*2.4. Ventilators*

While a standard neonatal ventilator (Sophie) was used to generate cf-NCPAP or s-NIPPV; vf-NCPAP was delivered using the Infant Flow Plus. The NCPAP level was set to 5 cmH2O throughout. S-NIPPV was delivered at a rate of 20 breaths/min and a peak pressure of 15 cmH2O. Synchronization with the infants' breathing efforts was achieved by an abdominal pneumatic trigger capsule (Respiration Sensor, Fritz Stephan, Gackenbach, Germany). Respiratory support was delivered via binasal prongs of appropriate size (EasyFlow, Fritz Stephan, Gackenbach, Germany, or Infant Flow LP, Vyaire Medical Inc., Chicago, IL, USA).
