This RCT aims to compare the efficacy and safety of postextubation respiratory support via HHHFNC at two different flow rates (6 L/min. versus 3 L/min) regarding successful extubation after a period of endotracheal positive pressure ventilation. We hypothesized that postextubation respiratory support via HHHFNC at a flow rate of 6 L/min. will result in a greater proportion of preterm infants being successfully extubated after a period of endotracheal positive pressure ventilation compared with HHHFNC at a flow rate of 3 L/min.