Control of hypertension during isoflurane or sevoflurane anesthesia with continuous infusion of nicardipine hydrochloride

In a multicenter study, the efficacy and tolerability of nicardipine hydrochloride (NIC) were examined when the drug was used to control hypertension during isoflurane or sevoflurane anesthesia in patients with or without a preoperative history of hypertension. Retrospectively, the 124 study patients were divided into four groups: patients without (group 1) or with (group 2) a preoperative history of hypertension who received isoflurane anesthesia, and those without (group 3) or with (group 4) a preoperative history of hypertension who received sevoflurane anesthesia. NIC infusion was started when systolic pressure exceeded 160 mm Hg or 30% above the control value determined before the induction of anesthesia. The ability of NIC to control hypertension was analyzed for 30 minutes after starting the infusion. Arterial pressure, heart rate, and urine volume were examined in each group. Mean doses of NIC infused during the 30-minute study period in groups 1, 2, 3, and 4 were 2.23, 2.13, 2.43, and 2.19 μg·kg^-1·min^-1, respectively. There were no significant differences between the four groups in the amount of NIC infused. In the four groups, no significant changes were seen in heart rate, and blood pressure was effectively controlled (group 1: 149.5/86.4 mm Hg and 113.3/63.0 mm Hg before and after the 30-minute study period, respectively; group 2: 156.6/91.2 mm Hg and 118.2/71.0 mm Hg; group 3: 153.4/90.1 mm Hg and 119.0/71.1 mm Hg; and group 4: 160.6/98.7 mm Hg and 124.1/76.8 mm Hg). The final blood pressure measurements were considered within normal ranges for the patients studied. A decrease in blood pressure was slightly delayed in both sevoflurane groups (groups 3 and 4) and in the isoflurane group with a preoperative history of hypertension (group 2). While urine output tended to increase in all groups, a significant increase was found only in group 1 (from 0.019 ± 0.011 mL·kg^-1·min^-1 before treatment to 0.087 ± 0.041 mL·kg^-1·min^-1 after treatment). In conclusion, NIC was effective and well tolerated in controlling hypertension during isoflurane or sevoflurane anesthesia.