1. Department of Emergency, Panyu Maternal and Child Care Service Centre of Guangzhou, Hexian Memorial Affiliated Hospital of Southern Medical University, Panyu, Guangzhou 511400, Guangdong Province, China
2. Department of Respiratory Medicine, Panyu Maternal and Child Care Service Centre of Guangzhou, Hexian Memorial Affiliated Hospital of Southern Medical University, Panyu, Guangzhou 511400, Guangdong Province, China