Caudal Anaesthesia in Ambulatory Colonoscopy: Lidocaine Only vs. Lidocaine/fentanyl Combination

Abstract

Background: This study aimed to compare the analgesic effects of caudal anaesthesia in patients undergoing ambulatory colonoscopy using lidocaine only or lidocaine/fentanyl combination. Methods: Fifty-one consecutive adult patients scheduled for colonoscopy participated in the study. Participants were randomly allocated into two equal groups (A and B). Caudal anaesthesia was instituted in both groups with 1.5% preservative free lidocaine (19.4 ml); 0.6 ml of normal saline was added in Group A and 30 mcg of fentanyl made to 0.6 ml in Group B. The time of onset and height of caudal block, Numeric Pain Rating Scale (NPRS) score at different stages during colonoscopy were evaluated and compared. The number of patients requiring rescue analgesia (fentanyl/midazolam) were also evaluated and compared. Results: Twenty-six patients in the saline-lidocaine group (A) and twenty-five patients in the fentanyl-lidocaine group (B) completed the study. The mean and standard deviation of the caudal block onset time (minute) in group A was 11.71 ± 4.26 comparable to group B which was 13.50 ± 4.85, p=0.15. The median NPRS while navigating the splenic flexure was 2 in group A and 3 in group B; and while navigating the hepatic flexure it was 5 in group A and 3 in group B. But p values are 0.285 and 0.031 respectively. Rescue analgesia was employed in fewer number of patients in group B (16%) compared to group A (34.6%). Conclusion: Caudal epidural block with lidocaine/fentanyl combination provided superior, safe and satisfactory anaesthesia for ambulatory colonoscopy.