism and changes in mitochondrial function in swine that undergo cardiac arrest with therapeutic application of CO.

The Evolving Role of Electroencephalography in Postarrest Care.

Electroencephalography is an accessible, portable, noninvasive and safe means of evaluating a patient's brain activity. It can aid in diagnosis and management decisions for post-cardiac arrest patients with seizures, myoclonus and other non-epileptic movements. It also plays an important role in a multimodal approach to neuroprognostication predicting both poor and favorable outcomes. Individuals ordering, performing and interpreting these tests, regardless of the indication, should understand the supporting evidence, logistical considerations, limitations and impact the results may have on postarrest patients and their families as outlined herein.

Thiamine as a metabolic resuscitator after out-of-hospital cardiac arrest

IntroductionThiamine is a key cofactor for aerobic metabolism, previously shown to improve mortality and neurological outcomes in a mouse model of cardiac arrest. We hypothesized that thiamine would decrease lactate and improve outcomes in post-arrest patients. MethodsSingle center, randomized, blinded, placebo-controlled, Phase II trial of thiamine in adults within 4.5 hours of return of spontaneous circulation after out-of-hospital cardiac arrest (OHCA), with coma and lactate ≥ 3 mmol/L. Participants received 500 mg IV thiamine or placebo twice daily for 2 days. Randomization was stratified by lactate > 5 or ≤ 5 mmol/L. The primary outcome of lactate was checked at baseline, 6, 12, and 24 hours, and compared using a linear mixed model to account for repeated measures. Secondary outcomes included SOFA score, pyruvate dehydrogenase, renal injury, neurological outcome, and mortality. ResultsOf 93 randomized patients, 76 were enrolled and included in the analysis. There was no difference in lactate over 24 hours (mean difference 0.34 mmol/L (95% CI: −1.82, 2.50), p = 0.43). There was a significant interaction between randomization lactate subgroup and the effect of the intervention on mortality (p = 0.01) such that mortality was higher with thiamine in the lactate > 5 mmol/L group and lower with thiamine in the < 5 mmol/L group. This subgroup difference prompted the Data and Safety Monitoring Board to recommend the study be terminated early. PDH activity increased over 72 hours in the thiamine group. There were no differences in other secondary outcomes. ConclusionIn this single-center randomized trial, thiamine did not affect lactate over 24 hours after OHCA.

Post Cardiac Arrest Care in the Cardiac Intensive Care Unit.

Cardiac arrests constitute a leading cause of mortality in the adult population and cardiologists are often tasked with the management of patients following cardiac arrest either as a consultant or primary provider in the cardiac intensive care unit. Familiarity with evidence-based practice for post-cardiac arrest care is a requisite for optimizing outcomes in this highly morbid group. This review will highlight important concepts necessary to managing these patients. Emerging evidence has further elucidated optimal care of post-arrest patients including timing for routine coronary angiography, utility of therapeutic hypothermia, permissive hypercapnia, and empiric aspiration pneumonia treatment. The complicated state of multi-organ failure following cardiac arrest needs to be carefully optimized by the clinician to prevent further neurologic injury and promote systemic recovery. Future studies should be aimed at understanding if these findings extend to specific patient populations, especially those at the highest risk for poor outcomes.

Simple approach to quantify hypoxic-ischemic brain injury severity from computed tomography imaging files after cardiac arrest

BackgroundGrey-white ratio (GWR) can estimate severity of cytotoxic cerebral edema secondary to hypoxic-ischemic brain injury after cardiac arrest and predict progression to death by neurologic criteria (DNC). Current approaches to calculating GWR are not standardized and have variable interrater reliability. We tested if measures of variance of brain density on early computed tomographic (CT) imaging after cardiac arrest could predict DNC. MethodsWe performed a retrospective cohort study, identifying post-arrest patients treated between 2011 and 2020 at our single center. We extracted demographic data from our registry and Digital Imaging and Communication in Medicine (DICOM) files for each patient’s first brain CT. We analyzed slices 15–20 of each DICOM, corresponding to the level of the basal ganglia while accommodating differences in patient anatomy. We extracted pixel arrays and converted the radiodensities to Hounsfield units (HU). To focus on brain tissue densities, we excluded HU > 60 and < 10. We calculated the variance of each patient’s HU distribution and the difference between the means of a two-group Gaussian finite mixture model. We compared these novel metrics to existing measures of cerebral edema, then randomly divided our data into 80% training and 20% test sets and used logistic regression to predict DNC. ResultsOf 1,133 included subjects, 457 (40%) were female, mean (standard deviation) age was 58 (16) years, and 115 (10%) progressed to DNC. CTs were obtained a median [interquartile range] of 4.2 [2.8–5.7] hours post-arrest. Our novel measures correlated weakly with GWR. HU variance, but not difference between mixture model means, differed significantly between subjects with and without sulcal or cistern effacement. GWR outperformed our novel measures in predicting progression to DNC with an area under the receiver operating characteristic curve (AUC) of 0.82, compared to HU variance (AUC = 0.73) and the difference between mixture model means (AUC = 0.56). ConclusionThere are differences in the distribution of HU on post-arrest CT in patients with qualitative measures of cerebral edema. Current methods to quantify cerebral edema outperform simple measures of attenuation variance on early brain CT. Further analyses could investigate if these measures of variance, or other distributional characteristics of brain density, have improved predictive performance on brain CTs obtained later in the clinical course or derived from discrete regions of anatomical interest.

