Effect of remifentanil on the auditory evoked response and haemodynamic changes after intubation and surgical incision

We have observed the effect of intubation and incision, as measured by theauditory evoked response (AER) and haemodynamic variables, in 12 patientsundergoing hernia repair or varicose vein surgery who received remifentanilas part of either an inhaled anaesthetic technique using isoflurane or aspart of a total i.v. technique using propofol. Anaesthesia was induced withremifentanil 1 microgram kg-1 and propofol, neuromuscular block wasachieved with atracurium 0.6 mg kg-1 before intubation, and anaesthesia wasmaintained with a continuous infusion of remifentanil in combination witheither a continuous infusion of propofol or inhaled isoflurane. The AER andhaemodynamic variables were measured before and after intubation andincision. The effects of intubation and incision on the AER andhaemodynamic variables were not significantly different between theremifentanil- propofol and remifentanil-isoflurane groups. However, thestudy had a low power for this comparison. When the data for the twoanaesthetic combinations were pooled, the only significant effects wereincreases in diastolic arterial pressure and heart rate immediately afterintubation; these were not seen 5 min after intubation. There were nocardiovascular responses to incision. There were no significant changes inthe AER after intubation or incision.