Intervention
Infants will be allocated in one of the two treatment groups in a 1:1 ratio according to the minimization method, using an interactive web-based electronic system.Infants will be electronically randomized into two groups:Control group (CG): surfactant administration when FiOLUS group (LUSG): surfactant administration when LUS > 8 on nCPAP (positive pressure 6–8 cmHThe LUSG will receive SRT as rescue therapy in case of LUS ≤ 8 but FiOThe cut-off of LUS > 8 is in agreement with previous studies [