Quantitative and Radiological Assessment of Post-cardiac-Arrest Comatose Patients with Diffusion-Weighted Magnetic Resonance Imaging.

BACKGROUND: Although magnetic resonance imaging, particularly diffusion-weighted imaging, has increasingly been used as part of a multimodal approach to prognostication in patients who are comatose after cardiac arrest, the performance of quantitative analysis of apparent diffusion coefficient (ADC) maps, as compared to standard radiologist impression, has not been well characterized. This retrospective study evaluated quantitative ADC analysis to the identification of anoxic brain injury by diffusion abnormalities on standard clinical magnetic resonance imaging reports. METHODS: The cohort included 204 previously described comatose patients after cardiac arrest. Clinical outcome was assessed by (1) 3-6 month post-cardiac-arrest cerebral performance category and (2) coma recovery to following commands. Radiological evaluation was obtained from clinical reports and characterized as diffuse, cortex only, deep gray matter structures only, or no anoxic injury. Quantitative analyses of ADC maps were obtained in specific regions of interest (ROIs), whole cortex, and whole brain. A subgroup analysis of 172 was performed after eliminating images with artifacts and preexisting lesions. RESULTS: Radiological assessment outperformed quantitative assessment over all evaluated regions (area under the curve [AUC] 0.80 for radiological interpretation and 0.70 for the occipital region, the best performing ROI, p = 0.011); agreement was substantial for all regions. Radiological assessment still outperformed quantitative analysis in the subgroup analysis, though by smaller margins and with substantial to near-perfect agreement. When assessing for coma recovery only, the difference was no longer significant (AUC 0.83 vs. 0.81 for the occipital region, p = 0.70). CONCLUSIONS: Although quantitative analysis eliminates interrater differences in the interpretation of abnormal diffusion imaging and avoids bias from other prediction modalities, clinical radiologist interpretation has a higher predictive value for outcome. Agreement between radiological and quantitative analysis improved when using high-quality scans and when assessing for coma recovery using following commands. Quantitative assessment may thus be more subject to variability in both clinical management and scan quality than radiological assessment.

Ketone Bodies after Cardiac Arrest: A Narrative Review and the Rationale for Use.

Cardiac arrest survivors suffer the repercussions of anoxic brain injury, a critical factor influencing long-term prognosis. This injury is characterised by profound and enduring metabolic impairment. Ketone bodies, an alternative energetic resource in physiological states such as exercise, fasting, and extended starvation, are avidly taken up and used by the brain. Both the ketogenic diet and exogenous ketone supplementation have been associated with neuroprotective effects across a spectrum of conditions. These include refractory epilepsy, neurodegenerative disorders, cognitive impairment, focal cerebral ischemia, and traumatic brain injuries. Beyond this, ketone bodies possess a plethora of attributes that appear to be particularly favourable after cardiac arrest. These encompass anti-inflammatory effects, the attenuation of oxidative stress, the improvement of mitochondrial function, a glucose-sparing effect, and the enhancement of cardiac function. The aim of this manuscript is to appraise pertinent scientific literature on the topic through a narrative review. We aim to encapsulate the existing evidence and underscore the potential therapeutic value of ketone bodies in the context of cardiac arrest to provide a rationale for their use in forthcoming translational research efforts.

Spontaneous Hypothermia As an Indicator of Early Diffuse Anoxic Brain Injury in Post-Cardiac Arrest Patients.

