Dexmedetomidine vs. Fentanyl-Midazolam Combination to Mitigate the Stress Response in Microlaryngoscopy: A Randomized Double-blind Clinical Trial.

Background: Laryngoscopy is the most painful noxious stimulus during anesthesia and surgery. Dexmedetomidine is increasingly used as a sedative in surgeries involving microlaryngoscopy. Objectives: This study aimed to evaluate the effect of dexmedetomidine and a combination of fentanyl and midazolam on mitigating the stress response in patients scheduled for microlaryngoscopy. Methods: This randomized, double-blind clinical trial enrolled 60 patients (28 males and 32 females) aged 18 - 65 years with the American Society of Anesthesiologists (ASA) physical status I - III. The patients were scheduled for microlaryngoscopy and equally divided into 2 groups. Group D received 1 μg/kg of dexmedetomidine and saline bolus dose over 10 minutes before general anesthesia (GA) induction, followed by 0.5 μg/kg/h of dexmedetomidine and saline infusions after GA induction. Group MF received 0.8 μg/kg of fentanyl plus 0.05 mg/kg of midazolam over 10 minutes before GA induction, followed by 1 μg/kg/h of fentanyl plus 0.05 mg/kg/h of midazolam as an infusion. The heart rate (HR) and mean arterial blood pressure (MAP) pressure were recorded from baseline until the end of surgery. Infusions were stopped at the end of the surgery. Results: The number of patients requiring propofol and intraoperative supplemental propofol was significantly lower in group D than in group MF. The heart rate was significantly lower in group D than in group MF (P = 0.022, 0.048, 0.032, 0.045, 0.041, 0.026, 0.030, and 0.036) from induction until the end of surgery; in addition, it was comparable between both groups at baseline and before induction. MAP was comparable between both groups for all measurements. Conclusions: Dexmedetomidine mitigates the hemodynamic changes related to microlaryngoscopy more effectively than the fentanyl-midazolam combination.