26 Jan 08
Is it time to retire high-concentration nitrous oxide?
By H Hopf
Anesthesiology 2007;102:200-201
During the past decade, anesthesiologists have increasingly recognized that the effects of anesthesia reach beyond the postanesthesia care unit. Researchers have extended their vision beyond studies of pain and postoperative nausea and vomiting in the postanesthesia care unit (still important outcomes) to studies of the impact of anesthesia on a broad range of postoperative outcomes, including cardiac complications and surgical wound infection. Myles et al.,1 in this issue of Anesthesiology, report an outstanding, large (2,050 patients), multicenter, pragmatic randomized controlled trial of the effect of intraoperative gas selection on a wide range of postoperative complications. Patients undergoing major surgery were randomly assigned to receive 80% oxygen with 20% nitrogen versus 30% oxygen with 70% nitrous oxide intraoperatively. Patients assigned to the high inspired oxygen-nitrous oxide avoidance group had fewer major postoperative complications and less frequent severe postoperative nausea and vomiting, and were more rapidly discharged from the intensive care unit, although hospital stay did not differ between groups. The authors conclude, The routine use of nitrous oxide in patients undergoing major surgery should be questioned. An alternative conclusion would be that the routine use of high inspired oxygen (which precludes high inspired nitrous oxide) in patients undergoing major surgery should become routine.