Discussion
BPD, death
RECRUITMENT
Functional LU has proven to be an important imaging technique in NICU to reduce radiation exposure [Current European recommendations consider LU a useful adjunct to determine RDS severity in experienced hands [In conclusion, relying only on the FiOOur hypothesis is that LUS may predict more accurately which preterm infants, assisted in nCPAP for RDS, may benefit from early surfactant administration. Instead of evaluating only the oxygen requirements, the use of semi-quantitative LU allows quantification of RDS severity in a score (LUS). LUS estimates the degree of lung aeration or lung recruitment, which reflects the amount of alveolar surface available for gas exchange. This hypothesis was confirmed by the ULTRASURF study [Therefore, we designed a study which overcomes these limitations. Specifically, we aimed to recruit a large cohort of patients and calculate a sample size powered to demonstrate an improvement in the composite clinical outcome of BPD or death; we stratified the recruitment for gestational age to include an adequate proportion of extremely preterm neonates; and we included several centers in different European countries to allow for an improved generalizability of the study results.All the participating centers have considerable experience in LU, LUS calculation, and non-invasive respiratory support. Moreover, in the preliminary meetings, we discussed respiratory management during the first hours of life and reached a consensus in order to uniform and standardize the respiratory management among the participating centers as much as possible to limit possible sources of bias.There are some limitations in our study design. First, the participating centers adopt different methods of surfactant delivery: LISA, INSURE, and IN-REC-SURE. Second, once the patient has received SRT, different respiratory strategies and devices are used to deliver non-invasive respiratory support among participating centers. However, although there is variability between centers, the same protocol is adopted within the center. Since we randomize on center, this is likely not to affect the differences between the two groups within the center.