Closed loop control of arterial hypertension following intracranial surgery using sodium nitroprusside. A comparison of intra-operative halothane or isoflurane.

Forty patients were chosen at random to receive halothane or isoflurane anaesthesia during craniotomy and a comparison of the postoperative hypertensive response was made using a microcomputer-based closed-loop arterial pressure control system with sodium nitroprusside to control and assess arterial pressure during the first 6 postoperative hours. A desired target systolic pressure was chosen for each patient and the frequency of hypertension, sodium nitroprusside requirements and quality of arterial pressure control were compared between the two groups. Thirty-five patients required sodium nitroprusside. The halothane group required a median dose of 15.2 mg (range 0-72) compared to 3.4 mg (range 0-87) in the isoflurane group. This difference is not statistically significant. Quality of arterial pressure control was satisfactory in both groups. In conclusion, arterial hypertension occurs frequently following intracranial surgery and is uninfluenced by the choice of halothane or isoflurane intra-operatively. This closed-loop arterial pressure control system functioned safely and effectively in this context.