MEASUREMENT OF THORACIC GAS VOLUME IN THE NEWBORN INFANT*

Abstract

Total lung capacity and thoracic gas volume, were measured plethysmographically in normal newborn infants and in infants with the respiratory distress syndrome. The results suggest that lung volume is established within a few hours after birth and changes little during the neonatal period. Infants with respiratory distress due to hyaline membrane disease have a significant decrease in lung volume which is apparent early in the course of the disease. Comparison with dilution methods used by other workers suggests that "trapped gas" may exist in the lungs of some normal newborn infants.