There is an Editorial View at the begnning of the issue that addresses that topic. Here's an excerpt. Sounds like the gist is "It doesn't matter; give high oxygen."
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The authors of the current study intended to examine the value of avoidance of nitrous oxide in reducing postoperative complications. The difficulty in designing such a study is that you cannot change the concentration of nitrous oxide without replacing the gas with another, such as nitrogen, oxygen, or helium. The nitrous oxide avoidance group also received 80% oxygen, previously suggested to be of benefit in preventing surgical site infection and postoperative nausea and vomiting, whereas the 70% nitrous oxide group received only 30% oxygen. Therefore, it is impossible to determine whether the beneficial effects reported resulted from high inspired oxygen, avoiding nitrous oxide, or a combination of the two. Fleischmann et al. found no difference in surgical site infection rate when comparing 70% nitrogen-30% oxygen versus 70% nitrous oxide-30% oxygen as the intraoperative gas mixture, but did not include an 80% oxygen group. These results suggest that avoidance of nitrous oxide may be less important than high inspired oxygen.
In the end, it may not matter to clinicians whether the benefits found in the study by Myles et al. resulted from avoidance of nitrous oxide or administration of high inspired oxygen, because administration of high inspired oxygen by necessity requires avoidance of 70% nitrous oxide. There is certainly plentiful evidence that nitrous oxide use is associated with an increased incidence of postoperative nausea and vomiting. Conversely, a randomized controlled trial in colon surgery patients demonstrated that high inspired oxygen reduced postoperative nausea and vomiting, suggesting that the reduced incidence in the study by Myles et al. could also result from high inspired oxygen. A number of other potential adverse effects of nitrous oxide have been reported in the literature, although their clinical relevance is not clear. There is some evidence for lack of harm from nitrous oxide (the study by Fleischmann et al.), but there is little evidence for benefit. Myles et al. add a compelling argument for eliminating nitrous oxide use in patients undergoing major surgery by showing potential harm from nitrous oxide (whether directly or through reducing the capacity to provide a high inspired oxygen concentration).