Introduction & Objective: Even a little bleeding can adversely affect the surgeon's ability to visualize the region to be operated in ENT operations. The aim of this study is to compare the effects of isoflurane and sevoflurane on hemodynamics and bleeding in controlled hypoten-sion.

Materials & Methods: This study was a double-blind clinical trial. Ninety patients who were candidates for endoscopic sinus surgery and tympanomastoidectomy in Amirkabir hospital of Arak were randomly assigned into two groups of isoflurane and sevoflurane. Remifentanil was infused at 0.1 µg/kg/min for both groups during surgery and the amount of bleeding and hemodynamic parameter were recorded. The data was analyzed by SPSS-20 and ANOVA statistical test.

 Results: Underlying and hemodynamic variables were similar between the two groups preop-eratively. The amount of blood loss during surgery showed that there were no significant dif-ferences between the two groups (P=0.802) and no significant differences in hemodynamic variables (heart rate, systolic/diastolic blood pressure and arterial oxygen saturation) were observed between the two groups during the surgery.

 Conclusion: It is concluded that there is no difference between sevoflurane and isoflurane in controlled hypotension. Thus, using these drugs in operations with excessive bleeding is rec-ommended.