Cerebral Edema Monitoring and Management Strategies: Results from an International Practice Survey.

BACKGROUND: Cerebral edema is a common, potentially life-threatening complication in critically ill patients with acute brain injury. However, uncertainty remains regarding best monitoring and treatment strategies, which may result in wide practice variations. METHODS: A 20-question digital survey on monitoring and management practices was disseminated between July 2022 and May 2023 to clinicians who manage cerebral edema. The survey was promoted through email, social media, medical conferences, and the Neurocritical Care Society Web site. We used the χ2 test, Fisher's exact test, analysis of variance, and logistic regression to report factors associated with practice variation, diagnostic monitoring methods, and therapeutic triggers based on practitioner and institutional characteristics. RESULTS: Of 321 participants from 160 institutions in 30 countries, 65% were from university-affiliated centers, 74% were attending physicians, 38% were woman, 38% had neurology training, and 55% were US-based. Eighty-four percent observed practice variations at their institutions, with "provider preference" being cited most (87%). Factors linked to variation included gender, experience, university affiliation, and practicing outside the United States. University affiliates tended to use more tests (median 3.87 vs. 3.43, p = 0.01) to monitor cerebral edema. Regarding management practices, 20% of respondents' preferred timing for decompressive hemicraniectomy was after 48 h, and 37% stated that radiographic findings only would be sufficient to trigger surgery. Fifty percent of respondents reported initiating osmotic therapy based on radiographic indications or prophylactically. There were no significant associations between management strategies and respondent or center characteristics. Twenty-seven percent of respondents indicated that they acquired neuroimaging at intervals of 24 h or less. Within this group, attending physicians were more likely to follow this practice (65.5% vs. 34.5%, p = 0.04). CONCLUSIONS: Cerebral edema monitoring and management strategies vary. Features associated with practice variations include both practitioner and institutional characteristics. We provide a foundation for understanding practice patterns that is crucial for informing educational initiatives, standardizing guidelines, and conducting future trials.

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.

COVID-19 and Cerebrovascular Disease.

COVID-19 has been associated with numerous neurological complications, with acute cerebrovascular disease being one of the most devastating complications. Ischemic stroke is the most common cerebrovascular complication of COVID-19, affecting between 1 and 6% of all patients. Underlying mechanisms for COVID-related ischemic strokes are thought to be due to vasculopathy, endotheliopathy, direct invasion of the arterial wall, and platelet activation. Other COVID-19-associated cerebrovascular complications include hemorrhagic stroke, cerebral microbleeds, posterior reversible encephalopathy syndrome, reversible cerebral vasoconstriction syndrome, cerebral venous sinus thrombosis, and subarachnoid hemorrhage. This article discusses the incidence of these cerebrovascular complications, risk factors, management strategies, prognosis and future research directions, as well as considerations in pregnancy-related cerebrovascular events in the setting of COVID-19.

2023 Guideline for the Management of Patients With Aneurysmal Subarachnoid Hemorrhage: A Guideline From the American Heart Association/American Stroke Association.

AIM: The "2023 Guideline for the Management of Patients With Aneurysmal Subarachnoid Hemorrhage" replaces the 2012 "Guidelines for the Management of Aneurysmal Subarachnoid Hemorrhage." The 2023 guideline is intended to provide patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with aneurysmal subarachnoid hemorrhage. METHODS: A comprehensive search for literature published since the 2012 guideline, derived from research principally involving human subjects, published in English, and indexed in MEDLINE, PubMed, Cochrane Library, and other selected databases relevant to this guideline, was conducted between March 2022 and June 2022. In addition, the guideline writing group reviewed documents on related subject matter previously published by the American Heart Association. Newer studies published between July 2022 and November 2022 that affected recommendation content, Class of Recommendation, or Level of Evidence were included if appropriate. Structure: Aneurysmal subarachnoid hemorrhage is a significant global public health threat and a severely morbid and often deadly condition. The 2023 aneurysmal subarachnoid hemorrhage guideline provides recommendations based on current evidence for the treatment of these patients. The recommendations present an evidence-based approach to preventing, diagnosing, and managing patients with aneurysmal subarachnoid hemorrhage, with the intent to improve quality of care and align with patients' and their families' and caregivers' interests. Many recommendations from the previous aneurysmal subarachnoid hemorrhage guidelines have been updated with new evidence, and new recommendations have been created when supported by published data.

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.

Household income is associated with functional outcomes in a multi-institutional cohort of patients with ischemic stroke and COVID-19.

