Standards for Studies of Neurological Prognostication in Comatose Survivors of Cardiac Arrest: A Scientific Statement From the American Heart Association

The Electrographic Effects of Ketamine on Patients With Refractory Status Epilepticus After Cardiac Arrest: A Single-Center Retrospective Cohort

PURPOSE

To investigate the effects of ketamine on patients with refractory status epilepticus after cardiac arrest.

METHODS

In this retrospective cohort, selected EEG segments from patients after cardiac arrest were classified into different EEG patterns (based on background continuity and burden of epileptiform discharges) and spectral profiles (based on the presence of frequency components). For patients who received ketamine, EEG data were compared before, during, and after ketamine infusion; for the no-ketamine group, EEG data were compared at three separated time points during recording. Ketamine usage was determined by clinical providers. Electrographic improvement in epileptiform activity was scored, and the odds ratio was calculated using the Fisher exact test. Functional outcome measures at time of discharge were also examined.

RESULTS

Of a total of 38 patients with postcardiac arrest refractory status epilepticus, 13 received ketamine and 25 did not. All patients were on ≥2 antiseizure medications including at least one sedative infusion (midazolam). For the ketamine group, eight patients had electrographic improvement, compared with only two patients in the no-ketamine group, with an odds ratio of 7.19 (95% confidence interval 1.16-44.65, P value of 0.0341) for ketamine versus no ketamine. Most of the patients who received ketamine had myoclonic status epilepticus, and overall neurologic outcomes were poor with no patients having a favorable outcome.

CONCLUSIONS

For postarrest refractory status epilepticus, ketamine use was associated with electrographic improvement, but with the available data, it is unclear whether ketamine use or EEG improvement can be linked to better functional recovery.

Mastering the brain in critical conditions: an update

Acute brain injuries, such as traumatic brain injury and ischemic and hemorragic stroke, are a leading cause of death and disability worldwide. While characterized by clearly distict primary events-vascular damage in strokes and biomechanical damage in traumatic brain injuries-they share common secondary injury mechanisms influencing long-term outcomes. Growing evidence suggests that a more personalized approach to optimize energy substrate delivery to the injured brain and prognosticate towards families could be beneficial. In this context, continuous invasive and/or non-invasive neuromonitoring, together with clinical evaluation and neuroimaging to support strategies that optimize cerebral blood flow and metabolic delivery, as well as approaches to neuroprognostication are gaining interest. Recently, the European Society of Intensive Care Medicine organized a 2-day course focused on a practical case-based clinical approach of acute brain-injured patients in different scenarios and on future perspectives to advance the management of this population. The aim of this manuscript is to update clinicians dealing with acute brain injured patients in the intensive care unit, describing current knowledge and clinical practice based on the insights presented during this course.

Increased task-relevant fMRI responsiveness in comatose cardiac arrest patients is associated with improved neurologic outcomes

Early prediction of the recovery of consciousness in comatose cardiac arrest patients remains challenging. We prospectively studied task-relevant fMRI responses in 19 comatose cardiac arrest patients and five healthy controls to assess the fMRI's utility for neuroprognostication. Tasks involved instrumental music listening, forward and backward language listening, and motor imagery. Task-specific reference images were created from group-level fMRI responses from the healthy controls. Dice scores measured the overlap of individual subject-level fMRI responses with the reference images. Task-relevant responsiveness index (Rindex) was calculated as the maximum Dice score across the four tasks. Correlation analyses showed that increased Dice scores were significantly associated with arousal recovery (P < 0.05) and emergence from the minimally conscious state (EMCS) by one year (P < 0.001) for all tasks except motor imagery. Greater Rindex was significantly correlated with improved arousal recovery (P = 0.002) and consciousness (P = 0.001). For patients who survived to discharge (n = 6), the Rindex's sensitivity was 75% for predicting EMCS (n = 4). Task-based fMRI holds promise for detecting covert consciousness in comatose cardiac arrest patients, but further studies are needed to confirm these findings. Caution is necessary when interpreting the absence of task-relevant fMRI responses as a surrogate for inevitable poor neurological prognosis.

Multiorgan failure in patients after out of hospital resuscitation: a retrospective single center study

BACKGROUND

Information on extracerebral system dysfunction is important for assessing the needs of critically ill patients after cardiac arrest.

AIMS

To describe the prevalence of organ dysfunction and patient severity after out of hospital cardiac arrest (OHCA) using scores commonly used in intensive care and the association between these and mortality.

METHODS

Retrospective analysis of observational data collected in real time in a tertiary medical center where care withdrawal is mostly illegal. Adult patients after nontraumatic OHCA with ROSC who survived for more than two hours were included. Primary outcome-prevalence of organ failure, based on common definitions for organ dysfunction, in the 1 days of hospitalization. Secondary outcomes-rates of survival to hospital discharge and survival with a good neurological outcome (CPC 1 or 2), and associations between organ dysfunction SOFA and APACHE-II scores and outcomes. Associations were assessed using fisher's exact test for categorical variables and Mann-Whitney and T test for continuous variables. Multivariable models were also constructed for all measurements showing associations in previous tests. For severity scores compatibility, we used receiver-operating curve (ROC).

RESULTS

Overall 369 patients (median age 75 years, 65% male) were included. Most arrests (64%) were witnessed, bystander CPR was provided in 15%. Median call to arrival time was 4 min. The presenting rhythm was asystole in 48% and VT/VF in 22%. Cardiovascular causes of arrest predominated (48%, n = 178). The median length of hospitalization was 5 days. Overall 28% of the patients (n = 98) survived to hospital discharge, mostly with a good neurological status (18.7%, n = 57). The rates of organ dysfunction were: hemodynamic instability 65% (n = 247), respiratory dysfunction 94% (n = 296), kidney dysfunction 70% (n = 259), hepatic dysfunction 14% (n = 50). The median SOFA score on day 1 was 9 and the median APACHE II score was 34. Modeling was limited by missing data. Neurological dysfunction (i.e. GCS and seizures) and kidney injury were consistently correlated with the outcomes in the multivariable models. Severity of critical illness assessed by above scoring systems correlated with mortality (all ROC curves had an AUC ranging between 0.728 and 0.849).

CONCLUSIONS

Multiorgan failure is common after ROSC (1-4). Therefore, the management of patients after ROSC may require advanced multidisciplinary care. Scores describing the severity of critical illness should be routinely reported in resuscitation research. Our unique setting where withdrawal of care is illegal, allows assessment of extremely ill patients and may assist in defining margins for futility.

Hyperacute autonomic and cortical function recovery following cardiac arrest resuscitation in a rodent model

OBJECTIVE

There is a complex interaction between nervous and cardiovascular systems, but sparse data exist on brain-heart electrophysiological responses to cardiac arrest resuscitation. Our aim was to investigate dynamic changes in autonomic and cortical function during hyperacute stage post-resuscitation.

METHODS

Ten rats were resuscitated from 7-min cardiac arrest, as indicators of autonomic response, heart rate (HR), and its variability (HRV) were measured. HR was monitored through continuous electrocardiography, while HRV was assessed via spectral analysis, whereby the ratio of low-/high-frequency (LF/HF) power indicates the balance between sympathetic/parasympathetic activities. Cortical response was evaluated by continuous electroencephalography and quantitative analysis. Parameters were quantified at 5-min intervals over the first-hour post-resuscitation. Neurological outcome was assessed by Neurological Deficit Score (NDS, range 0-80, higher = better outcomes) at 4-h post-resuscitation.

RESULTS

A significant increase in HR was noted over 15-30 min post-resuscitation (p < 0.01 vs.15-min, respectively) and correlated with higher NDS (rs = 0.56, p < 0.01). LF/HF ratio over 15-20 min was positively correlated with NDS (rs = 0.75, p < 0.05). Gamma band power surged over 15-30 min post-resuscitation (p < 0.05 vs. 0-15 min, respectively), and gamma band fraction during this period was associated with NDS (rs ≥0.70, p < 0.05, respectively). Significant correlations were identified between increased HR and gamma band power during 15-30 min (rs ≥0.83, p < 0.01, respectively) and between gamma band fraction and LF/HF ratio over 15-20 min post-resuscitation (rs = 0.85, p < 0.01).

INTERPRETATIONS

Hyperacute recovery of autonomic and cortical function is associated with favorable functional outcomes. While this observation needs further validation, it presents a translational opportunity for better autonomic and neurologic monitoring during early periods post-resuscitation to develop novel interventions.

Updated trends in the outcomes of out-of-hospital cardiac arrest from 2017-2021: Prior to and during the coronavirus disease (COVID-19) pandemic

Objective

This study aims to describe out-of-hospital cardiac arrest (OHCA) characteristics and trends before and during the coronavirus disease-2019 (COVID-19) pandemic in Taiwan.

