Journal of Research in Medical Sciences1735-1995101200501282530ENDep. of Anesthesia, Isfahan University of Medical SciencesDep. of ENT, Isfahan University of Medical SciencesDep. of Anesthesia, Isfahan University of Medical SciencesDep. of Anesthesia, Isfahan University of Medical Sciences2006082820060828Background: The antihypertensive drug, clonidine, is a centrally acting alpha 2 agonist, useful as a premedication because of its sedative and analgesic properties. We examined the effect of clonidine given as an oral premedication in producing a bloodless surgical field in patients undergoing endoscopic sinus surgery. We also evaluated the relation between bleeding volume and consumption of fentanyl and hydralazine to control hypotension. Methods: This prospective double - blinded clinical trial was performed on 113 patients (ASA I, ASA II). Fifty-two patients received oral clonidine (5 µg/kg) while the other 61 patients received placebo. During general anesthesia, the hemodynamic endpoint of the anesthetic management was maintenance of hypotension (MAP) at 70 mmHg for producing a bloodless surgical field. The direct control of MAP was attained with inspired concentration increments of halothane up to maximum of 1.5 vol % as needed. When it was unsuccessful, an intravenous fentanyl bolus of 2 µg/kg was also added. When both drugs failed, hydralazine , was given intravenously as a bolus and intermittently, 0.1mg/kg up to a maximum dose of 40 mg. Intraoperative bleeding was assessed on a six – point scale from 0 (= no bleeding) to 5 (= severe bleeding). Data were compared with chisquare test, fisher's exact test and Student t-test. Results: There was less bleeding volume in the clonidine group (mean ± SD) than in the placebo group (144 ± 75 Vs 225 ± 72 ml, P<0.05). Frequency of bleeding severity scores 3 and 4 (troublesome with repeated suction) were lower in the clonidine group than in the placebo group (12% Vs 35%, P< 0.05). Fentanyl requirement was significantly lower (112 ± 18 Vs 142 ± 21 µg, P < 0.05) in the clonidine group. Hydralazine requirement was significantly lower (0.45 ± 1.68 Vs 2.67 ± 4.33 Conclusion: Premedication with oral clonidine reduces bleeding in endoscopic sinus surgery and also decreases fentanyl, and hydralazine consumption for controlling hypotension. Keywords: Sinus surgery, Endoscopy, Clonidine, Hydralazine, Fentanyl, Bleedinghttp://jrms.mui.ac.ir/index.php/jrms/article/view/391http://jrms.mui.ac.ir/index.php/jrms/article/download/391/134