Sample size
BPD, death
The percentage from international databases of infants with GA between 25In a retrospective analysis of our data, the percentage of composite outcome of BPD and death at participating centers was 35%.Assuming the percentage of newborns with death or BPD is 35% (the most conservative condition) in the control group and a decrease to 25% in the experimental group, a sample size of 668 children (334 per arm) is required to obtain a statistical power of 80% with alpha 0.05.An interim analysis will be planned after 167 infants per arm are enrolled (334 total infants enrolled). Based on the results of the interim analysis, the study will continue to be carried out as follows:1: If the statistical 2: If the statistical 3: If the statistical 4: If the statistical Sample size calculations and trial simulations have been performed with R.