Effect of nitrous oxide on plasma homocysteine and folate in patients undergoing major surgery

Abstract

Background. Nitrous oxide (N2O) inhibits methionine synthetase resulting in elevated plasma homocysteine (Hcy) concentration after surgery. In epidemiological studies, hyperhomocysteinaemia is associated with increased risk of cardiovascular disease and dementia. Methods. Blood samples were obtained to measure plasma folate and Hcy concentrations from two centres participating in a multicentre randomized trial investigating the effects of N2O on the outcome after major surgery. The effect of N2O and duration of anaesthesia on plasma Hcy, and the relationship between hyperhomocysteinaemia and outcomes were assessed. Results. We enrolled 394 patients. The N 2O Group had an increase in plasma H..