Clinical Trial of Lyophilized Powder for inhalation of Recombinant Human Keratinocyte Growth Factor-2 (Rh-KGF-2) in The Treatment of Patients with Acute Respiratory Distress Syndrome

INTERVENTION: Experimental group:rhKGF‐2 drug product;Control group:Maintain previous treatment; CONDITION: Acute respiratory distress syndrome (ARDS) PRIMARY OUTCOME: Incidence of Sereve Adverse Events;Incidence of Adverse Events;Various Laboratory Parameters; INCLUSION CRITERIA: 1.Aged 18‐80; 2.Definitely diagnosed as Acute Respiratory Distress Syndrome according to the Berlin Definition; 3.Patients with a PaO2/FiO2 ratio < 200 mmHg undergoing invasive mechanical ventilation via endotracheal tube. 4.Patients diagnosed with ARDS within 72 hours prior to enrollment. 5.Those who have no plan for childbearing within the next year and agree to take effective contraceptive measures during the study period; women of childbearing age must have a negative serum pregnancy test. 6.Subjects fully understand the purpose of the trial, the nature and methods of the drug study, and the possible adverse reactions. They voluntarily sign the informed consent form to participate in the trial and agree to comply with the requirements of the trial protocol.