• Comparison of the respiratory support index (FIO2, mean airway pressure, respiratory index, oxygenation index) for Curosurf and Survanta over the first 3 days of life. [ Time Frame: 3 days after surfactant administration ] [ Designated as safety issue: No ]
  

• Organ blood flow responses to Curosurf and Survanta, to brain, through the Patent Ductus Arteriosus and superior mesenteric artery [ Time Frame: First hour after surfactant adminsitration ] [ Designated as safety issue: No ]
  
• Chronic lung disease or death [ Time Frame: duration of NICU stay ] [ Designated as safety issue: No ]
  

Specific Aims:

• To determine whether there is a sustained difference in the level of respiratory support during the first 3 days of life in extremely premature infants treated with Curosurf versus Survanta
• To determine whether Curosurf is associated with a higher incidence of hemodynamically significant PDA, compared with Survanta
• To determine whether there is a difference in the cerebral blood flow response to Curosurf versus Survanta
• To determine whether there is a difference in morbidity in very premature infants treated with Curosurf versus Survanta

We reasoned that if Curosurf was primarily responsible for improved survival rates, compared with Survanta, then there should be a sustained improvement in respiratory function in the first three days of life, when the direct pulmonary effects of the surfactant preparations would be most easily detected. It was also possible that Curosurf and Survanta could have effects on other systems that could secondarily affect long-term survival of the infant. These other organ systems would include, but not be limited to, the development of a hemodynamically significant Patent Ductus Arteriosus, Intraventricular Hemorrhage or Periventricular Leukomalacia, or Necrotizing Enterocolitis. We propose to examine how surfactant administration affected the hemodynamic precursors of these common morbidities of very premature infants.