Impulse oscillometry in the diagnosis of respiratory mechanics defects in chronic obstructive pulmonary disease

Abstract

Impulse oscillometry (IO) is an innovative method of diagnosing respiratory mechanics. However, there are many unexplored and contentious issues concerning changes in IO parameters, particularly in chronic obstructive pulmonary disease (COPD). The aim of the study was to compare IO with traditional pulmonary functional methods and to study its possibilities for diagnostics of respiratory mechanics disorders in patients with COPD. Methods. A cross-sectional cohort study was carried out, which included patients with COPD (n = 146: 137 (94%) men, 9 (6%) women; average age – 65 ± 9 years) from 2 medical institutions of Moscow – Acad. N.N.Burdenko The Main Military Clinical Hospital, Ministry of Defense and Federal Pulmonology Research Institute, Federal Medical and Biological Agency of Russia . Patients were divided into 4 groups depending on the severity of COPD according to the criteria of the Global Initiative for Chronic Obstructive Lung Disease (GOLD): stage I was diagnosed in 8 patients, stage II – in 43, III – in 54, IV – in 41. The parameters of IO (resistive resistance at an oscillation frequency of 5 Hz ( R rs5 ) and 20 Hz ( R rs20 ), ( R rs5 – R rs20 ), reactive resistance at an oscillation frequency of 5 Hz (Xrs5), area of reaction (A X ), resonance frequency (f res ) are analyzed; spirometry – forced expiratory volume in the 1st second (FEV 1 ), forced vital capacity (FVC) and FEV 1 /FVC; Body plethysmography (total lung capacity, intrathoracic gas volume, residual volume, total respiratory resistance), lung diffusion capacity. Results. The parameters of IO ( R rs5 , R rs5 – R rs20 , A X , ΔXrs5, and f res ) progressively increased from stage I to stage IV (GOLD) of airway obstruction, while statistically significant changes of R rs20 were not detected. The parameters of the traditional methods of investigation of respiratory mechanics and IO were mainly moderately and strongly correlated. Conclusion IO can be used as an alternative method for assessing respiratory mechanics in COPD.