Acute respiratory distress syndrome (ARDS) in neonates has been defined in 2017.The death rate is over 50%. HFOV and CMV are two main invasive ventilation strategies. However, which one is better needing to be further elucidated.

Severe acute respiratory distress syndrome (ARDS) is one of the serious complications in critically ill neonates. It can result in severe hypoxemia refractory to mechanical ventilation. Usually, invasive ventilation with low parameters is enough for neonates with mild and moderate ARDS. And extracorporeal membrane oxygenation is used to neonates with severe ARDS. However, extracorporeal membrane oxygenation can also lead to high death rate and need more technique and conditions. Mechanical ventilation with higher parameters was a substitute for such situations, but the death rate, complications and injuries of higher parameters is unknown. The purpose of the present study was to compare HFOV with CMV as invasive respiratory support strategies on decrease the mortality and morbidities in neonate with ARDS.

Inclusion Criteria:

• For a neonate to be included, the following four criteria must be fulfilled: (1)gestational age (GA) between 26+0 and 32+0 weeks (estimated on the postmenstrual date and early gestation ultrasonographic findings); (2)Birth weight less than 2000g; (3) assisted with CMV within 12 h after birth; (4)diagnosis with ARDS and/or RDS. (5)stabilization before randomization within 12 h after birth: FiO2<=0.30, pH>7.20, PaCO2<=60 mmHg, Paw <=7-8 cmH2O;

Exclusion Criteria:

• neonates with at least one of the following criteria are not eligible for the study: (1) Neonates who only needed noninvasive ventilation; (2) major congenital anomalies or chromosomal abnormalities; (3) neuromuscular diseases; (4) upper respiratory tract abnormalities; (5) need for surgery known before the first extubation; (6) Grade Ⅲ-IV-intraventricular hemorrhage (IVH); (7) congenital lung diseases or malformations or pulmonary hypoplasia.