Warm and humidified insufflation gas during gynecologic laparoscopic surgery reduces postoperative pain in predisposed patients-a randomized, controlled multi-arm trial

Background Postoperative pain remains a common problem in gynecologic laparoscopy, especially in head zone-related regions, triggered by intra-abdominal pressure during capnoperitoneum. Humidified and prewarmed insufflation gas may ameliorate pain and be beneficial. Methods This prospective randomized controlled parallel group multi-arm single-center study investigated the effects of temperature and humidity of insufflation gas on postoperative pain during gynecologic laparoscopy with a duration >= 60 min. Female participants (18-70 years) were blinded and randomly assigned-computer generated-to either insufflation with dry cold CO2 with forced air warming blanket (AIR), humidified warm gas without forced air warming blanket (HUMI), or humidified warm gas with forced air warming blanket (HUMI +). We hypothesized that using humidified warm gas resulted in lower pain scores and less analgesic consumption. The primary endpoint postoperative pain was assessed for different pain localizations every 12 h during 7 days after surgery. Secondary endpoints were demand for painkillers and epidural anesthetics, length of stay in recovery room, and hospital stay. (Registration: ClinicalTrials.gov NCT02781194-completed). Results 150 participants were randomized. Compared to group AIR (n = 48), there was significantly less pain in group HUMI + (n = 48) in the recovery room (- 1.068; 95% CI - 2.08 to - 0.061), as well as significantly less ibuprofen use at day two (- 0.5871 g +/- 0.258; p-value = 0.0471). Other variables did not change significantly. Stratification for presence of endometriosis or non-previous abdominal surgery in patient history revealed significantly less pain in both groups HUMI (n = 50) and HUMI + versus group AIR. Related side effects were not noted. Conclusion In the overall population, the use of warm, humidified insufflation gas did not yield clinically relevant effects; however, in predisposed patients with endometriosis and who could otherwise expect high pain levels, warm and humidified gas may be beneficial.

Automated summary

The study showed that using humidified warm gas during gynecologic laparoscopy can reduce postoperative pain and analgesic use, especially in patients with endometriosis or without previous abdominal surgery history.