Excluding studies with high risk of bias
When studies with high risk of bias were excluded, there was no difference in efficacy between any of the NRS modalities for the outcome MV. The results were unchanged for other outcomes (E-Figure 10 and E-Figure 11).Excluding studies which had enrolled neonates who had already received surfactantThe results were unchanged after excluding trials that had enrolled neonate who had already received surfactant prior to randomisation