A study of the changes in serum potassium concentration with suxamethonium using different anaesthetic agents.

Serum potassium concentrations were measured after administration of suxamethonium (1 mg/kg body wt.) in 101 patients in whom anaesthesia was induced by one of five different techniques. There was a maximum increase in serum potassium of 21.4% following induction with trichloroethylene compared with 4.4% with nitrous oxide/oxygen. There was only small increases in serum potassium with halothane and chloroform. In an additional 10 patients who received tubocurarine (3 mg) before induction of anaesthesia with thiopentone, the maximum increase in serum potassium was 10.6% following suxamethonium. It is concluded that the increase in serum potassium following induction of anaesthesia is the result of a combined effect of the anaesthetic agent and suxamethonium.