Extensive Evaluation of Pulmonary Function Abnormalities by Different Techniques in Turkish Children and Young Adults with Sickle Cell Disease

Pulmonary involvement in sickle cell disease (SCD) is a major cause of morbidity and mortality. Recent data about pulmonary function tests in children with SCD are conflicting. The objective of this study was to determine the pulmonary function abnormalities for the first time in Turkish children and young adults with SCD by different techniques such as plethysmography and impulse oscillometry (IOS). Fifty-eight patients with SCD and 51 healthy controls were included in the study. Spirometry, IOS, and plethysmography tests were applied. Lactate dehydrogenase (LDH) level as a hemolysis marker was measured. The median age was 15 years (min: 7, max: 22 years) in SCD group and 14 years (min: 7, max: 24 years) in healthy controls. The values of forced expiratory volume in 1 s (FEV1)% (P < 0.001) and forced vital capacity (FVC)% (P < 0.001) were lower in SCD patients than healthy controls, but FEV1/ FVC was normal. The resistance at 5Hz (R5)% (P < 0.001) and difference of resistance at 5 and 20Hz (R5%-R20%) (P=0.001) in IOS were higher in SCD group. In plethysmography, functional residual capacity (FRC)% (P = 0.002), residual volume (RV)% (P = 0.043), and total lung capacity (TLC)% (P < 0.001) levels were lower in SCD patients than healthy controls. RV% (P = 0.020) and RV/TLC (P = 0.010) levels were significantly lower in SCD patients with hydroxyurea usage than those without this therapy. Serum LDH levels were found to be negatively correlated with FVC% (P = 0.042) and TLC% (P=0.043) levels in SCD group. This study suggested that both obstructive and restrictive pulmonary dysfunctions were present in children and young adults with SCD. In addition, the increased total and peripheral airway resistance in IOS may be a predictor of small airway disease in SCD patients, despite normal lower airway indices in spirometry.