Application Value of Broadband 3-Dimensional Impulse Oscillometry in COPD

Objective To explore the correlation of respiratory resistance in stable COPD patients measured by broadband 3-dimensional impulse oscillometry (3D-IOS) and traditional pulmonary function test (PFT). To access the diagnostic value of 3D-IOS in COPD. Methods A total of 107 COPD patients and 61 healthy subjects as controls were chosen to collect and statistically analyze the data of R5, R5-R20, R20, X5 and Fres measured by broadband 3D-IOS and FEV1%pred, FVC%pred and FEV1/FVC by PFTs. The diagnostic value of broadband 3D-IOS parameters in COPD was evaluated by receiver operating characteristic curve (ROC). 3D-colored images used to show dynamic changes of respiratory resistance in COPD. Results The COPD group showed significant increases in R5, R20, R5-R20 and Fres, and a decrease in X5 (P 0.05). Fres and FEV1/FVC (r=-0.467), and X5 and FEV1%pred (r=0.412) showed the strongest correlation. The AUC of R5, R5-R20, X5 and Fres was 0.7808, 0.7659, 0.8947 and 0.9095, respectively. Typical 3D-colored images of COPD displayed a green pattern in the inhalation phase and yellow-red-blue graduation in the expiration phase. Conclusion R5, R5-R20, X5 and Fres measured by broadband 3D-IOS can reflect the change of respiratory resistance in COPD. And they have good correlation with the traditional lung function parameters (FEV1%pred, FVC%pred, FEV1/FVC). Fres has the highest diagnostic accuracy. Comprehensive analysis of R5, R5-R20, Fres and X5 helps to determine the degree of respiratory obstruction in COPD. X5 and Fres can reflect changes in lung tissue compliance. 3D-colored images can visually show the change of respiratory resistance and reactance in COPD.