1 West China School of Medicine, Sichuan University, Chengdu City, Sichuan Province, PR China.
2 Anesthesia & Operation Center of West China Hospital, Sichuan University, Chengdu City, Sichuan Province, PR China.
3 Anesthesia & Operation Center of West China Hospital, Sichuan University, Chengdu City, Sichuan Province, PR China. Electronic address: linjing@wchscu.cn.