Induction of anaesthesia with eltanolone at different rates of infusion in elderly patients

We have determined the effective dose of eltanolone (pregnanolone) required to induce anaesthesia in 30 ASA I and II patients aged 60 yr and over. Eltanolone 4 mg ml-1 was administered at a rate of 300 ml h-1 (group 1), 600 ml h-1 (group 2) or 1200 ml h-1 (group 3) until loss of consciousness, as judged by loss of verbal contact with the patient. Anaesthesia was induced successfully in all patients. The slower rates of induction were associated with a significant increase in induction time (ANOVA, P < 0.01) and a decrease in the induction dose (P < 0.01). There was a significant reduction in systolic arterial pressure after induction of anaesthesia in groups 2 and 3 (MANOVA, P < 0.01). This study suggests that the induction dose of eltanolone in unpremedicated older patients should not exceed 0.6 mg kg-1.