1. Department of Anesthesia, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
2. Department of Anesthesia, Chinese People's Liberation Army No. 94 Hospital, Nanchang, Jiangxi 330002, P.R. China
3. Department of Anesthesia, Ganzhou People's Hospital, Ganzhou, Jiangxi 310000, P.R. China