Clinical Study on the Safety and Preliminary Efficacy of hUC-MSCs Intravenous Infusion Therapy for ARDS

Inclusion Criteria: 1. Age greater than 18 years, regardless of gender; 2. Meeting the ARDS Berlin diagnostic criteria; 3. Definite diagnosis within 72 hours; 4. P/F \< 150mmHg; 5. Understanding and signing informed consent. Exclusion Criteria: 1. Women of childbearing potential with a positive serum pregnancy test before medication, pregnant women, or lactating women; 2. ARDS directly caused by physical or chemical factors; 3. Moderate to severe liver damage (Child-Pugh score \>12); 4. Chronic heart failure, New York Heart Association functional class IV; 5. Severe kidney disease undergoing renal replacement therapy; 6. Severe lung disease, Grade III or IV pulmonary hypertension, receiving oxygen therapy or ventilator support for more than one month in the six months prior to screening, end-stage lung disease, or severe physical limitations due to chest wall deformity; 7. Immunodeficiency, receiving immunosuppressive therapy within 2 weeks (except for low-dose corticosteroids), or with lymphoma, leukemia, or acquired immune deficiency syndrome; history of organ transplantation, bone marrow transplantation, or autologous hematopoietic stem cell suppression; 8. Expected survival time of less than 48 hours due to terminal illness; 9. Patients diagnosed with deep vein thrombosis (DVT) or pulmonary embolism (PE) in the past three months; 10. Patients receiving ECMO therapy; 11. Hepatitis B, hepatitis C, syphilis, or HIV infection. 12. eGFR \< 30ml/min/BSA; 13. ALT \> 5 × ULN; 14. Absolute neutrophil count \< 1500/μL; 15. Subjects who have participated in other clinical studies within the past month (excluding those who have not received intervention), or are currently participating in other experimental treatments; 16. Subjects deemed unlikely to benefit from the study by the investigator, or deemed unsuitable for participation in this study.