Water Colonoscopy Versus Air Colonoscopy for Unsedated Patients With Prior Abdominal or Pelvic Surgery: a Prospective Randomized, Controlled Trial

Water method with water exchange has been shown to reduce medication requirement and pain experienced during colonoscopy. It increases the success rate of cecal intubation in sedated and unsedated patients undergoing screening colonoscopy. Exchange of water during scope insertion minimizes distension of the colonic lumen and decreases loop formation. Exclusion of air from the colon during insertion by omission of air insufflations and suction removal of residual air prevent elongation of the colon. These maneuvers facilitate colonoscopy insertion in average patients and may enhance the success of difficult colonoscopy.

Prior abdominal or pelvic surgery is an independent factor for difficult colonoscopy, the probable adhesion may change the anatomy and increase the discomfort of patients. We postulate that these patients may benefit from using the water method for colonoscopy. In this proposal we test the hypothesis that compared with conventional air insufflations the water method with water exchange significantly enhances the success rate of cecal intubation in patients with prior abdominal or pelvic surgery.

The aim of the study is to compare the outcome of colonoscopy using the water method versus the conventional air method in patients with prior abdominal or pelvic surgery. The primary outcome is cecal intubation success rate. The secondary outcomes include cecal intubation time, maximum pain score during colonoscopy, overall pain score after colonoscopy and adenoma detection rate.