1. Department of Hepatobiliary Surgery, Qilu Hospital, Shandong University, Jinan, Shandong 250012, P.R. China
2. Department of Anesthesiology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
3. Department of Hepatobiliary Surgery, The People's Liberation Army General Hospital, Beijing 100853, P.R. China