Methods

We conducted a retrospective cohort study using a 5-year interrupted time series analysis. Eligible adults with non-traumatic OHCAs from January 2017 to December 2021 in 3 hospitals (university medical center, urban second-tier hospital, and rural second-tier hospital) were retrospectively enrolled. Variables were extracted from the emergency medical service reports and medical records. The years 2020 and 2021 were defined as the COVID-19 pandemic period. Outcomes included survival to admission after a sustained return of spontaneous circulation, survival to hospital discharge, and good neurological outcomes (cerebral performance category score 1 or 2).

Results

We analyzed 2819 OHCA, including 1227 from a university medical center, 617 from an urban second-tier hospital, and 975 from a rural second-tier hospital. The mean age was 71 years old, and 60% of patients were males. During the COVID-19 pandemic period, video-assisted endotracheal tube intubation replaced the traditional direct laryngoscopy intubation. The trends of outcomes in the pre-pandemic and pandemic periods varied among different hospitals. Compared with the pre-pandemic period, the outcomes at the university medical center during the COVID-19 pandemic were significantly poorer in several respects. The survival rate on admission dropped from 44.6% to 39.4% (P = 0.037), and the survival rate to hospital discharge fell from 17.5% to 14.9% (P = 0.042). Additionally, there was a notable decrease in patients' good neurological outcomes, declining from 13.2% to 9.7% (P = 0.048). In contrast, the outcomes in urban and rural second-tier hospitals during the COVID-19 pandemic did not significantly differ from those in the pre-pandemic period.

Conclusions

COVID-19 may alter some resuscitation management in OHCAs. There were no overall significant differences in outcomes before and during COVID-19 pandemic, but there were significant differences in outcomes when stratified by hospital types.

Trend of Outcome Metrics in Recent Out-of-Hospital-Cardiac-Arrest Research: A Narrative Review of Clinical Trials

Cardiopulmonary resuscitation (CPR) research traditionally focuses on survival. In 2018, the International Liaison Committee on Resuscitation (ILCOR) proposed more patient-centered outcomes. Our narrative review assessed clinical trials after 2018 to identify the trends of outcome metrics in the field OHCA research. We performed a search of the PubMed database from 1 January 2019 to 22 September 2023. Prospective clinical trials involving adult humans were eligible. Studies that did not report any patient-related outcomes or were not available in full-text or English language were excluded. The articles were assessed for demographic information and primary and secondary outcomes. We included 89 studies for analysis. For the primary outcome, 31 (35%) studies assessed neurocognitive functions, and 27 (30%) used survival. For secondary outcomes, neurocognitive function was present in 20 (22%) studies, and survival was present in 10 (11%) studies. Twenty-six (29%) studies used both survival and neurocognitive function. Since the publication of the COSCA guidelines in 2018, there has been an increased focus on neurologic outcomes. Although survival outcomes are used frequently, we observed a trend toward fewer studies with ROSC as a primary outcome. There were no quality-of-life assessments, suggesting a need for more studies with patient-centered outcomes that can inform the guidelines for cardiac-arrest management.

Predicting Neurologically Intact Survival for Advanced Age Adults After Successful Resuscitation of Out-of-Hospital Cardiac Arrest

We sought to predict survival to hospital discharge with favorable neurologic outcome for advanced age adults (≥65 years) after successful resuscitation of non-traumatic out-of-hospital cardiac arrest (OHCA). A retrospective observational cohort analysis was performed using the national Cardiac Arrest Registry to Enhance Survival database from January 1, 2013 to December 31, 2021. All nontraumatic OHCA occurring in advanced age adults who survived to hospital admission were included. The primary outcome was survival with favorable neurologic outcome defined as a cerebral performance category score of 1 or 2 at hospital discharge. Multivariable logistic regression including patient variables (age category, gender, co-morbidities) and OHCA characteristics (location, rhythm category, witnessed status, and who initiated cardiopulmonary resuscitation) were used to predict hospital outcome. 83,574 patients met study inclusion criteria with 19,298 (23.1%) surviving with favorable neurologic outcome. The median age was 75 years (interquartile range 69 to 82 years), 58.9% were male, and a majority of events occurred at home (67.3%). Age was found to have a linear, negative association with outcome. Survival with cerebral performance category 1 or 2 ranged from 28.8% in those between the age of 65 to 69 years (n = 23,161) and 13.7% for those age >90 years (n = 4,666). The regression model produced outcome probabilities ranging from 2.6% to 80.8% with a cross-validated AUROC of 0.742 (95% confidence interval 0.738 to 0.746) and a Brier score of 0.151. In conclusion, a simple model with basic patient and OHCA characteristics can predict hospital outcomes in advanced age adults with good discrimination and calibration.

Outcome of comatose patients following cardiac arrest: When mRS completes CPC

AIM

Good outcome in patients following cardiac arrest (CA) is usually defined as Cerebral Performance Category (CPC) 1-2, while CPC 3 is debated, and CPC 4-5 represent poor outcome. We aimed to assess when the modified Rankin Scale (mRS) can improve CPC outcome description, especially in CPC 3. We further aimed to correlate neuron specific enolase (NSE) with both functional measures to explore their relationship with neuronal damage.

METHODS

Peak NSE within the first 48 hours, and CPC and mRS at 3 months were prospectively collected for 665 consecutive comatose adults following CA treated between April 2016 and April 2023. For each CPC category, mRS was described. We considered good outcome as mRS 1-3, in line with existing recommendations. CPC and mRS were correlated to peak serum NSE using non-parametric assessments.

RESULTS

CPC 1, 2, 4 and 5 correlated almost perfectly with mRS in terms of good and poor outcomes. However, CPC 3 was heterogeneously associated to the dichotomized mRS (53.1% had good outcome (mRS 0-3), 46.9% poor outcome (mRS 4-6)). NSE was strongly correlated with CPC (Spearman's rho 0.616, P < 0.001) and mRS (Spearman's rho 0.613, P < 0.001).

CONCLUSION

CPC and mRS correlate similarly with neuronal damage. Whilst CPC 1-2 and CPC 4-5 are strongly associated with mRS 0-3 and, respectively, with mRS 5-6, CPC 3 is heterogenous: both good and poor mRS scores are found within this category. Therefore, we suggest that the mRS should be routinely assessed in patients with CPC 3 to refine outcome description.

Predicting in-hospital cardiac arrest outcomes: CASPRI and GO-FAR scores

It is important to predict the neurological prognoses of in-hospital cardiac arrest (IHCA) patients immediately after recovery of spontaneous circulation (ROSC) to make further critical management. The aim of this study was to confirm the usefulness of the Cardiac Arrest Survival Post-Resuscitation In-hospital (CASPRI) and Good Outcome Following Attempted Resuscitation (GO-FAR) scores for predicting the IHCA immediately after the ROSC. This is a retrospective analysis of patient data from a tertiary general hospital located in South Korea. A total of 488 adult patients who had IHCA and achieved sustained ROSC from September 2016 to August 2021 were analyzed to compare effectiveness of the CASPRI and GO-FAR scores related to neurologic prognosis. The primary outcome was Cerebral Performance Category (CPC) score at discharge, defined as a CPC score of 1 or 2. The secondary outcomes were survival-to-discharge and normal neurological status or minimal neurological damage at discharge. Of the 488 included patients, 85 (20.8%) were discharged with good prognoses (CPC score of 1 or 2). The area under the receiver operating characteristic curve of CASPRI score for the prediction of a good neurological outcome was 0.75 (95% CI 0.69-0.81), whereas that of GO-FAR score was 0.67 (95% CI 0.60-0.73). The results of this study show that these scoring systems can be used for timely and satisfactory prediction of the neurological prognoses of IHCA patients after ROSC.

Extracorporeal Cardiopulmonary Resuscitation

BACKGROUND

Around the world, survival rates after cardiac arrest range between <14% for in-hospital (IHCA) and <10% for outof- hospital cardiac arrest (OHCA). This situation could potentially be improved by using extracorporeal membrane oxygenation (ECMO) during cardiopulmonary resuscitation (CPR), i.e. by extracorporeal cardiopulmonary resuscitation (ECPR).

METHODS

A selective literature search of Pubmed and Embase using the searching string ((ECMO) OR (ECLS)) AND (ECPR)) was carried out in February 2023 to prepare an up-to-date review of published trials comparing the outcomes of ECPR with those of conventional CPR.

RESULTS

Out of 573 initial results, 12 studies were included in this review, among them three randomized controlled trials comparing ECPR with CPR, involving a total of 420 patients. The survival rates for ECPR ranged from 20% to 43% for OHCA and 20% to 30.4% for IHCA. Most of the publications were associated with a high degree of bias and a low level of evidence.

CONCLUSION

ECPR can potentially improve survival rates after cardiac arrest compared to conventional CPR when used in experienced, high-volume centers in highly selected patients (young age, initial shockable rhythm, witnessed cardiac arrest, therapy-refractory high-quality CPR). No general recommendation for the use of ECPR can be issued at present.

