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1956 – Lancet reports that
prolonged use of N2O anaesthesia may result in megaloblastic bone-marrow
changes. Triggers a host of research that reveals that N2O can inactivate
vitamin B12, specifically the conversion of homocysteine to methionine and
the associated DNA synthesis.
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1.Nitrous oxide rapidly reduces the activity of Methionine
synthase which can lead to megaloblastic haemopoiesis and impaired marrow
function. Exposure to N2O over 6 hours
or exposure for patients with existing B12/folate deficiency can cause these
changes and be dangerous. May be
dangerous in critically ill patients etc as well
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[INFO FOR ME:
Megaloblastic bone marrow changes: marcocytic anaemia resulting from the
suppression of DNA synthesis in red blood cell production. Immature and dysfunctional RBCs (megaloblasts) in the bone marrow]
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2. Subsquent increase in plasma homocysteine –
correlating with length of nitrous exposure (less conversion to
methionine). Homocysteine implicated. Moderate increases in homocysteine have
been linked to coronary artery disease – hence possibility that nitrous could
increase myocardial ischaemic events.
Currently not enough research done to confirm this, theoretical.
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