Effect of nitrous oxide exposure during surgery on the homocysteine concentrations of children.

Background: Nitrous oxide converts vitamin B12 to its nonmetabolically active form, inhibits methionine synthase, and results in an elevation of plasma total homocysteine (tHcy). The authors investigated the effect of nitrous oxide anesthesia on the plasma tHcy concentrations in children the morning after surgery and whether blood concentrations of folate and vitamins B12 and B6 were associated with any potential increase.

Methods: The authors measured plasma tHcy concentrations in 32 children before and 24 h after initial exposure to nitrous oxide (≥ 2 h).