OBJECTIVES: The COVID-19 pandemic has heightened awareness of health disparities associated with socioeconomic status (SES) across the United States. We examined whether household income is associated with functional outcomes after stroke and COVID-19. MATERIALS AND METHODS: This was a multi-institutional, retrospective cohort study of consecutively hospitalized patients with SARS-CoV-2 and radiographically confirmed stroke presenting from March through November 2020 to any of five comprehensive stroke centers in metropolitan Chicago, Illinois, USA. Zip-code-derived household income was dichotomized at the Chicago median. Logistic regression was used to examine the relationship between household income and good functional outcome (modified Rankin Scale 0-3 at discharge, after ischemic stroke). RESULTS: Across five hospitals, 159 patients were included. Black patients comprised 48.1%, White patients 38.6%, and Hispanic patients 27.7%. Median household income was $46,938 [IQR: $32,460-63,219]. Ischemic stroke occurred in 115 (72.3%) patients (median NIHSS 7, IQR: 0.5-18.5) and hemorrhagic stroke in 37 (23.7%). When controlling for age, sex, severe COVID-19, and NIHSS, patients with ischemic stroke and household income above the Chicago median were more likely to have a good functional outcome at discharge (OR 7.53, 95% CI 1.61 - 45.73; P=0.016). Race/ethnicity were not included in final adjusted models given collinearity with income. CONCLUSIONS: In this multi-institutional study of hospitalized patients with stroke, those residing in higher SES zip codes were more likely to have better functional outcomes, despite controlling for stroke severity and COVID-19 severity. This suggests that area-based SES factors may play a role in outcomes from stroke and COVID-19.

Consensus Clinical Guidance for Diagnosis and Management of Adult COVID-19 Encephalopathy Patients.

Encephalopathy, a common condition among patients hospitalized with COVID-19, can be a challenge to manage and negatively affect prognosis. While encephalopathy may present clinically as delirium, subsyndromal delirium, or coma and may be a result of systemic causes such as hypoxia, COVID-19 has also been associated with more prolonged encephalopathy due to less common but nevertheless severe complications, such as inflammation of the brain parenchyma (with or without cerebrovascular involvement), demyelination, or seizures, which may be disproportionate to COVID-19 severity and require specific management. Given the large number of patients hospitalized with severe acute respiratory syndrome coronavirus-2 infection, even these relatively unlikely complications are increasingly recognized and are particularly important because they require specific management. Therefore, the aim of this review is to provide pragmatic guidance on the management of COVID-19 encephalopathy through consensus agreement of the Global COVID-19 Neuro Research Coalition. A systematic literature search of MEDLINE, medRxiv, and bioRxiv was conducted between January 1, 2020, and June 21, 2021, with additional review of references cited within the identified bibliographies. A modified Delphi approach was then undertaken to develop recommendations, along with a parallel approach to score the strength of both the recommendations and the supporting evidence. This review presents analysis of contemporaneous evidence for the definition, epidemiology, and pathophysiology of COVID-19 encephalopathy and practical guidance for clinical assessment, investigation, and both acute and long-term management.

Impact of COVID-19 on neurocritical care delivery and outcomes in patients with severe acute brain injury - Assessing the initial response in the first US epicenter.

To investigate the pandemic's impact on critically ill patients with neurological emergencies, we compared care metrics and outcomes of patients with severe acute brain injury (SABI) before and during the initial COVID-19 surge at our institution. We included adult patients with SABI during two separate three-month time periods: 'pre-COVID vs COVID'. We further stratified the COVID cohort to characterize outcomes in patients requiring COVID-19 precautions (Patient Under Investigation, 'PUI'). The primary endpoint was in-hospital mortality; secondary endpoints included length of stay (LOS), diagnostic studies performed, time to emergent decompressive craniectomies (DCHC), ventilator management, and end-of-life care. We included 394 patients and found the overall number of admissions for SABI declined by 29 % during COVID (pre-COVID n = 231 vs COVID, n = 163). Our primary outcome of mortality and most secondary outcomes were similar between study periods. There were more frequent extubation attempts (72.1 % vs 76 %) and the mean time to extubation was shorter during COVID (55.5 h vs 38.2 h). The ICU LOS (6.10 days vs 4.69 days) and hospital LOS (15.32 days vs 11.74 days) was shorter during COVID. More PUIs died than non-PUIs (51.7 % vs 11.2 %), but when adjusted for markers of illness severity, this was not significant. We demonstrate the ability to maintain a consistent care delivery for patients with SABI during the pandemic at our institution. PUIs represent a population with higher illness severity at risk for delays in care. Multicenter, longitudinal studies are needed to explore the impact of the pandemic on patients with acute neurological emergencies.

