Addition of nitrous oxide and oxygen to carbon dioxide pneumoperitoneum during laparoscopic surgery for pain reduction: A double-blinded randomized controlled trial.

Abstract

To examine if peritoneal conditioning with an altered insufflation gas mixture is associated with reduced postoperative pain intensity compared to the standard insufflation gas (i.e., 100% CO₂). A prospective, single-centre, randomized, double-blind, superiority trial was performed. This study was conducted between 4 April 2019 and 10 February 2022 at the Jessa Hospital, Hasselt, Belgium. Patients scheduled for elective gynaecologic laparoscopic surgery. Seventy-four patients scheduled for elective gynaecologic laparoscopic surgery were randomised to receive either the standard insufflation gas with 100 CO₂ (n = 37; control group) or the altered gas mixture of 86% CO₂, 10% N₂O and 4% O₂ (n = 37; experimental group). Postoperative pain was assessed at 4, 8 and 24 hours after surgery and on postoperative day (POD) 7 by an 11-point Numeric Rating Scale, with 0 indicating no pain and 10 indicating worst imaginable pain. No significant differences were found between the control and experimental groups regarding postoperative pain at 4, 8 and 24 h after surgery, as well as on POD7. In addition, the median (25% and 75%) total amount of IV piritramide consumption during the first 24 h after surgery was not significantly different between groups (control group: 18.0 [10.0, 27.0] mg vs. experimental group: 17.0 [10.0, 34.0] mg, p = 0.62). The alternative insufflation gas mixture comprising 86% CO₂, 10% N₂O and 4% O₂ used for the pneumoperitoneum during gynaecologic laparoscopic surgery does not appear to reduce postoperative pain compared to the standard insufflation gas of 100% CO₂.