Effect of remifentanil on the haemodynamic response to orotracheal intubation

We have examined the effect of remifentanil on the haemodynamic response to orotracheal intubation in a randomized, double-blind study. We studied 40 patients allocated to one of four groups of 10 each, to receive the following immediately before induction of anaesthesia: remifentanil 1 mu g kg(-1) bolus over 30 s, followed by an infusion of 0.5 mu g kg(-1) min(-1); saline placebo only; glycopyrrolate 200 mu g and remifentanil 1 mu g kg(-1) bolus over 30 s, followed by an infusion of 0.5 mu g kg(-1) min(-1); or glycopyrrolate 200 mu g only. Anaesthesia was induced with propofol, vecuronium and 1% isoflurane with 66% nitrous oxide in oxygen. The trachea was intubated under direct laryngoscopy 3 min after induction of anaesthesia. Arterial pressure and heart rate were measured non-invasively, immediately before Induction of anaesthesia and then at 1-min intervals. Remifentanil was found to effectively attenuate the presser response to intubation (P<0.05 for the increase in mean arterial pressure; P<0.01 for the increase in heart rate). In the absence of a concurrent vagolytic agent, remifentanil was associated with bradycardia or hypotension, or both, in five of 10 patients, compared with one patient who received remifentanil and glycopyrrolate.