“…7,8,13,19,[21][22][23] Moreover, in other studies in the literature, using wider FiO 2 for indicating surfactant retreatment, such as the use of FiO 2 <0.3 and early rescue, multiple doses of surfactant were not associated to adverse outcomes. 7,8,13,19,[21][22][23] Therefore, we considered that the value of FiO 2 >0.4 for indicating the retreatment of patients under 26 weeks might have favored the association with bronchopulmonary dysplasia. Lim et al demonstrated that the use of surfactant with FiO 2 >0.3 in 25-28 weeks gestational age neonates is related to worse outcomes (bronchopulmonary dysplasia, death, necrotizing enterocolitis, and other morbidities) and the more recent European consensus guideline on the management of respiratory distress syndrome suggests surfactant administration when FiO 2 >0.3 is needed in all gestational ages.…”