BACKGROUND: Intravenous alfentanil is one of the effective methods to minimize the hemodynamic responses to laryngoscopy and endotracheal intubation. The purpose of this study is to get effective dose (ED50, ED95) of alfentanil to minimize the hemodynamic responses to laryngoscopy and endotracheal intubation.

METHODS: Sixty patients were divided into four groups. Each group received intravenous normal saline 5 ml (Control group), alfentanil 10µg/kg (Al10), alfentanil 20µg/kg (Al20) and alfentanil 30µg/kg (Al30), respectively. Mean arterial pressure (MAP) and heart rate (HR) were measured before and after intubation. We considered the doses of alfentanil effective when the increase in MAP and HR after intubation did not exceed 10% of those before intubation.

RESULTS: The ED50 of alfentanil was 12.7 (8.6-16.4)µg/kg for MAP, 20.1 (15.7-25.6)µg/kg for HR, respectively. The ED95 of alfentanil was 26.4 (21.7-36.2)µg/kg for MAP, 38.6 (31.2-56.7)µg/kg for HR, respectively.

CONCLUSIONS: Alfentanil was effective to minimize the hemodynamic responses to laryngoscopy and endotracheal intubation with its ED50 and ED95 as mentioned earlier.