title: A randomized controlled trial to determine the effect of humidified carbon dioxide (CO2) insufflation on postoperative pain following thoracoscopic procedures.
abstract: BACKGROUND
  It has previously been shown that the insufflation of humidified gas during laparoscopy results in less postoperative pain than is observed following the use of dry gas. Experimental evidence also suggests that dry gas insufflation during thoracoscopy results in greater structural injury to the pleura than occurs with the use of humidified gas. The present study was designed to determine the effect of humidified gas insufflation on postoperative pain following thoracoscopic procedures.
  
  
  METHODS
  Forty consecutive patients were prospectively randomized. Twenty patients were insufflated with humidified carbon dioxide (CO(2)), and 20 control patients received standard dry CO(2).
  
  
  RESULTS
  The patients' analogue pain score was significantly lower following humidified gas insufflation compared to dry gas insufflation when assessed at 6 h postoperatively, as well as on the 1st, 2nd, 3rd, and 14th postoperative days. The postoperative morphine consumption was lower in the humidified group than it was in the control group. The incidence of respiratory complications was identical for both groups.
  
  
  CONCLUSIONS
  The use of humidified gas appears to reduce postoperative pain but not the rate of respiratory complications.
authors.affiliation: Department of Surgery, Regionalspital, Thun, 3600 Thun, Switzerland.
authors.forename: W G
authors.initials: WG
authors.lastname: Mouton
authors.forename: M
authors.initials: M
authors.lastname: Naef
authors.forename: J R
authors.initials: JR
authors.lastname: Bessell
authors.forename: K T
authors.initials: KT
authors.lastname: Otten
authors.forename: H E
authors.initials: HE
authors.lastname: Wagner
authors.forename: G J
authors.initials: GJ
authors.lastname: Maddern
mesh_terms: D000769:Anesthesia, Inhalation / Q000379:methods*; D002245:Carbon Dioxide / Q000008:administration & dosage*; D006801:Humans; D006813:Humidity; D009020:Morphine / Q000008:administration & dosage; D010147:Pain Measurement; D010149:Postoperative Pain / Q000209:etiology / Q000517:prevention & control*; D011446:Prospective Studies; D012140:Respiratory Tract Diseases / Q000209:etiology; D013906:Thoracoscopy / Q000009:adverse effects
chemical_list: D002245:Carbon Dioxide; D009020:Morphine