1. Department of Anesthesiology, Zhangqiu District Maternal and Child Health Care Hospital, Jinan, Shandong 250200, P.R. China
2. Department of Anesthesiology, The Third Hospital of Jinan, Jinan, Shandong 250032, P.R. China
3. Department of Operating Room, Zhangqiu District Maternal and Child Health Care Hospital, Jinan, Shandong 250200, P.R. China
4. Department of Cardiovascular Medicine, The People's Hospital of Zhangqiu Area, Jinan, Shandong 250200, P.R. China
5. Department of Burn and Plastic Surgery, The People's Hospital of Zhangqiu Area, Jinan, Shandong 250200, P.R. China
6. Department of Anesthesiology, Jining No. 1 People's Hospital, Jining, Shandong 272011, P.R. China
7. Department of Anesthesiology, People's Hospital of Gaomi, Gaomi, Shandong 261500, P.R. China