1. Department of Anesthesiology, Affiliated Hospital of Chengde Medical University, Chengde City, 067000, P.R. China
2. Department of Laboratory Medicine, Affiliated Hospital of Chengde Medical University, Chengde City, 067000, P.R. China
3. Department of Gastrointestinal Surgery, Affiliated Hospital of Chengde Medical University, Chengde City, 067000, P.R. China