PT  - JOURNAL ARTICLE
AU  - Marija Vukoja
AU  - Dragana Milicic
AU  - Ivan Kopitovic
TI  - Impulse oscillometry in COPD: Correlation to spirometry and whole-body plethysmography
DP  - 2014 Sep 01
TA  - European Respiratory Journal
PG  - P3973
VI  - 44
IP  - Suppl 58
4099  - http://erj.ersjournals.com/content/44/Suppl_58/P3973.short
4100  - http://erj.ersjournals.com/content/44/Suppl_58/P3973.full
SO  - Eur Respir J2014 Sep 01; 44
AB  - Background: Spirometry is considered the gold standard test for diagnosing COPD. Alternatively, whole-body plethysmography and impulse oscillometry (IOS) are used to assess lung function.Aim: To determine correlation of parameters obtained by spirometry, whole-body plethysmography and IOS in patients with COPD.Methods: One hundred consecutive stable COPD outpatients at the Institute for Pulmonary Diseases of Vojvodina, Sremska Kamenica, Serbia in whom spirometry, whole-body plethysmography and IOS were performed. All patient had post-bronchodilator FEV1/FVC<70%.Results: Most patients had mild-to-moderate COPD (29 GOLD stage I; 49 stage II; 20 stage III and 2 stage IV). FEV1(%) showed moderate correlation with IOS parameters: resistance at 5Hz (R5, r=-0.37; p<0.001) and reactance X5 (X5, r=0.52; p<0.001), and weak correlation with resistance at 20Hz (R20, r=-0.22; p<0.03). Airway resistance (Rt) measured by plethysmography correlated well with R5 (r=0.73, p<0.001), X5 (r=-0.74, p<0.001) and R20 (r=0.57, p<0.001). Fifty-seven patients had normal values of R5 and X5, these patients had milder COPD compared to IOS positive patients (FEV1 74±17% vs. 57±17%, p<0.001; Rt 0.22±0.09 vs. 0.41±0.22, p<0.001). The mean values of R5 and X5 worsened as GOLD severity increased and correlated moderately with MRC scale (r=0.33, p<0.001 and r=-0.49 p<0.001, respectively).Conclusion: There is a limited sensitivity of IOS in detecting pulmonary function abnormality in COPD patients compared to spirometry,especially in patients with mild COPD. IOS parameters demonstrate good correlation with conventional lung measurements, worsen across GOLD stages and are in modest correlation with dyspnea.