The impact of water‐aided methods on pain reduction and adenoma detection rate during colonoscopy

Abstract

With the nationwide colorectal cancer screening program in place in Taiwan, there is an urgent need to promote techniques with a positive impact on adenoma detection rate (ADR) to minimize the risk of interval cancers. Despite widespread use of sedation, many patients in Taiwan still undergo unsedated or minimally sedated colonoscopy. Techniques that minimize pain will enhance the experience of colonoscopy, and facilitate participation in screening and surveillance. A review of water‐aided colonoscopy is appropriate at this time. Water exchange (WE), in particular, appears to be able to meet the needs of colonoscopy patients in Taiwan. Water‐aided methods are distinguished into water immersion (WI) and WE by the timing of removal of infused water—WI during withdrawal and WE during insertion. Both methods are typically performed with air pump turned off during the insertion phase of colonoscopy and thus are reported to produce less insertion pain as compared with traditional air insufflation (AI). Some colonoscopists do not require air exclusion with WI. The removal of water during insertion phase of colonoscopy, coupled with suctioning of residual air pockets, further enhance the pain reduction by WE. Head‐to‐head comparison of AI, WI, and WE has shown that WE reduced insertion pain to a greater extent than WI. Recent studies also showed that WE produced less insertion pain, with more patients completing colonoscopy without pain as compared with carbon dioxide (CO2) insufflation. WE also provides salvage cleaning during insertion and reduces distraction to inspection during withdrawal, both of which might help the colonoscopist to find more polyps. In recent randomized controlled trials comparing AI, WI, and WE, the secondary outcomes of overall ADR and right colon or proximal colon ADR were in favor of WE, but not WI. In conclusion, with practice WE is an easy and inexpensive way of insertion during colonoscopy. Its ability to reduce insertion pain and increase ADR may help improve the quality of colonoscopy. Colonoscopists in Taiwan should consider contributing to a study to assess whether the increase in ADR by WE is reproducible, and if so, whether the occurrence of interval cancers can be reduced or avoided.