Carbon dioxide insufflation during colonoscopy can significantly decrease post-interventional abdominal discomfort in deeply sedated patients: A prospective, randomized, double-blinded, controlled trial

Background and Aim:: CO₂ has been reported to be absorbed from the bowel more rapidly than air, resulting in a discomfort reduction after colonoscopy. Its role in deeply sedated patients is limited. This study was designed to investigate the efficacy and safety of CO₂ insufflation during colonoscopy in patients deeply sedated with propofol. Methods:: A total of 125 continuous patients were randomly assigned to receive either CO₂ (n=63) or air (n=62) insufflation during propofol-sedated colonoscopy. Postcolonoscopy abdominal pain, distention, and satisfaction were assessed at 1, 3, and 24h after the procedure, and the proportions of pain-free and distention-free patients were compared. Residual bowel gas in the colon and small bowel was evaluated at 1h after colonoscopy. End-tidal CO₂ and O₂ saturation was measured for safety analysis. Results:: There was a significant difference between the two groups regarding the postcolonoscopy abdominal pain, distention, and subjective satisfaction at 1h (P<0.001) and 3h (P<0.01) after the procedure. Patients' pain and distention at 1 and 3h after the procedure were significantly lower in the CO₂ group (P<0.01). Residual bowel gas in the colon and small bowel was significantly less in the CO₂ group (P<0.001). There was no significant difference in end-tidal CO₂ levels between two groups before, during, and after the procedure. Conclusions:: Compared with air, CO₂ insufflation during colonoscopy reduced postcolonoscopy abdominal discomfort and improved patients' satisfaction. It was safe to use CO₂ insufflation in deeply sedated colonoscopy.