A comparison of different doses of fentanyl for patients undergoing elective colonoscopy: a randomized double-blind clinical trial

Aim To investigate analgesic and side effects of different doses of fentanyl in combination with propofol for colonoscopy. Methods This prospective randomized double-blind study conducted between 2019 and 2020 included 64 patients. Patients were randomized: Group 1 (fentanyl 0.5 μg/kg) and Group 2 (fentanyl 1.0 μg/kg) both in combination with propofol. Ramsay sedation score (RSS) was obtained at 5 with an additional dose of propofol. The primary outcome was the patient’s postprocedural pain and adverse events during and after the procedure. Results The RSS means were statistically lower for Group 2 at the beginning and every 5 minutes of the procedure. Mean arterial pressure (MAP) for Group 2 (first, 5, 25 and 30 min) was significantly lower (p=0.000, and heart rate (HR) was significantly higher for Group 1 (during the entire procedure) (p=0.000) than in another group; peripheral oxygen saturation (SpO2 ) was significantly lower for measurements within both groups (Group 1, 5, 10, 15 min; Group 2, 5, 10,15 min) (p=0.000 and p=0.000, respectively). Anxiety (p=0.010), weakness (p=0.000) and confusion (p=0.023) proved to be significantly higher for Group 1, and hypotension (p=0.001) for Group 2 than in another group. No statistical significance of Visual Analogue Pain Scale (VAS) (p=0.501) and Aldrete recovery score (ARS) (p=0.845) was found. Conclusion There was no significance in postprocedural abdominal pain between the group of patients administered fentanyl at a dose of 0.5 μg/kg and the group of patients administered fentanyl at a dose of 1.0 μg/kg; however, prevalence of complications was more significant in the group with a fentanyl at a dose of 0.5 μg/kg.