A research study that will evaluate if giving surfactant medication to premature babies weighing < 1250 gm at birth during the second and third weeks of life will help their lungs. We are enrolling those premature babies who continue to require the breathing tube and the mechanical ventilator at days 7-10 of life.

Pulmonary surfactant is required for normal lung function. Data from a previous study suggest that as many as 75% of chronically ventilated extremely low birthweight premature infants have at least one episode of surfactant dysfunction beyond the first week of life, as measured in vitro, associated with a low surfactant protein B content. Furthermore, episodes of surfactant dysfunction are significantly associated with clinically significant respiratory decompensations. We hypothesize that booster doses of surfactant given during the second and third week of life to extremely low birth weight premature infants requiring persistent intubation and mechanical ventilation will improve their respiratory status during the first 28 days of life. We propose to enroll premature infants < 1250 gm birthweight, between days 7 and 10 of life who are intubated, and mechanically ventilated. Infants requiring persistent intubation and mechanical ventilation for respiratory support at 7-10 days of life will receive a total of 3 doses of Infasurf surfactant, 3 days apart, at the standard dose of 3 ml/kg. Primary outcome is the change in area under the respiratory severity score curve between days 7 and 28 of life. Total sample size is 88 infants, study duration is 36 months, and recruitment of study patients will occur at The Hospital of the University of Pennsylvania, in Philadelphia PA, Women and Children's Hospital in Buffalo, St. Louis Children's Hospital in St. Louis MO, Mercy Children's Hospital in Kansas City, Oakland Children's and Alta Bates Medical Center in Berkeley, CA and Long Island Jewish Medical Center, NY.

Inclusion Criteria:

• Less than or equal to1250 gm birthweight
• Day 7-10 of life
• Intubated and mechanically ventilated at day 7-10 of life

Exclusion Criteria:

• Infants intubated solely for apnea
• Serious congenital malformations
• Life expectancy < 7 days from enrollment
• Pulmonary hemorrhage at time of enrollment
• Active air leak syndrome at time of enrollment
• Bilateral grade IV intracranial hemorrhage
• Postnatal systemic steroid therapy for lung disease

Note: Prior surfactant therapy at birth is neither an inclusion nor exclusion criterion.