Optimal Dose of Surfactant for Preterm Infants With Respiratory Distress Syndrome

To date, the optimal dose of PS is inconsistent, although the recommended dose of PS is given in the 2019 update guideline. PS is not recommended to adult and pediatric ARDS. Systematic review indicates that PS does not reduce the incidences of BPD and death in infants with meconium aspiration syndrome(MAS, a subtype of NARDS). A reasonable speculation is that preterm infants with NARDS do not benefit from PS. And the speculation can explain why not all preterm infants with RDS can be beneficial from PS. In the era of pre-NARDS, the preterm infants fulfilling the definition of NARDS may have been considered as RDS in the first three days after birth. Meantime, the dose of PS given to infants with NARDS remains unknown. the aim of the present study is to assess the optimal dose of PS. the control group: PS is given according to the European RDS management guideline in 2019 edition. The study group: PS is stopped when the pressure is equal between before patent ductus arteriosus(bPDA) and after PDA(aPDA). the primary outcomes are the closure rate of PDA within 7 days, the incidence of BPD and/or death.