Background: Limitations in airflow are detected in some patients with sarcoidosis in association with a poor prognosis. The impulse oscillation system (IOS) is used to treat patients with obstructive lung disease, as it can sensitively detect increased airway resistance.
Objectives: To investigate the characteristics of parameters obtained with IOS in patients with sarcoidosis.
Methods: Forty-six pulmonary sarcoidosis patients at Chiba University Hospital and 20 healthy controls were enrolled. The subjects underwent IOS, pulmonary function testing and multidetector computed tomography. We evaluated the correlations between these indices in the pulmonary sarcoidosis patients and compared the pulmonary sarcoidosis patients with the healthy controls.
Results: The ratio of V50/V25, percentage of wall area (WA%), resistance at 5 Hz (R5) and difference between the R5 and R20 (R5-R20) values of the patients with pulmonary sarcoidosis were significantly increased compared to those observed in the controls. Inverse weak correlations were observed between the R5-R20 values and the forced expiratory volume in one second (r = -0.56; p <0.001). The R5-R20 values were correlated with the V50/V25 (r = 0.42; p < 0.005) and WA% (r = 0.43; p < 0.05) values. The WA% values were also significantly correlated with the V50/V25 (r = 0.32; p < 0.05) and R5 (r = 0.33; p < 0.05) values.
Conclusions: IOS parameters were found to be significantly correlated with pulmonary function parameters and the airway wall thickness in pulmonary sarcoidosis patients. IOS is considered to be useful for detecting early manifestations of airflow limitation in pulmonary sarcoidosis patients.