The investigators propose to test the hypothesis that Seattle bubble nasal continuous positive airway pressure (Seattle-PAP) supports respiratory physiology in very low birth weight (VLBW) infants more effectively than standard bubble nasal continuous positive airway pressure.

The primary outcome variable is work of breathing (WOB) over a two hour period, estimated from pressure-rate products, which are assessed with 6 Fr (2 mm) catheters placed in the distal esophagus for monitoring esophageal pressures (Pes), thereby estimating changes in pleural pressures during breath cycles. The following endpoints would also be assessed: Oxygen saturations and Fraction of Inspired Oxygen (FiO2) needed to keep saturations in acceptable ranges, Heart Rates (HR), transcutaneous carbon dioxide (TcPCO2), and respiratory rates throughout the 6 hour study period.

Objective determination of when an infant requires more or less respiratory support is difficult, but measurements of pressure-rate products as estimates of work of breathing, using esophageal catheters, can estimate an infant's respiratory effort. However, objective, simple-to-use, low cost, and non-invasive methods and tools to determine an infant's respiratory effort do not exist currently.

This study also is designed to test the hypothesis that infants' chest and abdominal movements can be assessed quantitatively from video images in ways that can be correlated with intrathoracic pressures, as measured with esophageal catheters.

Inclusion Criteria:

• infant born less than 32 weeks gestation
• admitted to texas pavilion for women
• between 6 and 72 hours post delivery
• stable on standard bubble nasal CPAP
• informed consent

Exclusion Criteria:

• major congenital anomalies or suspected chromosomal anomalies