The effect of sepsis and short-term exposure to nitrous oxide on the bone marrow and the metabolism of vitamin B 12 and folate

Abstract

It is recognised that prolonged anaesthesia with nitrous oxide (N₂0) induces megaloblastic anaemia by oxidising vitamin B₁₂ To determine whether sepsis aggravates the effect of H₂0 on haemopoiesis 5 patients with severe sepsis, who required surgery and were exposed to short-term (45 - 105 minutes) N₂0 anaesthesia, were studied. Hone had evidence of pre-operative vitamin B₁₂ or folate deficiency. The effect of the combination of N₂0 anaesthesia and sepsis on DNA synthesis in bone marrow cells was assessed morphologically, and by the deoxyuridine suppression test. In 3 patients exposed to the longest duration (75 - 105 minutes) of N₂0, addition of folinic acid and vitamin B₁₂ partially improved the utilisation of deoxyuridine in vitro. No patient had evidence of megaloblastic haemopoiesis as judged by bone marrow morphology. It is concluded that prolonged N₂0 anaesthesia in patients with severe sepsis may adversely affect DNA synthesis. Although this effect did not manifest as overt megaloblastic erythropoiesis, it may be prudent to avoid N₂0 in such patients.