Current methods to diagnose small airway disease in patients with COPD

ABSTRACT

The small airways are characterized by an internal diameter < 2 mm and absence of cartilage. Approximately 10–25% of total airway resistance in healthy lungs is due to the small airways, with their contribution to total airway resistance increasing substantially in chronic obstructive pulmonary disease (COPD). As the small airways are located in the lung periphery, they are not easily evaluable, which can potentially interfere with the diagnosis (especially at early stages), monitoring, detection of responses to clinical interventions, and prognostic evaluation in COPD. Here, we will discuss the currently available methods in clinical practice to evaluate small airway disease in COPD, focusing on the concept, advantages, and disadvantages of each method.

KEYWORDS:

• COPD
• small airways
• spirometry
• body plethysmography
• washout tests
• computed tomography

Financial & competing interests disclosure

Leitao Filho FS is sponsored by CNPq-Brazil (Science Without Borders Scholarship Program). Miranda Kirby gratefully acknowledges postdoctoral support from the Canadian Institutes of Health Research (CIHR) Integrated and Mentored Pulmonary and Cardiovascular Training program (IMPACT) and the CIHR Banting Postdoctoral Fellowship program. Don Sin is a Tier 1 Canada Research Chair and is supported by the Canadian Institutes of Health Research, Genome Canada, and the Canadian Respiratory Research Network (CRRN). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.