When I was training, we used nitrous oxide on just about every anesthetic. It was easy to use. It was inexpensive. It didn’t tend to effect hemodynamics so it was useful in less stable patients when combined with an opioid. It helped speed induction through the second gas effect. It was not metabolized so renal and liver insufficiency were of less concern.

However, a lot more is now known about the pharmacologic disadvantages, and potential harm, of nitrous oxide in certain patients. N2O interferes with the B12/folate pathway and methylates DNA. This discussion reviews some of those patients at risk of harm from nitrous oxide exposure during anesthesia. Read More …