Neurocritical care
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Delayed cerebral ischemia after subarachnoid hemorrhage (SAH) may be affected by a number of factors, including cerebral blood flow and oxygen delivery. Anemia affects about half of patients with SAH and is associated with worse outcome. Anemia also may contribute to the development of or exacerbate delayed cerebral ischemia. ⋯ The effects may vary with disease severity or the presence of vasospasm, but it remains unclear whether RBCTs are a marker of disease severity or a cause of worse outcome. Erythropoietin data are limited. The literature review further suggests that the results of the Transfusion Requirements in Critical Care Trial and subsequent observational studies on RBCT in general critical care do not apply to SAH patients and that randomized trials to address the role of RBCT in SAH are required.
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Disruption of the hypothalamic-pituitary-adrenal axes may occur after aneurysmal subarachnoid hemorrhage, resulting in hypopituitarism. An electronic literature search was conducted to identify articles with English-language abstracts published between 1980 and March 2011, which addressed hypothalamic-pituitary-adrenal axis insufficiency and hormone replacement. A total of 18 observational and prospective, randomized studies were selected for this review. ⋯ Overall, after acute subarachnoid hemorrhage, cortisol levels may initially be supranormal, decreasing toward normal levels over time. During the months to years after subarachnoid hemorrhage, pituitary deficiency may occur in one out of three patients. Limited data suggest modest outcome benefits with fludrocortisone and no benefit or harm from corticosteroids.
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Although clinicians are generally advised to use prophylactic therapy to reduce the risk for developing deep venous thrombosis in patients after repair of ruptured aneurysms, limited data are available to guide specific therapeutic decisions. An electronic literature search was conducted to identify English-language articles that addressed prophylactic treatment for deep venous thrombosis after subarachnoid hemorrhage published between 1980 and March 2011. A total of 12 articles were included in this review, including seven original research studies and one meta-analysis. ⋯ Unfractionated heparin is moderately effective but carries a small risk of intracranial hemorrhage. Low molecular weight heparin has been linked to an increased risk for intracranial hemorrhage. Limited data are available to direct the timing and duration of prophylactic therapies.
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Magnesium offers theoretic vascular and neuroprotective benefits for patients with subarachnoid hemorrhage. An electronic literature search was conducted to identify original research studies describing intravenous magnesium treatment in patients with SAH published in English between January 1990 and October 2010. ⋯ Due to inconsistently reported benefits and the occurrence of side effects, phase II data suggested that intravenous magnesium for SAH provided either no overall net benefit or uncertain trade-offs. Benefit was likewise not supported in the single phase III clinical trial.
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Delayed cerebral ischemia occurs in about 30% of patients during the first 2 weeks after subarachnoid hemorrhage, and can result in substantial disability and death. Research studies investigating the incidence of delayed cerebral ischemia and strategies for prevention and treatment are hampered by inconsistent use of terminology and definitions for this complication, and by reliance on indirect surrogate markers of ischemia. ⋯ Original research studies and consensus panel recommendations for definitions support limiting the use of combined measures that include both clinical and radiographic assessments, as well as indirect measures, and the current usage of the term vasospasm. Cerebral infarction was supported as the most appropriate definition for delayed cerebral ischemia in the context of clinical trials.