Carbon dioxide insufflation reduces discomfort due to flexible sigmoidoscopy in colorectal cancer screening

Background: Flexible sigmoidoscopy is currently recommended as a screening modality for colorectal cancer. However, a substantial number of patients experience discomfort because of the procedure, possibly limiting compliance and thus screening success. During endoscopy, air is commonly used to insufflate the bowel. Carbon dioxide rather than air insufflation has been shown to reduce procedure-related pain and discomfort in colonoscopy. The aim of the present study was to evaluate whether carbon dioxide insufflation reduces discomfort during and after flexible sigmoidoscopy for colorectal cancer screening. Methods: In a randomized, double-blinded design, 230 consecutive participant sin a population-based flexible sigmoidoscopy colorectal cancer screening trial were assigned to have their examination performed with either carbon dioxide or air insufflation. Patients were asked to grade discomfort experienced both during and in the hours after the procedure on a visual analogue scale. Results: Carbon dioxide insufflation significantly reduced the amount of discomfort at 1, 3 and 6 h after the sigmoidoscopy. One hour after the examination, 84% of patients in the CO2 group reported no discomfort, compared to 64% in the air group (P = 0.006). No differences between the groups were observed during the examination. Conclusions: Carbon dioxide insufflation significantly reduced post-examination discomfort. The use of carbon dioxide rather than air insufflation may contribute to better public acceptance for flexible sigmoidoscopy screening.