Prevalence and risk factors of sleep disturbance in adults with underlying health conditions during the ongoing COVID-19 pandemic.

To determine the prevalence of sleep disturbance during the coronavirus disease 2019 (COVID-19) pandemic among US adults who are more vulnerable to complications because of age and co-morbid conditions, and to identify associated sociodemographic and psychosocial factors. Cross-sectional survey linked to 3 active clinical trials and 2 cohort studies, conducted between 11/30/2020 and 3/3/2021. Five academic internal medicine practices and 2 federally qualified health centers. A total of 715 adults ages 23 to 91 years living with one or more chronic conditions. A fifth (20%) of participants reported poor sleep. Black adults were twice as likely to report poor sleep compared to Whites. Self-reported poor physical function (51%), stress (42%), depression (28%), and anxiety (36%) were also common and all significantly associated with poor sleep. Age ≥70 years and having been vaccinated for COVID-19 were protective against poor sleep. Sex, education, income, alcohol use, and employment status were not significantly associated with sleep quality. In this diverse sample of adults with chronic conditions, by race, ethnicity, and socioeconomic status, disparities in sleep health amid the ongoing pandemic were apparent. Worse physical function and mental health were associated with poor sleep and should be considered targets for health system interventions to prevent the many subsequent consequences of disturbed sleep on health outcomes. Measurements: self-reported sleep quality, physical function, stress, depression, and anxiety.

Persistent viral RNA shedding of SARS-CoV-2 is associated with delirium incidence and six-month mortality in hospitalized COVID-19 patients.

BACKGROUND: Persistent viral RNA shedding of SARS-CoV-2 following COVID-19 has increasingly been recognized, with limited understanding of its implications on outcomes in hospitalized COVID-19 patients. METHODS: We retrospectively assessed for persistent viral shedding across Northwestern Medicine Healthcare (NMHC) patients between March and August 2020. We assessed for predictors of persistent viral shedding, in-hospital delirium, and six-month mortality using binary logistic regression. RESULTS: Of the 2,518 hospitalized patients with an RT-PCR-confirmed diagnosis of COVID-19, 959 underwent repeat SARS-CoV-2 RT-PCR at least fourteen days from initial positive testing. Of those, 405 (42.2%) patients were found to have persistent viral shedding. Persistent viral shedding was associated with male sex, increased BMI, diabetes mellitus, chronic kidney disease, and exposure to corticosteroids during initial COVID-19 hospitalization. Persistent viral shedding was independently associated with incidence of in-hospital delirium after adjusting for factors including severity of respiratory dysfunction (OR 2.45; 95% CI 1.75, 3.45). Even after adjusting for age, severity of respiratory dysfunction, and occurrence of in-hospital delirium, persistent viral shedding remained significantly associated with increased six-month mortality (OR 2.43; 95% CI 1.42, 4.29). CONCLUSIONS: Persistent viral shedding occurs frequently in hospitalized COVID-19 patients and is associated with in-hospital delirium and increased six-month mortality.

Perceptions Regarding the SARS-CoV-2 Pandemic's Impact on Neurocritical Care Delivery: Results From a Global Survey.

BACKGROUND: The SARS-CoV-2 (COVID-19) pandemic has impacted many facets of critical care delivery. METHODS: An electronic survey was distributed to explore the pandemic's perceived impact on neurocritical care delivery between June 2020 and March 2021. Variables were stratified by World Bank country income level, presence of a dedicated neurocritical care unit (NCCU) and experiencing a COVID-19 patient surge. RESULTS: Respondents from 253 hospitals (78.3% response rate) from 47 countries (45.5% low/middle income countries; 54.5% with a dedicated NCCU; 78.6% experienced a first surge) participated in the study. Independent of country income level, NCCU and surge status, participants reported reductions in NCCU admissions (67%), critical care drug shortages (69%), reduction in ancillary services (43%) and routine diagnostic testing (61%), and temporary cancellation of didactic teaching (44%) and clinical/basic science research (70%). Respondents from low/middle income countries were more likely to report lack of surge preparedness (odds ratio [OR], 3.2; 95% confidence interval [CI], 1.8-5.8) and struggling to return to prepandemic standards of care (OR, 12.2; 95% CI, 4.4-34) compared with respondents from high-income countries. Respondents experiencing a surge were more likely to report conversion of NCCUs and general-mixed intensive care units (ICUs) to a COVID-ICU (OR 3.7; 95% CI, 1.9-7.3), conversion of non-ICU beds to ICU beds (OR, 3.4; 95% CI, 1.8-6.5), and deviations in critical care and pharmaceutical practices (OR, 4.2; 95% CI 2.1-8.2). Respondents from hospitals with a dedicated NCCU were less likely to report conversion to a COVID-ICU (OR, 0.5; 95% CI, 0.3-0.9) or conversion of non-ICU to ICU beds (OR, 0.5; 95% CI, 0.3-0.9). CONCLUSION: This study reports the perceived impact of the COVID-19 pandemic on global neurocritical care delivery, and highlights shortcomings of health care infrastructures and the importance of pandemic preparedness.