OBJECTIVES: To determine the association between spontaneous hypothermia (SH), defined as initial post-resuscitation core body temperature less than 34°C, and diffuse anoxic brain injury (DABI) on initial CT scan of the head (CTH) in post-cardiac arrest patients. DESIGN SETTING AND PARTICIPANTS: This was a retrospective, observational cohort study. This study was performed at the University of Rochester Medical Center Strong Memorial Hospital. All in-hospital and out-of-hospital cardiac arrest patients with return of spontaneous circulation admitted between January 1, 2022, and October 31, 2022, were included. MAIN OUTCOMES AND MEASURES: The primary outcomes were the odds of DABI on initial CTH for patients with SH compared with patients without SH post-cardiac arrest using a multivariable logistic regression controlling for patient covariates including basic demographics and arrest features. DABI on initial CTH was measured qualitatively and quantitatively using neuroradiologist interpretation and calculated gray-white matter ratio of the basal ganglia, respectively. Secondary outcome measures included length of stay (LOS), inpatient mortality, and those who underwent withdrawal of life-sustaining therapy (WOLST) or progression to brain death. RESULTS: Out of the observed 150 cases of cardiac arrest, 31 patients (21%) had SH. Of the 128 patients who had an initial CTH performed, 27 (21%) had DABI. The adjusted odds ratio of DABI on initial CTH associated with SH was 3.55 (95% CI, 1.08-11.64; p = 0.036) and 2.18 (95% CI, 0.69-6.91; p = 0.182) when DABI was measured qualitatively and quantitatively, respectively, after controlling for multiple covariates. There was a difference observed in LOS between the groups (3 vs. 10 d; p = 0.0005) and this was driven by early WOLST. CONCLUSIONS AND REVELANCE: Patients presenting with SH after cardiac arrest may be at greater risk of early DABI on initial CTH compared with those with higher body temperatures in the post-arrest period. Recognition of early SH may help to risk stratify post-cardiac arrest patients at highest risk of DABI.

Brain computed tomography after resuscitation from in-hospital cardiac arrest.

BACKGROUND: Few data characterize the role of brain computed tomography (CT) after resuscitation from in-hospital cardiac arrest (IHCA). We hypothesized that identifying a neurological etiology of arrest or cerebral edema on brain CT are less common after IHCA than after resuscitation from out-of-hospital cardiac arrest (OHCA). METHODS: We included all patients comatose after resuscitation from IHCA or OHCA in this retrospective cohort analysis. We abstracted patient and arrest clinical characteristics, as well as pH and lactate, to estimate systemic illness severity. Brain CT characteristics included quantitative measurement of the grey-to-white ratio (GWR) at the level of the basal ganglia and qualitative assessment of sulcal and cisternal effacement. We compared GWR distribution by stratum (no edema ≥1.30, mild-to-moderate <1.30 and >1.20, severe ≤1.20) and newly identified neurological arrest etiology between IHCA and OHCA groups. RESULTS: We included 2,306 subjects, of whom 420 (18.2%) suffered IHCA. Fewer IHCA subjects underwent post-arrest brain CT versus OHCA subjects (149 (35.5%) vs 1,555 (82.4%), p < 0.001). Cerebral edema for IHCA versus OHCA was more often absent (60.1% vs. 47.5%) or mild-to-moderate (34.3% vs. 27.9%) and less often severe (5.6% vs. 24.6%). A neurological etiology of arrest was identified on brain CT in 0.5% of IHCA versus 3.2% of OHCA. CONCLUSIONS: Although severe edema was less frequent in IHCA relative to OHCA, mild-to-moderate or severe edema occurred in one in three patients after IHCA. Unsuspected neurological etiologies of arrest were rarely discovered by CT scan in IHCA patients.

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

BACKGROUND: Grey-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. METHODS: We 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. RESULTS: Of 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). CONCLUSION: There 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.

Long-Term Neurocognitive Outcomes in Pediatric Nonfatal Drowning: Results of a Family Caregiver Survey.

