Nicardipine did not activate renin-angiotensin-aldosterone system during isoflurane or sevoflurane anesthesia.

Abstract

To investigate the changes of renin-angiotensin-aldosterone system by nicardipine administration during isoflurane or sevoflurane anesthesia. Twenty patients aged 40 to 70 yr for elective neurosurgery were studied. Anesthesia was induced with thiopental, midazolam and fentanyl and was maintained with nitrous oxide in oxygen and isoflurane or sevoflurane. When blood pressure was constant, 0.017 mg x kg(-1) nicardipine was administered as a bolus. Blood pressure, heart rate, and plasma concentrations of nicardipine, angiotensin I and II, aldosterone and renin activity were measured for 30 min after nicardipine administration. Blood pressure decreased for 30 min after nicardipine administration in both groups with lower values during sevoflurane anesthesia. Heart rate increased only in the isoflurane group. Plasma nicardipine concentrations did not differ between isoflurane and sevoflurane groups. Plasma renin activity and concentrations of angiotensin II and aldosterone did not change in either groups and there were no differences between groups. Plasma concentration of angiotensin I increased at 20 and 30 min after nicardipine administration in the isoflurane group but not in the sevoflurane group. The activity of renin-angiotensin-aldosterone system did not increase by a single dose administration of nicardipine in isoflurane or sevoflurane anesthesia.