Antagonism of mivacurium block with edrophonium from various degrees of spontaneous recovery

Seventy adult patients received mivacurium 0.15 mg kg^–1during anaesthesia with thiopentone, nitrous oxide and 0.5%halothane. Neuromuscular block was monitored using mechanomyographyand train-of-four stimulation. Edrophonium 0.75 mg kg^–1was administered 5 or 10 min after mivacurium, or when the firstresponse in the TOF (T1) had recovered to 5, 10, 25 or 50% ofcontrol in groups of 10 patients each. A control group was allowedto recover spontaneously. The mean time taken from administrationof mivacurium to attaining a TOF ratio of 0.7 was between 19.3and 24.9 min in the groups given edrophonium, regardless ofthe time of administration, compared with 26.7 min in the spontaneousrecovery group. The differences, however, were not significantamong the groups showing little advantage in antagonizing mivacuriumblock.