Characterization of Circulating Cold Shock Proteins FGF21 and RBM3 in a Multi-Center Study of Pediatric Cardiac Arrest.

Fibroblast Growth Factor 21 (FGF21) is a neuroprotective hormone induced by cold exposure that targets the β-klotho co-receptor. β-klotho is abundant in the newborn brain but decreases rapidly with age. RNA-Binding Motif 3 (RBM3) is a potent neuroprotectant upregulated by FGF21 in hypothermic conditions. We characterized serum FGF21 and RBM3 levels in patients enrolled in a prospective multi-center study of pediatric cardiac arrest (CA) via a secondary analysis of samples collected to evaluate brain injury biomarkers. Patients (n = 111) with remnant serum samples available from at least two of three available timepoints (0-24, 24-48 or 48-72 hours post-resuscitation) were included. Serum samples from 20 healthy controls were used for comparison. FGF21 was measured by Luminex and internally validated enzyme-linked immunoassay (ELISA). RBM3 was measured by internally validated ELISA. Of postarrest patients, 98 were managed with normothermia, while 13 were treated with therapeutic hypothermia (TH). FGF21 increased >20-fold in the first 24 hours postarrest versus controls (681 pg/mL [200-1864] vs. 29 pg/mL [15-51], n = 99 vs. 19, respectively, p < 0.0001, median [interquartile range]) with no difference in RBM3. FGF21 did not differ by sex, while RBM3 was increased in females versus males at 48-72 hours postarrest (1866 pg/mL [873-5176] vs. 1045 pg/mL [535-2728], n = 40 vs. 54, respectively, p < 0.05). Patients requiring extracorporeal membrane oxygenation (ECMO) postresuscitation had increased FGF21 versus those who did not at 48-72 hours (6550 pg/mL [1455-66,781] vs. 1213 pg/mL [480-3117], n = 7 vs 74, respectively, p < 0.05). FGF21 and RBM3 did not correlate (Spearman's rho = 0.004, p = 0.97). We conclude that in a multi-center study of pediatric CA patients where normothermic targeted temperature management was largely used, FGF21 was markedly increased postarrest versus control and highest in patients requiring ECMO postresuscitation. RBM3 was sex-dependent. We provide a framework for future studies examining the effect of TH on FGF21 or use of FGF21 therapy after pediatric CA.

Brain-derived extracellular vesicles as serologic markers of brain injury following cardiac arrest: A pilot feasibility study

AimAssessment of neurologic injury within the immediate hours following out-of-hospital cardiac arrest (OHCA) resuscitation remains a major clinical challenge. Extracellular vesicles (EVs), small bodies derived from cytosolic contents during injury, may provide the opportunity for “liquid biopsy” within hours following resuscitation, as they contain proteins and RNA linked to cell type of origin. We evaluated whether micro-RNA (miRNA) from serologic EVs were associated with post-arrest neurologic outcome. MethodsWe obtained serial blood samples in an OHCA cohort. Using novel microfluidic techniques to isolate EVs based on EV surface marker GluR2 (present on excitatory neuronal dendrites enriched in hippocampal tissue), we employed reverse transcription quantitative polymerase chain reaction (RT-qPCR) methods to measure a panel of miRNAs and tested association with dichotomized modified Rankin Score (mRS) at discharge. ResultsEVs were assessed in 27 post-arrest patients between 7/3/2019 and 7/21/2022; 9 patients experienced good outcomes. Several miRNA species including miR-124 were statistically associated with mRS at discharge when measured within 6 hours of resuscitation (AUC = 0.84 for miR-124, p < 0.05). In a Kendall ranked correlation analysis, miRNA associations with outcome were not strongly correlated with standard serologic marker measurements, or amongst themselves, suggesting that miRNA provide distinct information from common protein biomarkers. ConclusionsThis study explores the associations between miRNAs from neuron-derived EVs (NDEs) and circulating protein biomarkers within 6 hours with neurologic outcome, suggesting a panel of very early biomarker may be useful during clinical care. Future work will be required to test larger cohorts with a broader panel of miRNA species.

