Double burst stimulation for monitoring neuromuscular blockade for tracheal intubation.

Responses to double burst stimulation were palpated every 15 s after intravenous administration of vecuronium 0.2 mg.kg-1 in 60 adult patients under anaesthesia. Intubating conditions and neuromuscular responses to tracheal intubation were assessed at disappearance of one or both palpable responses to double burst stimulation in groups of 30 patients randomly divided, although in group A patients, tracheal intubation could be performed at disappearance of one palpable response to double burst stimulation; 27 out of 30 patients (90%) had mild to moderate bucking on intubation. In this group, only five patients (16.66%) had good intubating conditions. In group B, where tracheal intubation was attempted at disappearance of both palpable responses, intubating conditions were good in 28 out of 30 patients (93.33%) and there was no response to tracheal intubation in 26 out of 30 patients (86.66%). Palpation of evoked response to double burst stimulation can be used to predict intubating conditions and neuromuscular response to tracheal intubation with nondepolarising muscle relaxants such as vecuronium.