1. Department of Internal Medicine, The Second Hospital of Shandong University, Jinan, Shandong 250033, P.R. China
2. Department of Anesthesiology, Jinan Central Hospital, Jinan, Shandong 250013, P.R. China
3. Department of Thoracic Surgery, Affiliated Hospital of Shandong Academy of Medical Sciences, Jinan, Shandong 250031, P.R. China