Postarrest Neuroprognostication: Practices and Opinions of Canadian Physicians.

Objective, evidence-based neuroprognostication of postarrest patients is crucial to avoid inappropriate withdrawal of life-sustaining therapies or prolonged, invasive, and costly therapies that could perpetuate suffering when there is no chance of an acceptable recovery. Postarrest prognostication guidelines exist; however, guideline adherence and practice variability are unknown. To investigate Canadian practices and opinions regarding assessment of neurological prognosis in postarrest patients. An anonymous electronic survey was distributed to physicians who care for adult postarrest patients. Of the 134 physicians who responded to the survey, 63% had no institutional protocols for neuroprognostication. While the use of targeted temperature management did not affect the timing of neuroprognostication, an increasing number of clinical findings suggestive of a poor prognosis affected the timing of when physicians were comfortable concluding patients had a poor prognosis. Variability existed in what factors clinicians' thought were confounders. Physicians identified bilaterally absent pupillary light reflexes (85%), bilaterally absent corneal reflexes (80%), and status myoclonus (75%) as useful in determining poor prognosis. Computed tomography, magnetic resonance imaging, and spot electroencephalography were the most useful and accessible tests. Somatosensory evoked potentials were useful, but logistically challenging. Serum biomarkers were unavailable at most centers. Most (79%) physicians agreed ≥2 definitive findings on neurologic exam, electrophysiologic tests, neuroimaging, and/or biomarkers are required to determine a poor prognosis with a high degree of certainty. Distress during the process of neuroprognostication was reported by 70% of physicians and 51% request a second opinion from an external expert. Significant variability exists in post-cardiac arrest neuroprognostication practices among Canadian physicians.

Target temperature in post-arrest comatous patients. Is something changed in the postpandemic era?

IntroductionThe recommended target temperature in the treatment of comatous patients after cardiac arrest has recently changed. We analyzed the impact on the neurological outcome of a change in the target temperature from July 2021. Material and methodsThis was a retrospective analysis comparing the discharge status of 78 patients with a target temperature of 33 °C (group 1) with that of 24 patients with a target temperature of 36.5 °C (group 2). Pearson chi-square and Mann-Whitney U tests were used. ResultsThe initial rhythm was defibrillable in 65% of group 1 and 71% of group 2, and cardiac arrest was witnessed in 93% of group 1 and 96% of group 2. There was an adverse outcome (death or vegetative state) in 37 patients in group 1 (47%) compared to 18 in group 2 (74%) (Pearson chi-square 5.612, p = 0.018). ConclusionsIn our series of patients, the temperature control target temperature change from 33 °C to 36.5 °C was associated with worse neurological outcome. Further studies are needed to evaluate the outcome of a generalized modification of temperature control targets in comatose patients after cardiac arrest in our postpandemic era.

Somatosensory evoked potential for post-arrest neuroprognostication.

Several guidelines recommend utilizing SSEPs, when available, as part of a multimodal approach to neuroprognostication in patients who remain comatose post-arrest. The evidence suggests somatosensory evoked potentials are an accurate and precise test for predicting a poor neurologic prognosis following cardiac arrest. Bilaterally absent cortical N20 potentials 24-48 hours post return of spontaneous circulation is specific for a poor prognosis post-arrest, while the presence of N20 potentials does not imply a favorable outcome due to poor sensitivity of the test. Research into other components of SSEPs that can be utilized to prognosticate post-arrest patients is ongoing. Individuals ordering, performing, and interpreting these tests must understand their indication, supporting evidence, logistical considerations, limitations, and the impact results may have on post-arrest patients and their families as outlined herein.

