Thoracic gas volume in early childhood.

A total body plethysmograph is descirbed which was used to study thoracic gas volume (TGV) in infants and young children from birth to 2 1/2 years, and was suitable for use even in very sick babies. Normal TGV values were obtained in 42 studies of 35 healthy infants and young children, and 16 children with abnormal lung volume are described. TGV correlated well with length, weight, chest circumference, and age in the healthy infants. A low TGV was found in children with respiratory difficulties after cardiac and thoracic surgery, in respiratory distress syndrome of the newborn, and in association with pulmonary infection and chest cage abnormalities. Abnormally high TGV was most frequently seen in infants with small airways disease.