Comparison of neuromuscular block in the diaphragm and hand after administration of tubocurarine, pancuronium and alcuronium.

Abstract

The onset and offset of neuromuscular block in the diaphragm and in the adductor pollicis muscle were recorded using unilateral supramaximal stimulation of phrenic and ulnar nerves. Thirty patients were allocated randomly to receive tubocurarine 0.4-0.5 mg kg-1, pancuronium 0.07-0.08 mg kg-1 or alcuronium 0.2-0.3 mg kg-1. In all cases the onset of neuromuscular block occurred in the diaphragm before adductor pollicis, and spontaneous recovery was evident first in the diaphragm. There was a correlation between the time of spontaneous reappearance of twitch in the diaphragm and in the adductor pollicis only in the patients who received pancuronium (r = 0.97, P less than 0.05 for reappearance of the first twitch of the train-of-four of each muscle). The duration of paralysis in the diaphragm was less than 5 min in five patients who received tubocurarine and in one who received alcuronium; this corresponded to a period of paralysis in the adductor pollicis muscle of more than 25 min in each case.