Effects of remifentanil and alfentanil on the cardiovascular responses to induction of anaesthesia and tracheal intubation in the elderly

Background. We compared the effects of remifentanil and alfentanil on arterial pressure and heart rate at induction of anaesthesia and tracheal intubation in 40 ASA I-III patients aged greater than 65 yr, in a randomized double-blind study. Methods. Patients received either remifentanil 0.5 mug kg(-1) over 30 s, followed by an infusion of 0.1 mug kg min(-1) (group R) or alfentanil 10 mug kg(-1) over 30 s, followed by an infusion of saline (group A). Anaesthesia was then induced with propofol, rocuronium, and 1% isoflurane with 66% nitrous oxide in oxygen. Results. Systolic arterial pressure (SAP) and mean arterial pressure (MAP) decreased after the induction of anaesthesia (P<0.05) and increased for 3 min after intubation in both groups (P<0.05), but remained below baseline values throughout. Heart rate remained stable after induction of anaesthesia but increased significantly from baseline after intubation for I and 4 min in groups R and A, respectively (P<0.05). There were no significant between-group differences in SAP, MAP, and heart rate. Diastolic pressure was significantly higher in group A than group R at 4 and 5 min after intubation (P<0.05), Hypotension (SAP <100 mm Hg) occurred in four patients in group R and three patients in group A. Conclusions. Remifentanil and alfentanil similarly attenuate the pressor response to laryngoscopy and intubation, but the incidence of hypotension confirms that both drugs should be used with caution in elderly patients.