PROLONGED INFUSION OF SUXAMETHONIUM IN INFANTS AND CHILDREN

The pattern of neuromuscular blockade during the infusion of suxamethonium in adults is well established. To maintain constant blockade the requirement for suxamethonium increases ("tachyphylaxis") over the first 60-90 min (Lee, 1975; Ramsay et al., 1980; Carnie, 1982), and de-creases thereafter ( " bradyphylaxis") at least in the presence of the inhalation anaesthetic agents halothane (Futter, Donati and Bevan, 1983), enflurane (Donati and Bevan, 1982) and isoflurane (Donati and Bevan, 1983). During the stage of tachyphylaxis, the characteristics of the block change. The initial depolarizing block develops fade in response to tetanic or train-of-four stimulation (Lee, 1975). The appearance of this "phase II block " is dose- and time-related and is associated with prolonged spontaneous recovery (Futter, Donati and Bevan, 1983; Donati an