1. Intensive Care Unit, The Affiliated Hospital of Guilin Medical University, Guilin, Guangxi Zhuang Autonomous Region 541001, P.R. China
2. Department of Cardiology, Foresea Life Insurance Nanning Hospital, Nanning, Guangxi Zhuang Autonomous Region 530000, P.R. China
3. Department of Physiology, Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530000, P.R. China