The onset of ablation of the evoked adductor pollicis muscle twitch in children: a clinical perspective.

The time to loss of the adductor pollicis muscle response to ulnar nerve stimulation at 1 Hz (twitch) after succinylcholine, 1.5 mg.kg-1 intravenously (IV), or vecuronium, 0.1 mg.kg-1 (IV), administration was assessed visually in 134 children, age 2-13 yr, during clinically determined, deep halothane, enflurane and isoflurane anaesthesia. The overall time to twitch ablation and duration of succinylcholine's action is in agreement with published times obtained under controlled experimental conditions; the onset time following vecuronium is comparable to those observed during a similar anaesthetic background measured under controlled experimental conditions. Twitch ablation after succinylcholine was achieved in half the time needed following vecuronium regardless of anaesthetic agent. Succinylcholine's and vecuronium's onset time as well as succinylcholine's duration is adequately assessed by the outlined, simple clinical means. The choice of inhalation agent does not affect the time to visible twitch ablation in a clinically relevant manner; nor does it make an appreciable difference, in clinical terms, in succinylcholine's duration of action.