BACKGROUND: Propofol and alfentanil are frequently combined for general anesthesia. However, hypotension and bradycardia are common during anesthetic induction and maintenance. The purpose of this study was to compare the response of different doses of ephedrine to investigate an optimal dose of ephedrine for attenuation of the hemodynamic changes.

METHODS: Eighty patients of ASA physical status 1 or 2 were assigned to one of four groups. Each patient received normal saline (E0), ephedrine 0.15 mg/kg (E15), 0.2 mg/kg (E20), 0.25 mg/kg (E25) after assessment of baseline hemodynamic values. If hemodynamic parameters are stabilized after intubation, baseline values were assessed by average during 3 minutes. Then each dose of ephedrine was given to each patient. The changes in systolic/diastolic blood pressure (SBP/DBP), mean arterial pressure (MAP), and heart rate (HR) were measured every one minute for 10 minutes.

RESULTS: The use of ephedrine was effective for attenuation of the hemodynamic changes. E15, E20, and E25 showed statistical difference in BP and HR compared with E0. There was no statistical difference between E20, E25. Moderate hypertension (SBP 160-179 or DBP 100-109) is occurred each 4, 6 cases in E20, E25.

CONCLUSIONS: All group of ephedrine injection resulted in elevation of BP, but did not caused HR change. Injection of ephedrine 0.2 mg/kg or 0.25 mg/kg led to excessive blood pressure elevation. Therefore, we consider more than 0.15 mg/kg of ephedrine is not necessary to minimize hemodynamic changes during propofol-alfentanil anesthesia.