Comparison of evoked electromyography and mechanical activity during vecuronium-induced neuromuscular blockade.

The relationship of compound electromyography to mechanical myography was investigated in 20 patients given vecuronium in a dose of 0.1 mg kg-1. Mechanical response was affected less quickly and recovered faster than the electrical response. Although there was a good correlation between the two throughout the study, a shift towards mechanical responses was observed in all cases for the onset of blockade and recovery from blockade. Moreover, during recovery the mechanical responses became greater than the control value in all patients. This was also reflected in the statistically significant difference (P less than 0.05) of the regression lines relating tension and electromyography (TI as well as train-of-four ratio) between onset of, and recovery from, neuromuscular block.