Clinical Trial of CG-BM1 Allogeneic Human Bone Marrow Mesenchymal Stem Cell Injection in the Treatment of Acute Respiratory Distress Syndrome

• Age ≥18 years; male or female.
• Currently receiving mechanical ventilation; confirmed or clinically diagnosed infection-induced moderate-to-severe ARDS; diagnosis of moderate-to-severe ARDS meets the 2012 Berlin Definition.
• No improvement in moderate-to-severe ARDS after 24 hours of conventional clinical treatment. No improvement is defined as PaO2/FiO2 remaining ≤200 mmHg after 24 hours of the above conventional conservative treatment, or from a value above 200 mmHg to ≤200 mmHg; for severe ARDS, this period may be shortened to 8 hours.
• No possibility of conception (or impregnating a sexual partner), childbearing, or breastfeeding during the study period and for 6 months after cell infusion.

Exclusion Criteria:

• More than 7 days since first meeting ARDS criteria (2012 Berlin Definition) at enrollment.
• Pregnancy or breastfeeding.
• History of malignancy requiring treatment within the past 2 years or malignancy requiring treatment at screening.
• At screening, grade 3 or 4 pulmonary hypertension or severe chronic respiratory disease with PaCO2 >50 mmHg; history of severe end-stage lung disease.
• At screening, large pleural effusion or atelectasis that is not promptly resolved or rapidly recurs after resolution (chest X-ray showing >50% unilateral lung atelectasis).
• At screening, severe cardiopulmonary malformation affecting cardiopulmonary function.
• Prior lung transplantation.
• Deep vein thrombosis at screening or history of pulmonary embolism within 3 months before screening.
• Transfusion-related adverse reaction within 4 weeks before admission.
• Active bleeding within the past 24 hours requiring massive transfusion support.
• Cardiac arrest within 4 weeks before admission.
• Positive HIV antibody or positive Treponema pallidum antibody at screening.
• Hepatic failure at screening (MELD score >30).
• Long-term hemodialysis, known severe renal impairment (estimated glomerular filtration rate \<30 mL/min/1.73 m2), or current use of extracorporeal membrane oxygenation (ECMO).
• Severe cerebral herniation at screening.
• Expected survival \<24 hours.
• Invasive blood pressure and central venous pressure are not monitored or not planned to be monitored.
• Participation in another interventional clinical trial within 3 months or 5 half-lives before infusion.
• Any other factor that, in the investigator's judgment, makes the participant unsuitable for this trial.
• . Known hypersensitivity to any component of the study drug (the main component is bone marrow mesenchymal stem cells; excipients include dimethyl sulfoxide, human serum albumin,etc.).