Functional residual capacity and static compliance during the first year in preterm infants treated with surfactant

Individual lung development during the first year of life was studied in su rfactant treated preterm infants with respiratory distress syndrome (RDS) a nd healthy controls, as well as in a group who subsequently developed chron ic lung disease of the newborn (CLDN). Lung development was assessed from f unctional residual capacity (FRC) and compliance of the respiratory system (Crs). Twenty-one infants with RDS after pre term birth received surfactant treatment. Six of them developed CLDN. Eighteen preterm infants without RD S served as a control group. Lung function measurements were performed at t erm age and 4, 8, and 12 months afterwards. FRC was obtained by means of th e closed-system helium dilution technique whereas static Crs was obtained b y means of the weighted spirometer technique. At term age, FRC was lower in the CLDN group compared with uncomplicated RDS and controls (p < 0.05). No significant differences between groups were found in the development of FR C du ri ng the fi rst year of life (p = 0.4). No differences were found in Crs during the first year of life in surfactant treated infants who recover ed from uncomplicated RDS and the control group. However, lower values were found in the CLDN group (p < 0.05). We conclude that surfactant treated in fants without CLDN have similar lung development during the first year of l ife as control preterm infants.