اثر كلونيدين در خونريزي حين عمل جراحي ميكروسكوپي گوش مياني

Efficacy of Clonidine on Intraoperative Bleeding in Middle Ear Microsurgery

background: To evaluate the efficacy of clonidine as a premedication for producing a bloodless surgical field compared with placebo in patients undergoing middle ear microsurgery. .Materials and Methods: This prospective double-blinded clinical trial was performed on 51 patients (ASA I, IT), aged 15-60 yr undergoing middle ear microsurgery who had no history of hypertension, known diabetes and cardiovascular disease, concomitant treatment with monoamino oxidase inhibitors, tricyclic acid (TCA), non­steroidal anti-inflammatory drugs (NSAIDs) and antihypertensive drugs or beta blockers, known hypersensitivity to the study drug, and severe psychological disorders entered our study. They were randomly assigned to receive either 200 [ig PO clonidine or placebo 90 min prior the operation under double blind condition. Anesthesia was similar in both groups. Intraoperative bleeding was assessed on a four-point scale from 0=no bleeding (excellent surgical condition) to 3=abundant (troublesome) bleeding (continuous suction) according to the surgeon opinion. Systemic blood pressure and heart rate were measured before and during the surgery. Intraoperative bleeding, antihypertensive requirements, cardiovascular changes after intubation, post operative bleeding and reoperations were compared between two groups. Results: Clonidine group had a bloodless surgical field than placebo group (Mann-Whitney U test, p <0.05). It was significant in all surgical steps from skin incision and graft preparation, tympanomeatal flap elevation, to removing middle ear pathology and graft insertion. Intraoperative consumption of antihypertensive drugs for reducing bleeding (nitroglycerine ana inderal) were significantly lower in the clonidine group (Fisherʹs exact test, p<0.05). Heart rate and blood pressure were lower in the clonidine group, but their difference was not statistically significant. Their was no significant difference in post operative bleeding and the rate of graft failure (reoperation) between two groups. conclusion: Clonidine as a premedication can provide a blood less surgical field and can improve surgical visibility during microsurgery