Neurocritical care
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Delayed cerebral ischemia (DCI) after subarachnoid hemorrhage can be evaluated using clinical assessment, non-invasive and invasive techniques. An electronic literature search was conducted on English-language articles investigating DCI in human subjects with subarachnoid hemorrhage. A total of 31 relevant papers were identified evaluating the role of clinical assessment, transcranial Doppler, computed tomographic angiography, and computed tomographic perfusion. ⋯ Transcranial Doppler is a useful screening tool for middle cerebral artery vasospasm, with less utility in evaluating other intracranial vessels. Computed tomographic angiography correlates well with digital subtraction angiography. Computed tomographic perfusion may help predict DCI when used early or identify DCI when used later.
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Hemodynamic augmentation therapy is considered standard treatment to help prevent and treat vasospasm and delayed cerebral ischemia. Standard triple-H therapy combines volume expansion (hypervolemia), blood pressure augmentation (hypertension), and hemodilution. An electronic literature search was conducted of English-language papers published between 2000 and October 2010 that focused on hemodynamic augmentation therapies in patients with subarachnoid hemorrhage. ⋯ Overall, hypertension was associated with higher cerebral blood flow, regardless of volume status (normo- or hypervolemia), with neurological symptom reversal seen in two-thirds of treated patients. Limited data were available for evaluating inotropic agents or hemodynamic augmentation in patients with additional unsecured aneurysms. In the context of sparse data, no incremental risk of aneurysmal rupture has been reported with the induction of hemodynamic augmentation.
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Prophylactic use of hypervolemia and hypertension is believed to present an option to decrease the incidence of symptomatic vasospasm after aneurysmal subarachnoid hemorrhage and improve neurologic outcome. A Medline literature search was conducted to review available evidence regarding volume management after subarachnoid hemorrhage. Quality of selected studies was evaluated, using the standardized GRADE system. ⋯ Complication frequency was repeatedly reported to be higher with the application of prophylactic hypervolemia. In summary, prophylactic hyperdynamic therapy after subarachnoid hemorrhage has not been adequately shown to effectively raise cerebral blood flow or improve neurological outcome. In contrast, there is evidence for harm using overly aggressive hydration.
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Cerebral vasospasm and delayed cerebral ischemia account for significant morbidity and mortality after aneurysmal subarachnoid hemorrhage. While most patients are managed with triple-H therapy, endovascular treatments have been used when triple-H treatment cannot be used or is ineffective. An electronic literature search was conducted to identify English language articles published through October 2010 that addressed endovascular management of vasospasm. ⋯ Both have generally been shown to successfully treat vasospasm and improve neurological condition, with no clear benefit from one treatment compared with another. There are reports of complications with both therapies including vessel rupture during angioplasty, intracranial hypertension, and possible neurotoxicity associated with papaverine. Limited data are available evaluating nicardipine or verapamil, with positive benefits reported with nicardipine and inconsistent benefits with verapamil.
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Practice Guideline
Triggers for aggressive interventions in subarachnoid hemorrhage.
Ischemia is a common cause of secondary neuronal injury after aneurysmal subarachnoid hemorrhage. An electronic literature search was conducted to identify clinical signs and laboratory data that could serve as predictors for delayed cerebral ischemia and define triggers for additional diagnostic testing or more aggressive intervention. ⋯ Using data from these studies and expert opinion, a variety of clinical signs and monitoring data were identified as potentially useful triggers for additional tests or aggressive treatments. These data were used to develop a sequence that might be employed in the clinical management of subarachnoid hemorrhage to determine which patients need additional attention, testing, or interventions to reduce/prevent ischemia caused by vasospasm.