Cognitive Biases and Shared Decision Making in Acute Brain Injury

Many patients hospitalized after severe acute brain injury are comatose and require life-sustaining therapies. Some of these patients make favorable recoveries with continued intensive care, while others do not. In addition to providing medical care, clinicians must guide surrogate decision makers through high-stakes, emotionally charged decisions about whether to continue life-sustaining therapies. These consultations require clinicians first to assess a patient's likelihood of recovery given continued life-sustaining therapies (i.e., prognosticate), then to communicate that prediction to surrogates, and, finally, to elicit and interpret the patient's preferences. At each step, both clinicians and surrogates are vulnerable to flawed decision making. Clinicians can be imprecise, biased, and overconfident when prognosticating after brain injury. Surrogates can misperceive the choice and misunderstand or misrepresent a patient's wishes, which may never have been communicated clearly. These biases can undermine the ability to reach choices congruent with patients' preferences through shared decision making (SDM). Decision science has extensively studied these biases. In this article, we apply that research to improving SDM for patients who are comatose after acute brain injury. After introducing SDM and the medical context, we describe principal decision science results as they relate to neurologic prognostication and end-of-life decisions, by both clinicians and surrogates. Based on research regarding general processes that can produce imprecise, biased, and overconfident prognoses, we propose interventions that could improve SDM, supporting clinicians and surrogates in making these challenging decisions.

Early Shared Decision-Making for Older Adults with Traumatic Brain Injury: Using Time-Limited Trials and Understanding Their Limitations

Older adults account for a disproportionate share of the morbidity and mortality after traumatic brain injury (TBI). Predicting functional and cognitive outcomes for individual older adults after TBI is challenging in the acute phase of injury. Given that neurologic recovery is possible and uncertain, life-sustaining therapy may be pursued initially, even if for some, there is a risk of survival to an undesired level of disability or dependence. Experts recommend early conversations about goals of care after TBI, but evidence-based guidelines for these discussions or for the optimal method for communicating prognosis are limited. The time-limited trial (TLT) model may be an effective strategy for managing prognostic uncertainty after TBI. TLTs can provide a framework for early management: specific treatments or procedures are used for a defined period of time while monitoring for an agreed-upon outcome. Outcome measures, including signs of worsening and improvement, are defined at the outset of the trial. In this Viewpoint article, we discuss the use of TLTs for older adults with TBI, their potential benefits, and current challenges to their application. Three main barriers limit the implementation of TLTs in these scenarios: inadequate models for prognostication; cognitive biases faced by clinicians and surrogate decision-makers, which may contribute to prognostic discordance; and ambiguity regarding appropriate endpoints for the TLT. Further study is needed to understand clinician behaviors and surrogate preferences for prognostic communication and how to optimally integrate TLTs into the care of older adults with TBI.

Red blood cell distribution width for the prediction of outcomes after cardiac arrest

The red blood cell distribution width (RDW) is a routinely available blood marker that measures the variation of the size/volume of red blood cells. The aim of our study was to investigate the prognostic value of RDW in cardiac arrest patients and to assess whether RDW improves the prognostic value of three cardiac arrest-specific risk scores. Consecutive adult cardiac arrest patients admitted to the ICU of a Swiss university hospital were included. The primary outcome was poor neurological outcome at hospital discharge assessed by Cerebral Performance Category. Of 702 patients admitted to the ICU after cardiac arrest, 400 patients (57.0%) survived, of which 323 (80.8%) had a good neurological outcome. Higher mean RDW values showed an independent association with poor neurological outcomes at hospital discharge (adjusted OR 1.27, 95% CI 1.14 to 1.41; p < 0.001). Adding the maximum RDW value to the OHCA- CAHP- and PROLOGUE cardiac arrest scores improved prognostic performance. Within this cohort of cardiac arrest patients, RDW was an independent outcome predictor and slightly improved three cardiac arrest-specific risk scores. RDW may therefore support clinical decision-making.

Associations between clinical characteristics of cardiac arrest and early CT head findings of hypoxic ischaemic brain injury following out-of-hospital cardiac arrest

BACKGROUND/OBJECTIVE

Post-cardiac arrest patients are vulnerable to hypoxic-ischaemic brain injury (HIBI), but HIBI may not be identified until computed tomography (CT) scan of the brain is obtained post-resuscitation and stabilization. We aimed to evaluate the association of clinical arrest characteristics with early CT findings of HIBI to identify those at the highest risk for HIBI.

METHODS

This is a retrospective analysis of out-of-hospital cardiac arrest (OHCA) patients who underwent whole-body imaging. Head CT reports were analyzed with an emphasis on findings suggestive of HIBI; HIBI was present if any of the following were noted on the neuroradiologist read: global cerebral oedema, sulcal effacement, blurred grey-white junction, and ventricular compression. The primary exposure was duration of cardiac arrest. Secondary exposures included age, cardiac vs noncardiac etiology, and witnessed vs unwitnessed arrest. The primary outcome was CT findings of HIBI.

RESULTS

A total of 180 patients (average age 54 years, 32% female, 71% White, 53% witnessed arrest, 32% cardiac etiology of arrest, mean CPR duration of 15 ± 10 minutes) were included in this analysis. CT findings of HIBI were seen in 47 (48.3%) patients. Multivariate logistic regression demonstrated a significant association between CPR duration and HIBI (adjusted OR = 1.1, 95% CI 1.01-1.11, p < 0.01).

CONCLUSION

Signs of HIBI are commonly seen on CT head within 6 hours of OHCA, occurring in approximately half of patients, and are associated with CPR duration. Determining risk factors for abnormal CT findings can help clinically identify patients at higher risk for HIBI and target interventions appropriately.

Current animal models of extracorporeal cardiopulmonary resuscitation: A scoping review

Aim

Animal models of Extracorporeal Cardiopulmonary Resuscitation (ECPR) focusing on neurological outcomes are required to further the development of this potentially life-saving technology. The aim of this review is to summarize current animal models of ECPR.

Methods

A comprehensive database search of PubMed, EMBASE, and Web of Science was undertaken. Full-text publications describing animal models of ECPR between January 1, 2000, and June 30, 2022, were identified and included in the review. Data describing the conduct of the animal models of ECPR, measured variables, and outcomes were extracted according to pre-defined definitions.

Results

The search strategy yielded 805 unique reports of which 37 studies were included in the final analysis. Most studies (95%) described using a pig model of ECPR with the remainder (5%) describing a rat model. The most common method for induction of cardiac arrest was a fatal ventricular arrhythmia through electrical stimulation (70%). 10 studies reported neurological assessment of animals using physical examination, serum biomarkers, or electrophysiological findings, however, only two studies described a multimodal assessment. No studies reported the use of brain imaging as part of the neurological assessment. Return of spontaneous circulation was the most reported primary outcome, and no studies described the neurological status of the animal as the primary outcome.

Conclusion

Current animal models of ECPR do not describe clinically relevant neurological outcomes after cardiac arrest. Further work is needed to develop models that more accurately mimic clinical scenarios and can test innovations that can be translated to the application of ECPR in clinical medicine.

Value of EEG in outcome prediction of hypoxic-ischemic brain injury in the ICU: A narrative review

Prognostication of comatose patients after cardiac arrest aims to identify patients with a large probability of favourable or unfavouble outcome, usually within the first week after the event. Electroencephalography (EEG) is a technique that is increasingly used for this purpose and has many advantages, such as its non-invasive nature and the possibility to monitor the evolution of brain function over time. At the same time, use of EEG in a critical care environment faces a number of challenges. This narrative review describes the current role and future applications of EEG for outcome prediction of comatose patients with postanoxic encephalopathy.

Prognostication and Goals of Care Decisions in Severe Traumatic Brain Injury: A Survey of The Seattle International Severe Traumatic Brain Injury Consensus Conference Working Group

Abstract Best practice guidelines have advanced severe traumatic brain injury (TBI) care; however, there is little that currently informs goals of care decisions and processes despite their importance and frequency. Panelists from the Seattle International severe traumatic Brain Injury Consensus Conference (SIBICC) participated in a survey consisting of 24 questions. Questions queried use of prognostic calculators, variability in and responsibility for goals of care decisions, and acceptability of neurological outcomes, as well as putative means of improving decisions that might limit care. A total of 97.6% of the 42 SIBICC panelists completed the survey. Responses to most questions were highly variable. Overall, panelists reported infrequent use of prognostic calculators, and observed variability in patient prognostication and goals of care decisions. They felt that it would be beneficial for physicians to improve consensus on what constitutes an acceptable neurological outcome as well as what chance of achieving that outcome is acceptable. Panelists felt that the public should help to define what constitutes a good outcome and expressed some support for a "nihilism guard." More than 50% of panelists felt that if it was certain to be permanent, a vegetative state or lower severe disability would justify a withdrawal of care decision, whereas 15% felt that upper severe disability justified such a decision. Whether conceptualizing an ideal or existing prognostic calculator to predict death or an unacceptable outcome, on average a 64-69% chance of a poor outcome was felt to justify treatment withdrawal. These results demonstrate important variability in goals of care decision making and a desire to reduce this variability. Our panel of recognized TBI experts opined on the neurological outcomes and chances of those outcomes that might prompt consideration of care withdrawal; however, imprecision of prognostication and existing prognostication tools is a significant impediment to standardizing the approach to care-limiting decisions.

