A prospective randomized controlled trial of water exchange plus cap versus water exchange colonoscopy in unsedated Veterans.

Background and Aims: Water exchange (WE) and cap-assisted colonoscopy (CAC) separately reduced pain during insertion in unsedated patients. We hypothesized that compared with WE, WECAC could significantly lower real-time maximum insertion pain (RTMIP).
Methods: Veterans without escort were recruited, randomized, blinded, and examined at three United States Veterans Affairs sites. The primary outcome was RTMIP, highest segmental pain (0 = no pain, 10 = most severe pain) during insertion.
Results: Randomization [WECAC (n = 143) and WE (n = 137)] produced even distribution of a racially diverse group of males and females of low socioeconomic status. Intention-to-treat analysis reported results of WECAC (listed first) and WE (listed second): cecal intubation [93%, 94.2%]; mean (SD) of RTMIP [2.9 (2.5), 2.6 (2.4)]; the proportion with no pain (28.7%, 27.7%); the insertion time [18.6 (15.6), 18.8 (15.9) min]; overall ADR (55.2%, 62.8%), all P values were > 0.05. When RTMIP was binarized as "no pain" (0) vs. "some pain" (1-10), or "low pain" (0-7) vs. "high pain" (8-10), different significant predictors (see text) of RTMIP were identified.
Conclusions: Unsedated colonoscopy was appropriate for unescorted Veterans. WE alone was sufficient. Adding a cap did not reduce RTMIP. Patient specific factors and application of WE with insertion suction of infused water contributed to high and low RTMIP, respectively. For unesorted patients, selecting those with low anxiety, avoiding low body mass index, history of depression or self-reported poor health and adhering to the steps of WE can minimize RTMIP to ensure success of unsedated colonoscopy.
(Copyright © 2024 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)