Impulse oscillometry in the assessment of lung function in children with chronic nonspecific lung diseases

Introduction. The article proposes an approach to evaluating the main parameters of impulse oscillometry (IOS) in children with chronic nonspecific lung diseases (CNSLD) using multivariate statistical methods. Aim. To identify types of ventilatory disorders in children with CNSLD using cluster analysis based on impulse oscillometry data. Materials and methods. A total of 71 children were examined, including 10 conditionally healthy children and 61 patients with CNSLD. Lung function was evaluated using IOS. The analyzed parameters included: Z5Hz—total respiratory impedance at an oscillation frequency of 5 Hz; R5Hz—total resistance at 5 Hz; R20Hz—proximal airway resistance at 20 Hz; X5Hz—reactance at 5 Hz; frequency dependence of resistance—D(Rrs5–Rrs20); delta Xrs5; and resonance frequency (Fres). Results. Analysis of the IOS data allowed all subjects to be divided into three clusters. The first cluster included children with the highest values of the main parameters studied. The clinical course of the disease in this group was characterized by pronounced clinical symptoms. Median values of the main respiratory impedance parameters in children of the second cluster remained within normal ranges; however, 20% of the children in this group showed increased values of X5Hz, D(Rrs5–Rrs20), delta Xrs5, and Fres with slightly elevated or normal R20Hz and R5Hz values, indicating ventilatory disorders at the level of the distal airways. The health status of children in the third cluster was more favorable compared to patients in the first and second clusters, and their IOS parameters were 1.5–2 times lower than those of children in the first and second clusters, indicating the absence of airway dysfunction. Conclusion. The presented IOS parameters will enable the practicing physician to make informed decisions regarding individual patients for better assessment of disease progression and treatment efficacy.