Prognosis of Cardiac Arrest-Peri-arrest and Post-arrest Considerations

There has been only a small improvement in survival and neurologic outcomes in patients with cardiac arrest in recent decades. Type of arrest, length of total arrest time, and location of arrest alter the trajectory of survival and neurologic outcome. In the post-arrest phase, clinical markers such as blood markers, pupillary light response, corneal reflex, myoclonic jerking, somatosensory evoked potential, and electroencephalography testing can be used to help guide neurological prognostication. Most of the testing should be performed 72 hours post-arrest with special considerations for longer observation periods in patients who underwent TTM or who had prolonged sedation and/or neuromuscular blockade.

Serum proteome profiles in patients treated with targeted temperature management after out-of-hospital cardiac arrest

BACKGROUND

Definition of temporal serum proteome profiles after out-of-hospital cardiac arrest may identify biological processes associated with severe hypoxia-ischaemia and reperfusion. It may further explore intervention effects for new mechanistic insights, identify candidate prognostic protein biomarkers and potential therapeutic targets. This pilot study aimed to investigate serum proteome profiles from unconscious patients admitted to hospital after out-of-hospital cardiac arrest according to temperature treatment and neurological outcome.

METHODS

Serum samples at 24, 48, and 72 h after cardiac arrest at three centres included in the Target Temperature Management after out-of-hospital cardiac arrest trial underwent data-independent acquisition mass spectrometry analysis (DIA-MS) to find changes in serum protein concentrations associated with neurological outcome at 6-month follow-up and targeted temperature management (TTM) at 33 °C as compared to 36 °C. Neurological outcome was defined according to Cerebral Performance Category (CPC) scale as "good" (CPC 1-2, good cerebral performance or moderate disability) or "poor" (CPC 3-5, severe disability, unresponsive wakefulness syndrome, or death).

RESULTS

Of 78 included patients [mean age 66 ± 12 years, 62 (80.0%) male], 37 (47.4%) were randomised to TTM at 36 °C. Six-month outcome was poor in 47 (60.3%) patients. The DIA-MS analysis identified and quantified 403 unique human proteins. Differential protein abundance testing comparing poor to good outcome showed 19 elevated proteins in patients with poor outcome (log₂-fold change (FC) range 0.28-1.17) and 16 reduced proteins (log₂(FC) between - 0.22 and - 0.68), involved in inflammatory/immune responses and apoptotic signalling pathways for poor outcome and proteolysis for good outcome. Analysis according to level of TTM showed a significant protein abundance difference for six proteins [five elevated proteins in TTM 36 °C (log₂(FC) between 0.33 and 0.88), one reduced protein (log₂(FC) - 0.6)] mainly involved in inflammatory/immune responses only at 48 h after cardiac arrest.

CONCLUSIONS

Serum proteome profiling revealed an increase in inflammatory/immune responses and apoptosis in patients with poor outcome. In patients with good outcome, an increase in proteolysis was observed, whereas TTM-level only had a modest effect on the proteome profiles. Further validation of the differentially abundant proteins in response to neurological outcome is necessary to validate novel biomarker candidates that may predict prognosis after cardiac arrest.

Paucity of neuroprognostic testing after cardiac arrest in the United States

BACKGROUND

Withdrawal of life-sustaining therapies for perceived poor neurological prognosis is the most common cause of death for patients hospitalized after resuscitation from cardiac arrest. Accurate neuroprognostication is challenging and high stakes, so guidelines recommend multimodality testing. We quantified the frequency and timing with which guideline recommended diagnostics were acquired prior to in-hospital death after cardiac arrest.

METHODS

We performed a retrospective cohort study using the Optum® deidentified Electronic Health Record dataset for 2010 to 2021. We included in-hospital decedents admitted after resuscitation from non-traumatic cardiac arrest. We quantified the number of decedents who underwent head computed tomographic imaging, electroencephalography, somatosensory evoked potentials, brain magnetic resonance imaging, or evaluation by a neurologist, as well as the timing of these tests.

RESULTS

Of 34,585 included patients, median age was 66 [interquartile range 53 - 79] years and 13,609 (39%) were female. Median hospital length of stay was 0 days [0-1] days, and only 16% of deaths occurred on or after day three. Only 3,245 patients (9%) had at least one neurodiagnostic test acquired and only 1,708 (5%) were evaluated by a neurologist. The most common neurological diagnostic test to be obtained was CT imaging, acquired in 3,004 (9%) of the overall cohort. Only 852 patients (2%) of patients had at least two diagnostic modalities obtained.

DISCUSSION

In this retrospective cohort, we found few patients hospitalized after out-of-hospital cardiac arrest underwent guideline-recommended prognostic testing. If validated in prospective cohorts with more granular clinical information, better guideline adherence and more frequent use of multimodality neuroprognostication offer an opportunity to improve quality of post-arrest care.

Do Neuroprognostic Studies Account for Self-Fulfilling Prophecy Bias in Their Methodology? The SPIN Protocol for a Systematic Review

Self-fulfilling prophecy bias occurs when a perceived prognosis leads to treatment decisions that inherently modify outcomes of a patient, and thus, overinflate the prediction performance of prognostic methods. The goal of this series of systematic reviews is to characterize the extent to which neuroprognostic studies account for the potential impact of self-fulfilling prophecy bias in their methodology by assessing their adequacy of disclosing factors relevant to this bias.

Methods

Studies evaluating the prediction performance of neuroprognostic tools in cardiac arrest, malignant ischemic stroke, traumatic brain injury, subarachnoid hemorrhage, and spontaneous intracerebral hemorrhage will be identified through PubMed, Cochrane, and Embase database searches. Two reviewers blinded to each other's assessment will perform screening and data extraction of included studies using Distiller SR and following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We will abstract data pertinent to the methodology of the studies relevant to self-fulfilling prophecy bias.

Results

We will conduct a descriptive analysis of the data. We will summarize the reporting of mortality according to timing and mode of death, rates of exposure to withdrawal of life-sustaining therapy, reasoning behind limitations of supportive care, systematic use of standardized neuroprognostication algorithms and whether the tool being investigated is part of such assessments, and blinding of treatment team to results of neuroprognostic test being evaluated.

CONCLUSIONS

We will identify if neuroprognostic studies have been transparent in their methodology to factors that affect the self-fulfilling prophecy bias. Our results will serve as the foundation for standardization of neuroprognostic study methodologies by refining the quality of the data derived from such studies.

Preliminary Prognostication for Good Neurological Outcomes in the Early Stage of Post-Cardiac Arrest Care

We investigated prognostic strategies for predicting good outcomes in the early stage of post-cardiac-arrest care using multiple prognostic tests that are available until 24 h after the return of spontaneous circulation (ROSC). A retrospective analysis was conducted on 138 out-of-hospital cardiac-arrest patients who underwent prognostic tests, including the gray-white-matter ratio (GWR-BG), the Glasgow Coma Scale motor (GCS-M) score before sedative administration, and the neuron-specific enolase (NSE) level measured at 24 h after the ROSC. We investigated the prognostic performances of the tests as single predictors and in various combination strategies. Classification and regression-tree analysis were used to provide a reliable model for the risk stratification. Out of all the patients, 55 (44.0%) had good outcomes. The NSE level showed the highest prognostic performance as a single prognostic test and provided improved specificities (>70%) and sensitivities (>98%) when used in combination strategies. Low NSE levels (≤32.1 ng/mL) and high GCS-M (≥4) scores identified good outcomes without misclassification. The overall accuracy for good outcomes was 81.8%. In comatose patients with low NSE levels or high GCS-M scores, the premature withdrawal of life-sustaining therapy should be avoided, thereby complying with the formal prognostication-strategy algorithm after at least 72 h from the ROSC.

Guidelines for Neuroprognostication in Comatose Adult Survivors of Cardiac Arrest

BACKGROUND

Among cardiac arrest survivors, about half remain comatose 72 h following return of spontaneous circulation (ROSC). Prognostication of poor neurological outcome in this population may result in withdrawal of life-sustaining therapy and death. The objective of this article is to provide recommendations on the reliability of select clinical predictors that serve as the basis of neuroprognostication and provide guidance to clinicians counseling surrogates of comatose cardiac arrest survivors.

