Small airways dysfunction after lobectomy due to lung cancer estimated by forced oscillation technique in comparison with IPF and COPD

<b>Background</b>: Forced oscillation technique (FOT) is becoming increasingly widespread measurement method used for assessment of small airways functions. <b>Objective</b>: In the present study we attempted to assess a presence of small airways dysfunction (SAD) in patients after lobectomy in comparison with IPF and COPD patients. <b>Methods</b>: 22 patients after lobectomy due to lung cancer stage I or II, 28 patients with idiopathic pulmonary fibrosis and 17 patients with chronic obstructive pulmonary disease were enrolled in the study. All patients performed spirometry (FEV₁, FVC, FEV₁/FVC, MEF₅₀, MEF₂₅, FEF_25-75, MIF₅₀), plethysmography (R_aw, TLC, RV, RV/TLC) and a test using the forced oscillation technique- resistance (R at 5Hz, 11Hz and 19Hz, inspiratory, expiratory and total), reactance (X at 5Hz, 11Hz), Fres and expiratory flow limitation. The ANOVA Kruskal-Wallis test followed-by a multiple comparison test were used to evaluate the differences in oscillatory parameters between-groups. <b>Results</b>: In pulmonary function tests patients after lobectomy presented small airway dysfunction with statistically significant higher MEF₅₀, MEF₂₅, FEF_25-75 (p&lt;0.001 for all parameters) when compared with IPF patients. In FOT this group of patients presented also higher values of resistance, expiratory reactance and expiratory flow limitation in comparison with IPF patients. R5-19, which reflects small airways dysfunction, occurred to be similarly elevated as in COPD patients (0.5 vs 0.6 cmH₂O/L/s). Patients suffering from COPD presented the highest limitations of spirometric and oscillometric results with a statistically significant difference when compared with studied groups of patients. Abnormalities of reactance at 11Hz were observed more frequently than at 5Hz in all groups of patients. <b>Conclusion</b>: Patients after lobectomy presents SAD, more expressed than IPF patients but less pronounced than COPD patients.