Post-extubation Use RAM Cannula Versus Short Binasal Prong Interfaces in Preterm Infants

Preterm infants will be randomized to receive post-extubation non invasive respiratory support either through RAM cannula or SBPs. Neonates in both groups will be uniformly managed as per unit protocol as following: Extubation criteria : * Birth weight \< 1000 gram :MAP \<7 cmH2O and FIO2 \<0.30 * Birth weight\>1000 gram :MAP \>8 cmH2O and FIO2 \<0.30 Re intubation criteria : * FIO2\>0.60 to maintain SaO2 \>88% OR PaO2 \> 45 mmHg * PaCO2 {arterial} \> 55-60 with PH \< 7.25 * Apnea and requiring bag and mask ventilation * Evidence of increased work of breathing {retractions -grunting -chest wall distortion } plus abnormal chest x ray