Bedirhan GUNEL, Ayse SENCAN
Çukurova Anestezi ve Cerrahi Bilimler Dergisi - 2026;9(2):378-389
Aim: To estimate the median effective dose (ED??) of propofol required to achieve well-tolerated and motionless colonoscope advancement through the rectosigmoid junction in adult patients undergoing colonoscopy. Methods: This prospective dose-finding study was conducted from September 12, 2025 to October 15, 2025. Adults aged <65 years, ASA I-III, and BMI <30 kg/m² undergoing elective colonoscopy were included. Intravenous bolus propofol was given using a modified Dixon up-and-down method, starting at 1.5 mg/kg with 0.1 mg/kg stepwise adjustments. After induction, a 2-minute observation allowed peak effect assessment. Success (MOAA/S <=2 without pain, movement, or verbal response) prompted a 0.1 mg/kg dose decrease for the next patient; failure prompted an increase. Crossovers were defined as changes from success to failure or vice versa. Results: After eight crossover points, the study concluded at the 27th patient. The estimated ED?? of propofol for successful colonoscope insertion was 1.026 mg/kg (95% CI, 0.735-1.317 mg/kg). Conclusion: This study estimated the ED?? of propofol required for well-tolerated and motionless passage of the colonoscope through the rectosigmoid junction in selected adult patients. These findings may contribute to individualized initial bolus dose titration and provide preliminary data for future confirmatory studies with larger and more diverse populations.
