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. Fifteen articles describing original research that included some discussion of triggers were identified and reviewed. Quality of evidence was considered very low to moderate for included studies. 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.