1. Department of Anesthesiology, The Eighth People's Hospital of Guangzhou Affiliated to Guangzhou Medical College, Guangzhou, Guangdong 510060, P.R. China
2. Department of Anesthesiology, Affiliated Foshan Hospital of Sun Yat‑sen University, Foshan, Guangdong 528000, P.R. China
3. Department of Anesthesiology, Central Hospital of Panyu District, Guangzhou, Guangdong 510060, P.R. China