Physiological Changes With High-Flow Nasal Cannula

After informed consent is obtained, eligible infants who are stable on nCPAP therapy of 5-7
cm H20 achieved with a ventilator, an underwater "bubble" system, or a variable-flow device
will be enrolled.

All subjects will have physiologic data and electrical impedance tomography collected at:

1. Baseline nCPAP for 15 minutes

2. Upon transition to high flow nasal cannula at 8 LPM for 6 hours. Data collection is
obtained after infant is calm for 15 minutes at the beginning and end of this 6 hour
period

3. Then upon return to baseline NCPAP for a final 15 minutes of data collection.

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