ARDS is a severe disease in ICU, and could induce high mortality. Glycocalyx is an important matrix construction which covers endothelial cells, it could protect endothelial cells injury and the glycocalyx biomarkers could predict pulmonary injury.

Decorin is a member of the small leucine-rich proteoglycan (SLRP) family, contains a single glycosaminoglycan (GAG) chain and a core protein with 12 leucine-rich repeats. In the previous study, decorin is associated with cardiac and liver fibrosis, however, the effects of decorin on ARDS pulmonary fibrosis have not been clarified.

Inclusion Criteria:

1. Age > 18yrs and <80yrs
2. Meet ARDS Berlin definition
3. With mechanical ventilation

Exclusion Criteria:

1. have chronic pulmonary disease
2. have use heparin or low molecular heparin or chondroitin sulfuric acid

patients have been diagnosed ARDS with mechanical ventilation, and do not been used heparin, molecular heparin, chondroitin sulfuric acid.