研究目的:
Neonatal respiratory distress syndrome (RDS) remains a major respiratory disorder for the increasing preterm population, and its incidence has been confirmed to be increased gradually with decreased gestational age. Previous studies demonstrated incidences of 90% at 24 weeks', 80% at 28 weeks', 57% at 30-31 weeks', and 25% at 35-36 weeks' gestational age(GA). However, these figures were mainly performed in the pre-neonatal acute respiratory distress syndrome (ARDS) era, in which ARDS was usually considered as RDS, and surfactant was therefore used repeatedly. In fact, no studies have indicated beneficial effects of surfactant for adult and pediatric ARDS, and therefore, its exact action for neonatal ARDS was needed to be further elucidated. In 2017, the international ARDS collaborative group provided the first consensus definition for neonatal ARDS, and the exact incidence of neonatal ARDS and mortality were unknown.