Electrical and mechanical responses after neuromuscular blockade with vecuronium, and subsequent antagonism with neostigmine or edrophonium.

Six unpremedicated patients who had given their informed consent were given vecuronium 0.08 mg kg-1 before elective surgery. Recovery from neuromuscular blockade was measured electrically and mechanically. Neuromuscular blockade was antagonized 1 h after the administration of vecuronium with two doses of neostigmine 2.5 mg (three patients) or edrophonium 0.5 mg kg-1 (three patients). Although the onset of initial recovery was similar, subsequent recovery was faster when measured electrically (EMG) than when measured mechanically. Recovery appeared to be faster in younger patients. Reintroduction of neuromuscular blockade occurred after the second dose of neostigmine 2.5 mg, given to antagonize the block. This did not occur after either dose of edrophonium 0.5 mg kg-1.