Dexmedetomidine Versus Ketamine Combined With Fentanyl for Sedation-Analgesia in Colonoscopy Procedures: A Randomized Prospective Study

Colonoscopy is a painful, embarrassing and short-term procedure that needs temporary sedation and rapid recovery. The aim of this study was to compare the sedation and analgesia effect and hemodynamic changes due to bolus intravenous injection of dexmedetomidine and ketamine during elective colonoscopy. This clinical trial was conducted on 70 patients aged 20-70 years, candidates for elective colonoscopy, who randomly divided into two equal groups. For all patients 0.03 mg/kg midazolam 10 min before procedure was injected. Fentanyl 1 µ/kg was administrated in both groups 5 min before procedure, and one min before colonoscopy. K group received 0.5 mg/kg ketamine and D group received 1 µ/kg dexmedetomidine. Then, the normal saline infusion was used as maintenance. Fentanyl 25-50 µg was prescribed as the rescue dose if needed during the procedure. Hemodynamic changes, sedation level during procedure, patients and colonoscopists satisfaction were recorded in recovery. The mean heart rate and mean blood pressure was significantly less in the dexmedetomidine group than in the ketamine group. All of the patients in the ketamine group were deep to moderately sedated during colonoscopy, and the amount of fentanyl required in this group is much less than dexmedetomidine group (68.02±25.63 vs 91.45±38.62 µg P-0.003). In terms of satisfaction, only 42% of patients in the dexmedetomidine group were completely satisfied with colonoscopy, while 65% of Ketamine group had complete satisfaction with colonoscopy (P=0.001). The level of colonoscopist satisfaction during colonoscopy was similar in both group, and complete satisfaction was 43%. In patients undergoing colonoscopy, IV bolus injection of dexmedetomidine in comparison with ketamine provides less patients satisfactory and low level of sedation with supplemental multiple doses of fentanyl during the procedure.