BACKGROUND: Etomidate is frequently used as an induction agent in the elderly patients. We compared the induction dose of etomidate in the elderly patients.

METHODS: Sixty ASA 1-2 patients were randomly allocated to four groups. They were Group 1 (age < 65, receiving 0.2 mg/kg of etomidate, n = 15), Group 2 (age < 65, receiving 0.3 mg/kg of etomidate, n = 15), Group 3 (age ≥ 65, receiving 0.2 mg/kg of etomidate, n = 15), and Group 4 (age > or = 65, receiving 0.3 mg/kg of etomidate, n = 15). The time interval from etomidate infusion to loss of verbal response and eyelash reflex, to decrease BIS 50, to return of bispectral index (BIS) 50 were measured. Mean arterial pressure (MAP), heart rate (HR), responses to isolated forearm test and postoperative recall were recorded.

RESULTS: Time interval were not significantly different between groups. BIS value did not show statistical differences between groups, though value of group 1 at 1 min after intubation was higher than that of group 2. MAP and HR were increased after intubation in 4 groups. The changes in MAP were significantly different between group 1 and 2. Isolated forearm test was positive in 10, 6, 4, 3 patients in groups 1, 2, 3 and 4, respectively. Only 1 patient in group 1 showed postoperative recall.

CONCLUSIONS: Age does not influence the BIS value in these etomidate doses. Loss of consciousness and hemodynamic changes during induction with 0.2 mg/kg of etomidate were inappropriate in younger patients, whereas they were appropriate with 0.2 and 0.3 mg/kg of etomidate in the elderly patients.