Small airway dysfunction and flow and volume bronchodilator responsiveness in patients with chronic obstructive pulmonary disease

Forced Expiratory Flow at 25%-75% Links COPD Physiology to Emphysema and Disease Severity in the SPIROMICS Cohort

“…This is exaggerated in emphysema due to loss of the parenchymal elastic recoil and alveolar tethering that normally keep these airways open. 1, [8][9][10][11][12][13] Air trapping and hyperinflation contribute to decreased ventilatory efficiency and the sensation of dyspnea. 10,11 Beyond the extensive evaluation of early disease, studies of FEF25%-75% and its relationship to clinical or radiographic characteristics of disease severity have been limited.…”

“…10,11,31 Prior studies suggest that small airways disease and bronchodilator response may be associated, and that participants who are older, female, and have more severe disease show less bronchodilator response. 12,32 The pathophysiology behind this association is not well understood. Bronchodilators are thought to improve symptoms by decreasing lung hyperinflation.…”

Cystic fibrosis transmembrane conductance regulator in COPD: a role in respiratory epithelium and beyond

“…In turn, these changes may result in increased COPD exacerbations and bacterial colonisation, which may further contribute to COPD progression through increased SAD and emphysema development [ 175 ]. Patients with COPD and SAD have poorer health status, worse spirometry results and more severe lung hyperinflation than those without SAD [ 174 , 176 ]. In the small airways of patients with COPD who experience frequent exacerbations, measures of SAD were associated strongly with neutrophilic inflammation [ 177 ].…”

Respiratory impedance is correlated with airway narrowing in asthma using three‐dimensional computed tomography

“…Recently, the usefulness of respiratory impedance has been demonstrated in several respiratory diseases, including asthma . Respiratory impedance comprises the resistance and reactance of the respiratory system, which provides information regarding respiratory function .…”

“…Recently, the usefulness of respiratory impedance has been demonstrated in several respiratory diseases, including asthma. [2][3][4][5][6][7][8][9][10][11][12][13] Respiratory impedance comprises the resistance and reactance of the respiratory system, which provides information regarding respiratory function. [14][15][16] Respiratory resistance is the forward pressure of conducting airways and is considered an index of airway calibre.…”