OBJECTIVE: To probe into the effects of different administration timing of pulmonary surfactant on airway inflammation and pulmonary injury in children with neonatal respiratory distress syndrome（NRDS）. METHODS: A total of 63 children with NRDS admitted into the hospital from Oct. 2019 to Oct. 2021 were extracted to be divided into the early-stage group

intermediate-stage group and late-stage group via the random number table method

with 21 cases in each group. All three groups were treated with pulmonary surfactant injection. The early-stage group was given pulmonary surfactant injection within 4 h after birth

the intermediate-stage group was given pulmonary surfactant from 4 to 8 h after birth

and the late-stage group was given pulmonary surfactant more than 8 h after birth. Rehabilitation process

incidence of adverse events and blood gas analysis indicators [arterial partial pressure of oxygen（PaCO

2

）

arterial partial pressure of oxygen（PaO

2

）

inspired oxygen concentration(FiO

2

]

and pulmonary injury indicators [pulmonary surfactant relate-staged protein A（SP-A）

Toll-like receptor 4（TLR-4）

Toll-like receptor 2（TLR-2）]

airway inflammation indicators [nuclear factor-kB（NF-κB）

c-Jun N-terminal protein kinase（JNK）] before and after treatment were counted among three groups. RESULTS:（1） After treatment of 24 h

the levels of PaCO

2

FiO

2

SP-A

TLR-4

TLR-2

NF-κB and JNK in the early-stage group were lower than those in the intermediate-stage group and late-stage group

and PaO

2

was higher than that in the intermediate-stage group and late-stage group（P

<

0.05）. After treatment of 24 h

there was no significant difference in above indicators between the intermediate-stage group and late-stage group（P

>

0.05）.（2） The duration of oxygen therapy and mechanical ventilation in the early-stage group were shorter than those in the intermediate-stage group and late-stage group

the differences were statistically significant（P

<

0.05）. There were no significant differences in the duration of oxygen therapy and mechanical ventilation between the intermediate-stage group and late-stage group（P

>

0.05）. There was no significant difference in the length of stay among three groups（P

>

0.05）.（3） There were no significant differences in the incidence of adverse events and mortality among three groups（P

>

0.05）. CONCLUSIONS: Different timings of pulmonary surfactant administration have significant differences in the effects of pulmonary surfactant in children with NRDS. Among them

administration within 4 h of birth can significantly improve the blood gas indicators

reduce the airway inflammation

and delay the pulmonary injury.