1. Department of Medicine, Xi'an Peihua University, Xi'an, Shaanxi 710125, P.R. China
2. Department of Neurosurgery, Jinan Jiyang District People's Hospital, Jinan, Shandong 251401, P.R. China
3. Department of Intensive Care Medicine, College of Anesthesiology, Weifang Medical University, Weifang, Shandong 261053, P.R. China