This study compared water exchange colonoscopy and CO2 insufflation colonoscopy without sedation in a randomized trial. The primary end point was the proportion of patients who reported moderate or severe procedural pain at discharge. Secondary outcomes included the proportion reporting no pain. 473 individuals who were willing to undergo unsedated colonoscopy were randomized to water exchange colonoscopy or CO2 colonoscopy.
The authors conclude that there was no significant reduction in moderate or severe pain among the participants when comparing the two groups. The secondary outcome of no pain was significantly more frequent in the water exchange group. The study is published in Endoscopy.