Oral clonidine premedication decreases intraoperative bleeding in patients undergoing endoscopic sinus surgery

ABSTRACT

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. This prospective double - blinded clinical trial was performed on 113 patients [ASA I, ASA II]. Fifty-two patients received oral clonidine [5 micro g/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 micro g/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. 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 micro g, P < 0.05] in the clonidine group. Hydralazine requirement was significantly lower [0.45 +/- 1.68 Vs 2.67 +/- 4.33 mg, P<0.05] as well. Premedication with oral clonidine reduces bleeding in endoscopic sinus surgery and also decreases fentanyl, and hydralazine consumption for controlling hypotension