A randomized controlled trial to determine the effect of humidified carbon dioxide (CO2) insufflation on postoperative pain following thoracoscopic procedures

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 (CO2), and 20 control patients received standard dry CO2. 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. Conclusion: The use of humidified gas appears to reduce postoperative pain but not the rate of respiratory complications.