Structural Brain Injury on Brain Magnetic Resonance Imaging in Acute Respiratory Distress Syndrome.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is an acute inflammatory respiratory failure condition that may be associated with brain injury. We aimed to describe the types of structural brain injuries detected by brain magnetic resonance imaging (MRI) among patients with ARDS. METHODS: We retrospectively reviewed and collected data on brain injuries as detected by brain MRI during index hospitalization of all patients with ARDS at a single tertiary center in the United States from January 2010 to October 2018 (pre-COVID era). Structural brain injuries were classified as cerebral ischemia (ischemic infarct and hypoxic-ischemic brain injury) or cerebral hemorrhage (intraparenchymal hemorrhage, cerebral microbleeds, subarachnoid hemorrhage, and subdural hematoma). Descriptive statistics were conducted. RESULTS: Of the 678 patients with ARDS, 66 (9.7%) underwent brain MRI during their ARDS illness. The most common indication for brain MRI was encephalopathy (45.4%), and the median time from hospital admission to MRI was 10 days (interquartile range 4-17). Of 66 patients, 29 (44%) had MRI evidence of brain injury, including cerebral ischemia in 33% (22 of 66) and cerebral hemorrhage in 21% (14 of 66). Among those with cerebral ischemia, common findings were bilateral globus pallidus infarcts (n = 7, 32%), multifocal infarcts (n = 5, 23%), and diffuse hypoxic-ischemic brain injury (n = 3, 14%). Of those with cerebral hemorrhage, common findings were cerebral microbleeds (n = 12, 86%) and intraparenchymal hemorrhage (n = 2, 14%). Patients with ARDS with cerebral hemorrhage had significantly greater use of rescue therapies, including prone positioning (28.6% vs. 5.8%, p = 0.03), inhaled vasodilator (35.7% vs. 11.5%, p = 0.046), and recruitment maneuver (14.3% vs. 0%, p = 0.04). CONCLUSIONS: Structural brain injury was not uncommon among selected patients with ARDS who underwent brain MRI. The majority of brain injuries seen were bilateral globus pallidus infarcts and cerebral microbleeds.

Cerebral microbleeds in acute respiratory distress syndrome.

BACKGROUND: Cerebral microbleeds (CMB) have been observed in patients with critical illness. We sought to examine the frequency of CMB in patients with acute respiratory distress syndrome (ARDS) and association with neurologic complications including acute cerebral ischemia and seizures. METHODS: A retrospective review of patients with ARDS from January 2010 to October 2018 was performed. Patients with brain MRIs with susceptibility weighted imaging or gradient echo sequences were included. We compared neurologic complications and intensive care unit outcomes between patients with and without CMB. Cerebral small vessel disease (CSVD) was defined as the presence of CMB, lacunar infarcts, enlarged perivascular spaces, and white matter hyperintensities. RESULTS: Of 678 patients with ARDS, 61 met inclusion criteria. Median age was 54 years (IQR 42-63) and 28 were males. Of 12 (20%) with CMB, 10 had lobar CMB. Four patients had CMB in the corpus callosum, all involving the splenium. Neurologic complications were more common in those with CMB including acute cerebral ischemia (41.7% versus 10.2%, p=0.008) and seizures (33.3% versus 8.2%, p=0.021). ARDS rescue therapies were more commonly used in patients with CMB (p=0.005). There was no difference in hospital mortality (41.7% versus 34.7%, p=0.652). Patients with CMB did not have a higher CSVD score than those without CMB when accounting for the presence of CMB (median=1 versus 0, p=0.891). CONCLUSION: CMB were present in twenty percent of patients with ARDS who had MRI and were more commonly seen in patients requiring ARDS rescue therapies.

MRI of Cerebrovascular Injury Associated With COVID-19 and Non-COVID-19 Acute Respiratory Distress Syndrome: A Matched Case-Control Study.