METHODS

A narrative systematic review was completed using Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Candidate predictors, which included clinical variables and prediction models, were selected based on clinical relevance and the presence of an appropriate body of evidence. The Population, Intervention, Comparator, Outcome, Timing, Setting (PICOTS) question was framed as follows: "When counseling surrogates of comatose adult survivors of cardiac arrest, should [predictor, with time of assessment if appropriate] be considered a reliable predictor of poor functional outcome assessed at 3 months or later?" Additional full-text screening criteria were used to exclude small and lower-quality studies. Following construction of the evidence profile and summary of findings, recommendations were based on four GRADE criteria: quality of evidence, balance of desirable and undesirable consequences, values and preferences, and resource use. In addition, good practice recommendations addressed essential principles of neuroprognostication that could not be framed in PICOTS format.

RESULTS

Eleven candidate clinical variables and three prediction models were selected based on clinical relevance and the presence of an appropriate body of literature. A total of 72 articles met our eligibility criteria to guide recommendations. Good practice recommendations include waiting 72 h following ROSC/rewarming prior to neuroprognostication, avoiding sedation or other confounders, the use of multimodal assessment, and an extended period of observation for awakening in patients with an indeterminate prognosis, if consistent with goals of care. The bilateral absence of pupillary light response > 72 h from ROSC and the bilateral absence of N20 response on somatosensory evoked potential testing were identified as reliable predictors. Computed tomography or magnetic resonance imaging of the brain > 48 h from ROSC and electroencephalography > 72 h from ROSC were identified as moderately reliable predictors.

CONCLUSIONS

These guidelines provide recommendations on the reliability of predictors of poor outcome in the context of counseling surrogates of comatose survivors of cardiac arrest and suggest broad principles of neuroprognostication. Few predictors were considered reliable or moderately reliable based on the available body of evidence.

Factors Associated with Early Withdrawal of Life-Sustaining Treatments After Out-of-Hospital Cardiac Arrest: A Subanalysis of a Randomized Trial of Prehospital Therapeutic Hypothermia

BACKGROUND

The objective of this study is to describe incidence and factors associated with early withdrawal of life-sustaining therapies based on presumed poor neurologic prognosis (WLST-N) and practices around multimodal prognostication after out-of-hospital cardiac arrest (OHCA).

METHODS

We performed a subanalysis of a randomized controlled trial assessing prehospital therapeutic hypothermia in adult patients admitted to nine hospitals in King County with nontraumatic OHCA between 2007 and 2012. Patients who underwent tracheal intubation and were unconscious following return of spontaneous circulation were included. Our outcomes were (1) incidence of early WLST-N (WLST-N within < 72 h from return of spontaneous circulation), (2) factors associated with early WLST-N compared with patients who remained comatose at 72 h without WLST-N, (3) institutional variation in early WLST-N, (4) use of multimodal prognostication, and (5) use of sedative medications in patients with early WLST-N. Analysis included descriptive statistics and multivariable logistic regression.

RESULTS

We included 1,040 patients (mean age was 65 years, 37% were female, 41% were White, and 44% presented with arrest due to ventricular fibrillation) admitted to nine hospitals. Early WLST-N accounted for 24% (n = 154) of patient deaths and occurred in half (51%) of patients with WLST-N. Factors associated with early WLST-N in multivariate regressions were older age (odds ratio [OR] 1.02, 95% confidence interval [CI]: 1.01-1.03), preexisting do-not-attempt-resuscitation orders (OR 4.67, 95% CI: 1.55-14.01), bilateral absent pupillary reflexes (OR 2.4, 95% CI: 1.42-4.10), and lack of neurological consultation (OR 2.60, 95% CI: 1.52-4.46). The proportion of patients with early WLST-N among all OHCA admissions ranged from 19-60% between institutions. A head computed tomography scan was obtained in 54% (n = 84) of patients with early WLST-N; 22% (n = 34) and 5% (n = 8) underwent ≥ 1 and ≥ 2 additional prognostic tests, respectively. Prognostic tests were more frequently performed when neurological consultation occurred. Most patients received sedating medications (90%) within 24 h before early WLST-N; the median time from last sedation to early WLST-N was 4.2 h (interquartile range 0.4-15).

CONCLUSIONS

Nearly one quarter of deaths after OHCA were due to early WLST-N. The presence of concerning neurological examination findings appeared to impact early WLST-N decisions, even though these are not fully reliable in this time frame. Lack of neurological consultation was associated with early WLST-N and resulted in underuse of guideline-concordant multimodal prognostication. Sedating medications were often coadministered prior to early WLST-N and may have further confounded the neurological examination. Standardizing prognostication, restricting early WLST-N, and a multidisciplinary approach including neurological consultation might improve outcomes after OHCA.

Assessment of Brain Magnetic Resonance and Spectroscopy Imaging Findings and Outcomes After Pediatric Cardiac Arrest

Importance

Morbidity and mortality after pediatric cardiac arrest are chiefly due to hypoxic-ischemic brain injury. Brain features seen on magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) after arrest may identify injury and aid in outcome assessments.

Objective

To analyze the association of brain lesions seen on T2-weighted MRI and diffusion-weighted imaging and N-acetylaspartate (NAA) and lactate concentrations seen on MRS with 1-year outcomes after pediatric cardiac arrest.

Design, Setting, and Participants

This multicenter cohort study took place in pediatric intensive care units at 14 US hospitals between May 16, 2017, and August 19, 2020. Children aged 48 hours to 17 years who were resuscitated from in-hospital or out-of-hospital cardiac arrest and who had a clinical brain MRI or MRS performed within 14 days postarrest were included in the study. Data were analyzed from January 2022 to February 2023.

Exposure

Brain MRI or MRS.

Main Outcomes and Measures

The primary outcome was an unfavorable outcome (either death or survival with a Vineland Adaptive Behavior Scales, Third Edition, score of <70) at 1 year after cardiac arrest. MRI brain lesions were scored according to region and severity (0 = none, 1 = mild, 2 = moderate, 3 = severe) by 2 blinded pediatric neuroradiologists. MRI Injury Score was a sum of T2-weighted and diffusion-weighted imaging lesions in gray and white matter (maximum score, 34). MRS lactate and NAA concentrations in the basal ganglia, thalamus, and occipital-parietal white and gray matter were quantified. Logistic regression was performed to determine the association of MRI and MRS features with patient outcomes.

Results

A total of 98 children, including 66 children who underwent brain MRI (median [IQR] age, 1.0 [0.0-3.0] years; 28 girls [42.4%]; 46 White children [69.7%]) and 32 children who underwent brain MRS (median [IQR] age, 1.0 [0.0-9.5] years; 13 girls [40.6%]; 21 White children [65.6%]) were included in the study. In the MRI group, 23 children (34.8%) had an unfavorable outcome, and in the MRS group, 12 children (37.5%) had an unfavorable outcome. MRI Injury Scores were higher among children with an unfavorable outcome (median [IQR] score, 22 [7-32]) than children with a favorable outcome (median [IQR] score, 1 [0-8]). Increased lactate and decreased NAA in all 4 regions of interest were associated with an unfavorable outcome. In a multivariable logistic regression adjusted for clinical characteristics, increased MRI Injury Score (odds ratio, 1.12; 95% CI, 1.04-1.20) was associated with an unfavorable outcome.

Conclusions and Relevance

In this cohort study of children with cardiac arrest, brain features seen on MRI and MRS performed within 2 weeks after arrest were associated with 1-year outcomes, suggesting the utility of these imaging modalities to identify injury and assess outcomes.

Neurologic Complications of Cardiac and Pulmonary Disease

OBJECTIVE

The heart and lungs work as a functional unit through a complex interplay. The cardiorespiratory system is responsible for the delivery of oxygen and energy substrates to the brain. Therefore, diseases of the heart and lungs can lead to various neurologic illnesses. This article reviews various cardiac and pulmonary pathologies that can lead to neurologic injury and discusses the relevant pathophysiologic mechanisms.

LATEST DEVELOPMENTS

We have lived through unprecedented times over the past 3 years with the emergence and rapid spread of the COVID-19 pandemic. Given the effects of COVID-19 on the lungs and heart, an increased incidence of hypoxic-ischemic brain injury and stroke associated with cardiorespiratory pathologies has been observed. Newer evidence has questioned the benefit of induced hypothermia in patients with out-of-hospital cardiac arrest. Further, global collaborative initiatives such as the Curing Coma Campaign are underway with the goal of improving the care of patients with coma and disorders of consciousness, including those resulting from cardiac and pulmonary pathologies.

ESSENTIAL POINTS

The neurologic complications of cardiorespiratory disorders are common and present in various forms such as stroke or hypoxic and anoxic injury related to cardiac or respiratory failure. With the emergence of the COVID-19 pandemic, neurologic complications have increased in recent years. Given the intimate and interdependent dynamics of the heart, lungs, and brain, it is crucial for neurologists to be aware of the interplay between these organs.

