TIMING OF TRACHEAL INTUBATION - MONITORING THE ORBICULARIS OCULI, THEADDUCTOR POLLICIS OR USE A STOPWATCH

The most suitable time for tracheal intubation, following vecuronium 0 .1 mg kg(-1), was estimated in 120 patients. The trachea was intubated at cessation of the visually observed response of the orbicularis ocu li muscle to facial nerve stimulation (group 1; n=30), or of the manua lly detected response of the adductor pollicis to ulnar nerve stimulat ion (group 2; n=30), or after waiting 3 min (group 3; n=30), or 4 min (group 4; n=30). There were no significant differences in intubation s cores between the four groups of patients. Loss of response to train-o f-four stimulation occurred significantly sooner in group 1 (orbicular is oculi) than in group 2 (adductor pollicis) P=0.021). However, intub ating conditions were poor in four patients (14%) in group 1, compared with none in group 2 and one in groups 3 and 4, respectively. Thus, c ontrary to expectations, the cessation of the response of the orbicula ris oculi muscle did not guarantee good or even satisfactory intubatin g conditions. The results suggest that in fit adult patients it is as good to wait 3 min after injection of vecuronium 0.1 mg kg(-1) before tracheal intubation, as to use a nerve stimulator.