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

Objective 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). Design A prospective, single‐centre, randomized, double‐blind, superiority trial was performed. Setting This study was conducted between 4 April 2019 and 10 February 2022 at the Jessa Hospital, Hasselt, Belgium. Population Patients scheduled for elective gynaecologic laparoscopic surgery. Methods 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). Main Outcome Measures 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. Results 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). Conclusion 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.