title: Carbon dioxide insufflation for colonoscopy: evaluation of gas volume, abdominal pain, examination time and transcutaneous partial CO2 pressure.
abstract: BACKGROUND
  Insufflation with carbon dioxide (CO(2)) in colonoscopy has not been widely adopted and, consequently, limited data are available on insufflated gas volume and blood pCO(2). The aim of this study was to compare CO(2) and air as an insufflation agent in patients undergoing colonoscopy without sedation in terms of insufflated gas volume, pCO(2), pain and examination time.
  
  
  METHODS
  This was a randomized, double-blind, control trial. Consecutive patients presenting for colonoscopy, excluding those with lung or malignant disease, were randomized into two groups: insufflation with air or with CO(2), respectively. Insufflated gas volume, pain, pCO(2) and examination time were assessed.
  
  
  RESULTS
  The study cohort comprised 120 patients (66 randomized to CO(2) group). No significant difference in insufflated gas volumes was found between the CO(2) and air groups. The mean pCO(2) measured before, during (the peak value) and 30 min after colonoscopy were 40, 43 and 40 mmHg, respectively, in both groups. The pain scores in the air group were significantly greater than those in the CO(2) group until 3 h after the examination. There was a significant faster cecal intubation time and a trend toward shorter examination time in the CO(2) group.
  
  
  CONCLUSIONS
  The CO(2) gas volume used in our study (14.0 L) was much greater than that reported by others (8.3 L), but the pCO(2) values were still within the normal reference range, indicating the safety of CO(2) insufflation over a greater range of CO(2) gas volume. Among our patients, CO(2) insufflation was associated with relatively less pain and a shorter examination time. Based on our results, we recommend that CO(2) become the standard gas for insufflation in patients undergoing colonoscopy without sedation.
authors.affiliation: Department of Gastroenterology, Akita Red Cross Hospital, 222-1 Kami-kitade-saruta, Akita, Akita, 010-1495, Japan. h-yamano@h9.dion.ne.jp
authors.forename: Hiro-o
authors.initials: HO
authors.lastname: Yamano
authors.forename: Kenjirou
authors.initials: K
authors.lastname: Yoshikawa
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Kimura
authors.forename: Eiichirou
authors.initials: E
authors.lastname: Yamamoto
authors.forename: Eiji
authors.initials: E
authors.lastname: Harada
authors.forename: Toyoki
authors.initials: T
authors.lastname: Kudou
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Katou
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Kentarou
authors.initials: K
authors.lastname: Satou
mesh_terms: D015746:Abdominal Pain / Q000209:etiology* / Q000517:prevention & control; D000368:Aged; D000388:Air; D001784:Blood Gas Analysis; D002245:Carbon Dioxide / Q000008:administration & dosage* / Q000378:metabolism; D003113:Colonoscopy / Q000379:methods*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007327:Insufflation / Q000379:methods; D008297:Male; D008875:Middle Aged; D013997:Time Factors
chemical_list: D002245:Carbon Dioxide