Objective To investigate the value of lung ultrasound in the dynamic observation of pulmonary surfactant (PS) in the treatment of respiratory distress syndrome(RDS) in premature infants. Methods Thirty preterm infants diagnosed with RDS were transferred from our obstetrics department to the neonatal intensive care unit from June to December 2018 prospectively. Lung ultrasound was performed and scored before and after PS use at 6h

12h

18h

and 24h. The aim was to observe the effect of PS on preterm neonates with RDS and the dynamic change of lung ultrasound at different times. Results Before the use of PS

16 cases (53%) of the children showed bilateral white lung in lung ultrasound

14 cases (47%) of alveolar interstitial syndrome

and 11 cases (37%) of subpleural lung consolidation; after 6 hours of PS use

3 cases (10%) showed bilateral white lung

and 2 cases (6.7%) showed subpleural lung consolidation

which was significantly better than that before PS use

and the difference was statistically significant (c2 were 11.09 and 6.29

respectively; P was 0.001 and 0.012

respectively). At 12h

18h

and 24h after PS use

bilateral white lung and lung consolidation were not seen in the lung ultrasound of all preterm neonates with RDS. Compared with that before PS

the difference was statistically significant (c2 = 19.18

P <0.001)

but the difference was not statistically significant compared with that at 6 hours after PS use (c2 = 1.40

P = 0.24). Further

lung ultrasound score was used for analysis. The lung ultrasound score at 6h

12h

18h

and 24h after PS was 19.3 ± 4.0

17.4 ± 3.9

17.6 ± 4.0

and 17.9 ± 4.2

respectively

which was lower than that before PS use. And the difference was statistically significant (all P< 0.05). However

the differences of lung ultrasound score at 6h

12h

18h

and 24h after PS use were not statistically significant (all P> 0.05). Conclusion Lung ultrasound can dynamically evaluate the effect of PS in the treatment of preterm neonates with RDS. After 6 hours of PS

the pulmonary condition can be improved significantly.