Physiological Changes With High-Flow Nasal Cannula

Inclusion Criteria: * 23 to 28+6 weeks gestational age at birth * Corrected gestational age less than or equal to 30 weeks * Over 72 hours of life * Stable on Nasal CPAP of 5-7cm H20 * Hemodynamically stable * Tolerating routine handling * Nares size appropriate for Fisher \& Paykel Optiflow Jr 2 HFNC size XS or small * Successfully extubated for 12 hours after administration of surfactant * Caffeine Citrate at a maintenance dose of 5 to 10 mg /kg * Transcutaneous monitoring in place * Stable blood gas (pH\>/= 7.25 and PaCO2 \<60 mmHg torr) Exclusion Criteria: * Prior pneumothorax or evidence of pulmonary interstitial emphysema. * Prior or current pulmonary hemorrhage * Congenital airway malformations * Major cardiopulmonary malformations * Congenital Diaphragmatic hernia or untreated bowel obstruction * Poor respiratory drive unresponsive to CPAP therapy * Requirement of a nCPAP of \>8 cmH20 or FiO2 \> 0.3 to maintain oxygen saturations between 90-95 percent. * Receiving positive pressure breaths or SIPAP on prongs * Conflicting clinical trial * Clinically unstable per physician discretion