Isoflurane: its use to induce hypotension in neurosurgical patients.

The use of isoflurane to induce arterial hypotension was studied in 40 adults undergoing neurosurgery. In 70% of patients, isoflurane, up to 2.0% (inspired), decreased mean arterial pressure (MAP) to the desired level for surgery; for the remainder, a higher concentration (3.0-4.0%) was required. Tachycardia, which could be slowed by labetalol, occurred in 13 patients (32%); the incidence was significantly higher in those who had not received an opiate either as premedication or intra-operatively. No post-operative complications attributable to hypotension were seen. It is concluded that isoflurane is a safe and effective agent for the induction of hypotension in neurosurgical operations.