• L K Rao, A M Francis, U Wilcox, J P Miller, and P Nagele.
• Department of Anesthesiology, Washington University, St Louis, MO, USA.
• Anaesthesia. 2010 Jul 1;65(7):710-5.

SummaryNitrous oxide inactivates vitamin B(12) with detrimental consequences for folate and methionine metabolism, detectable by an increase in total plasma homocysteine. We hypothesised that a pre-operative vitamin B(12) and folate infusion prevents nitrous oxide-induced homocysteine increase. Sixty-three healthy patients having elective surgery were randomly allocated to receive either B-vitamin plus nitrous oxide; placebo plus nitrous oxide or placebo plus air. Fifty-nine patients completed the study. After intravenous B-vitamin infusion, plasma vitamin B(12) and folate concentrations increased 35-fold and 12-fold, respectively, on the first postoperative measurement. Patients who received B-vitamins developed a similar increase (18%) in homocysteine after nitrous oxide (1.9 micromolxl(-1); 95% CI 0.2-3.6 micromolxl(-1)) as those who did not (22%; 2.7 micromolxl(-1); 95% CI 0.6-4.8 micromolxl(-1)). Patients not receiving nitrous oxide had no homocysteine change (0.5 micromolxl(-1); 95% CI -0.8-1.9 micromolxl(-1)), indicating that pre-operative intravenous B-vitamins may not prevent nitrous oxide-induced hyperhomocysteinaemia.

27 keywords...

hide…