Association Between Postresuscitation 12-Lead ECG Features and Early Mortality After Out-of-Hospital Cardiac Arrest: A Post Hoc Subanalysis of the PEACE Study

Background Once the return of spontaneous circulation after out-of-hospital cardiac arrest is achieved, a 12-lead ECG is strongly recommended to identify candidates for urgent coronary angiography. ECG has no apparent role in mortality risk stratification. We aimed to assess whether ECG features could be associated with 30-day survival in patients with out-of-hospital cardiac arrest. Methods and Results All the post-return of spontaneous circulation ECGs from January 2015 to December 2018 in 3 European centers (Pavia, Lugano, and Vienna) were collected. Prehospital data were collected according to the Utstein style. A total of 370 ECGs were collected: 287 men (77.6%) with a median age of 62 years (interquartile range, 53-70 years). After correction for the return of spontaneous circulation-to-ECG time, age >62 years (hazard ratio [HR], 1.78 [95% CI, 1.21-2.61]; P=0.003), female sex (HR, 1.5 [95% CI, 1.05-2.13]; P=0.025), QRS wider than 120 ms (HR, 1.64 [95% CI, 1.43-1.87]; P<0.001), the presence of a Brugada pattern (HR, 1.49 [95% CI, 1.39-1.59]; P<0.001), and the presence of ST-segment elevation in >1 segment (HR, 1.75 [95% CI, 1.59-1.93]; P<0.001) were independently associated with 30-day mortality. A score ranging from 0 to 26 was created, and by dividing the population into 3 tertiles, 3 classes of risk were found with significantly different survival rate at 30 days (score 0-4, 73%; score 5-7, 66%; score 8-26, 45%). Conclusions The post-return of spontaneous circulation ECG can identify patients who are at high risk of mortality after out-of-hospital cardiac arrest earlier than other forms of prognostication. This provides important risk stratification possibilities in postcardiac arrest care that could help to direct treatments and improve outcomes in patients with out-of-hospital cardiac arrest.

Disability-Adjusted Life-Years After Adult In-Hospital Cardiac Arrest in the United States

We sought to estimate disability-adjusted life-years (DALYs) because of adult in-hospital cardiac arrest (IHCA) and to compare IHCA DALY to other leading causes of death and disability in the United States. DALY were calculated as the sum of years of life lost and years lived with disability. The years of life lost were calculated using all adult IHCA with complete data from the American Heart Association Get With The Guidelines-Resuscitation database for 2015 to 2019. Cerebral performance category scores and published disability weights were used to estimate the years lived with disability for survivors. The cohort's DALY were extrapolated to a national level to estimate the total United States DALY and were compared with a published ranking of the leading causes of DALY in the United States for 2018. Data were reported as DALY total and rate per 100,000. A total of 99,897 IHCA were included from 329 hospitals. The total IHCA DALY increased from 2,208,310 in 2015 to 2,225,722 in 2019. A modest decrease in the DALY rate was observed from 689 per 100,000 in 2015 to 678 per 100,000 in 2019. In 2018, the rate of IHCA DALY were 728 per 100,000, which represented the 11th leading cause of DALY. When combined with out-of-hospital cardiac arrest (1,322 per 100,000), sudden cardiac arrest (2,050 per 100,000) was found the be the 2nd leading cause of DALY after ischemic heart disease (2,681 per 100,000) in 2018. In conclusion, adult IHCA is a leading cause of DALY in the United States and has increased over time because of the expansion of the Get With The Guidelines-Resuscitation database.

Temperature Control After Cardiac Arrest: A Narrative Review

Cardiac arrest (CA) is a critical public health issue affecting more than half a million Americans annually. The main determinant of outcome post-CA is hypoxic-ischemic brain injury (HIBI), and temperature control is currently the only evidence-based, guideline-recommended intervention targeting secondary brain injury. Temperature control is a key component of a post-CA care bundle; however, conflicting evidence challenges its wide implementation across the vastly heterogeneous population of CA survivors. Here, we critically appraise the available literature on temperature control in HIBI, detail how the evidence has been integrated into clinical practice, and highlight the complications associated with its use and the timing of neuroprognostication after CA. Future clinical trials evaluating different temperature targets, rates of rewarming, duration of cooling, and identifying which patient phenotype benefits from different temperature control methods are needed to address these prevailing knowledge gaps.

Trigeminal nerve stimulation for prolonged disorders of consciousness: A randomized double-blind sham-controlled study

BACKGROUND

Trigeminal nerve stimulation (TNS) has been proposed as a promising intervention for coma awakening. However, the effect of TNS on patients with prolonged disorders of consciousness (pDoC) is still unclear.

OBJECTIVE

This study aimed to investigate the therapeutic effects of TNS in pDoC caused by stroke, trauma, and anoxia.

METHODS

A total of 60 patients (male =25, female =35) aged over 18 who were in a vegetative state or minimally conscious state were randomly assigned to the TNS (N = 30) or sham TNS (N = 30) groups. 4 weeks of intervention and a followed up for 8 weeks were performed. The Glasgow Coma Scale (GCS) and Coma Recovery Scale-Revised (CRS-R) scores as primary outcomes were assessed at baseline and at 2, 4, 8, and 12 weeks.

RESULTS

The score changes in the TNS group over time for CRS-R (2-week: mean difference = 0.9, 95% CI = [0.3, 1.5], P = 0.006; 4-week: 1.6, 95% CI = [0.8, 2.5], P < 0.001; 8-week: mean difference = 2.4, 95% CI = [1.3, 3.5], P < 0.001; 12-week: mean difference = 2.3, 95% CI = [1.1, 3.4], P < 0.001) and GCS (4-week: mean difference = 0.7, 95% CI = [0.3, 1.2], P = 0.002; 8-week: mean difference = 1.1, 95% CI = [0.6, 1.7], P < 0.001; 12-week: 1.1, 95% CI = [0.5, 1.7], P = 0.003) were higher than those in the sham group. 18-Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) revealed that the metabolism of the right parahippocampal cortex, right precuneus, and bilateral middle cingulate cortex was significantly increased in TNS group.

CONCLUSION

The results of this study indicate that TNS could increase local brain metabolism and may promote functional recovery in patients with prolonged disorders of consciousness.

REGISTRATION INFORMATION

Name of the registry: Chinese Clinical Trial Registry.

REGISTRATION NUMBER

ChiCTR1900025573. The date that the study was submitted to a registry: 2019-09-01. The date when the first patient was enrolled was 2021-01-20.

Extracorporeal cardiopulmonary resuscitation dissemination and integration with organ preservation in the USA: ethical and logistical considerations

Use of extracorporeal membrane oxygenation (ECMO) in cardiopulmonary resuscitation, termed eCPR, offers the prospect of improving survival with good neurological function after cardiac arrest. After death, ECMO can also be used for enhanced preservation of abdominal and thoracic organs, designated normothermic regional perfusion (NRP), before organ recovery for transplantation. To optimize resuscitation and transplantation outcomes, healthcare networks in Portugal and Italy have developed cardiac arrest protocols that integrate use of eCPR with NRP. Similar dissemination of eCPR and its integration with NRP in the USA raise novel ethical issues due to a non-nationalized health system and an opt-in framework for organ donation, as well as other legal and cultural factors. Nonetheless, eCPR investigations are ongoing, and both eCPR and NRP are selectively employed in clinical practice. This paper delineates the most pressing relevant ethical considerations and proposes recommendations for implementation of protocols that aim to promote public trust and reduce conflicts of interest. Transparent policies should rely on protocols that separate lifesaving from organ preservation considerations; robust, centralized eCPR data to inform equitable and evidence-based allocations; uniform practices concerning clinical decision-making and resource utilization; and partnership with community stakeholders, allowing patients to make decisions about emergency care that align with their values. Proactively addressing these ethical and logistical challenges could enable eCPR dissemination and integration with NRP protocols in the USA, with the potential to maximize lives saved through both improved resuscitation with good neurological outcomes and increased organ donation opportunities when resuscitation is unsuccessful or not in accordance with individuals' wishes.

Explainable artificial intelligence-based prediction of poor neurological outcome from head computed tomography in the immediate post-resuscitation phase

Predicting poor neurological outcomes after resuscitation is important for planning treatment strategies. We constructed an explainable artificial intelligence-based prognostic model using head computed tomography (CT) scans taken immediately within 3 h of resuscitation from cardiac arrest and compared its predictive accuracy with that of previous methods using gray-to-white matter ratio (GWR). We included 321 consecutive patients admitted to our institution after resuscitation for out-of-hospital cardiopulmonary arrest with circulation resumption over 6 years. A machine learning model using head CT images with transfer learning was used to predict the neurological outcomes at 1 month. These predictions were compared with the predictions of GWR for multiple regions of interest in head CT using receiver operating characteristic (ROC)-area under curve (AUC) and precision recall (PR)-AUC. The regions of focus were visualized using a heatmap. Both methods had similar ROC-AUCs, but the machine learning model had a higher PR-AUC (0.73 vs. 0.58). The machine learning-focused area of interest for classification was the boundary between gray and white matter, which overlapped with the area of focus when diagnosing hypoxic- ischemic brain injury. The machine learning model for predicting poor outcomes had superior accuracy to conventional methods and could help optimize treatment.