BACKGROUND: Drowning is a leading cause of brain injury in children. Long-term outcome data for drowning survivors are sparse. This study reports neurocognitive outcomes for 154 children hospitalized following drowning. METHODS: A survey for parent caregivers was distributed online. Likert scale items assessed 10 outcome variables in four domains: motor (three), perception (three), language (three), and social/emotional (one). Cluster analysis, outcome relative risk, and descriptive statistics were applied. RESULTS: Of 208 surveys received, 154 met inclusion criteria. Coma was the most common admission status (n = 137). Cluster analysis identified three outcome groups: Mild (n = 39), Moderate (n = 75), and Severe (n = 40). Motor impairment with cognitive and perceptual sparing (deefferentation) was present in Moderate (P < 1 × 10-26) and Severe (P < 1 × 10-12) but absent in Mild. Locked-in state was endorsed in both Moderate (83%) and Severe (70%). The strongest predictor of good outcome (Mild) was hospitalization with no medical intervention (relative risk [RR] = 6.7). Responsivity on admission (RR = 4.2) or discharge (RR = 12.22) also predicted good outcome. In-hospital prognostication and counseling predicted outcome weakly (RR = 1.3) or not at all. CONCLUSIONS: Long-term outcomes in pediatric drowning ranged widely. Overall, motor impairments exceeded perceptual or cognitive (P < 1 × 10-18), with "locked-in state" endorsed in most (93 of 154). The strongest predictors of good outcome were the lack of necessity for interventions and responsivity on admission or discharge. The eponym "Conrad syndrome" is proposed for locked-in state following nonfatal drowning in children.

Optimization of Nutrition after Brain Injury: Mechanistic and Therapeutic Considerations.

Emerging science continues to establish the detrimental effects of malnutrition in acute neurological diseases such as traumatic brain injury, stroke, status epilepticus and anoxic brain injury. The primary pathological pathways responsible for secondary brain injury include neuroinflammation, catabolism, immune suppression and metabolic failure, and these are exacerbated by malnutrition. Given this, there is growing interest in novel nutritional interventions to promote neurological recovery after acute brain injury. In this review, we will describe how malnutrition impacts the biomolecular mechanisms of secondary brain injury in acute neurological disorders, and how nutritional status can be optimized in both pediatric and adult populations. We will further highlight emerging therapeutic approaches, including specialized diets that aim to resolve neuroinflammation, immunodeficiency and metabolic crisis, by providing pre-clinical and clinical evidence that their use promotes neurologic recovery. Using nutrition as a targeted treatment is appealing for several reasons that will be discussed. Given the high mortality and both short- and long-term morbidity associated with acute brain injuries, novel translational and clinical approaches are needed.

Neuroleptic Malignant Syndrome Status Post Anoxic Brain Injury: A Case Presentation of Heightened Susceptibility in the Brain Injury Population.

Neuroleptic malignant syndrome (NMS), a potentially life-threatening neurological emergency characterized by muscle rigidity, altered mental status (AMS), autonomic instability, and hyperthermia, is most commonly precipitated by high-potency first-generation antipsychotics due to central dopamine receptor blockade. There is a heightened risk of NMS in animals with ischemic brain injury (IBI) or traumatic brain injury (TBI) due to the resulting death of dopaminergic neurons from injury and the dopamine receptor blockade elicited upon recovery. To the best of our knowledge, this will be the first documented case of a critically ill patient, with a history of prior exposure to antipsychotics, who suffered an anoxic brain injury with subsequent development of NMS after the initiation of haloperidol for the treatment of acute agitation. Further investigation is necessary to expand upon the existing literature suggesting the role of alternative agents, including amantadine, due to its impact on dopaminergic transmission, as well as dopamine and glutamine release. Furthermore, NMS can be difficult to diagnose due to variable clinical presentation and lack of absolute diagnostic criteria, which is further compounded with central nervous system (CNS) injury, where neurological abnormalities and AMS may be attributed to the injury, rather than a medication effect, especially in the early period. This case highlights the significance of prompt recognition with appropriate treatment of NMS in vulnerable and susceptible patients suffering from brain injury.

Neuroimaging mimics of anoxic brain injury: A review.