OBJECTIVES: Cerebrovascular injury associated with COVID-19 has been recognized, but the mechanisms remain uncertain. Acute respiratory distress syndrome (ARDS) is a severe pulmonary injury, which is associated with both ischemic and hemorrhagic stroke. It remains unclear if cerebrovascular injuries associated with severe COVID-19 are unique to COVID-19 or a consequence of severe respiratory disease or its treatment. The frequency and patterns of cerebrovascular injury on brain MRI were compared among patients with COVID-19 ARDS and non-COVID-19 ARDS. DESIGN: A case-control study. SETTING: A tertiary academic hospital system. PATIENTS: Adult patients (>18 yr) with COVID-19 ARDS (March 2020 to July 2021) and non-COVID-19 ARDS (January 2010-October 2018) who underwent brain MRI during their index hospitalization. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Cerebrovascular injury on MRI included cerebral ischemia (ischemic infarct or hypoxic ischemic brain injury) and intracranial hemorrhage (intraparenchymal, subarachnoid, or subdural, and cerebral microbleed [CMB]).Twenty-six patients with COVID-19 ARDS and sixty-six patients with non-COVID ARDS underwent brain MRI during the index hospitalization, resulting in 23 age- and sex-matched pairs. The frequency of overall cerebrovascular injury (57% vs 61%), cerebral ischemia (35% vs 43%), intracranial hemorrhage (43% vs 48%), and CMB (52% vs 41%) between COVID-19 ARDS and non-COVID-19 ARDS patients was similar (all p values >0.05). However, four of 26 patients (15%) with COVID-19 and no patients with non-COVID-19 ARDS had disseminated leukoencephalopathy with underlying CMBs, an imaging pattern that has previously been reported in patients with COVID-19. CONCLUSIONS: In a case-control study of selected ARDS patients with brain MRI, the frequencies of ischemic and hemorrhagic cerebrovascular injuries were similar between COVID-19 versus non-COVID-19 ARDS patients. However, the MRI pattern of disseminated hemorrhagic leukoencephalopathy was unique to the COVID-19 ARDS patients in this cohort.

Implications of Causes of Intracranial Hemorrhage During Left Ventricular Assist Device Support.

BACKGROUND: Intracranial hemorrhage (ICH) is a frequent complication in patients with an implanted left ventricular assist device (LVAD) for advanced heart failure. Bloodstream infection is known to be associated with ICH in patients with LVAD, but its effects on ICH-associated mortality are unknown. We compared characteristics and mortality of infection-associated, traumatic, and spontaneous hemorrhages. METHODS: Patients in an LVAD registry at a tertiary care center were reviewed for this cohort study. ICH included intraparenchymal hemorrhage, subarachnoid hemorrhage, and subdural hemorrhage. Hemorrhages were categorized into infectious, traumatic, and spontaneous by the presence or absence of concurrent device-associated infection or antecedent trauma. RESULTS: Of 683 patients with an LVAD, 73 experienced ICH (10.7%). Intraparenchymal hemorrhage was the most prevalent (72%), followed by subarachnoid hemorrhage (27%) and subdural hemorrhage (23%), with multiple concurrent hemorrhage subtypes in 16 patients (22%). Median time from implantation to ICH was shorter in spontaneous ICH than in infection-associated ICH (100 days vs. 252 days, p = 0.048). The prevalence of the different subtypes of ICH were similar between spontaneous and infection-associated ICH, and no differences were seen in mortality between the different causes of ICH. CONCLUSIONS: Although spontaneous ICH occurred earlier after LVAD implantation than infection-associated ICH, no difference in mortality was seen between the different causes of ICH.

Prevalence and Outcome of Acute Respiratory Distress Syndrome in Traumatic Brain Injury: A Systematic Review and Meta-Analysis.

OBJECTIVES: Acute respiratory distress syndrome (ARDS) in patients with traumatic brain injury (TBI) is associated with increased mortality. Information on the prevalence of ARDS and its neurological outcome after TBI is sparse. We aimed to systematically review the prevalence, risk factors, and outcome of ARDS in TBI population. DATA SOURCES: PubMed and four other databases (Embase, Cochrane Library, Web of Science Core Collection, and Scopus) from inception to July 6, 2020. STUDY SELECTION: Randomized controlled trials (RCTs) and observational studies in patients older than 18 years old. DATA EXTRACTION: Two independent reviewers extracted the data. Study quality was assessed by the Cochrane Risk of Bias tool for RCTs, the Newcastle-Ottawa Scale for cohort and case-control studies. Good neurological outcome was defined as Glasgow Outcome Scale ≥ 4. Random-effects meta-analyses were conducted to estimate pooled outcome prevalence and their 95% confidence intervals (CI). DATA SYNTHESIS: We included 20 studies (n = 2830) with median age of 44 years (interquartile range [IQR] = 35-47, 64% male) and 79% (n = 2237) suffered severe TBI. In meta-analysis, 19% patients (95% CI = 0.13-0.27, I2 = 93%) had ARDS after TBI. The median time from TBI to ARDS was 3 days (IQR = 2-5). Overall survival at discharge for the TBI cohort was 70% (95% CI = 0.64-0.75; I2 = 85%) and good neurological outcome at any time was achieved in 31% of TBI patients (95% CI = 0.23-0.40; I2 = 88%). TBI cohort without ARDS had higher survival (67% vs. 57%, p = 0.01) and good neurological outcomes (34% vs. 23%, p = 0.02) compared to those with ARDS. We did not find any specific risk factors for developing ARDS. CONCLUSION: In this meta-analysis, approximately one in five patients had ARDS shortly after TBI with the median time of 3 days. The presence of ARDS was associated with worse neurological outcome and mortality in TBI. Further research on prevention and intervention strategy of TBI-associated ARDS is warranted.

