Fu-Shan Xue1, Chao Sun2, Gao-Pu Liu2, Gui-Zhen Yang2. 1. Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. Electronic address: xuefushan@aliyun.com. 2. Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.