Diffuse cortical diffusion changes on magnetic resonance imaging (MRI) are characteristically ascribed to global cerebral anoxia, typically after cardiac arrest. Far from being pathognomonic, however, this neuroimaging finding is relatively nonspecific, and can manifest in a myriad of disease states including hypoxia, metabolic derangements, infections, seizure, toxic exposures, and neuroinflammation. While these various conditions can all produce a neuroimaging pattern of widespread cortical diffusion restriction, many of these underlying causes do have subtly unique imaging features that are appreciable on MRI and can be of clinical and diagnostic utility. Specific populations of neurons are variably sensitive to certain types of injury, whether due to differences in perfusion, receptor type density, or the unique tropisms of infectious organisms. In this narrative review, we discuss a number of distinct etiologies of diffuse cortical diffusion restriction on MRI, the unique pathophysiologies responsible for tissue injury, and the resulting neuroimaging characteristics that can be of assistance in differentiating them. As widespread cortical injury from any cause often presents with altered mental status or coma, the differential diagnosis can be enhanced with rapid acquisition of MRI when clinical history or detailed physical examination is limited. In such settings, the distinct imaging features discussed in this article are of interest to both the clinician and the radiologist.

Early risk stratification for progression to death by neurological criteria following out-of-hospital cardiac arrest.

BACKGROUND: Some patients resuscitated from out-of-hospital cardiac arrest (OHCA) progress to death by neurological criteria (DNC). We hypothesized that initial brain imaging, electroencephalography (EEG), and arrest characteristics predict progression to DNC. METHODS: We identified comatose OHCA patients from January 2010 to February 2020 treated at a single quaternary care facility in Western Pennsylvania. We abstracted demographics and arrest characteristics; Pittsburgh Cardiac Arrest Category, initial motor exam and pupillary light reflex; initial brain computed tomography (CT) grey-to-white ratio (GWR), sulcal or basal cistern effacement; initial EEG background and suppression ratio. We used two modeling approaches: fast and frugal tree (FFT) analysis to create an interpretable clinical risk stratification tool and ridge regression for comparison. We used bootstrapping to randomly partition cases into 80% training and 20% test sets and evaluated test set sensitivity and specificity. RESULTS: We included 1,569 patients, of whom 147 (9%) had diagnosed DNC. Across bootstrap samples, >99% of FFTs included three predictors: sulcal effacement, and in cases without sulcal effacement, the combination of EEG background suppression and GWR ≤ 1.23. This tree had mean sensitivity and specificity of 87% and 81%. Ridge regression with all available predictors had mean sensitivity 91 % and mean specificity 83%. Subjects falsely predicted as likely to progress to DNC generally died of rearrest or withdrawal of life sustaining therapies due to poor neurological prognosis. Two of these cases awakened from coma during the index hospitalization. CONCLUSIONS: Sulcal effacement on presenting brain CT or EEG suppression with GWR ≤ 1.23 predict progression to DNC after OHCA.

Top Ten Tips Palliative Care Clinicians Should Know About Disorders of Consciousness: A Focus on Traumatic and Anoxic Brain Injury.

Palliative care (PC) teams commonly encounter patients with disorders of consciousness (DOC) following anoxic or traumatic brain injury (TBI). Primary teams may consult PC to help surrogates in making treatment choices for these patients. PC clinicians must understand the complexity of predicting neurologic outcomes, address clinical nihilism, and appropriately guide surrogates in making decisions that are concordant with patients' goals. The purpose of this article was to provide PC providers with a better understanding of caring for patients with DOC, specifically following anoxic or TBI. Many of the tips acknowledge the uncertainty of DOC and provide strategies to help tackle this dilemma.

Long-term outcomes of post-cardiac arrest patients with severe neurological and functional impairments at hospital discharge.

