LUNG-FUNCTION IN INFANTS WITH SICKLE-CELL DISEASE

We performed pulmonary function testing in 20 infants (11 male and 9 f emale; ages 3-30 months) with sickle cell disease to assess whether ab normal lung function develops early in life. Respiratory system compli ance (C-rs) and resistance (R-rs) were measured by the passive occlusi on technique, functional residual capacity (FRC) was measured by the n itrogen washout technique, and tidal flow-volume loops and partial exp iratory flow-volume curves were obtained by the thoracoabdominal compr ession technique to detect airway obstruction. Patients with Hb SS (Gr oup I, n = 12) had significantly lower hemoglobin levels and a higher (but not significant) incidence of acute chest syndrome (ACS), vasoocc lusive crisis (VOC), splenic sequestration, transfusions, and history of intermittent bronchospasm compared to with patients with hemoglobin opathies Hb SC, Hb Sbt and Hb SF (Group II; n = 8). Both groups had el evated FRC, decreased maximum expiratory flows at FRC (V-max,V-FRC'), and decreased time needed to reach peak expiratory flow (t(me)/t(E)), suggesting lower airway obstruction (LAO) and hyperinflation. Restrict ive disease was found in only three patients of Group I. Our findings suggest that in sickle cell disease (especially among patients with Hb SS), abnormal lung function (predominantly LAG) may be present in ear ly infancy. Airway reactivity may play a role in the pathogenesis, but the relation to VOC or ACS remains unclear. (C) 1997 Wiley-Liss, Inc.