Timing and Outcomes After Coronary Angiography Following Out-of-Hospital Cardiac Arrest Without Signs of ST-Segment Elevation Myocardial Infarction

BackgroundThere is broad consensus that resuscitated out-of-hospital cardiac arrest (OHCA) patients with ST-segment elevation myocardial infarction (STEMI) should receive immediate coronary angiography (CAG); however, factors that guide patient selection and optimal timing of CAG for post-arrest patients without evidence of STEMI remain incompletely described. ObjectiveWe sought to describe the timing of post-arrest CAG in actual practice, patient characteristics associated with decision to perform immediate vs. delayed CAG, and patient outcomes after CAG. MethodsWe conducted a retrospective cohort study at seven U.S. academic hospitals. Resuscitated adult patients with OHCA were included if they presented between January 1, 2015 and December 31, 2019 and received CAG during hospitalization. Emergency medical services run sheets and hospital records were analyzed. Patients without evidence of STEMI were grouped and compared based on time from arrival to CAG performance into “early” (≤ 6 h) and “delayed” (> 6 h). ResultsTwo hundred twenty-one patients were included. Median time to CAG was 18.6 h (interquartile range [IQR] 1.5–94.6 h). Early catheterization was performed on 94 patients (42.5%) and delayed catheterization was performed on 127 patients (57.5%). Patients in the early group were older (61 years [IQR 55–70 years] vs. 57 years [IQR 47–65] years) and more likely to be male (79.8% vs. 59.8%). Those in the early group were more likely to have clinically significant lesions (58.5% vs. 39.4%) and receive revascularization (41.5% vs. 19.7%). Patients were more likely to die in the early group (47.9% vs. 33.1%). Among survivors, there was no significant difference in neurologic recovery at discharge. ConclusionsOHCA patients without evidence of STEMI who received early CAG were older and more likely to be male. This group was more likely to have intervenable lesions and receive revascularization.

549: ANALYSIS OF NEUROPROTECTIVE COLD SHOCK PROTEINS IN A MULTICENTER STUDY OF PEDIATRIC CARDIAC ARREST

Introduction: The efficacy of hypothermic neuroprotection varies by age. Cold exposure stimulates production of cold stress hormones (CSHs) which trigger thermogenesis and may be neuroprotective. FGF21 is a neuroprotective CSH that requires the Beta-klotho (KLB) co-receptor to signal. KLB is abundant in the newborn brain, decreases with age, and is virtually absent in adults. Thus, infants and young children may uniquely benefit from FGF21/KLB mediated neuroprotection. In vitro studies revealed that FGF21 upregulates the powerful neuroprotectant RNA-Binding Motif-3 (RBM3) in developmentally immature neurons (but not mature neurons). We sought to characterize FGF21 and RBM3 serum levels in children after cardiac arrest (CA) and evaluate their interdependence. Methods: Secondary analysis of serum samples collected in a multi-institutional prospective observational study evaluating biomarkers after pediatric CA. We measured FGF21 (Luminex) and RBM3 (ELISA) levels. All patients with serum from at least two timepoints (0-24h, 24-48h, 48-72h) were included. We also included serum from healthy controls. FGF21 and RBM3 levels at each timepoint were compared to controls (Wilcoxon-Ranksum); the relationship between FGF21/RBM3 at each timepoint was also evaluated (Spearman). Results: A total of 296 samples from 111 post-arrest patients were analyzed, and 20 samples from controls. Median age of the post-arrest cohort was 31.3 months (IQR: 6.9-129.9); 37.3 months (IQR: 18.6-63.6) for controls. Median FGF21 levels in the controls was 282pg/mL (IQR: 64-736), and did not differ significantly at 0-24h, 24-48h, and 48-72h (383 [IQR: 72-867], 723 [IQR: 167-1,688] and 552 [IQR: 210-1,225], respectively, P>0.05). Median control RBM3 was 2,944pg/mL (IQR: 969-8,241), and did not differ significantly at 0-24h, 24-48h, and 48-72h (1,538 [IQR: 757-4,146], 1,454 [625-3,543] and 1,526 [IQR: 613-3,591], respectively, P>0.05). FGF21 and RBM3 were correlated at 0-24h and 48-72h (Spearman’s coefficient of 0.384 and 0.223, respectively; P< 0.05 for both). Conclusions: After pediatric CA, serum FGF21 levels trend upward and RBM3 levels downward and correlate at early and late timepoints. Ongoing studies are examining their relationship to age, demographics, CA endophenotype, use of hypothermia, other serum biomarkers, and outcomes.