BACKGROUND: Patients resuscitated from cardiac arrest who have severe neurological or functional disability at discharge require high-intensity long-term support. However, few data describe the long-term survival and health-care utilization for these patients. METHODS: We identified a cohort of cardiac arrest survivors ≥ 18 years of age, treated at a single center in Western Pennsylvania from January 2010 to December 2019, with a modified Rankin scale (mRS) of 5 at hospital discharge. We recorded demographics, cardiac arrest characteristics, and neurological exam at hospital discharge. We characterized long term survival and mortality through December 31, 2020 through National Death Index query. We described survival time overall and in subgroups using Kaplan-Meier curves and compared using log-rank tests.We linked cases with administrative data to determine 30, 90 day, and one-year hospital readmission rate. For subjects unable to follow commands at discharge, we reviewed records from index hospitalization to the present to describe improvement in neurological status and return home. RESULTS: We screened 2,687 patients of which 975 survived to discharge. We identified 190 subjects with mRS of 5 at hospital discharge who were sent to non-hospice settings. Of these, 43 (23%) did not follow commands at discharge. One-year mortality was 38% (n = 71) with a median survival time of 4.2 years (IQR 0.3-10.9). Duration of survival was shorter in older subjects but did not differ based on, sex, or ability to follow commands at hospital discharge. Within the first year of discharge, 58% (n = 111) of subjects had at least one hospitalization with a median length of stay of 8 days [IQR 3-19]. Of subjects who did not follow commands at hospital discharge, 5/43 (11%) followed commands and 9 (21%) were reportedly living at home on subsequent encounters. CONCLUSIONS: Of survivors treated over a decade at our institution, 20% (n = 190) were discharged from the hospital with severe functional disability. One-year mortality was 38%, and hospital readmissions were frequent. Few patients discharged unable to follow commands regained the ability over the period of observation, but many did return to living at home. These data can help inform decision maker expectations for patient trajectory and life expectancy.

Society for cardiovascular angiography and intervention shock classification predicts mortality after out-of-hospital cardiac arrest.

BACKGROUND: Shock is common in patients resuscitated from out-of-hospital-cardiac arrest (OHCA). Shock severity can be classified using the Society for Cardiovascular Angiography and Intervention (SCAI) Shock Classification. We aimed to examine the association of SCAI Shock Stage with in-hospital mortality and neurological outcome in comatose OHCA patients undergoing targeted temperature management (TTM). METHODS: This study included 213 comatose adult patients who underwent TTM after OHCA between January 2007 and December 2017. SCAI shock stage (A through E) was assigned using data from the first 24 hours, with shock defined as SCAI shock stage C/D/E. Good neurological outcome was defined as a modified Rankin Scale (mRS) less than 3. RESULTS: In-hospital mortality was higher in the 144 (67.6%) patients with shock (46.5% v. 23.2%, unadjusted OR 2.88, 95% CI 1.51-5.51, p = 0.001). After multivariable adjustment, each SCAI shock stage was incrementally associated with an increased risk of in-hospital mortality (adjusted OR 1.80 per stage, 95% CI 1.20-2.71, p = 0.003). Good neurological outcome was less likely in patients with shock (31.9% vs. 53.6%, unadjusted OR 0.41, 95% CI 0.23-0.73, p = 0.002) and a higher SCAI shock stage was incrementally associated with a lower likelihood of good neurological outcome after multivariable adjustment (adjusted OR 0.67 per stage, 95% CI 0.48-0.93, p = 0.015). CONCLUSION: Higher shock severity, defined using the SCAI Shock Classification, was associated with increased in-hospital mortality and a lower likelihood of good neurological outcome in OHCA patients treated with TTM.

Beyond Extracorporeal Cardiopulmonary Resuscitation: Systems of Care Supporting Cardiac Arrest Patients.

