1. Intensive Care Unit, West China Hospital of Sichuan University, Chengdu 610041, China
2. Intensive Care Unit, The Third People’s Hospital of Chengdu City, Sichuan 610031, China
3. Department of Respiratory Medicine, The People’s Hospital of Pujiang County, Sichuan 611630, China
4. Department of Anaesthesiology, West China Hospital of Sichuan University, Chengdu 610041, China