title: Minimizing postcolonoscopy abdominal pain by using CO(2) insufflation: a prospective, randomized, double blind, controlled trial evaluating a new commercially available CO(2) delivery system.
abstract: BACKGROUND
  Abdominal pain after colonoscopy is a common, distressing symptom resulting from bowel distension by insufflated gas. CO(2), unlike air, is rapidly cleared from the colon by passive absorption. A commercially available CO(2) delivery system has only recently become available. The effects of CO(2) and air insufflation on residual bowel gas and postprocedure pain were compared.
  
  
  METHODS
  One hundred patients were randomized to undergo colonoscopy with insufflation of air (n = 51) or CO(2) (n = 49) by means of a regulator; 97 patients completed the study. Patients with active GI bleeding, inflammatory bowel disease, or previous colectomy were excluded. Pain scores (ordinal scale: 0 = none, to 5 = extreme) were recorded immediately after colonoscopy and at 1, 6, and 24 hours. Residual colonic gas was evaluated on abdominal radiographs at 1 hour.
  
  
  RESULTS
  Residual colonic gas and postprocedural pain at 1 and 6 hours were significantly less in the CO(2) group. 71% of patients insufflated with room air had colonic distension in excess of 6 cm versus 4% for those in the CO(2) group. 94% of patients insufflated with CO(2) had minimal colonic gas versus 2% in whom air was used (p < 0.0001). Of patients insufflated with air, 45% and 31% had pain at, respectively, 1 hour and 6 hours, versus 7% and 9%, respectively, for those insufflated with CO(2) (respectively, p < 0.0001 and p < O.02). No complications resulted from use of the CO(2) delivery system.
  
  
  CONCLUSIONS
  Insufflation of CO(2) rather than air significantly reduces abdominal pain and bowel distension after colonoscopy. CO(2) may be insufflated safely and effectively with the new CO(2) delivery system.
authors.affiliation: McMaster University Medical Center, Hamilton, Ontario, Canada.
authors.forename: Katica
authors.initials: K
authors.lastname: Sumanac
authors.forename: Ian
authors.initials: I
authors.lastname: Zealley
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Fox
authors.forename: John
authors.initials: J
authors.lastname: Rawlinson
authors.forename: Bruno
authors.initials: B
authors.lastname: Salena
authors.forename: John K
authors.initials: JK
authors.lastname: Marshall
authors.forename: Giles W
authors.initials: GW
authors.lastname: Stevenson
authors.forename: Richard H
authors.initials: RH
authors.lastname: Hunt
mesh_terms: D015746:Abdominal Pain / Q000209:etiology / Q000517:prevention & control*; D000328:Adult; D000368:Aged; D000388:Air; D002245:Carbon Dioxide / Q000008:administration & dosage; D003106:Colon; D003113:Colonoscopy / Q000009:adverse effects*; D004311:Double-Blind Method; D005260:Female; D005740:Gases; D006801:Humans; D007327:Insufflation; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D011860:Radiography, Abdominal
chemical_list: D005740:Gases; D002245:Carbon Dioxide