Department of Intensive Care Unit of Cardiovascular Surgery, Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 96 Dongchuan Road, Guangzhou, 510080, Guangdong, China. Guangdong General Hospital, School of Medicine, South China University of Technology, 106 Zhongshan Er Road, Guangzhou, 510080, Guangdong, China. Department of Critical Care Medicine, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan Er Road, Guangzhou, 510080, Guangdong, China. Department of Critical Care Medicine, Xiaolan People's Hospital of Zhongshan, Zhongshan, Guangdong, China. Department of Intensive Care Unit, People's Hospital of Baise, Baise, Guangxi, China. Department of Surgical Intensive Care Unit, The First Affiliated Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China. Department of Critical Care Medicine, Xinjiang Kashgar First People's Hospital, Kashgar, Xinjiang, China. Department of Emergency, Cangzhou Central Hospital, Cangzhou, Hebei, China. Department of Intensive Care Unit, Yangjiang City People's Hospital, Yangjiang, Guangdong, China. Department of Intensive Care Unit, Chaozhou People's Hospital, Chaozhou, Guangdong, China. Department of Epidemiology, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan Er Road, Guangzhou, 510080, Guangdong, China. Department of Intensive Care Unit of Cardiovascular Surgery, Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 96 Dongchuan Road, Guangzhou, 510080, Guangdong, China. gghccm@163.com.