Preterm Infant Inhaled Albuterol Dosing

Subjects will be evaluated in 3 sessions. The sessions will occur within a 7 day time span, beginning between 14 or more days from birth and at a corrected gestational age of 28w0d to 33w6d. In each session, pulmonary function tests (PFTs) will be performed prior to and 15 minutes after a dose of albuterol. The dose will be different in each session. In the first session, a sinlge dose of 180 micrograms (2 puffs) of albuterol sulfate via metered dose inhaler. The dose will be 270 micrograms in the second session and 360 micrograms in the third session. PFTs will be performed during quiet sleep while the baby is spontaneously breathing or while the baby is intubated and receiving mechanical ventilation. Resistance and compliance will be measured using the single breath occlusion technique.