1. Department of Anesthesiology, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
2. Department of Anesthesiology, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
3. Department of Pharmacology, Ningxia Hui Medicine Modern Engineering Research Center and Collaborative Innovation Center, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China