Implications of nimodipine prophylaxis of cerebral vasospasm on anesthetic management during intracranial aneurysm clipping

Nimodipine, a calcium entry blocking agent similar in structure to nifedipine but with selective cerebrovascular dilating effects, has potential use in the therapy and prevention of cerebral vasospasm after intracranial hemorrhage. The authors summarize the effects of calcium entry blockers, review the pharmacology of nimodipine, and discuss both the known and possible interactions of oral nimodipine with physical and pharmacological interventions that neuroanesthesiologists employ for patients with cerebral vasospasm during craniotomy for aneurysm clipping. In a series of 26 patients undergoing aneurysm clipping, the authors found that intraoperative blood pressure tended to be reduced by nimodipine. Although the number of patients was limited by the fact that they were enrolled in a multi-center nimodipine aneurysm study and thus had to meet the criteria for that study, it is concluded that prophylaxis of cerebral vasospasm with nimodipine in patients with ruptured intracranial aneurysm results only in a favorable tendency toward lower systemic blood pressure during craniotomy.