Understanding the Impact of Pulmonary Rehabilitation on Airway Resistance in Patients with Severe COPD: A Single-Center Retrospective Study

We investigated the effect of pulmonary rehabilitation (PR) on airway resistance in chronic obstructive pulmonary disease (COPD) patients with severe airway obstruction and hyperinflation. This retrospective cohort study was conducted with data from severe COPD cases with those who underwent an 8-week PR program. Main inclusion criteria were having severe airflow obstruction (defined as a forced expiratory volume in one second (FEV ) 120%). Primary outcomes were airway resistance (R ) and airway conductance (G ) which were measured by body plethysmography, and other measurements were performed, including 6-minute walk test (6-MWT), modified Medical Research Council dyspnea scale (mMRC) and COPD assessment test (CAT). Twenty-six severe and very severe COPD patients (FEV 35.0 ± 13.1%; RV/TLC, 163.5 ± 29.4) were included in the analyses, mean age 62.6 ± 5.8 years and 88.5% males. Following rehabilitation, significant improvements in total specific airway resistance percentage (sR %, p = 0.040) and total specific airway conductance percentage (sG %; p = 0.010) were observed. The post-rehabilitation mMRC scores and CAT values were significantly decreased compared to baseline results (p < 0.001 and p < 0.001, respectively). Although there were significant improvements in 6-MWT value (p < 0.001), exercise desaturation (ΔSaO , p = 0.026), the changes in measured lung capacity and volume values were not significant. We concluded that PR may have a positive effect on airway resistance and airway conductance in COPD patients with severe airflow obstruction.