Proceedings of the First Curing Coma Campaign NIH Symposium: Challenging the Future of Research for Coma and Disorders of Consciousness.

Coma and disorders of consciousness (DoC) are highly prevalent and constitute a burden for patients, families, and society worldwide. As part of the Curing Coma Campaign, the Neurocritical Care Society partnered with the National Institutes of Health to organize a symposium bringing together experts from all over the world to develop research targets for DoC. The conference was structured along six domains: (1) defining endotype/phenotypes, (2) biomarkers, (3) proof-of-concept clinical trials, (4) neuroprognostication, (5) long-term recovery, and (6) large datasets. This proceedings paper presents actionable research targets based on the presentations and discussions that occurred at the conference. We summarize the background, main research gaps, overall goals, the panel discussion of the approach, limitations and challenges, and deliverables that were identified.

Clinical review of cerebral venous thrombosis in the context of COVID-19 vaccinations: Evaluation, management, and scientific questions.

BACKGROUND: Vaccine induced immune mediated thrombocytopenia or VITT, is a recent and rare phenomenon of thrombosis with thrombocytopenia, frequently including cerebral venous thromboses (CVT), that has been described following vaccination with adenovirus vaccines ChAdOx1 nCOV-19 (AstraZeneca) and Ad26.COV2·S Johnson and Johnson (Janssen/J&J). The evaluation and management of suspected cases of CVT post COVID-19 vaccination are critical skills for a broad range of healthcare providers. METHODS: A collaborative comprehensive review of literature was conducted among a global group of expert neurologists and hematologists. FINDINGS: Strategies for rapid evaluation and treatment of the CVT in the context of possible VITT exist, including inflammatory marker measurements, PF4 assays, and non-heparin anticoagulation.

CSF lipocalin-2 increases early in subarachnoid hemorrhage are associated with neuroinflammation and unfavorable outcome.

Lipocalin-2 mediates neuro-inflammation and iron homeostasis in vascular injuries of the central nervous system (CNS) and is upregulated in extra-CNS systemic inflammation. We postulate that cerebrospinal fluid (CSF) and blood lipocalin-2 levels are associated with markers of inflammation and functional outcome in subarachnoid hemorrhage (SAH). We prospectively enrolled 67 SAH subjects, serially measured CSF and plasma lipocalin-2, matrix metallopeptidase 9 (MMP-9), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) on post-SAH days 1-5 and assessed outcome by modified Rankin Scale (mRS) every 3 months. Unfavorable outcome is defined as mRS > 2. Twenty non-SAH patients undergoing lumbar drain trial were enrolled as controls. Lipocalin-2 was detectable in the CSF and significantly higher in SAH compared to controls (p < 0.0001). Higher CSF LCN2 throughout post-SAH days 1-5 was associated with unfavorable outcome at 3 (p = 0.0031) and 6 months (p = 0.014). Specifically, higher CSF lipocalin-2 on post-SAH days 3 (p = 0.036) and 5 (p = 0.016) were associated with unfavorable 3-month outcome. CSF lipocalin-2 levels positively correlated with CSF IL-6, TNF-α and MMP-9 levels. Higher plasma lipocalin-2 levels over time were associated with worse 6-month outcome. Additional studies are required to understand the role of lipocalin-2 in SAH and to validate CSF lipocalin-2 as a potential biomarker for SAH outcome.

Global Incidence of Neurological Manifestations Among Patients Hospitalized With COVID-19-A Report for the GCS-NeuroCOVID Consortium and the ENERGY Consortium.

