Randomized clinical trial to compare the efficacy to improve the quality of surgical field of hypotensive anesthesia with clonidine or dexmedetomidine during functional endoscopic sinus surgery.

Purpose: Intense bleeding of the surgical field is a potential factor influencing success of functional endoscopic sinus surgery (FESS). Hypotensive anesthesia with α2 intravenous agonists reduces intraoperative bleeding, but which is the best agent is unknown. The main objective of this trial was to compare the current standard adjuvant drug for hypotensive anesthesia, clonidine, with the recently available alternative dexmedetomidine.

Methods: A randomized clinical trial compared the efficacy of clonidine and dexmedetomidine during FESS. Treatment was open label for the anesthesiologist and operating surgeon, but blind for an external evaluator who evaluated video-recorded surgeries. A Boezaart scale was assessed every 30 min during FESS until surgery completion. Main end-point was the proportion of patients with mean Boezaart scores > 2 (heavy bleeding) by external blinded evaluator. Secondary end-points included other bleeding parameters, surgery duration, hemodynamic measures and surgical complications.

Results: 94 patients were randomized. There were no significant differences in the proportion of patients with mean Boezaart scores > 2 in clonidine (42.6%) and dexmedetomidine (42.6%). Consistently, no differences were observed in secondary variables of bleeding, duration or complications. Small differences in mean heart rate were observed that might reflect different pharmacological profiles of the products, but are of uncertain clinical relevance.

Conclusions: No significant differences were observed between clonidine and dexmedetomidine when used as anesthetic adjuvants in the reduction of surgical bleeding in FESS. A longer experience with clonidine and its lower costs suggest it may be a preferable option as an adjuvant for hypotensive anesthesia.