Continuous Monitoring of Cerebral Autoregulation in Adults Supported by Extracorporeal Membrane Oxygenation.

BACKGROUND: Impaired cerebral autoregulation (CA) is one of several proposed mechanisms of acute brain injury in patients supported by extracorporeal membrane oxygenation (ECMO). The primary aim of this study was to determine the feasibility of continuous CA monitoring in adult ECMO patients. Our secondary aims were to describe changes in cerebral oximetry index (COx) and other metrics of CA over time and in relation to functional neurologic outcomes. METHODS: This is a single-center prospective observational study. We measured COx, a surrogate measurement of cerebral blood flow measured by near-infrared spectroscopy, which is an index of CA derived from the moving correlation between mean arterial pressure (MAP) and slow waves of regional cerebral oxygen saturation. A COx value that approaches 1 indicates impaired CA. Using COx, we determined the optimal MAP (MAPOPT) and lower and upper limits of autoregulation for individual patients. These measurements were examined in relation to modified Rankin Scale (mRS) scores. RESULTS: Fifteen patients (median age 57 years [interquartile range 47-69]) with 150 autoregulation measurements were included for analysis. Eleven were on veno-arterial ECMO (VA-ECMO), and four were on veno-venous ECMO (VV-ECMO). Mean COx was higher on postcannulation day 1 than on day 2 (0.2 vs. 0.09, p < 0.01), indicating improved CA over time. COx was higher in VA-ECMO patients than in VV-ECMO patients (0.12 vs. 0.06, p = 0.04). Median MAPOPT for the entire cohort was highly variable, ranging from 55 to 110 mm Hg. Patients with mRS scores 0-3 (good outcome) at 3 and 6 months spent less time outside MAPOPT compared with patients with mRS scores 4-6 (poor outcome) (74% vs. 82%, p = 0.01). The percentage of time when observed MAP was outside the limits of autoregulation was higher on postcannulation day 1 than on day 2 (18.2% vs. 3.3%, p < 0.01). CONCLUSIONS: In ECMO patients, it is feasible to monitor CA continuously at the bedside. CA improved over time, most significantly between postcannulation days 1 and 2. CA was more impaired in VA-ECMO patients than in VV-ECMO patients. Spending less time outside MAPOPT may be associated with achieving a good neurologic outcome.

Common Data Elements for Disorders of Consciousness: Recommendations from the Working Group on Biospecimens and Biomarkers.

BACKGROUND: In patients with disorders of consciousness (DoC), laboratory and molecular biomarkers may help define endotypes, identify therapeutic targets, prognosticate outcomes, and guide patient selection in clinical trials. We performed a systematic review to identify common data elements (CDEs) and key design elements (KDEs) for future coma and DoC research. METHODS: The Curing Coma Campaign Biospecimens and Biomarkers work group, composed of seven invited members, reviewed existing biomarker and biospecimens CDEs and conducted a systematic literature review for laboratory and molecular biomarkers using predetermined search words and standardized methodology. Identified CDEs and KDEs were adjudicated into core, basic, supplemental, or experimental CDEs per National Institutes of Health classification based on level of evidence, reproducibility, and generalizability across different diseases through a consensus process. RESULTS: Among existing National Institutes of Health CDEs, those developed for ischemic stroke, traumatic brain injury, and subarachnoid hemorrhage were most relevant to DoC and included. KDEs were common to all disease states and included biospecimen collection time points, baseline indicator, biological source, anatomical location of collection, collection method, and processing and storage methodology. Additionally, two disease core, nine basic, 24 supplemental, and 59 exploratory biomarker CDEs were identified. Results were summarized and generated into a Laboratory Data and Biospecimens Case Report Form (CRF) and underwent public review. A final CRF version 1.0 is reported here. CONCLUSIONS: Exponential growth in biomarkers development has generated a growing number of potential experimental biomarkers associated with DoC, but few meet the quality, reproducibility, and generalizability criteria to be classified as core and basic biomarker and biospecimen CDEs. Identification and adaptation of KDEs, however, contribute to standardizing methodology to promote harmonization of future biomarker and biospecimens studies in DoC. Development of this CRF serves as a basic building block for future DoC studies.

Continuous Monitoring of Cerebral Autoregulation in Adults Supported by Extracorporeal Membrane Oxygenation.

