With the increased use of prenatal steroids and surfactant in the management of respiratory distress, preterm neonates are often capable of discharge at earlier post conceptional age than before. We studied the pulmonary status of these infants prior to discharge to assess the resolution of their pulmonary dysfunction as well as the extent of their pulmonary reserve. Based on comprehensive pulmonary function tests on 74 preterm infants, range BW: 765 to 3357g, GA: 24 to 35wks, mean±SD study weight: 2.1±0.3kg, PCA: ≈36wks. Mean ± sem data are reported for function residual capacity (FRC), lung compliance (CL), resistance (RT), partial forced expiratory flow at (FEF-FRC), peak to peak esophageal pressure(Pptp) and minute ventilation (MV): Table These data indicate that all infants were able to maintain appropriate MV with mildly elevated Pptp and energetics. The level of pulmonary dysfunction with low CL was associated with decreased pulmonary reserve especially babies of BW<1000g who show obstructive airway desease (*p<0.05), airflow abnormalities, low FRC/kg and delayed somatic growth. These babies deserve specialized followup and care.

Table 1
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