1. Department of Orthopaedic Surgery; Peking Union Medical College Hospital; Peking Union Medical College; Beijing 100007 China
2. Department of Anaesthesia and Intensive Care; The Chinese University of Hong Kong; Hong Kong 999077 China
3. State-Key Laboratory of Digestive Disease and Institute of Digestive Disease; LKS Institute of Health Science; The Chinese University of Hong Kong; Hong Kong 999077 China