The main variable will be the need for endotracheal intubation. This will be defined as the need to use the fraction of inspired oxygen (FiO2) greater than 0.30 and 7 cmH2O or more of CPAP pressure for maintaining a target oxygen saturation of 88-94 % for preterm infants with gestational age less or equal to 27 6/7 weeks, or a FiO2 higher than 0.35 and 7 cmH2O or more of CPAP pressure for maintaining a target oxygen saturation of 88-94 % for preterm infants with gestational age higher or equal to 28 0/7 weeks gestation.