title: Carbon dioxide insufflation during colonoscopy: a randomised controlled trial.
abstract: OBJECTIVE
  To determine if carbon dioxide (CO₂), insufflated during colonoscopy reduces pain experienced by patients post colonoscopy compared to air.
  
  
  METHODS
  A randomised, double-blinded, controlled trial with 205 consecutive consented patients referred for elective colonoscopy was undertaken at MidCentral Health Gastroenterology Department. Patients were randomised to colonic insufflation with either air or CO₂. A comparison of reported pain was undertaken using a 0-10 point numeric rating scale at several time periods; intra procedure, 10, 30, and 60 minutes post procedure. In addition groups were compared on the proportion of participants reporting 0 pain levels at each of the same time periods.
  
  
  RESULTS
  CO₂ insufflation was provided to 108 patients and air to 97 patients. No differences in mean pain scores or the proportion of those who report zero pain were found between the groups intra procedure. However, those who received CO₂ insufflation were found to have significantly lower mean pain scores (p<0.001) and to have a significantly greater proportion of persons reporting 0 pain scores (p<0.001) at all three observation times post procedure than those who received air.
  
  
  CONCLUSIONS
  Those receiving CO₂ during colonoscopy experienced less post colonoscopy pain than those who received air insufflation. Carbon dioxide should be considered as the insufflating gas during colonoscopy.
authors.affiliation: Gastroenterology Department, MidCentral Health, Private Bag, Palmerston North, New Zealand. Anne.cleland@midcentraldhb.govt.nz.
authors.forename: Anne
authors.initials: A
authors.lastname: Cleland
authors.forename: Jenny
authors.initials: J
authors.lastname: Carryer
authors.forename: Steve
authors.initials: S
authors.lastname: La Grow
mesh_terms: D015746:Abdominal Pain / Q000517:prevention & control*; D000368:Aged; D000388:Air; D002245:Carbon Dioxide; D003113:Colonoscopy / Q000009:adverse effects / Q000379:methods*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007327:Insufflation / Q000009:adverse effects / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010149:Postoperative Pain / Q000517:prevention & control*
chemical_list: D002245:Carbon Dioxide