Low lung capacity and hypoxemia in children with thalassemia major.

We evaluated lung function in 17 children with thalassemia major in stable condition receiving blood transfusions at regular intervals and subcutaneous desferoxamine daily. Total lung capacity (TLC) was below 2 SD of normal values for height in 7 of the 17 children and arterialized capillary PO2 was below the normal range in 15. We studied lung mechanics in 4 children with reduced TLC and found static and dynamic compliance below 2 SD of normal values for height in 3, and lung recoil at TLC above normal values and specific upstream conductance (Gus/TLC) above 2 SD of normal values in all 4. Although these alterations in lung function have been described in patients with pulmonary fibrosis, we found no fibrosis in autopsy specimens of lung from 8 other patients with thalassemia. The rate constant of carbon monoxide diffusion (kCO) was above the predicted mean in 14 of 15 children. These findings can be explained by a decrease in the growth of airspace relative to the vascular bed and major airways during childhood.