Pathophysiology of Brain Injury and Neurological Outcome in Acute Respiratory Distress Syndrome: A Scoping Review of Preclinical to Clinical Studies.

Acute respiratory distress syndrome (ARDS) has been associated with secondary acute brain injury (ABI). However, there is sparse literature on the mechanism of lung-mediated brain injury and prevalence of ARDS-associated secondary ABI. We aimed to review and elucidate potential mechanisms of ARDS-mediated ABI from preclinical models and assess the prevalence of ABI and neurological outcome in ARDS with clinical studies. We conducted a systematic search of PubMed and five other databases reporting ABI and ARDS through July 6, 2020 and included studies with ABI and neurological outcome occurring after ARDS. We found 38 studies (10 preclinical studies with 143 animals; 28 clinical studies with 1175 patients) encompassing 9 animal studies (n = 143), 1 in vitro study, 12 studies on neurocognitive outcomes (n = 797), 2 clinical observational studies (n = 126), 1 neuroimaging study (n = 15), and 13 clinical case series/reports (n = 15). Six ARDS animal studies demonstrated evidence of neuroinflammation and neuronal damage within the hippocampus. Five animal studies demonstrated altered cerebral blood flow and increased intracranial pressure with the use of lung-protective mechanical ventilation. High frequency of ARDS-associated secondary ABI or poor neurological outcome was observed ranging 82-86% in clinical observational studies. Of the clinically reported ABIs (median age 49 years, 46% men), the most common injury was hemorrhagic stroke (25%), followed by hypoxic ischemic brain injury (22%), diffuse cerebral edema (11%), and ischemic stroke (8%). Cognitive impairment in patients with ARDS (n = 797) was observed in 87% (range 73-100%) at discharge, 36% (range 32-37%) at 6 months, and 30% (range 25-45%) at 1 year. Mechanisms of ARDS-associated secondary ABI include primary hypoxic ischemic injury from hypoxic respiratory failure, secondary injury, such as lung injury induced neuroinflammation, and increased intracranial pressure from ARDS lung-protective mechanical ventilation strategy. In summary, paucity of clinical data exists on the prevalence of ABI in patients with ARDS. Hemorrhagic stroke and hypoxic ischemic brain injury were commonly observed. Persistent cognitive impairment was highly prevalent in patients with ARDS.

Neurologic complications of COVID-19.

Patients with COVID-19 have a fairly high risk of neurologic complications, including encephalopathy, stroke, central nervous system infection, seizures, and neuromuscular diseases. Many report losing their senses of smell and taste, and many survivors report lingering neurocognitive impairment. The diagnosis and treatment of these complications does not differ from that in other patients, although sophisticated testing may not be readily available for a patient in intensive care and respiratory isolation. Clinicians should therefore be alert to these complications.

Acute ischemic stroke and COVID-19.

Ischemic stroke may be a presenting feature of COVID-19. Its etiology remains unclear, but severe COVID-19 disease might increase the risk of large-artery strokes. More evidence is needed to substantiate the current reports and provide insights for optimal management.

Intracerebral Hemorrhage in a Young Urban Population: Etiologies and Outcomes in Patients 50 and Younger.

GOAL: There is limited research on intracerebral hemorrhage in young urban populations. There is reduced access to healthcare and a high prevalence of multiple comorbidities in this vulnerable population. We studied the etiologies and outcomes of spontaneous intracerebral hemorrhage in an urban North Philadelphia cohort aged 50 years old and younger. MATERIALS AND METHODS: A retrospective chart review of subjects 50 years old and younger who presented with spontaneous intracerebral hemorrhage at Temple University Hospital was conducted. A novel scoring system was used to classify the cause of each intracerebral hemorrhage. This system was used to assign a degree of likelihood that hypertension, amyloid angiopathy, tumor, oral anticoagulants, vascular malformations, infrequent causes, or cryptogenic etiologies were present. Aneurysmal subarachnoid hemorrhage was excluded. The prevalence of each risk factor and outcomes were analyzed. FINDINGS: Of the 110 patients in the study, the most common etiology was hypertension (82.7%). There was no statistically significant difference in mortality between patients with multiple possible etiologies for their hemorrhage. Vascular malformations and cavernomas were rare (5.5%). CONCLUSIONS: Hypertension was the most common cause of intracerebral hemorrhage in a young urban population. The presence of multiple possible etiologies does not correlate with a worse prognosis of mortality. There is a need for further research into hemorrhagic stroke in young populations.