Abstract: Abstract Objective: To evaluate the effect of haemodynamic changes during induction of general anesthesia and the dexmedetomidine-sparing effect of anesthetics in abdominal surgery patients undergoing general anaesthesia. Methods: This was a prospective, randomized, double-blind, placebo-controlled study. 48 patients (ASA I～II) aged 18 to 65 years old undergoing abdominal operation under general anesthesia were randomly divided into group D(intravenous 1μg ?kg-1 Dex for 10 min before induction of general anesthesia) and group C (0.9% normal saline was given as control). The haemodynamic changes including blood pressure and heart rate during induction of general anesthesia was observed, and the consumption of anesthetics was recorded. Results: The heart rate was significantly decreased in group D than that in group C after DEX administration（P＜0.01）. The minimum of blood pressure was significantly increased in group D than that in group C before tracheal intubation（P＜0.01）, while the minimum of heart rate was contrary. The maximum of heart rate was significantly decreased in group D than that in group C after tracheal intubation（P＜0.01）.The consumption of anesthetics was significantly less in group D than that in group C（P＜0.05）. Conclusion: Dexmedetomidine can attenuate hemodynamic responses and reduce requirements of propofol, fentanyl and sevoflurane. Dexmedetomidine play a very good complementary role in general anesthesia.

Key words: dexmedetomidine, general anesthesia, haemodynamics, anesthetics, sparing