N(2)O strongly prevents adhesion formation and postoperative pain in open surgery through a drug-like effect

BACKGROUND: Microsurgical tenets and peritoneal conditioning during laparoscopic surgery (LS) decrease postoperative adhesions and pain. For a trial in human, the strong beneficial effects of N(2)O needed to be confirmed in open surgery (OS). RESULTS: In a mouse model for OS, the effect of the gas environment upon adhesions was evaluated. Experiment I evaluated desiccation and the duration of exposure to CO(2), N(2)O or CO(2) + 4%O(2). Experiment II evaluated the dose-response curve of adding N(2)O to CO(2). Experiment III compared humidified CO(2) + 10% N(2)O during LS and OS. In OS, 30- and 60-min exposure to non-humidified CO(2) caused mortality of 33 and 100%, respectively. Mortality was prevented by humidification, by dry N(2)O or dry CO(2) + 4%O(2). Adhesions increased with the duration of exposure to CO(2) (p < 0.0001) and decreased slightly by humidification or by the addition of 4% O(2). N(2)O strongly decreased adhesions at concentrations of 5% or greater. With humidified CO(2) + 10% N(2)O, adhesion formation was similar in OS and LS. CONCLUSIONS: The drug-like and strong beneficial effect of low concentrations of N(2)O is confirmed in OS.