Dose-response relationship of alfentanil inhibiting gag reflex when combined with propofol in elderly patients undergoing painless gastroscopy / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the dose-response relationship of alfentanil inhibiting gag reflex when combined with propofol in elderly patients undergoing painless gastroscopy.Methods:Patients of American Society of Anesthesiologists physical statusⅠor Ⅱ, aged ≥60 yr, scheduled for elective painless gastroscopy, were selected. Propofol 1.5 mg/kg combined with alfentanil was given intravenously in all the patients. The dose of alfentanil was determined by the Dixon up-and-down method. The initial dose of alfentanil was set at 5 μg/kg. The dose of alfentanil in the next patient was determined according to the development of gag reflex, and the ratio between the two successive doses was 1.1. The median effective dose (ED 50) and 95% confidence interval of alfentanil-induced inhibition of gag reflex when combined with propofol in elderly patients undergoing painless gastroscopy were calculated using the by up-and-down sequential allocation. Results:The ED 50 (95% confidence interval) of alfentanil-induced inhibition of gag reflex when combined with propofol 1.5 mg/kg was 2.8 (2.4-3.2) μg/kg in elderly patients undergoing painless gastroscopy. Conclusion:When combined with propofol 1.5 mg/kg, the ED 50 of alfentanil inhibiting gag reflex is 2.8 μg/kg in elderly patients undergoing painless gastroscopy.