Effect of remifentanil on the haemodynamic response to orotracheal intubation

We have examined the effect of remifentanil on the haemodynamic response toorotracheal intubation in a randomized, double-blind study. We studied 40patients allocated to one of four groups of 10 each, to receive thefollowing immediately before induction of anaesthesia: remifentanil 1microgram kg-1 bolus over 30 s, followed by an infusion of 0.5 microgramkg-1 min-1; saline placebo only; glycopyrrolate 200 micrograms andremifentanil 1 microgram kg-1 bolus over 30 s, followed by an infusion of0.5 microgram kg-1 min-1; or glycopyrrolate 200 micrograms only.Anaesthesia was induced with propofol, vecuronium and 1% isoflurane with66% nitrous oxide in oxygen. The trachea was intubated under directlaryngoscopy 3 min after induction of anaesthesia. Arterial pressure andheart rate were measured non- invasively, immediately before induction ofanaesthesia and then at 1- min intervals. Remifentanil was found toeffectively attenuate the pressor response to intubation (P < 0.05 forthe increase in mean arterial pressure; P < 0.01 for the increase inheart rate). In the absence of a concurrent vagolytic agent, remifentanilwas associated with bradycardia or hypotension, or both, in five of 10patients, compared with one patient who received remifentanil andglycopyrrolate.