Elsevier

Gastrointestinal Endoscopy

Volume 76, Issue 3, September 2012, Pages 657-666
Gastrointestinal Endoscopy

Review article
Water-aided colonoscopy: a systematic review

https://doi.org/10.1016/j.gie.2012.04.467Get rights and content

Background

Water-aided methods for colonoscopy are distinguished by the timing of removal of infused water, predominantly during withdrawal (water immersion) or during insertion (water exchange).

Objective

To discuss the impact of these approaches on colonoscopy pain and adenoma detection rate (ADR).

Setting

Randomized, controlled trial (RCT) that compared water-aided methods and air insufflation during colonoscope insertion.

Patients

Patients undergoing colonoscopy.

Intervention

Medline, PubMed, and Google searches (January 2008-December 2011) and personal communications of manuscripts in press were considered to identify appropriate RCTs.

Main Outcome Measurements

Pain during colonoscopy and ADR. RCTs were grouped according to whether water immersion or water exchange was used. Reported pain scores and ADR were tabulated based on group assignment.

Results

Pain during colonoscopy is significantly reduced by both water immersion and water exchange compared with traditional air insufflation. The reduction in pain scores was qualitatively greater with water exchange as compared with water immersion. A mixed pattern of increases and decreases in ADR was observed with water immersion. A higher ADR, especially proximal to the splenic flexure, was obtained when water exchange was implemented.

Limitations

Differences in the reports limit application of meta-analysis. The inability to blind the colonoscopists exposed the observations to uncertain bias.

Conclusion

Compared with air insufflation, both water immersion and water exchange significantly reduce colonoscopy pain. Water exchange may be superior to water immersion in minimizing colonoscopy discomfort and in increasing ADR. A head-to-head comparison of these 3 approaches is required.

Section snippets

Methods

Because the last review1 covered the literature through 2007, Medline, PubMed, and Google (January 2008-December 2011), searches were considered to identify appropriate RCTs (published or in press). In 9 RCTs, the pain scale of 0 = no pain and 10 = most severe or worst pain was used. In 2, a scale of 0 = no pain and 100 = most severe or worst pain was used,7, 11 and in 1, the scale of 0 = no pain and 5 = most severe or worst pain was used.8 The pain scores in the latter 3 RCTs were recomputed

Results

Our review identified 12 RCTs that compared air insufflation with water-aided methods. Access to the full report for writing an editorial comment17 provided the needed information in 1 report.

Table 1 shows the demographic and procedure-related variables. In each of these studies, the randomization appeared to have distributed equivalent patients to each of the air and water groups evenly. The mean (SD) or median (IQR) pain score in the air insufflation and water-aided method groups are shown in

Discussion

The emerging interest in water-aided methods for colonoscopy is suggested by recent RCTs,2, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 observational studies,4, 5, 18, 19 retrospective reports,6, 10, 20, 21, 22, 23, 24, 25 commentaries,26, 27, 28, 29, 30, 31, 32, 33, 34 hypothesis papers,35 editorials,35, 36, 37, 38 and reviews.39, 40, 41, 42, 43 Water immersion entails distention of the colon by infused water, which is removed predominantly during withdrawal. On the other hand, the explicit goal

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    DISCLOSURE: The study was supported in part by Veterans Affairs Medical Research Funds at Veterans Affairs Greater Los Angeles Healthcare System and an American College of Gastroenterology Clinical Research Award (F.W.L). No other financial relationships relevant to this publication were disclosed.

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