MEASUREMENT OF PULMONARY STATUS AND SURFACTANT PROTEIN-LEVELS DURING DEXAMETHASONE TREATMENT OF NEONATAL RESPIRATORY-DISTRESS SYNDROME

Background - Early postnatal use of dexamethasone in infants with resp iratory distress syndrome (RDS) has been shown effectively to improve pulmonary status and to allow early weaning off mechanical ventilation . However, the mechanisms to explain the beneficial effects of dexamet hasone in ventilatory dependent preterm infants remain unclear. Method s - A double blind, placebo controlled study was performed to determin e the change in pulmonary ventilation of premature infants with RDS as a result of dexamethasone treatment, and to evaluate the effect of de xamethasone on the levels of surfactant-associated proteins A (SP-A) a nd D (SP-D) in the tracheal fluid from 34 premature infants with RDS a nd 29 control subjects. Results - Dexamethasone treatment decreased fr actional inspired oxygen concentration (FIO2), arterial carbon dioxide tension (PCO2),, mean airway pressure (MAP), and facilitated successf ul weaning from mechanical ventilation. SP-A concentrations in the tra cheal aspirates were increased at days 7 and 14, and SP-D concentratio ns were increased during the period from days 3 to 14 in the dexametha sone treated group compared with the control group. However, albumin l evels in the tracheal aspirate samples were decreased after dexamethas one treatment over the period from days 3 to 14. There was an inverse correlation between PCO2 values and SP-A concentrations. Conclusions - These result suggest that early use of dexamethasone can improve pulm onary status and also increase SP-A and SP-D levels in the tracheal fl uid in premature infants with RDS.