Edrophonium as an antagonist of vecuronium-induced neuromuscular block in the elderly.

Abstract

Train-of-four stimuli were applied to the ulnar nerve using an accelograph in 10 elderly patients (aged 70-82 years) and 10 younger patients (aged 27-54 years). Anaesthesia was induced with thiopentone 5 mg.kg-1 and was maintained with nitrous oxide (66%) oxygen and sevoflurane (1 MAC). Vecuronium 0.1 mg.kg-1 was used for paralysis, and reversed with intravenous edrophonium 0.75 mg.kg-1 and atropine 0.015 mg.kg-1 when the train-of-four ratio returned to 25%. The times from initial administration of vecuronium to completion of maximal block were 211.5 (SD 66.9) s and 154.0 (SD 39.7) s in the elderly and younger patients, respectively (p < 0.05). The times from maximal block to 25% recovery of train-of-four ratio were 64.8 (SD 36.3) min and 61.8 (SD 36.3) min in the elderly and younger patients, respectively. There was no statistically significant difference between them. The reversal times from 25% to 75% of the train-of-four ratio after the administration of edrophonium were 210.0 (SD 136.7) s and 177.0 (SD 100.4) s in the elderly and younger patients, respectively. There was no statistically significant difference between them. The authors were unable to show that healthy elderly patients differ significantly from younger patients in the neuromuscular blocking effect of vecuronium and the reversal effect of edrophonium.