Reduction of multitasking distractions underlies the higher adenoma detection rate of water exchange compared to air insufflation - blinded analysis of withdrawal phase videos.

Background: Experts have hypothesized that a reduction of multitasking distractions and improved bowel cleanliness can explain why insertion water exchange enhances adenoma detection rate.

Objective: The purpose of this study was to test the role of both distractions during withdrawal and bowel cleanliness in enhancing adenoma detection rate using coded video records of colonoscopy.

Methods: The withdrawal phase of videos of 299 consecutive colonoscopies from two randomized controlled trials comparing water exchange versus air insufflation at a regional hospital in Taiwan were coded. The primary outcome was distractions; activities that preclude full attention being paid to inspection of the mucosa for polyps. A single blinded reviewer collected the data.

Results: There were significant agreements in inter-rater reliability indexes. Compared to air insufflation, water exchange had significantly fewer distractions; higher diagnostic yield (intervention time and number), adenoma detection rate, and Boston Bowel Preparation Scale score. Water exchange had a higher withdrawal technique score (predominantly adequacy of cleaning). The association between increased adenoma detection rate and water exchange was mediated by the number of distractions and withdrawal time, but not the Boston Bowel Preparation Scale score.

Conclusion: The speculation by experts that a reduction of multitasking distractions underlies the significantly higher adenoma detection rate of water exchange is supported by the current study. Increased bowel cleanliness did not contribute to the increased adenoma detection rate by use of water exchange.