Comparison with other studies
A lot of research has varified the diagnostic value of LUS on neonatal lung diseases2, 28, 33-34. The difference between theirs and ours is we focused on predictive value. As we found these abnormal LUS sign at early stage right after birth do not have significant specificity for certain diseases, we only use LUS to predict respiratory need that concerns all kinds of severe lung diseases. Recently, some study also paied attention to predictive value of LUS in neonatology14-16, 35. They evaluated mostly predictive value of PS need in preterm infants whereas we study need of all kinds of respiratory support, including CPAP and MV that closely relate to severe lung disease. So we believe our study is a good complement to current studies and very useful since it can provide evidence to offer early interventions to those high risk infants.