1. The Second Clinical Medical School of Lanzhou University, Lanzhou, Gansu 730030, P.R. China
2. Department of Surgical Oncology, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
3. Department of Critical Care Medicine, The Donggang Branch of The First Hospital of Lanzhou University, Lanzhou, Gansu 730030, P.R. China
4. Department of Critical Care Medicine, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
5. Department of General Surgery, The Second Hospital of Lanzhou University, Key Laboratory of Digestive System Tumors of Gansu Province, Lanzhou, Gansu 730030, P.R. China