Background: We investigated whether a relationship between small airways dysfunction and bronchodilator responsiveness exists in patients with chronic obstructive pulmonary disease (COPD). Methods: We studied 100 (20 female; mean age: 68±10 years) patients with COPD (forced expiratory volume in 1 second [FEV1]: 55% pred ±21%; FEV1/forced vital capacity [FVC]: 53%±10%) by impulse oscillometry system. Resistance at 5 Hz and 20 Hz (R5 and R20, in kPa·s·L-1) and the fall in resistance from 5 Hz to 20 Hz (R5 – R20) were used as indices of total, proximal, and peripheral airway resistance; reactance at 5 Hz (X5, in kPa·s·L-1) was also measured. Significant response to bronchodilator (salbutamol 400 µg) was expressed as absolute (≥0.2 L) and percentage (≥12%) change relative to the prebronchodilator value of FEV1 (flow responders, FRs) and FVC (volume responders, VRs). Results: Eighty out of 100 participants had R5 – R20 >0.03 kPa·s·L-1 (> upper normal limit) and, compared to patients with R5 – R20 ≤0.030 kPa·s·L-1, showed a poorer health status, lower values of FEV1, FVC, FEV1/FVC, and X5, along with higher values of residual volume/total lung capacity and R5 (P1.
- Bronchodilator responsiveness
- Small airways
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine
- Public Health, Environmental and Occupational Health
- Health Policy