Management of Cyanide Agent Exposure

Note that in the clinical assessment of hypoxia, skin colour assessment complicated by the presence of cyanohaemoglobin produces a cherry red colouration 

5 summarises the essential stages in the management of cyanide exposure 

A primary goal in management is to remove cyanide from cytochrome oxidase so aerobic metabolism can resume. Since cyanide has a higher affinity for ferric iron, sodium nitrite is administered to oxidise haemoglobin (Fe to methaemoglobin 

Fifty per cent of all iron in humans is present as ferrous iron (Fe ) in haemoglobin. Only 0.5 % of all iron in humans is present as ferric iron (Fe ) in cytochrome oxidase, an enzyme in the mitochondria. Therefore, the body has a large reservoir of ferrous iron in haemoglobin that can be changed to ferric iron-producing methaemoglobin that binds cyanide and releases cyanide from cytochrome oxidase. 

Another primary goal is to convert cyanide to the much less toxic thiocyanate. Sodium thiosulphate accelerates this detoxification of cyanide to thiocyanate. 

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