Water Exchange Versus Carbon Dioxide for Colonoscopy

Colonoscopy is commonly used in screening for colorectal cancer. A refined technique of colonoscopy involving the use of water as the sole modality to aid colonoscope insertion, water exchange, has been described in recent research papers to decrease patient discomfort and pain, and to reduce the need for sedation during colonoscopy when compared with standard air insufflation. Carbon dioxide insufflation has been described to decrease patient discomfort after colonoscopy. No randomized trial has so far compared the use of water exchange to carbon dioxide insufflation. Our hypothesis is that water exchange inflicts less discomfort to patients undergoing colonoscopy than carbon dioxide insufflation. Patients undergoing screening colonoscopy in two centers in Norway, one center in Poland and one center in The Netherlands will be enrolled and randomized to examination of either of the two methods.