1. a Department of General Thoracic surgery , General Hospital of Ningxia Medical University , Yinchuan, Ningxia , China
2. b Respiratory and Critical Care Medicine, General Hospital of Ningxia Medical University , Yinchuan, Ningxia , China
3. c Department of Nursing , General Hospital of Ningxia Medical University , Yinchuan, Ningxia , China
4. d School of Nursing, Ningxia Medical University , Yinchuan City, Ningxia , China