OPTIMUM TIME FOR NEOSTIGMINE ADMINISTRATION TO ANTAGONIZE VECURONIUM-INDUCED NEUROMUSCULAR BLOCKADE

We followed the recovery time course in 46 patients antagonized by neo stigmine (0.036 mg kg(-1)) at different levels of vecuronium-induced n euromuscular blockade ranging from post-tetanic count 1 to train-of-fo ur ratio 0.4 and in 15 patients during spontaneous recovery. Non-linea r regression curve fit analyses showed that the optimal time for neost igmine administration was when the first twitch in the train of four ( T1) was between 1% and 10%. Visual analyses of the scattergram in whic h the level of block, when neostigmine was given, was plotted against total recovery time (the time elapsed from administration of the last dose of vecuronium to train-of-four ratio 0.7) gave the same result. T he reduction in total recovery time achieved by neostigmine was 32.6 m in (SE diff. 6.0 min). To achieve the optimum effect, neostigmine must therefore be given 32.6 min plus the required time for peak effect of neostigmine (5.3-7.1 min), i.e. 37.9-39.7 min, before train-of-four r atio 0.7 is reached. During spontaneous recovery this corresponds to a T1 between 1% and 15%.