Comparison of Methods to Distend the Colon During Insertion: CO2, Air Insufflation, Water-aided Colonoscopy

Study Summary

Insufflation of the colon, usually with room air, is necessary to distend the lumen for exploration. Carbon dioxide (CO2) insufflation instead of room air insufflation (AI) has been shown to decrease symptoms of abdominal pain or discomfort during the procedure and particularly during the following 24 hours. CO2 is is rapidly absorbed by the intestinal mucosa and exhaled through respiration. AI colonoscopy has usually been the reference standard to compare colonoscopy using CO2 insufflation. In two recent articles AI was compared to either CO2 insufflation and Water-aided colonoscopy (WAC), which entails infusion of water to facilitate insertion to the cecum. WAC can be categorized broadly in Water Immersion (WI) and Water Exchange (WE). In WI water is infused during the insertion phase of colonoscopy, with removal of infused water predominantly during withdrawal. Occasional use of insufflation may be allowed. WE entails complete exclusion of insufflation, removal of residual colonic air pockets and feces, and suction of infused water predominantly during insertion to minimize distention. During the withdrawal phase insufflation is used to distend the colonic lumen. In the WAC arms of the two mentioned articles the insertion method used was WI, with infusion of water at room temperature or at 37°C. During withdrawal, air insufflation or either air or CO2 insufflation were employed. Compared to AI, CO2 insufflation and WI (using room air insufflation or CO2 insufflation during withdrawal) were effective in both studies in decreasing sedation requirement, pain and tolerance scores, with patients' higher willingness to repeat the procedure. Until now no direct comparison has been made within a single study about pain score during colonoscopy using AI, CO2 insufflation, WI/CO2, WE/CO2, WI/AI and WE/AI. In this study we test the hypothesis that, compared to AI, CO2 insufflation and WAC/CO2-AI methods will decrease pain score during colonoscopy, with reduction of sed

Primary Outcome

Pain assessed using a visual analogue scale (VAS) with a score 0=absence of pain, 2=simply "discomfort", 10=the worst possible pain. Before the procedure, an endoscopic nurse will explain the VAS scoring system to the patients. Every 60 seconds during colonoscopy patients will be asked about discomfort or pain. The responses will be recorded, and the maximum pain score noted.

Interventions

• OTHER Air Insufflation method.
• OTHER CO2 insufflation
• OTHER Water Immersion/CO2
• OTHER Water Exchange/CO2
• OTHER Water Immersion/AI