ARDS :Pediatric acute respiratory distress syndrome (ARDS) is a severe lung injury caused by pneumonia, sepsis, and trauma.Diagnostic criteria: 1.Acute onset；2.FiO2/ PaO2＜ 26.7 kPa (200mmHg, ARDS); 3.Chest X-ray showed that the double lung transparent brightness is generally lower, the glass sample, with bronchial inflatable sign, and even double lung field common density increased, the heart shadow is not clear, a white lung, as the most important performance；4. Echocardiography, left atrial hypertension; 5.The gestational age >35 week, have maternal age cholestasis (severe), sepsis or meconium aspiration syndrome (MAS) understanding of history, and with the exception of the primary pulmonary surfactant (PS) lack of；6.Need to use a ventilator.