Abstract: Respiratory function tests and arterial blood gas analysis were performed
on 59 patients with β-thalassemia major (27 M, 22 F, age range: 18-45
years). All investigations were performed 24 h before the patients received
a blood transfusion or when they were in a stable state hematologic condition.
Echocardiography was performed in all patients and the ejection fraction
was employed as a measure of cardiac function. No patient had clinical
signs of pulmonary dysfunction. Pulmonary function tests, however, showed
a reduction of all main parameters (TLC, FEV1, FEV1/FVC, FEF 25-75% and
RV) in most patients with β-thalassemia major, indicating a restrictive
type of dysfunction. Arterial blood gas values were within the normal
range. There was no evidence that the observed abnormalities in pulmonary
function were secondary to congestive heart failure. The low hemoglobin
concentration and a fall in the diffusing capacity of the alveolar-capillary
membrane, together with the dependence of the reduced pulmonary diffusing
capacity on age and serum ferritin levels, as well as of the entity of
restrictive disease on age, suggests that pulmonary dysfunctions in patients
with TM are due mainly to lung fibrosis and/or interstitial edema related
to iron overload. Also iron deposition due to repeated blood transfusions
may play a central role in determining lung alterations although the majority
of patients are well chelated, suggesting that more than one causal mechanism
could be involved. |