Water method for unsedated colonoscopy

The advancement of the scope into the cecum is termed cecal intubation and is mandatory for colonoscopy to be effective. Air is the usual medium to distend the bowel. However, air insertion can lengthen the colon (much like an accordion) and result in discomfort that may prevent cecal intubation, particularly in the unsedated patient.

The authors of this study used warm water, rather than air, to distend the colon based on their prior experience with this technique. They previously found that when water was infused into the colon instead of air during colonoscope insertion, approximately 50 percent of the colon exams could be completed without sedation. Based on this background information, researchers in California hypothesized that the novel water method would enhance cecal intubation and increase the proportion of patients willing to have another colonoscopy with no sedation.

An unsedated colonoscopy program was instituted in 2002 at the Veterans Affairs Sepulveda Ambulatory Care Center in California. From June 2005 to May 2006, the air method was used for colonoscopy. From June 2006 to October 2007 the water method was used. With the latter method, the air pump was disabled and "warm to touch" tap water in lieu of air was used. Sixty-two veterans were examined using the air method and 63 veterans were examined using the water method. The cecal intubation rate with the air method was 76 percent, while the water method was 97 percent. The proportion of patients who reported a willingness to repeat an unsedated colonoscopy was significantly higher with the water method at 90 percent compared with 69 percent for the air method.

This was a single center, observational, nonrandomized study in a small elderly male population. Despite these limitations, researchers note that the positive findings of enhanced cecal intubation rates, increased patient reported willingness to have another colonoscopy and improved cleanliness of the colon are sufficiently provocative to warrant calling for their confirmation by a randomized controlled trial with patients in the U.S. for unsedated colonoscopy.

By American Society for Gastrointestinal Endoscopy