Small airways disease and severe asthma

Abstract

The small airways of the lungs are commonly affected in pediatric and adult asthma. Small airways disease has been related to asthma control, severity, and risk of exacerbation. Diagnosis of small airways disease can be best made through evaluation of surgical lung specimens. Noninvasive techniques including spirometry, plethysmography, nitrogen washout, impulse oscillometry, and cross-sectional imaging have been utilized to assess and infer the extent of small airways disease in asthma and can be used longitudinally to assess response to treatment. Patients with small airways disease seem to benefit from inhaled asthma medications that have improved capacity to reach the distal lung compartment. This is especially important for patients with severe asthma, who rely upon high doses of inhaled corticosteroid and bronchodilators for asthma control. This review will describe the techniques which may be utilized to assess small airways disease, discuss the prevalence and characteristics of small airways disease in severe asthma, and highlight how small airway disease may complicate severe asthma treatment.

Dupilumab improves lung function in patients with uncontrolled, moderate-to-severe asthma

“…A potential limitation of these findings was our reliance on spirometry (FEF 25-75% ) to assess small airways function. This technique is regarded by some to be less than optimal, as measurements can be influenced by large airway obstruction [33]. While a reliable, non-invasive index for diagnosis and monitoring of small airways disease remains elusive, other techniques such as imaging with computed tomography or magnetic resonance imaging, plethysmography and impulse oscillometry have proven valuable in some studies [34].…”

Pulmonary Function and Effects of Body Position in Patients with Obstructive Sleep Apnea

“…Associations between lung volume and severity of OSA were also reported in studies matching subjects for BMI, or that adjusted for BMI [21,22]. FEF is considered an early marker of small airway disease [30]. The association between FEF 25-75 and the value of AHI suggests the possibility of a relationship between OSA and lower airway pulmonary function.…”

How to use peak expiratory flow rate

“…They are susceptible to mucus plugging and collapse. Asthma is now recognised to affect the small airways4 as well as the larger airways, and peak flow may not fully assess the full extent of airway obstruction in the bronchial tree.…”