Additional analyses
IVH
PNEUMOTHORAX
An interim analysis will be planned after 167 infants are enrolled for each arm (334 total infants enrolled). The analysis will aim to compare treatment arms with respect to efficacy, safety, futility, and, if necessary, a sample size adjustment. In the interim, the prespecified stopping rules for safety are: a mortality rate > 40%, a rate of severe IVH > 30%, and a pneumothorax rate of > 10% in the LUSG compared to CG. The interim analysis will be performed by an independent statistician, blinded for treatment allocation. The statistician will report to the independent Data and Safety Monitoring Board (DSMB) which will have unblinded access to all data and will discuss the results of the interim analysis with the Steering Committee in a joint meeting. The Steering Committee will decide whether to continue the trial and will report to the central Ethics Committee.