چكيده لاتين :
Introduction: 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 mo 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 mo g/kg was also added. When both drugs failed,
hydralazine, was given intravenously as a bolus and intermittently, O.lmg/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, fisherיs 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 mo 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.
Conclusion: Premedication with oral clonidine reduces bleeding in endoscopic sinus surgery and also decreases fentanyl,
and hydralazine consumption for controlling hypotension.
