The traditional concept believes that the etiology of neonatal respiratory distress syndrome (RDS) is immature development of lung,especially the surfactant synthesis system,and RDS is still one of the major causes of mortality and morbidity in newborns, especially premature infants[1].In recent years, using pulmonary surfactant replacement therapy (PS treatment) in the treatment of respiratory distress syndrome (RDS) is a major breakthrough in neonatal medicine [2].Combined with clinical practice and experience,and through Meta analysis of related randomized controlled trials (RCTs),it confirms that natural surfactant treatment can reduce mortality,the incidence of pulmonary air leaks (pneumothorax and interstitial lung emphysema),and the incidence of bronchopulmonary dysplasia (BPD) or 28-day-old mortality.For RDS in preterm infants whose gestation is <35 weeks ,surfactant replacement therapy is also more effective than in nearly term and full term infants.Therefore, in the analysis of cases of different gestational age groups,the investigators should focus on the study of premature infants cases.Due to less relevant research for using PS treatment to cure newborn RDS in high altitude area,this retrospective study conducts statistics and analysis of recently three-year cases in some hospital of high altitude area,to explore the treatment effect of the high altitude region and the impact of altitude on the treatment.

in order to explore feasibility and efficacy for PS treatment of newborn RDS in high-altitude area ,and its efficacy at different altitudes, the investigators conduct a multi-center retrospective study of RDS cases in Qinghai and Tibet these two high-altitude area,and use RDS cases under the unique conditions to do statistics and analysis.

Inclusion Criteria:

• diagnosed with respiratory distress syndrome(RDS)

Exclusion Criteria:

• major congenital abnormalities

the preterm infants less than 37 weeks were included in the study