EARLY DETECTION OF PULMONARY FUNCTION ABNORMALITIES IN CYSTIC FIBROSIS

Abstract

We studied gas exchange in 19 children with cystic fibrosis in whom measurement of lung volumes, flow rates and airway conductance, diffusing capacity and mixing efficiency were normal. A significant decrease in arterial oxygen tension was found together with a significant increase in alveolar-arterial difference for oxygen and physiologic dead space/tidal volume ratio. These findings are consistent with evidence that early in cystic fibrosis the site of obstruction is in the small airways. It is also suggested from these data that blood gas abnormalities occur before other parameters of lung function become abnormal.