1. Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China;
2. Department of General Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China;
3. Department of Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shannxi, China