Introduction: Out-of-hospital cardiac arrest (OHCA) is a major cause of death and disability in the United States. Cardiac arrest centers (CAC) are necessary for the management of these critically ill and complex post arrest patients due to their specialized services and provider expertise. We report the case of a patient with OHCA and the systems of care involved in his resuscitation and recovery. Case Report: Emergency medical services attended a 39-year-old male with ongoing bystander cardiopulmonary resuscitation (CPR) after a witnessed collapse. Despite receiving appropriate advanced cardiac life support, including three defibrillations, he remained in refractory ventricular fibrillation. A prehospital physician identified him as an extracorporeal cardiopulmonary resuscitation (ECPR) candidate due to his age, witnessed arrest, refractory rhythm, and functional status. He was expedited to a CAC but no longer qualified for ECPR due to the time limit. He was resuscitated by the multiple teams activated prior to his arrival. He eventually had sustained return of circulation, was taken to the catheterization lab for emergent percutaneous coronary intervention, and recovered with a good neurologic outcome. Conclusion: Cardiac arrest centers may be capable of advanced interventions including ECPR. However, the systems of care offered by these centers is itself a lifesaving intervention. As this case highlights, despite not receiving the specified intervention (ECPR) the systems of care required to offer such a resource led to this favorable outcome.

Factors predicting rehabilitation outcomes after severe acquired brain injury in trauma, stroke and anoxia populations: A cohort study.

Severe acquired brain injury has long-term physical and cognitive effects. Identifying patient variables predictive of recovery in different brain injury populations would generate improved prognostic information and help rehabilitation teams set appropriate therapeutic goals. This cohort study of 447 NHS neurorehabilitation inpatients aimed to identify functional and cognitive predictors of recovery following severe acquired brain injury caused by trauma, stroke and anoxia. Motor and cognitive impairment ratings were collected at admission and discharge using the Functional Independence Measure and Functional Assessment Measure (FIM+FAM), and injury-related and demographic data were collated from medical records. Predictors of physical, cognitive and overall recovery were identified via hierarchical regression analyses. Several key findings emerged. Firstly, on-admission motor skills predicted functional and overall outcomes across groups. Secondly, on-admission social interaction skills predicted cognitive discharge outcomes in stroke and trauma, and overall outcomes for stroke, but did not predict anoxia outcomes. Thirdly, age predicted all forms of recovery for stroke only. Further group-specific factors were also identified as predicting motor and cognitive recovery, indicating that factors key to the rehabilitation trajectory may differ between populations. These variables should be considered in rehabilitation goal planning, although further research is required to explore their contributions to recovery.

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

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

Awakening from post anoxic coma with burst suppression with identical bursts.

BACKGROUND: Electroencephalography (EEG) is commonly used after cardiac arrest. Burst suppression with identical bursts (BSIB) has been reported as a perfectly specific predictor of poor outcome but published case series are small. We describe two patients with BSIB who awakened from coma after cardiac arrest. METHODS: We identified two out-of-hospital cardiac arrest (OHCA) patients with coma and BSIB. We determined the etiology of arrest, presenting neurological examination, potential confounders to neurological assessment, neurodiagnostics and time to awakening. We reviewed and interpreted EEGs using 2021 American Clinical Neurophysiology Society guidelines. We quantified identicality of bursts by calculating pairwise correlation coefficients between the first 500 ms of each aligned burst. RESULTS: In case one we present a 62-year-old man with OHCA secondary to septic shock. EEG showed burst suppression pattern, with bursts consisted of high amplitude generalized spike waves in lock-step with myoclonus (inter-burst correlation = 0.86). He followed commands 3 days after arrest, when repeat EEG showed a continuous, variable and reactive background without epileptiform activity. Case two was a 49-year-old woman with OHCA secondary to polysubstance overdose. Initial EEG revealed burst suppression with high amplitude generalized polyspike-wave bursts with associated myoclonus. She followed commands on post-arrest day 4, when repeat EEG showed a continuous, variable and reactive background with frequent runs of bifrontal predominant sharply contoured rhythmic delta activity. CONCLUSION: These cases highlight the perils of prognosticating with a single modality in comatose cardiac arrest patients.