Department of Anesthesia First Affiliated Hospital of Xi''an Jiaotong University Xi''an710061 Shaanxi China;
Department of Anesthesia Ali people''s Hospital Ali region Tibet859400 China;
Department of Neurology The first affiliated Hospital of Xi''an Medical College Xi''an710061 Shaanxi China;
Dexmedetomidine; Sufentanil; Leg fracture; General anesthesia; Awakening period;