Pulmonary function abnormalities in homozygous beta-thalassemia.

Pulmonary function tests were performed on 19 patients with homozygous beta-thalassemia ranging in age from 10 to 29 years. These included patients who had and had not received transfusions. None of the 19 subjects had completely normal pulmonary function. Residual volume (in 16 of 19 patients), ratio of residual volume to total lung capacity (12 of 19), and airway resistance (16 of 19) were abnormally increased; maximum expiratory flow (15 of 19) and peak flow (10 of 19) were abnormally reduced. Single-breath carbon monoxide diffusion was normal in 16 of 19. These results indicate that mild to moderate small airway obstruction and hyperinflation are common in thalassemia and that patient age, transfusion history, and iron accumulation are not important factors in the genesis of these pulmonary abnormalities.