Abstract: Objective To investigate the blood gas indexes of hospitalized neonates with blood transfusion nationwide,and provide data support for in-depth research on the reference range of blood gas in newborns at different stages. Methods We conducted a multi-center retrospective study of 5 669 newborns with blood transfusion admitted to 46 hospitals in China between January 1, 2017 and June 30, 2018 as the research objects. According to a unified data collection table, the diagnosis and treatment data of hospitalized newborns were collected. Based on the gestational age, these newborns were categorized into three groups：<32 w group, 32~36 w group, and ≥37 w group. The blood gas values were statistically analyzed. Results The pH value of newborns fluctuated slightly with the increase of gestational age and age, but the overall trend generally increased. PO₂ showed that the <32 w group showed a decreasing trend with increasing age, and the ≥37 w group increased from 0~1 day （61.80 mmHg） to 4~5 days （72.50 mmHg） and then stabilized. Comparison of PO₂ among the three groups at the same age, PO₂ in preterm infants was greater than that of full-term infants at 0~3 days. PCO₂ showed that PCO₂ gradually decreased with the increase of gestational age among the three groups at the same day. The HCT value showed a gradual decrease trend with the increase of day and gestational age. SaO₂ showed that the ≥37 w group increased from 0~1 day （93%） to 2~3 days （96.40%） and then stabilized. Conclusion Changes in blood gas related indexes of newborns with different gestational ages and days of ages were significant. The reference ranges of neonatal blood gas indexes based on gestational age can help guide the clinical accurate diagnosis and treatment of neonatal diseases.

Key words: Newborn, Blood gas index, Reference range