Testing the precautionary principle: a scoping review comparing potable tap and sterile water for irrigation in colonoscopy.

Background: Most guidelines recommend use of sterile water in single-use plastic bottles for irrigation in colonoscopy, a recommendation extrapolated from case reports of infection linked to endoscopic retrograde cholangiopancreatography. Our objective was to identify evidence exploring the impact of tap versus sterile water in colonoscopy on patient, health care resource, and environmental outcomes.

Methods: We performed a scoping review and included any study examining the effects of irrigation source during colonoscopy. A health information specialist searched Embase, MEDLINE, CINAHL, and Web of Science from inception to March 2024 using Peer Review of Electronic Search Strategies standards. Two reviewers performed screening and data extraction using a standardized form. We conducted a quantitative analysis of patient outcomes.

Results: Of 335 identified articles, we included 3. All were prospective studies published between 1996 and 2002. Overall, 137 colonoscopies and 38 flexible sigmoidoscopies were reported. Two studies compared sterile versus tap water, with 7 of 118 (6%) and 35 of 327 (11%) positive water cultures, respectively. There were no clinical adverse events. One study compared tap water at warm versus room temperature and measured patient pain scores (2/10 and 4/10, respectively). Infectious complications were not reported.

Conclusion: There is limited evidence to support either tap or sterile water in irrigation for colonoscopy, but potable tap water may be a safe choice and is environmentally and economically more beneficial than sterile water. In the context of the climate crisis and increasing economic health care burden, tap water in reusable bottles should be strongly considered for irrigation in colonoscopy. Registration: Open Science Framework Registry, https://osf.io/8dgck.