BACKGROUND: In most brain operations, the endotracheal tube is kept in postoperatively for airway maintenance during radiologic examinations. But the endotracheal tube causes tracheal irritation and hemodynamic changes. Inhalation anesthetics can not be administered during transport, and minimal concentration is exhaled for several hours after the end of inhalation. The present study was designed : (1) to determine the end tidal isoflurane concentration after the end of administration ; (2) to investigate the effects of intravenous anesthetics in patients with tracheal intubation during radiologic examination postoperatively. METHODS: We selected forty adult patients who were scheduled for elective neurosurgical operation with postoperative brain CT (computerized tomography). The study was performed in 2 steps; in the step 1 (n = 10), end tidal isoflurane concentration was checked after ending inhalation. In the step 2 (n = 30), patients were divided into one of three groups according to anesthesia method; group I (using isoflurane), group P (change from isoflurane to propofol about an hour before operation end), group M (using midazolam instead of propofol, compared to group P). In each group, the frequency of bucking and incidence of hypertension were checked during postoperative radiologic examinations. RESULTS: Minimal concentrations of isoflurane were detected in exhaled gas for about 2 hours after the end of isoflurane inhalation. The frequency of bucking was significantly lower in the group P and M than in group I (P = 0.002). In group P, the incidence of hypertension was significantly reduced compared to group M and I (P = 0.031). CONCLUSIONS: These results suggest that the change of anesthetic technique (from inhalation to intravenous) in the late period of operation, provides postoperative hemodynamic stability, a more comfortable state and minimal environmental pollution in comparison to inhalation anesthesia only.