The hypothesis behind the present study was that remifentanil produces greater haemodynamic stability during rigid bronchoscopy than does the conventional propofol injection technique.

This was a double-blind, parallel-group, randomized study. All patients received propofol (2-3 mg/kg) and rocuronium (0.6 mg/kg iv) at induction of anaesthesia. Patients then received either remifentanil (n =11; 1 μg/kg bolus over 1min followed by infusion of 0.5 μg/kg) or fentanyl (n =11; 2 μg/kg bolus followed by saline placebo infusion). Escape medications of propofol, atropine and ephedrine were given as required. Their lungs were ventilated with 100% oxygen via a Sanders' injector. Haemodynamic instability was defined as one of the following: lacrimation, sweating; systolic blood pressure =20 mmHg above or below preoperative baseline for 1 min; and heart rate >100 or <50 beats/min for 1 min.

There were no significant differences in patient characteristics nor duration of bronchoscopy between the two groups. Remifentanil was found to attenuate significantly the haemodynamic response to insertion of a rigid bronchoscope (P < 0.05 for increase in arterial pressure; P < 0.01 for increase in heart rate). During bronchoscopy, five patients showed somatic or autonomic responses in the fentanyl group, compared with none in the remifentanil group (P < 0.01). ST-segment changes occurred in eight patients in the fentanyl group compared with four patients in the remifentanil group (P < 0.05). The total doses of escape medications used and the total episodes of haemodynamic instability during bronchoscopy were significantly reduced in remifentanil infusion group.