Data collection
Heart rate (HR), RR, FiO2, venous/capillary pH and pvCO2, mWCAS, and the neonatal pain and discomfort scale (EDIN) were collected at baseline (H0), in the 15 minutes following admission, while the infant received a blend of air/oxygen using nasal cannula at a maximal flow rate of 1 L/min. The same physiological variables, except for capillary blood gas analysis, were collected 1 hour after HFNC initiation at the flow rate allocated by randomization (H1).
At H0 and H1, ROX was calculated as SpO2/FiO2 to RR.
Predefined HFNC failure criteria included the occurrence, within 48 hours of randomization, of one or more of the following: increase, compared to H0, in respiratory distress score (i.e, 1 point in mWCAS) or respiratory rate (i.e, >10 breath per min with RR> 60 bpm), increase in discomfort (1 point in EDIN score), and severe apnea episodes requiring bag and mask ventilation.