Preterm infants are eligible to the study if they they match the following inclusion criteria: (1) Gestational age between 240/7 and 286/7 weeks; (2) diagnosis of RDS. The diagnosis of RDS will be based on clinical manifestations (tachypnea, nasal flaring and or grunting) and a fraction of inspired oxygen (FiO2) greater than 0.25 for target saturation of peripheral oxygen (SpO2) 89% to 94%;; (3) Age less than 2 hours; (4)Informed parental consent has been obtained.~Neonates will be randomized and assigned either to nCPAP or NHFOV arms with a 1:1ratio, when patients fulfill all inclusion criteria. Randomization cannot be done earlier. Simple randomization will be done according to a computer-generated random number table and will be posted in a specific secured website 24/7 available. Twins will be allocated in the same treatment group. Infants randomized to one arm cannot crossover to the other or vice- versa during the study. For all the groups, if the fraction of inspired oxygen (FiO2) requirement is persistently higher than 0.30 per target SpO2 89-94% after starting the respiratory support, newborns receive Surfactant by LISA technique, administration of surfactant (Curosurf,Chiesi Pharmaceutics, Parma, Italy) 200 mg/kg.~After the administration of surfactant, if FiO2 requirement is persistently >0.4 to keep SpO2 89-94% or severe apnea episodes are present (defined as recurrent apnea with >3 episodes/h associated with heart rate <100/min or a single episode of apnea requiring bag and mask ventilation within a 24-hour period ) or at the blood gas (arterial or free-flowing capillary blood) PaCO2>60 mmHg and potential of hydrogen (pH)<7.20 obtained at least 1 hour after commencement of the assigned treatment, newborns are intubated and mechanically ventilated.~For all the newborns enrolled in the study, arterial or free-flowing capillary blood gas is checked every 6-12 hours, a cerebral and cardiac ultrasound screening is performed within 24 hrs. Further controls follow the routine of the ward.
This will be a prospective, multi-center, two-arms,parallel, randomized, controlled trial with a superiority design,conducted in China. The investigators conduct this multi-centre, randomized, controlled trial to test the hypothesis that NHFOV is more effective than nCPAP in the treatment of respiratory distress syndrome (RDS) in infants with a gestational age of less than 28 weeks when used as a primary noninvasive ventilation (NIV) mode.