1. Department of pulmonary diseases, Heilongjiang Academy of Traditional Chinese Medicine, 33# Xidazhi Street, Harbin 150036, Heilongjiang, China
2. Department of Respiratory Medicine, Fourth Affiliated Hospital, Harbin Medical University, 37# Yiyuan Street, Harbin 150001, Heilongjiang, China
3. Department of Intensive Care Unit, Fourth Affiliated Hospital, Harbin Medical University, 37# Yiyuan Street, Harbin 150001, Heilongjiang, China
4. University of Tokyo, 3-8-1# Bunkyo ku, Tokyo 1130033, Tokyo, Japan