Background: Impaired cerebral autoregulation (CA) is one of several proposed mechanisms of acute brain injury in patients supported by extracorporeal membrane oxygenation (ECMO). The primary aim of this study was to determine the feasibility of continuous CA monitoring in adult ECMO patients. Our secondary aims were to describe changes in cerebral oximetry index (COx) and other metrics of CA over time and in relation to functional neurologic outcomes. Methods: This is a single-center prospective observational study. We measured Cox, a surrogate measurement of cerebral blood flow, measured by near-infrared spectroscopy, which is an index of CA derived from the moving correlation between mean arterial pressure and slow waves of regional cerebral oxygen saturation. A COx value that approaches 1 indicates impaired CA. Using COx, we determined the optimal MAP (MAPOPT), lower and upper limits of autoregulation for individual patients. These measurements were examined in relation to modified Rankin Scale (mRS) scores. Results: Fifteen patients (median age=57 years [IQR=47-69]) with 150 autoregulation measurements were included for analysis. Eleven were on veno-arterial ECMO and 4 on veno-venous. Mean COx was higher on post-cannulation day 1 than on day 2 (0.2 vs 0.09, p<0.01), indicating improved CA over time. COx was higher in VA-ECMO patients than in VV-ECMO (0.12 vs 0.06, p=0.04). Median MAPOPT for entire cohort was highly variable, ranging 55-110 mmHg. Patients with mRS 0-3 (good outcome) at 3 and 6 months spent less time outside of MAPOPT compared to patients with mRS 4-6 (poor outcome) (74% vs 82%, p=0.01). The percentage of time when observed MAP was outside the limits of autoregulation was higher on post-cannulation day 1 than on day 2 (18.2% vs 3.3%, p<0.01). Conclusions: In ECMO patients, it is feasible to monitor CA continuously at the bedside. CA improved over time, most significantly between post-cannulation days 1 and 2. CA was more impaired in VA-ECMO than VV-ECMO. Spending less time outside of MAPOPT may be associated with achieving a good neurologic outcome.

Therapies for Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage.

Delayed cerebral ischemia (DCI) is one of the most important complications of subarachnoid hemorrhage. Despite lack of prospective evidence, medical rescue interventions for DCI include hemodynamic augmentation using vasopressors or inotropes, with limited guidance on specific blood pressure and hemodynamic parameters. For DCI refractory to medical interventions, endovascular rescue therapies (ERTs), including intraarterial (IA) vasodilators and percutaneous transluminal balloon angioplasty, are the cornerstone of management. Although there are no randomized controlled trials assessing the efficacy of ERTs for DCI and their impact on subarachnoid hemorrhage outcomes, survey studies suggest that they are widely used in clinical practice with significant variability worldwide. IA vasodilators are first line ERTs, with better safety profiles and access to distal vasculature. The most commonly used IA vasodilators include calcium channel blockers, with milrinone gaining popularity in more recent publications. Balloon angioplasty achieves better vasodilation compared with IA vasodilators but is associated with higher risk of life-threatening vascular complications and is reserved for proximal severe refractory vasospasm. The existing literature on DCI rescue therapies is limited by small sample sizes, significant variability in patient populations, lack of standardized methodology, variable definitions of DCI, poorly reported outcomes, lack of long-term functional, cognitive, and patient-centered outcomes, and lack of control groups. Therefore, our current ability to interpret clinical results and make reliable recommendations regarding the use of rescue therapies is limited. This review summarizes existing literature on rescue therapies for DCI, provides practical guidance, and identifies future research needs.

One-Year Outcome Trajectories and Factors Associated with Functional Recovery Among Survivors of Intracerebral and Intraventricular Hemorrhage With Initial Severe Disability.

