Increase of FeNO after acute bronchodilation test in asthmatic patients: a clue for small airways disease?

Exhaled nitric oxide (FeNO) is known to be a marker of TH2 airway inflammation, but several studies have shown that its value is affected by acute changes in airways caliber. Most of FeNO production occurs in the small conductive airways, but studies have investigated the relationship between FeNO and small airways caliber changes in asthma. Impulse oscillometry (IOS) unlike spirometry can assess the obstruction of small peripheral airwaysThe aim of this study was to evaluate whether changes in FeNO after acute bronchodilation test are associated with specific features of asthmatic patients.This observational retrospective study included 52 adult asthmatic patients who underwent FeNO, IOS and simple spirometry before and after inhalation of albuterol (400 mcg). Results were stratified by FeNO response, being "positive" an increase >10% compared to the basal values. A significant response to albuterol was defined according to international guidelines for spirometry, and as a decrease >29.1% of AX (abbreviations in table) for IOS.FeNO responders showed significant differences (p<0,05) in terms of basal X5, R5-20, AX, Fres and X5. We found no difference in other spirometric or IOS values, both basal and post-bronchodilation (table 1).Our study shows that changes in FeNO values after acute bronchodilation can identify patients with small airways disease, making this test a possible alternative to IOS.
Source: European Respiratory Journal - Category: Respiratory Medicine Authors: Tags: Monitoring airway disease Source Type: research