Suxamethonium pains and electromyograph recordings in children.

Surface electromyography was used to investigate muscle activity in children following the administration of suxamethonium. The duration, amplitude and frequency of muscle action potentials recorded in children were similar to those in adults. Twenty-three children had muscle action potential frequencies in excess of 50 Hz, but only two suffered pain after operation. The relationship between high frequency discharge rates of motor units noted in adults in earlier studies does not apply to children.