1. Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, China
2. Medical College of Xiangya, Central South University, Changsha, China
3. Department of Anesthesiology, People’s Hospital of Yuxi City, Yuxi, China
4. National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China