Peritoneal limited conditioning reduces postoperative pain: a randomized controlled trial in robot-assisted laparoscopic myomectomy

Postoperative pain is related to the gas used for laparoscopy as demonstrated for 100 % nitrous oxide in 2002 by Tsereteli. In a previous trial, we demonstrated that the use of full conditioning adding 10 % nitrous oxide and 4 % oxygen to the CO₂ pneumoperitoneum with humidification and altering the temperature of the insufflation gas, the use of Hyalobarrier gel, and the administration of 5 mg dexamethasone significantly reduced postoperative pain and decreased adhesions. As we believed that just altering the insufflation gas by adding 10 % of nitrous oxide and 4 % of oxygen would reduce pain and adhesions by itself, we performed a randomized controlled trial on women undergoing robot-assisted laparoscopic myomectomy. Fourteen women undergoing robot-assisted laparoscopic myomectomy were randomized 1:1 receiving 86 % CO₂ + 10 % N₂O + 4 % O₂ or 100 % CO₂. Outcome parameters were postoperative pain (visual analog scale (VAS)) and adhesions observed at second-look laparoscopy after 14 days. Pain and painkiller intake were significantly reduced by using the altered insufflation gas (p < 0.05). Adhesions did not show a significant difference, although the study group tended to have less adhesions (p < 0.21). Addition of 10 % N₂O and 4 % O₂ to the pneumoperitoneum significantly decreased postoperative pain, even in a low number of participants, which suggests a strong effect.