Abstract 319: Computational Analysis Of Brain Imaging To Predict Post-arrest Brain Death

Background: Grey-white matter ratio ( GWR) can estimate severity of cerebral edema after cardiac arrest and predict progression to brain death. Current approaches to calculating GWR have variable interrater reliability. We tested if a computational technique to quantify the distribution of whole-brain x-ray attenuation at hospital admission could predict ultimate progression to brain death. Methods: We identified in- and out-of-hospital post-arrest patients at our single center treated between 2018-2019. We extracted demographic data from our registry and Digital Imaging and Communication in Medicine (DICOM) files for the first post-arrest CT. We analyzed the 17th slice of each DICOM, corresponding to the level of the basal ganglia. We extracted the 512x512 array of Hounsfield units (HU). We excluded HU &gt;40 or &lt;10 to focus on brain tissue densities. We summarized each patient’s distribution of HU and calculated the variance as a proxy for GWR. We randomly divided our data into 75% training set and 25% test set, used univariate logistic regression to predict brain death, identified a highly specific cutoff to rule out progression to brain death, and calculated test set sensitivity and specificity at this cutoff. We performed all analyses using Python. Results: Of 413 included patients, 163 (39%) were female, median [IQR] age was 63 [52 - 73] years, and 39 (9%) progressed to brain death. CTs were obtained a median [IQR] of 4.47 [3.03 to 6.35] hours post-arrest. HU variation predicted brain death with an area under the receiver operating characteristic curve (AUROC) of 0.81 in the training set and 0.88 in the test set. The odds ratio (OR) of progression to brain death with decreasing HU variation was 0.85 (95% confidence interval [CI], 0.80 - 0.91; P &lt; 0.001). A cutoff of 53.9 had a sensitivity of 36% (95% CI, 30.10% to 41.33%) at 97% specificity (95% CI, 89.91% to 100%) in the training set and a sensitivity of 45% (95% CI, 34.63% to 54.73%) at 100% specificity in the test set. Conclusion: Preserved HU variation excludes progression to brain death in comatose post-arrest patients with high specificity.

Abstract 182: The Incidence And Indication For Palliative Care Consultation In A Cohort Of Out Of Hospital Cardiac Arrest Patients

Introduction: The indications for palliative care consultation are varied and integration of palliative care is often left to physician discretion. We sought to describe the population of post-arrest patients who receive a palliative care consultation and identify common indications for the consultation. Methods: Our study is a single center retrospective chart review from the Colorado Cardiac Arrest Registry (CCAR) including 541 patients admitted to the ICU after OHCA. Data abstracted included race, sex, preferred language, age, placement of a palliative care consult and number of palliative care meetings. A chi-squared test was used to determine statistical significance with a cutoff p value &lt;0.05. Each palliative care consultation was reviewed and the indication for palliative care consultation was coded using thematic analysis. Results: Of the 541 patients in the study sample, a palliative care consult order was placed for 73 (13.5%) patients and 55 (10.2%) patients had at least one documented palliative care meeting. Code status changed after the first palliative care meeting in 4 patients. When comparing men to women, 15% of men and 11% of women received a consult. A consult was placed in 18.7% of patients identifying as Hispanic, compared to 13.9% in white patients and 12.6% in black patients. In patients whose preferred language was not English or Spanish, 28.6% received a consult compared to 13.5% of patients preferring English or Spanish. None of these differences were statistically significant. The most common themes identified as the indication for the palliative care consultation were 1.) conflict between the physician and family; 2.) low health literacy; 3.) within family discordance on goals of care and; 4.) the need for specialty social work such as assistance with hospice planning. Conclusions: Our study found a low incidence of palliative care consultation and more frequent consultation for non-English or Spanish speaking patients, with four major prevailing themes. Further study is needed to better understand and optimize the utilization of palliative care consultation in post-cardiac arrest patients.

