1. Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P.R. China
2. Department of Anesthesia, First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
3. Department of Thoracic Surgery, First Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China