Assessing Static Lung Hyperinflation by Whole-Body Plethysmography, Helium Dilution, and Impulse Oscillometry System (IOS) in Patients with COPD.

Lung hyperinflation is a feature of chronic obstructive pulmonary disease (COPD) and can determine pivotal consequence on symptoms, exercise tolerance and quality of life. Despite the relevance of assessing lung hyperinflation, there is still no single consensus as to what volume should be taken into account. We investigate which spirometric measurement is more reliable in assessing static lung hyperinflation and which is more related with impulse oscillometry system (IOS) measurements in COPD. Fifty-five COPD patients were enrolled. TLC, RV and RV:TLC ratio were obtained both with helium and plethysmography techniques. IOS measurements (X5, Fres and R5-R20) were performed. Pearson and Spearman correlation determined the relationships between the functional parameters that evaluate static hyperinflation (RV: TLC, TLC, RV) and IOS measurements. As expected, we reported a statistically significant difference between these two techniques in terms of mean percentage values of TLC (7.57 ± 3.26 L; p= 0.02) and RV (15.24 ± 7.51 L; p=0.04), while RV:TLC measured with the two methods was similar (5.21 ± 4.69%; p=0.27). The correlation analysis showed that IOS parameters, such as difference in resistance between 5 Hz and 20 Hz (R(5-20)) and resonant frequency (Fres), were positively correlated with RV:TLC ratio, while reactance at 5 Hz (X(5)) was negatively correlated with it. In particular, we pointed out a weak correlation between RV:TLC (%) (Pleth) and R(5-20) (r=0.3, p=0.04), Fres (r=0.3; p=0.03), while X5 had a mild correlation with RV:TLC (%) (r=-0.5;p<0.0001). Moreover, we noticed a strong relationship between RV:TLC (%)(He) and X5 (r=-0.7; p=0.0001) and a mild correlation between RV:TLC (%) (He) and Fres (r=0.4; p=0.003). Between R5-R20 and RV:TLC, there was a weak correlation (r=0.3; p=0.001). No correlation between TLC, RV (L,%) (both helium and Pleth derived) and IOS parameters (R(5-20), X5, Fres) was found. RV:TLC can represent the most reliable parameter in the assessment of hyperinflation, considering the absence of significant difference in its measurement between the two techniques. IOS provides supplementary information in the assessment of static hyperinflation.

D'Ascanio M ，Viccaro F ，Calabrò N ，Guerrieri G ，Salvucci C ，Pizzirusso D ，Mancini R ，De Vitis C ，Pezzuto A ，Ricci A ... -  《International Journal of Chronic Obstructive Pulmonary Disease》

Impulse oscillometry in COPD: identification of measurements related to airway obstruction, airway conductance and lung volumes.

Kolsum U ，Borrill Z ，Roy K ，Starkey C ，Vestbo J ，Houghton C ，Singh D ... -  《-》

Evaluation of respiratory impedance in patients with chronic obstructive pulmonary disease by an impulse oscillation system.

Gong SG ，Yang WL ，Zheng W ，Liu JM ... -  《-》

Application Value of Broadband 3-Dimensional Impulse Oscillometry in COPD.

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. 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. The COPD group showed significant increases in R5, R20, R5-R20 and Fres, and a decrease in X5 (P<0.05). With the increase of GOLD grade, R5, R5-R20 and Fres increased whereas X5 decreased (P<0.05). Compared with FEV1%pred, FVC%pred and FEV1/FVC in the COPD group, R5, R5-R20 and Fres were negatively collated (P<0.05), whereas X5 was positively collated (P<0.01). R20 was uncorrelated with the traditional lung function parameters (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. 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.

Tang Z ，Li M ，Chu G ，Mou Y ，Chen Q ，Zhu H ... -  《International Journal of Chronic Obstructive Pulmonary Disease》

[The diagnostic utility of the Macao predictive values of impulse oscillometry for chronic obstructive pulmonary disease in patients over 45 years old].

Zhang Xi ，Zhang Z ，Cheng K ，Liang Z ，Lu S ，Feng Z ... -  《-》