Importance: Patients who survive severe intracerebral hemorrhage (ICH) and intraventricular hemorrhage (IVH) typically have poor functional outcome in the short term and understanding of future recovery is limited. Objective: To describe 1-year recovery trajectories among ICH and IVH survivors with initial severe disability and assess the association of hospital events with long-term recovery. Design, Setting, and Participants: This post hoc analysis pooled all individual patient data from the Clot Lysis: Evaluating Accelerated Resolution of Intraventricular Hemorrhage phase 3 trial (CLEAR-III) and the Minimally Invasive Surgery Plus Alteplase for Intracerebral Hemorrhage Evacuation (MISTIE-III) phase 3 trial in multiple centers across the US, Canada, Europe, and Asia. Patients were enrolled from August 1, 2010, to September 30, 2018, with a follow-up duration of 1 year. Of 999 enrolled patients, 724 survived with a day 30 modified Rankin Scale score (mRS) of 4 to 5 after excluding 13 participants with missing day 30 mRS. An additional 9 patients were excluded because of missing 1-year mRS. The final pooled cohort included 715 patients (71.6%) with day 30 mRS 4 to 5. Data were analyzed from July 2019 to January 2022. Exposures: CLEAR-III participants randomized to intraventricular alteplase vs placebo. MISTIE-III participants randomized to stereotactic thrombolysis of hematoma vs standard medical care. Main Outcomes and Measures: Primary outcome was 1-year mRS. Patients were dichotomized into good outcome at 1 year (mRS 0 to 3) vs poor outcome at 1 year (mRS 4 to 6). Multivariable logistic regression models assessed associations between prospectively adjudicated hospital events and 1-year good outcome after adjusting for demographic characteristics, ICH and IVH severity, and trial cohort. Results: Of 715 survivors, 417 (58%) were male, and the overall mean (SD) age was 60.3 (11.7) years. Overall, 174 participants (24.3%) were Black, 491 (68.6%) were White, and 49 (6.9%) were of other races (including Asian, Native American, and Pacific Islander, consolidated owing to small numbers); 98 (13.7%) were of Hispanic ethnicity. By 1 year, 129 participants (18%) had died and 308 (43%) had achieved mRS 0 to 3. In adjusted models for the combined cohort, diabetes (adjusted odds ratio [aOR], 0.50; 95% CI, 0.26-0.96), National Institutes of Health Stroke Scale (aOR, 0.93; 95% CI, 0.90-0.96), severe leukoaraiosis (aOR, 0.30; 95% CI, 0.16-0.54), pineal gland shift (aOR, 0.87; 95% CI, 0.76-0.99]), acute ischemic stroke (aOR, 0.44; 95% CI, 0.21-0.94), gastrostomy (aOR, 0.30; 95% CI, 0.17-0.50), and persistent hydrocephalus by day 30 (aOR, 0.37; 95% CI, 0.14-0.98) were associated with lack of recovery. Resolution of ICH (aOR, 1.82; 95% CI, 1.08-3.04) and IVH (aOR, 2.19; 95% CI, 1.02-4.68) by day 30 were associated with recovery to good outcome. In the CLEAR-III model, cerebral perfusion pressure less than 60 mm Hg (aOR, 0.30; 95% CI, 0.13-0.71), sepsis (aOR, 0.05; 95% CI, 0.00-0.80), and prolonged mechanical ventilation (aOR, 0.96; 95% CI, 0.92-1.00 per day), and in MISTIE-III, need for intracranial pressure monitoring (aOR, 0.35; 95% CI, 0.12-0.98), were additional factors associated with poor outcome. Thirty-day event-based models strongly predicted 1-year outcome (area under the receiver operating characteristic curve [AUC], 0.87; 95% CI, 0.83-0.90), with significantly improved discrimination over models using baseline severity factors alone (AUC, 0.76; 95% CI, 0.71-0.80; P < .001). Conclusions and Relevance: Among survivors of severe ICH and IVH with initial poor functional outcome, more than 40% recovered to good outcome by 1 year. Hospital events were strongly associated with long-term functional recovery and may be potential targets for intervention. Avoiding early pessimistic prognostication and delaying prognostication until after treatment may improve ability to predict future recovery.

Regional Variability in the Care and Outcomes of Subarachnoid Hemorrhage Patients in the United States.

Background and Objectives: Regional variability in subarachnoid hemorrhage (SAH) care is reported in physician surveys. We aimed to describe variability in SAH care using patient-level data and identify factors impacting hospital outcomes and regional variability in outcomes. Methods: A retrospective multi-center cross-sectional cohort study of consecutive non-traumatic SAH patients in the Vizient Clinical Data Base, between January 1st, 2009 and December 30th, 2018 was performed. Participating hospitals were divided into US regions: Northeast, Midwest, South, West. Regional demographics, co-morbidities, severity-of-illness, complications, interventions and discharge outcomes were compared. Multivariable logistic regression was performed to identify factors independently associated with primary outcomes: hospital mortality and poor discharge outcome. Poor discharge outcome was defined by the Nationwide Inpatient Sample-SAH Outcome Measure, an externally-validated outcome measure combining death, discharge disposition, tracheostomy and/or gastrostomy. Regional variability in the associations between care and outcomes were assessed by introducing an interaction term for US region into the models. Results: Of 109,034 patients included, 24.3% were from Northeast, 24.9% Midwest, 34.9% South, 15.9% West. Mean (SD) age was 58.6 (15.6) years and 64,245 (58.9%) were female. In-hospital mortality occurred in 21,991 (20.2%) and 44,159 (40.5%) had poor discharge outcome. There was significant variability in severity-of-illness, co-morbidities, complications and interventions across US regions. Notable findings were higher prevalence of surgical clipping (18.8 vs. 11.6%), delayed cerebral ischemia (4.3 vs. 3.1%), seizures (16.5 vs. 14.8%), infections (18 vs. 14.7%), length of stay (mean [SD] days; 15.7 [19.2] vs. 14.1 [16.7]) and health-care direct costs (mean [SD] USD; 80,379 [98,999]. vs. 58,264 [74,430]) in the West when compared to other regions (all p < 0.0001). Variability in care was also associated with modest variability in hospital mortality and discharge outcome. Aneurysm repair, nimodipine use, later admission-year, endovascular rescue therapies reduced the odds for poor outcome. Age, severity-of-illness, co-morbidities, hospital complications, and vasopressor use increased those odds (c-statistic; mortality: 0.77; discharge outcome: 0.81). Regional interaction effect was significant for admission severity-of-illness, aneurysm-repair and nimodipine-use. Discussion: Multiple hospital-care factors impact SAH outcomes and significant variability in hospital-care and modest variability in discharge-outcomes exists across the US. Variability in SAH-severity, nimodipine-use and aneurysm-repair may drive variability in outcomes.