The Effect of Humidified and Heated CO2 During Gynecologic Laparoscopic Surgery

Literature Review Article

Kissler S, Haas M, Strohmeier R, Schmitt H, et al. The Effect of Humidified and Heated CO2 During Gynecologic Laparoscopic Surgery on Analgesic Requirements and Postoperative Pain. J Am Assoc Gynecol Laparosc 2004;11:473-7. 

Paul C. Lin, M.D., Seattle Reproductive Medicine

The objective of this study was to determine humidification or heating of CO2 used for pneumoperitoneum during laparoscopic surgery affected analgesic requirements, postoperative pain or patient satisfaction. The authors planned to study ninety women in a prospective, randomized, double-blind, controlled trial with 30 women distributed among each of three groups: I: humidified heated gas , II: non-humidified heated gas, III: non-humidified non-heated gas (the control group). Power analysis to determine sample size was not performed. All surgeries were done by a principal author. Preoperative and intraoperative pain regimens were identical. Postoperative pain was assessed at 2 hour and 6 hours postoperatively and on postoperative day one by face-to-face interviews or phone conversations. Statistical analysis was performed using both the Mann-Whitney U-test and the Chi-squared test. The study was halted after 53 subjects because no significant difference in pain could be observed. No differences were noted in the type of surgery, age or weight of the subjects, time of operation or volume of gas used during the laparoscopy.

Results revealed the percentage of the patients complaining of abdominal pain was significantly higher in group I when compared to group III (59% v. 17%, P=0.01). Shoulder pain was not different among groups. No differences in need for postoperative pain medication or in sleep were noted among groups. Overall patient satisfaction with the surgery was noted to be significantly higher in the control group than in Groups I or II (24% v. 20% v. 0%, P=0.04 comparing groups I with III).

The authors concluded there was no significant benefit in using heated and/or humidified CO2 gas in laparoscopic gynecologic surgery involving adnexal surgery, uterine myomata or adhesiolysis.

Elizabeth Pritts, M.D., Assistant Professor, Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, University of Wisconsin, Madison, Wisconsin. 

This is an interesting and well-designed study. The main drawback is the lack of a power analysis to determine the number of patients required in each group to demonstrate statistically significant differences in the various parameters The author correctly notes there are conflicting data regarding the effect of humidified and heated insufflation gas on postoperative pain. However, he omits the largest, multicenter randomized controlled trial 1 that demonstrated both decreased postoperative pain scores and decreased recovery room stays in women administered humidified heated CO2 for insufflation. Furthermore, animal data demonstrated decreased de novo adhesion formation in porcine models 2, possibly conferring more benefit than just postoperative pain for women interested in future fertility. This current study, although well-designed, falls short of providing useful guidance regarding the use of humidified, heated CO2 for insufflation.


  1. Ott DE, Recih H, Love B, McCovey R, Toledo A, Liu CY, Syed R, Kumar K. Reduction of laparoscopic-induced hypothermia, postoperative pain and recovery room length of stay by pre-conditioning gas with the Insuflow device: a prospective randomized controlled multi-center study. JSLS 1998;2(4):321-9.

  2. Ozel H, Avsar FM, Topaloglu S, Sahin M. Induction and assessment methods used in experimental adhesion studies. Wound Repair Regen 2005;12(4):358-64.  

The above review and commentary on this article were written by SRS members. Publication of these summaries does not reflect endorsement of any particular procedure or treatment. Views expressed in these summaries do not necessarily reflect the views of SRS or ASRM.



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