Tehran University of Medical Sciences (TUMS) Academic Journal of Surgery 2423-3218 8 4 2025 12 31 120 127 EN Behzad Ahsan Department of Anesthesiology, Kurdistan University of Medical Sciences, Sanandaj, Iran Qazal Ghaderi Department of Pediatric Nursing, Iran University of Medical Sciences, Tehran, Iran Negin Maghsomi Student Research Committee, Kurdistan University of Medical Sciences, Sanandaj, Iran Khaled Rahmani Department of Family and Community Medicine, School of Medicine, Kurdistan University of Medical Science, Sanandaj, Iran Shahrokh Ebnerasooli Department of Anesthesia, Faculty of Medical, Kurdistan University of Medical Sciences, Sanandaj, Iran Karim Naseri Department of Anesthesiology, Kurdistan University of Medical Sciences, Sanandaj, Iran Mohamad Azad Majedi Department of Anesthesiology, Kurdistan University of Medical Sciences, Sanandaj, Iran 2025 08 03 Background: Intraoperative bleeding is a challenge in functional endoscopic sinus surgery (FESS). This study aimed to compare the effects of Dexmedetomidine and Remifentanil on intraoperative bleeding, hemodynamic stability, and postoperative pain in patients undergoing paranasal sinus surgery. Methods: In this randomized controlled trial, 100 adult patients undergoing paranasal sinus surgery were randomly assigned to receive either Dexmedetomidine (0.2 μg/kg/h) or Remifentanil (0.25 μg/kg/min) by continuous intravenous infusion during surgery. General anesthesia was administered in both groups. The primary outcome was intraoperative blood loss, assessed both by volume (in milliliters) and bleeding severity (on a 5-point Likert scale). Secondary outcomes included systolic and diastolic blood pressure, heart rate, Visual Analog Scale (VAS) pain scores, and surgery duration. Results: There was no significant difference in mean intraoperative blood loss between groups (Dexmedetomidine:114.76 ± 1 26.65 mL vs. Remifentanil: 119.20 ± 47.28 mL; p = 0.81). However, bleeding severity was significantly lower in the Dexmedetomidine group, with 76% experiencing mild bleeding compared to 56% in the Remifentanil group, and 16% in the latter experiencing severe bleeding (p = 0.008). Postoperative VAS pain scores were significantly lower in the Dexmedetomidine group (2.04 ± 0.53 vs. 3.12 ± 1.08; p < 0.001). Hemodynamic parameters decreased substantially over time in both groups, with no clinically significant intergroup differences, except at isolated time points. Conclusions: While both Dexmedetomidine and Remifentanil effectively maintained hemodynamic stability during FESS, Dexmedetomidine resulted in milder bleeding severity and better postoperative analgesia, supporting its use as a preferred agent for controlled hypotension in sino-nasal surgery. https://ajs.tums.ac.ir/index.php/ajs/article/view/319