Comparison of carbon dioxide and air insufflation during consecutive EGD and colonoscopy in moderate-sedation patients: a prospective, double-blind, randomized controlled trial

Background and Aims Endoscopy is performed with air insufflation and is usually associated with abdominal pain. It is well recognized that carbon dioxide (CO 2 ) is absorbed more quickly into the body than air; however, to date, few studies have investigated the use of CO 2 insufflation during consecutive EGD and colonoscopy (CEC). Thus, this study evaluated the efficacy of CO 2 insufflation compared with air insufflation in CEC. Methods From March 2014 to April 2016, a total of 215 consecutive patients were randomly assigned to receive CO 2 insufflation (CO 2 group, n = 108) or air insufflation (air group, n = 107). Abdominal pain after CEC was recorded on a visual analogue scale (VAS). The amount of sedatives administered, use of analgesics, polyp detection rate (PDR), adenoma detection rate (ADR), abdominal circumference, and adverse events were also analyzed. Results Baseline patient characteristics were not significantly different between the groups. Abdominal pain on the VAS in the CO 2 group and air group 1 hour after CEC was, respectively, 13.8 and 20.1 ( P = .010), 3 hours after CEC was 8.3 and 12.5 ( P = .056), 6 hours after CEC was 3.5 and 5.3 ( P = .246), and 1 day after CEC was 1.8 and 3.4 ( P = .192). The dose of sedative administered, analgesic usage, PDR, ADR, and adverse events were not statistically different between the groups. However, the increase in abdominal circumference was significantly higher in the air group than in the CO 2 group. Conclusions CO 2 insufflation was superior to air insufflation with regard to the pain score on the VAS in the hour after CEC. (Clinical trial registration number: KCT0001491.)