Prospective RCT Of Water Exchange (WE) vs. WE Plus Cap-Assisted Colonoscopy

This will be a multi-VA site, unblinded investigators, prospective randomized control trial (RCT). Randomization (WE, WE + cap) will be based on computer generated random numbers placed inside opaque sealed envelopes. The envelope (in pre-arranged order set up by statistics consultant) will be opened to reveal the code when the colonoscopist is ready to insert the endoscope to begin the examination. This will be a comparison of two arms (WE, WE + cap) to see which one is less painful.

Patients who are willing to participate will sign an informed consent before starting the colonoscopy procedure. Separate parallel randomization will be set up at each site, stratified type of colonoscopy (screening, surveillance, diagnostic). All subjects will have scheduled unsedated colonoscopy as a result of lack of escort or personal preference for no sedation. Randomization will be set up by statistics consultant.

Control Method: One arm of the study will include unsedated colonoscopy with water exchange (WE) as the control method. Residual air in the colon will be removed and water will be infused to guide insertion through an airless lumen. Infused water will be removed by suction, along with residual fecal debris, predominantly during insertion.

Study method: The other arm will include unsedated colonoscopy with water exchange (WE) and the addition of a cap, fitted to the colonoscope per manufacturer instruction.

Inclusion criteria

• Informed/educated (about pros and cons of the unsedated option) Veterans undergoing:

• diagnostic
• surveillance (follow up of polyps)
• screening (first-time) colonoscopy at participating sites
• choosing scheduled unsedated colonoscopy for any reason (lack of escort, personal preference)

Exclusion criteria

• decline to be randomized
• unable to give consent or respond to questionnaires
• history of colon surgery
• active inflammatory bowel disease
• lower gastrointestinal bleeding (except for occult blood or FIT positive in the context of colon cancer screening)
• therapeutic colonoscopy (e.g., hemostasis, removal of large polyp)
• proctosigmoidoscopy
• bidirectional endoscopy
• inadequate consumption of bowel preparation
• known history of severe diverticulosis or diverticulitis
• history of abdominal surgery previously requiring sedation for colonoscopy
• current narcotic/anxiolytic medication use
• prior unsuccessful experience with unsedated colonoscopy
• emergent colonoscopy
• evidence of colonic obstruction based on pre-colonoscopy clinical evaluation
• current participation in other studies
• medical condition that could increase the risk associated with colonoscopy

• active cardiac
• or pulmonary disease
• or other serious disease
• medical condition that would preclude a benefit from colonoscopic screening

• cancer
• or any terminal illness
• prosthetic heart valve
• anticoagulant therapy
• nonmedical problems

• psychiatric disorders
• excessive use of alcohol
• need for special precautions in performing colonoscopy

• antibiotic prophylaxis
• request of on demand sedation