Abstract 185: Dual Processing In Surrogate Decision Makers Of Out Of Hospital Cardiac Arrest Patients: A Secondary Qualitative Analysis

Introduction: Out-of-hospital cardiac arrest (OHCA) is an unexpected event that frequently renders patients incapacitated therefore requiring a surrogate decision maker (SDM) to act as a proxy. When exercising judgement under uncertainty, people engage in one of two cognitive processing styles (i.e., dual processing): “fast” processing - automatic and intuitive or “slow” processing - deliberative and rational. Understanding which style(s) SDMs use in making decisions for post-arrest patients is critical to ensuring that (1) patients’ wishes are respected and (2) evidence-based neuro-prognostication is supported. Methods: We conducted a secondary analysis of semi-structured interviews with SDMs for OHCA patients. Potential subjects were contacted 30 days after discharge/death. The interviews were recorded and transcribed verbatim. Two investigators thematically coded the transcripts. We conducted secondary coding to specifically explore cognitive processing styles used by SDMs. Results: Over 5-months, 34 SDMS were approached and 12 SDMs agreed to be interviewed. SDMs were spouses/partners (5), adult children (3), parent (1) and siblings (3). Within this sample, 66.7% (8/12) of SDMs decided to withdraw life sustaining therapy or discontinue resuscitative efforts for the patient. Our secondary coding yielded variation in cognitive processing styles, with SDMs describing both fast and slow styles. SDMs who employed “fast” cognitive processing described (1) making their decision based on group consensus, (2) employing an affect heuristic (deciding based on “gut feeling” or temporary emotional state), (3) employing an availability heuristic (deciding based on examples of other patients or scenarios that immediately come to mind), and (4) deciding based on providers’ opinions without consulting other sources. SDMs who utilized “slow” cognitive processing described (1) focusing on the patient’s wishes when deciding and (2) gathering information to make an informed decision. Conclusions: SDMs utilized “fast” and “slow” cognitive processing approaches to decision making for OHCA patients. Future study should explore the relationship between SDMs’ cognitive processing styles and their decisions for post-arrest care.

Metformin protects against cardiac and renal damage in diabetic cardiac arrest patients

IntroductionMetformin is a first-line diabetic therapy that improves survival in a wide number of ischemic pathologies. We tested the association of metformin with markers of cardiac and renal injury in diabetic post-arrest patients. MethodsWe performed a retrospective analysis of clinical outcomes in diabetic cardiac arrest patients with and without metformin therapy at a single academic medical center. We used generalized linear models to test the independent association of metformin, insulin, and other hypoglycemic agents with peak 24-hour serum creatinine and peak 24-hour serum troponin. ResultsMetformin prescription at the time of SCA was independently associated with lower 24-hour peak serum troponin and lower 24-hour peak serum creatinine when compared to non-metformin patients. ConclusionMetformin pretreatment may offer cardiac and renal protection for diabetic patients during sudden cardiac arrest.

Immediate Versus Delayed Cardiac Catheterization in Post-Arrest Patients Without ST Elevation Myocardial Infarction: Is Survivorship Bias an Important Influence?: March 2022 Annals of Emergency Medicine Journal Club

Immediate Versus Delayed Cardiac Catheterization in Post-Arrest Patients Without ST Elevation Myocardial Infarction: Is Survivorship Bias an Important Influence?: March 2022 Annals of Emergency Medicine Journal Club

Abstract 13347: Oxygen Metabolism After Cardiac Arrest: Patterns and Association With Survival

Introduction: How mitochondrial damage from cardiac arrest (CA) and resuscitation affects oxygen metabolism, and whether changes in metabolism are associated with outcome, is not well understood. We previously reported an association between higher oxygen consumption (VO2) in the first 12 hours after return of spontaneous circulation (ROSC) and survival in 17 post-arrest (PA) patients. The present study was conducted to investigate the association of VO2, VCO2 and RQ with survival in a larger PA cohort. Methods: From adult patients enrolled in several CA trials at our center, we selected those receiving targeted temperature management with ≥60 minutes of post-ROSC metabolic data collected in the first 24 hours after ROSC, using a gas exchange monitor that measures continuous VO2, VCO2 and RQ.The area under the curve (AUC) for VO2, VCO2 and RQ was calculated using all available values in the first 12 and 24 hours after ROSC. For both time periods, logistic regression was used to describe the relationship between survival and each AUC. We adjusted for temperature, sedation, and vasopressor s. Hourly medians were plotted by survival. Results: Of 64 patients included, 32 (50%) survived. There was no significant association between survival and AUC-VO2 or AUC-VCO2 in the first 12 (n=43) or 24 (n=64) hours after ROSC. 21 (49%) had a median RQ &lt;0.7 in the first 12 hours, and there was an association between survival and AUC-RQ in this time period (see table). Conclusion: There were no significant associations between VO2, VCO2 and survival in the first 12 and 24 hours after ROSC. RQ was abnormally low in many patients, and higher RQ in the first 12 hours after ROSC was associated with survival.