Water exchange provides salvage cleansing and improves adenoma detection, but drawbacks include prolonged procedure time. Cap-assisted colonoscopy decreases cecal intubation time but is limited by impaired views when feces lodge in the cap.

To investigate the impact of combined water-exchange and cap-assisted colonoscopy (WCC) on detection of adenomas and proximal colon serrated polyps.

Retrospective, single-center, single-colonoscopist, consecutive group observational study.

Veterans Affairs outpatient endoscopy suite.

Outpatients undergoing screening or surveillance colonoscopy.

WCC data collected from 100 consecutive patients were compared to a control group of 101 consecutive patients examined with conventional air insufflation colonoscopy during the prior 4-month period.

Adenoma detection rate (ADR), adenomas detected per colonoscopy, proximal colon serrated polyp detection rate, and proximal colon serrated polyps per colonoscopy rate.

Compared with controls, the WCC group had a higher polyp detection rate (93.0% vs 84.2%; P = .07), ADR (75.0% vs 59.4%; P = .02), proximal colon ADR (61.0% vs 47.5%; P = .07), proximal colon serrated polyp detection rate (24.0% vs 9.9%; P = .009), number of adenomas per colonoscopy (2.70 vs 1.50; P = .002), and mean number of proximal colon serrated polyps per colonoscopy (0.38 vs 0.12; P = .004).

Retrospective study; single, unblinded endoscopist.

ADR and adenomas per colonoscopy are both sensitive indicators of colonoscopy quality. WCC merges two simple methods to improve the performance of screening and surveillance colonoscopy. The data suggest that larger, prospective studies are necessary to determine if there are differences between water-exchange combined with cap-assisted maneuvers and the individual components used alone in lesion detection in screening and surveillance colonoscopy.