Long-term outcomes and prognostic factors of extracorporeal cardiopulmonary resuscitation in patients older than 75 years: a single-centre retrospective study

BACKGROUND

Few studies have assessed older adult patients who received extracorporeal cardiopulmonary resuscitation (ECPR) after cardiac arrest, and outcomes and prognostic factors of ECPR in this population remain unclear. This study aimed to assess the long-term outcomes and prognostic factors among patients older than 75 years who received ECPR after experiencing cardiac arrest.

METHODS

This is a single-centre, retrospective case-control study conducted between August 2010 and July 2019. Consecutive patients older than 75 years who had in-hospital (IHCA) or out-of-hospital cardiac arrest (OHCA) and received ECPR at the Emergency Department in the Hyogo Emergency Medical Center, Hyogo, Japan, were included. The primary outcome was a favourable neurological outcome, defined as a Cerebral Performance Category score of 1-2 at 1 year after the event. Univariate logistic regression was used to determine the association between variables and patient outcomes.

RESULTS

Of the 187 patients with cardiac arrest who received ECPR, 30 were older than 75 years and 28 (15% of the cohort receiving ECPR) were examined in this study. The median age of the patients was 79 years (IQR 77-82), and there were 13 (46%) male patients. Neurological outcomes were favourable for seven (25%) patients, five of whom had IHCA and two with out-of-hospital OHCA. On univariate analysis, patients with a favourable outcome had a shorter median total collapse time (TCT) than those with an unfavourable outcome (favourable: 18.0 min (IQR 13.0-33.5) vs unfavourable: 44.0 min (IQR 25.0-53.0); p=0.049).

CONCLUSION

In selected patients older than 75 years, ECPR could be beneficial by providing a shorter TCT, which may contribute to favourable neurological outcomes. Nevertheless, further studies are needed to validate these findings.

Identification of predictors for neurological outcome after cardiac arrest in peripheral blood mononuclear cells through integrated bioinformatics analysis and machine learning

Neurological prognostication after cardiac arrest (CA) is important to avoid pursuing futile treatments for poor outcome and inappropriate withdrawal of life-sustaining treatment for good outcome. To predict neurological outcome after CA through biomarkers in peripheral blood mononuclear cells, four datasets were downloaded from the Gene Expression Omnibus database. GSE29546 and GSE74198 were used as training datasets, while GSE92696 and GSE34643 were used as verification datasets. The intersection of differentially expressed genes and hub genes from multiscale embedded gene co-expression network analysis (MEGENA) was utilized in the machine learning screening. Key genes were identified using support vector machine recursive feature elimination (SVM-RFE), least absolute shrinkage and selection operator (LASSO) logistic regression, and random forests (RF). The results were validated using receiver operating characteristic curve analysis. An mRNA-miRNA network was constructed. The distribution of immune cells was evaluated using cell-type identification by estimating relative subsets of RNA transcripts (CIBERSORT). Five biomarkers were identified as predictors for neurological outcome after CA, with an area under the curve (AUC) greater than 0.7: CASP8 and FADD-like apoptosis regulator (CFLAR), human protein kinase X (PRKX), miR-483-5p, let-7a-5p, and let-7c-5p. Interestingly, the combination of CFLAR minus PRKX showed an even higher AUC of 0.814. The mRNA-miRNA network consisted of 30 nodes and 76 edges. Statistical differences were found in immune cell distribution, including neutrophils, NK cells active, NK cells resting, T cells CD4 memory activated, T cells CD4 memory resting, T cells CD8, B cells memory, and mast cells resting between individuals with good and poor neurological outcome after CA. In conclusion, our study identified novel predictors for neurological outcome after CA. Further clinical and laboratory studies are needed to validate our findings.

Therapeutic Hypothermia Following Cardiac Arrest After the TTM2 trial - More Questions Raised Than Answered

For almost 20 years, therapeutic hypothermia has been a cornerstone of modern post-cardiac arrest care lowering mortality, and improvin neurologic outcome compared to conventional therapy. This was challenged by the first TTM-trial in 2013, which did not show a benefit for hypothermia at 33°C compared to controlled normothermia at 36°C. Now, the TTM2 trial showed no benefit of hypothermia compared to fever prevention alone. While TTM1 and TTM2 suggest that hypothermia might not be helpful, a deep dive into the trials reveals that this conclusion does not hold true. Here, we focus on patient selection, suboptimal application of hypothermia, interaction of standard sedation with hypothermia, high incidence of post-arrest fever, and withdrawal of life support based on per-protocol neurologic prognostication in the TTM2-trial. Of particular interest, contemporary trials and registries using intravascular cooling in TTM-like patients repeatedly reported much lower mortality rates than those described in both TTM1 and TTM2.

Cardiac Arrest and Neurologic Recovery: Insights from the Case of Mr. Damar Hamlin

The association between brain injury after cardiac arrest and poor survival outcomes has led to longstanding pessimism. However, the publicly witnessed cardiac arrest, resuscitation, and acute management of Mr. Damar Hamlin and his favorable neurologic recovery provides some optimism. Mr. Hamlin's case highlights the neurologic advances of the last 2 decades and presents the opportunity to improve outcomes for all cardiac arrest patients in key areas: (1) effectively implementing the American Heart Association "Chain of Survival" to prevent initial brain injury and promote neuroprotection; (2) revisiting the process of neurologic prognostication and re-defining the brain recovery during the early periods, and (3) incorporating neurorehabilitation into existing cardiac rehabilitation models to support holistic recovery. ANN NEUROL 2023.

Successful resuscitation and neurological monitoring of a dog with out-of-hospital cardiopulmonary arrest due to pentobarbital overdose

OBJECTIVE

To describe the clinical signs, electroencephalographic (EEG) findings, treatment, and outcome in a dog after successful resuscitation from out-of-hospital cardiopulmonary arrest (OHCA) induced by pentobarbital intoxication.

CASE SUMMARY

A 10-year-old, male intact Jack Russell Terrier was referred for management of refractory status epilepticus and presented dead on arrival. After 7 minutes of cardiopulmonary resuscitation, return of spontaneous circulation was achieved, but the dog remained comatose, apneic, and lacked brainstem reflexes on neurological examination 6 hours following resuscitation. Magnetic resonance imaging showed polioencephalomalacia consistent with prolonged epileptiform activity, and EEG was initially concerning for electrocerebral inactivity. Following supportive care that included short-term mechanical ventilation, the dog made a full recovery and was discharged from the hospital alive 7 days postresuscitation. It was later revealed that the dog had been administered an unknown amount of pentobarbital during transportation, which likely contributed to the OHCA, clinical, and EEG findings.

NEW INFORMATION PROVIDED

This is the first report to describe the full recovery and hospital discharge of a dog suffering OHCA and the first description of EEG findings in a clinical veterinary patient following cardiopulmonary arrest and successful resuscitation. Factors likely contributing to successful patient outcome and potential benefits and limitations of EEG in monitoring postcardiac arrest patients are discussed.

Self-fulfilling prophecies and machine learning in resuscitation science

INTRODUCTION

Growth of machine learning (ML) in healthcare has increased potential for observational data to guide clinical practice systematically. This can create self-fulfilling prophecies (SFPs), which arise when prediction of an outcome increases the chance that the outcome occurs.

METHODS

We performed a scoping review, searching PubMed and ArXiv using terms related to machine learning, algorithmic fairness and bias. We reviewed results and selected manuscripts for inclusion based on expert opinion of well-designed or key studies and review articles. We summarized these articles to explore how use of ML can create, perpetuate or compound SFPs, and offer recommendations to mitigate these risks.

RESULTS

We identify-four key mechanisms through which SFPs may be reproduced or compounded by ML. First, imperfect human beliefs and behavior may be encoded as SFPs when treatment decisions are not accounted for. Since patient outcomes are influenced by a myriad of clinical actions, many of which are not collected in data, this is common. Second, human-machine interaction may compound SFPs through a cycle of mutual reinforcement. Third, ML may introduce new SFPs stemming from incorrect predictions. Finally, historically correct clinical choices may become SFPs in the face of medical progress.

CONCLUSION

There is a need for broad recognition of SFPs as ML is increasingly applied in resuscitation science and across medicine. Acknowledging this challenge is crucial to inform research and practice that can transform ML from a tool that risks obfuscating and compounding SFPs into one that sheds light on and mitigates SFPs.

