Maximal mid-expiratory flow is a surrogate marker of lung clearance index for assessment of adults with bronchiectasis

Abstract

Little is known about the comparative diagnostic value of lung clearance index (LCI) and maximal mid-expiratory flow (MMEF) in bronchiectasis. We compared the diagnostic performance, correlation and concordance with clinical variables, and changes of LCI and MMEF% predicted during bronchiectasis exacerbations (BEs). Patients with stable bronchiectasis underwent history inquiry, chest high-resolution computed tomography (HRCT), multiple-breath nitrogen wash-out test, spirometry and sputum culture. Patients who experienced BEs underwent these measurements during onset of BEs and 1 week following antibiotics therapy. Sensitivity analyses were performed in mild, moderate and severe bronchiectasis. We recruited 110 bronchiectasis patients between March 2014 and September 2015. LCI demonstrated similar diagnostic value with MMEF% predicted in discriminating moderate-to-severe from mild bronchiectasis. LCI negatively correlated with MMEF% predicted. Both parameters had similar concordance in reflecting clinical characteristics of bronchiectasis and correlated significantly with forced expiratory flow in one second, age, HRCT score, Pseudomonas aeruginosa colonization, cystic bronchiectasis, ventilation heterogeneity and bilateral bronchiectasis. In exacerbation cohort (n = 22), changes in LCI and MMEF% predicted were equally minimal during BEs and following antibiotics therapy. In sensitivity analyses, both parameters had similar diagnostic value and correlation with clinical variables. MMEF% predicted is a surrogate of LCI for assessing bronchiectasis severity.

Patients hospitalized with an infective exacerbation of bronchiectasis unrelated to cystic fibrosis: Clinical, physiological and sputum characteristics

“…20,21 While the results need to be interpreted with caution given the known variability of FEF , this associative signal warrants further research with larger patient numbers and prospective trials given the rapidly growing body of evidence within the literature. 29 Older age, sputum production, the presence of poorer lung function (measured by FEV 1 ) and the presence of P. aeruginosa in sputum are factors known to be associated with exacerbations and this was confirmed. 23 This study reports greater rates of readmission than others recently published.…”

“…Small airway inflammation and reactivity is of increasing importance in bronchiectasis. 28 Studies are demonstrating that measures of small airway function such as forced mid-expiratory flow (FEF ) may reflect mucus plugging and sputum clearance, 29 and improvements in FEF have been noted with mucolytic treatment in COPD. 30 A significant association was noted between FEF 25-75 reversibility and exacerbation frequency with each 0.46 change in FEF 25-75 reversibility associated with an increased risk of two or more exacerbations.…”

Residual volume/total lung capacity ratio confers limited additive significance to lung clearance index for assessment of adults with bronchiectasis

“…Patients were aged 18 years or greater, and had no exacerbation for more than 4 weeks. Exacerbation should meet three or more criteria (persisting for >24hrs): significantly increased cough frequency; increased sputum purulence/volume; dyspnea; fever; hemoptysis; exercise intolerance; chest pain; increased pulmonary infiltration [ 6 , 14 ]. Exclusion criteria were antibiotics use within 4 weeks, malignancy, and failure to undergo measurements.…”

“…Ventilation heterogeneity, which exists in physiologic conditions [ 1 ], aggravates in chronic airway diseases including cystic fibrosis (CF) [ 2 ] and bronchiectasis [ 3 – 6 ]. The underlying causes for worsening ventilation heterogeneity are multifaceted, including mucus plugging [ 5 ] and airway remodeling [ 7 ] which are cascades of lung infections [ 8 , 9 ].…”

“…post-tuberculous infection) [ 3 ]. Lung clearance index (LCI) has been shown to sensitively detect ventilation heterogeneity and correlate with disease severity metrics, such as high-resolution computed tomography (HRCT) scores, in bronchiectasis [ 3 – 6 ]. Compared with spirometry, LCI conferred greater sensitivity in identifying early-stage lung structural disorders, which are likely related to small airways [ 3 ].…”