title: Carbon dioxide insufflation during colonoscopy can significantly decrease post-interventional abdominal discomfort in deeply sedated patients: A prospective, randomized, double-blinded, controlled trial.
abstract: OBJECTIVE
  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 24 h 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 1 h 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 1 h (P < 0.001) and 3 h (P < 0.01) after the procedure. Patients' pain and distention at 1 and 3 h 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.
authors.affiliation: Therapeutic Endoscopy Center, Chang Gang Memorial Hospital and University College of Medicine, Keelung, Taiwan.
authors.forename: Shuo-Wei
authors.initials: SW
authors.lastname: Chen
authors.affiliation: Department of anesthesiology, Chang Gang Memorial Hospital and University College of Medicine, Keelung, Taiwan.
authors.forename: Chung-Kun
authors.initials: CK
authors.lastname: Hui
authors.affiliation: Therapeutic Endoscopy Center, Chang Gang Memorial Hospital and University College of Medicine, Keelung, Taiwan.
authors.forename: Jia-Jang
authors.initials: JJ
authors.lastname: Chang
authors.affiliation: Therapeutic Endoscopy Center, Chang Gang Memorial Hospital and University College of Medicine, Keelung, Taiwan.
authors.forename: Tsung-Shih
authors.initials: TS
authors.lastname: Lee
authors.affiliation: Department of Radiology, Chang Gang Memorial Hospital and University College of Medicine, Keelung, Taiwan.
authors.forename: Siu-Cheung
authors.initials: SC
authors.lastname: Chan
authors.affiliation: Therapeutic Endoscopy Center, Chang Gang Memorial Hospital and University College of Medicine, Keelung, Taiwan.
authors.forename: Cheng-Hung
authors.initials: CH
authors.lastname: Chien
authors.affiliation: Therapeutic Endoscopy Center, Chang Gang Memorial Hospital and University College of Medicine, Keelung, Taiwan.
authors.forename: Ching-Chih
authors.initials: CC
authors.lastname: Hu
authors.affiliation: Therapeutic Endoscopy Center, Chang Gang Memorial Hospital and University College of Medicine, Keelung, Taiwan.
authors.forename: Chih-Lang
authors.initials: CL
authors.lastname: Lin
authors.affiliation: Therapeutic Endoscopy Center, Chang Gang Memorial Hospital and University College of Medicine, Keelung, Taiwan.
authors.forename: Li-Wei
authors.initials: LW
authors.lastname: Chen
authors.affiliation: Therapeutic Endoscopy Center, Chang Gang Memorial Hospital and University College of Medicine, Keelung, Taiwan.
authors.forename: Ching-Jung
authors.initials: CJ
authors.lastname: Liu
authors.affiliation: Therapeutic Endoscopy Center, Chang Gang Memorial Hospital and University College of Medicine, Keelung, Taiwan.
authors.forename: Cho-Li
authors.initials: CL
authors.lastname: Yen
authors.affiliation: Therapeutic Endoscopy Center, Chang Gang Memorial Hospital and University College of Medicine, Keelung, Taiwan.
authors.forename: Po-Jen
authors.initials: PJ
authors.lastname: Hsieh
authors.affiliation: Therapeutic Endoscopy Center, Chang Gang Memorial Hospital and University College of Medicine, Keelung, Taiwan.
authors.forename: Cheng-Kun
authors.initials: CK
authors.lastname: Liu
authors.affiliation: Therapeutic Endoscopy Center, Chang Gang Memorial Hospital and University College of Medicine, Keelung, Taiwan.
authors.forename: Chih-Sheng
authors.initials: CS
authors.lastname: Su
authors.affiliation: Therapeutic Endoscopy Center, Chang Gang Memorial Hospital and University College of Medicine, Keelung, Taiwan.
authors.forename: Chia-Ying
authors.initials: CY
authors.lastname: Yu
authors.affiliation: Therapeutic Endoscopy Center, Chang Gang Memorial Hospital and University College of Medicine, Keelung, Taiwan.
authors.forename: Rong-Nan
authors.initials: RN
authors.lastname: Chien
mesh_terms: D015746:Abdominal Pain / Q000209:etiology / Q000517:prevention & control*; D000328:Adult; D000368:Aged; D002245:Carbon Dioxide / Q000008:administration & dosage*; D003113:Colonoscopy / Q000009:adverse effects*; D054810:Deep Sedation; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007327:Insufflation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D011183:Postoperative Complications / Q000209:etiology / Q000517:prevention & control*; D011446:Prospective Studies
chemical_list: D002245:Carbon Dioxide
keywords: CO2 insufflation; colonoscopy; propofol