Abstract

Plasma potassium levels were measured during induction with thiopentone or ketamine and subsequent administration of suxamethonium. The presence and magnitude of fasciculations following suxamethonium were noted. In addition arterial blood gases and glucose levels were measured. All patients displayed a small decrease in plasma potassium levels following the induction agents and a similar rise after the muscle relaxant. The rise occurred less rapidly after the thiopentone-suxamethonium sequence, but no other major differences with respect to potassium emerged in the two groups who received suxamethonium. In the third group, who received ketamine but no relaxant, potassium levels remained below the baseline values. The incidence and degree of fasciculations following suxamethonium 1 mg/kg appeared significantly less with the ketamine induction. Present induction techniques utilize the familiar sequence of barbiturate-suxamethonium-endo-tracheal intubation, with occasional interposition of a potent inhalational agent. The fasciculations,