The SLANT Score Predicts Poor Neurologic Outcome in Comatose Survivors of Cardiac Arrest: An External Validation Using a Retrospective Cohort

BACKGROUND

Hypoxic brain injury is the leading cause of death in comatose patients following resuscitation from cardiac arrest. Neurological outcome can be difficult to prognosticate following resuscitation, and goals of care discussions are often informed by multiple prognostic tools. One tool that has shown promise is the SLANT score, which encompasses five metrics including initial nonshockable rhythm, leukocyte count after targeted temperature management, total adrenaline dose during resuscitation, lack of bystander cardiopulmonary resuscitation, and time to return of spontaneous circulation. This cohort study aimed to provide an external validation of this score by using a database of comatose cardiac arrest survivors from our institution.

METHODS

We retrospectively queried our database of cardiac arrest survivors, selecting for patients with coma, sustained return of spontaneous circulation, and use of targeted temperature management to have a comparable sample to the index study. We calculated SLANT scores for each patient and separated them into risk levels, both according to the original study and according to a Youden index analysis. The primary outcome was poor neurologic outcome (defined by a cerebral performance category score of 3 or greater at discharge), and the secondary outcome was in-hospital mortality. Univariable and multivariable analyses, as well as a receiver operator characteristic curve, were used to assess the SLANT score for independent predictability and diagnostic accuracy for poor outcomes.

RESULTS

We demonstrate significant association between a SLANT group with increased risk and poor neurologic outcome on univariable (p = 0.005) and multivariable analysis (odds ratio 1.162, 95% confidence interval 1.003-1.346, p = 0.046). A receiver operating characteristic analysis indicates that SLANT scoring is a fair prognostic test for poor neurologic outcome (area under the curve 0.708, 95% confidence interval 0.536-0.879, p = 0.024). Among this cohort, the most frequent SLANT elements were initial nonshockable rhythm (84.5%) and total adrenaline dose ≥ 5 mg (63.9%). There was no significant association between SLANT score and in-hospital mortality (p = 0.064).

CONCLUSIONS

The SLANT score may independently predict poor neurologic outcome but not in-hospital mortality. Including the SLANT score as part of a multimodal approach may improve our ability to accurately prognosticate comatose survivors of cardiac arrest.

Neurophysiological and Clinical Correlates of Acute Posthypoxic Myoclonus

SUMMARY

Prognostication following cardiorespiratory arrest relies on the neurological examination, which is supported by neuroimaging and neurophysiological testing. Acute posthypoxic myoclonus (PHM) is a clinical entity that has prognostic significance and historically has been considered an indicator of poor outcome, but this is not invariably the case. "Malignant" and more "benign" forms of acute PHM have been described and differentiating them is key in understanding their meaning in prognosis. Neurophysiological tests, electroencephalogram in particular, and clinical phenotyping are crucial in defining subtypes of acute PHM. This review describes the neurophysiological and phenotypic markers of malignant and benign forms of acute PHM, a clinical approach to evaluating acute PHM following cardiorespiratory arrest in determining prognosis, and gaps in our understanding of acute PHM that require further study.

Limbic pathway vulnerability associates with neurologic outcome in children after cardiac arrest

AIM

To analyze whether brain connectivity sequences including diffusion tensor imaging (DTI) and resting state functional magnetic resonance imaging (rsfMRI) identify vulnerable brain regions and networks associated with neurologic outcome after pediatric cardiac arrest.

METHODS

Children aged 2 d-17 y with cardiac arrest were enrolled in one of 2 parent studies at a single center. Clinically indicated brain MRI with DTI and rsfMRI and performed within 2 weeks after arrest were analyzed. Tract-wise fractional anisotropy (FA) and axial, radial, and mean diffusivity assessed DTI, and functional connectivity strength (FCS) assessed rsfMRI between outcome groups. Unfavorable neurologic outcome was defined as Pediatric Cerebral Performance Category score 4-6 or change > 1 between 6 months after arrest vs baseline.

RESULTS

Among children with DTI (n = 28), 57% had unfavorable outcome. Mean, radial, axial diffusivity and FA of varying direction of magnitude in the limbic tracts, including the right cingulum parolfactory, left cingulum parahippocampal, corpus callosum forceps major, and corpus callosum forceps minor tracts, were associated with unfavorable neurologic outcome (p < 0.05). Among children with rsfMRI (n = 12), 67% had unfavorable outcome. Decreased FCS in the ventromedial and dorsolateral prefrontal cortex, insula, precentral gyrus, anterior cingulate, and inferior parietal lobule were correlated regionally with unfavorable neurologic outcome (p < 0.05 Family-Wise Error corrected).

CONCLUSION

Decreased multimodal connectivity measures of paralimbic tracts were associated with unfavorable neurologic outcome after pediatric cardiac arrest. Longitudinal analysis correlating brain connectivity sequences with long term neuropsychological outcomes to identify the impact of pediatric cardiac arrest in vulnerable brain networks over time appears warranted.

Nonconvulsive status epilepticus following cardiac arrest: overlooked, untreated and misjudged

AIMS

Seizures and status epilepticus (SE) are detected in almost a third of the comatose cardiac arrest survivors. As the literature is quite exhaustive regarding SE with motor symptoms in those patients, little is known about nonconvulsive SE (NCSE). Our aim was to compile the evidence from the literature of the frequency and outcome of NCSE in adult patients remaining in coma after resuscitation.

METHODS

The medical search PubMed was screened for most relevant articles reporting the emergence and outcome of NCSE in comatose post-resuscitated adult patients.

RESULTS

We identified 11 cohort studies (four prospective observational, seven retrospective) including 1092 patients with SE in 29-96% and NCSE reported in 1-20%. EEG evaluation started at a median of 9.5 h (range 7.5-14.8) after cardiac arrest, during sedation and targeted temperature management (TTM). Favorable outcome after NCSE occurred in 24.5%. We found no study reporting EEG to detect or exclude NCSE in patients remaining in coma prior to the initiation of TTM and without sedation withing the first hours after ROSC.

DISCUSSION

Studies on NCSE after ROSC are scarce and unsystematic, reporting favorable outcome in every fourth patient experiencing NCSE after ROSC. This suggests that NCSE is often overlooked and outcome after NCSE is not always poor. The low data quality does not allow firm conclusions regarding the effects of NCSE on outcome calling for further investigation. In the meantime, clinicians should avoid equating NCSE after ROSC with poor prognosis.

Multimodal monitoring: practical recommendations (dos and don'ts) in challenging situations and uncertainty

With the advancements in modern medicine, new methods are being developed to monitor patients in the intensive care unit. Different modalities evaluate different aspects of the patient's physiology and clinical status. The complexity of these modalities often restricts their use to the realm of clinical research, thereby limiting their use in the real world. Understanding their salient features and their limitations can aid physicians in interpreting the concomitant information provided by multiple modalities to make informed decisions that may affect clinical care and outcomes. Here, we present a review of the commonly used methods in the neurological intensive care unit with practical recommendations for their use.

Prognostication after cardiac arrest: how EEG and evoked potentials may improve the challenge

About 80% of patients resuscitated from CA are comatose at ICU admission and nearly 50% of survivors are still unawake at 72 h. Predicting neurological outcome of these patients is important to provide correct information to patient's relatives, avoid disproportionate care in patients with irreversible hypoxic-ischemic brain injury (HIBI) and inappropriate withdrawal of care in patients with a possible favorable neurological recovery. ERC/ESICM 2021 algorithm allows a classification as "poor outcome likely" in 32%, the outcome remaining "indeterminate" in 68%. The crucial question is to know how we could improve the assessment of both unfavorable but also favorable outcome prediction. Neurophysiological tests, i.e., electroencephalography (EEG) and evoked-potentials (EPs) are a non-invasive bedside investigations. The EEG is the record of brain electrical fields, characterized by a high temporal resolution but a low spatial resolution. EEG is largely available, and represented the most widely tool use in recent survey examining current neuro-prognostication practices. The severity of HIBI is correlated with the predominant frequency and background continuity of EEG leading to "highly malignant" patterns as suppression or burst suppression in the most severe HIBI. EPs differ from EEG signals as they are stimulus induced and represent the summated activities of large populations of neurons firing in synchrony, requiring the average of numerous stimulations. Different EPs (i.e., somato sensory EPs (SSEPs), brainstem auditory EPs (BAEPs), middle latency auditory EPs (MLAEPs) and long latency event-related potentials (ERPs) with mismatch negativity (MMN) and P300 responses) can be assessed in ICU, with different brain generators and prognostic values. In the present review, we summarize EEG and EPs signal generators, recording modalities, interpretation and prognostic values of these different neurophysiological tools. Finally, we assess the perspective for futures neurophysiological investigations, aiming to reduce prognostic uncertainty in comatose and disorders of consciousness (DoC) patients after CA.