• Tomoki Nishiyama.
• Department of Anesthesiology, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
• J Anesth. 2005 Jan 1;19(3):213-7.

PurposeThe purpose of this study was to compare hemodynamic and catecholamine changes due to a sudden increase in inhalation anesthetic concentrations (isoflurane and sevoflurane) during surgery.MethodsThirty patients aged 40-70 years scheduled for lower abdominal surgery were anesthetized with either isoflurane or sevoflurane with nitrous oxide and epidural block. During surgery the isoflurane or sevoflurane concentration was kept at 0.5 minimum alveolar concentration (MAC) (end-tidal concentration) for 15 min. Then the isoflurane or sevoflurane concentration (inhalation concentration) was changed to 1.5 MAC and maintained at that level for 10 min. Thereafter, it was decreased to 0.5 MAC for 10 min. Blood pressure, heart rate, and plasma concentrations of epinephrine and norepinephrine were measured.ResultsThe blood pressure decreased significantly in both groups after increasing the anesthetic concentration, and it increased after decreasing the concentration. The decrease in systolic blood pressure was significantly larger in the isoflurane group. The heart rate increased significantly after increasing the anesthetic concentration only in the isoflurane group. Plasma concentrations of epinephrine and norepinephrine increased significantly in the isoflurane group, whereas the epinephrine concentration (but not the norepinephrine concentration) decreased in the sevoflurane group.ConclusionDuring surgery a sudden increase in isoflurane concentration induced larger changes in hemodynamics and sympathetic nerve activity than sevoflurane.

31 keywords...

hide…