Importance: The COVID-19 pandemic continues to affect millions of people globally, with increasing reports of neurological manifestations but limited data on their incidence and associations with outcome. Objective: To determine the neurological phenotypes, incidence, and outcomes among adults hospitalized with COVID-19. Design, Setting, and Participants: This cohort study included patients with clinically diagnosed or laboratory-confirmed COVID-19 at 28 centers, representing 13 countries and 4 continents. The study was performed by the Global Consortium Study of Neurologic Dysfunction in COVID-19 (GCS-NeuroCOVID) from March 1 to September 30, 2020, and the European Academy of Neurology (EAN) Neuro-COVID Registry (ENERGY) from March to October 2020. Three cohorts were included: (1) the GCS-NeuroCOVID all COVID-19 cohort (n = 3055), which included consecutive hospitalized patients with COVID-19 with and without neurological manifestations; (2) the GCS-NeuroCOVID COVID-19 neurological cohort (n = 475), which comprised consecutive patients hospitalized with COVID-19 who had confirmed neurological manifestations; and (3) the ENERGY cohort (n = 214), which included patients with COVID-19 who received formal neurological consultation. Exposures: Clinically diagnosed or laboratory-confirmed COVID-19. Main Outcomes and Measures: Neurological phenotypes were classified as self-reported symptoms or neurological signs and/or syndromes assessed by clinical evaluation. Composite incidence was reported for groups with at least 1 neurological manifestation. The main outcome measure was in-hospital mortality. Results: Of the 3055 patients in the all COVID-19 cohort, 1742 (57%) were men, and the mean age was 59.9 years (95% CI, 59.3-60.6 years). Of the 475 patients in the COVID-19 neurological cohort, 262 (55%) were men, and the mean age was 62.6 years (95% CI, 61.1-64.1 years). Of the 214 patients in the ENERGY cohort, 133 (62%) were men, and the mean age was 67 years (95% CI, 52-78 years). A total of 3083 of 3743 patients (82%) across cohorts had any neurological manifestation (self-reported neurological symptoms and/or clinically captured neurological sign and/or syndrome). The most common self-reported symptoms included headache (1385 of 3732 patients [37%]) and anosmia or ageusia (977 of 3700 patients [26%]). The most prevalent neurological signs and/or syndromes were acute encephalopathy (1845 of 3740 patients [49%]), coma (649 of 3737 patients [17%]), and stroke (222 of 3737 patients [6%]), while meningitis and/or encephalitis were rare (19 of 3741 patients [0.5%]). Presence of clinically captured neurologic signs and/or syndromes was associated with increased risk of in-hospital death (adjusted odds ratio [aOR], 5.99; 95% CI, 4.33-8.28) after adjusting for study site, age, sex, race, and ethnicity. Presence of preexisting neurological disorders (aOR, 2.23; 95% CI, 1.80-2.75) was associated with increased risk of developing neurological signs and/or syndromes with COVID-19. Conclusions and Relevance: In this multicohort study, neurological manifestations were prevalent among patients hospitalized with COVID-19 and were associated with higher in-hospital mortality. Preexisting neurological disorders were associated with increased risk of developing neurological signs and/or syndromes in COVID-19.

International Practice Variability in Treatment of Aneurysmal Subarachnoid Hemorrhage.

Prior research suggests substantial between-center differences in functional outcome following aneurysmal subarachnoid hemorrhage (aSAH). One hypothesis is that these differences are due to practice variability. To characterize practice variability, we sent a survey to 230 centers, of which 145 (63%) responded. Survey respondents indicated that an estimated 65% of ruptured aneurysms were treated endovascularly. Sixty-five percent of aneurysms were treated within 24 h of symptom onset, 18% within 24-48 h, and eight percent within 48-72 h. Centers in the United States (US) and Europe (EU) treat aneurysms more often endovascularly (72% and 70% vs. 51%, respectively, US vs. other p < 0.001, and EU vs. other p < 0.01) and more often within 24 h (77% and 64% vs. 46%, respectively, US vs. other p < 0.001, EU vs. other p < 0.01) compared to other centers. Most centers aim for euvolemia (96%) by administrating intravenous fluids to 0 (53%) or +500 mL/day (41%) net fluid balance. Induced hypertension is more often used in US centers (100%) than in EU (87%, p < 0.05) and other centers (81%, p < 0.05), and endovascular therapies for cerebral vasospasm are used more often in US centers than in other centers (91% and 60%, respectively, p < 0.05). We observed significant practice variability in aSAH treatment worldwide. Future comparative effectiveness research studies are needed to investigate how practice variation leads to differences in functional outcome.