Acinar and conductive ventilation heterogeneity in severe CF lung disease: Back to the model

Verbanck, Sylvia; Paiva, Manuel; Schuermans, Daniël; Malfroot, Anne; Vincken, Walter; Vanderhelst, Eef

doi:10.1016/j.resp.2013.05.011

Cited by 38 publications

(61 citation statements)

References 19 publications

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“…Total washout duration was abbreviated, and intratest variability was lower. Abbreviated MBW protocols potentially improve success rates, especially in patients with severe lung disease or patients with brief attention spans (20)(21)(22). However, there is a decrease in sensitivity to detect treatment differences associated with these abbreviated MBW protocol LCIs (23).…”

Section: Lung Clearance Index Cutoff Valuesmentioning

confidence: 99%

Multiple-Breath Washout as a Lung Function Test in Cystic Fibrosis. A Cystic Fibrosis Foundation Workshop Report

et al. 2015

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The lung clearance index (LCI) is a lung function parameter derived from the multiple-breath washout (MBW) test. Although first developed 60 years ago, the technique was not widely used for many years. Recent technological advances in equipment design have produced gains in popularity for this test among cystic fibrosis (CF) researchers and clinicians, particularly for testing preschool-aged children. LCI has been shown to be feasible and sensitive to early CF lung disease in patients of all ages from infancy to adulthood. A workshop was convened in January 2014 by the North American Cystic Fibrosis Foundation to determine the readiness of the LCI for use in multicenter clinical trials as well as clinical care. The workshop concluded that the MBW text is a valuable potential outcome measure for CF clinical trials in preschool-aged patients and in older patients with FEV 1 in the normal range. However, gaps in knowledge about the choice of device, gas, and standardization across systems are key issues precluding its use as a clinical trial end point in infants. Based on the current evidence, there are insufficient data to support the use of LCI or MBW parameters in the routine clinical management of patients with CF.

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Section: Lung Clearance Index Cutoff Valuesmentioning

confidence: 99%

Multiple-Breath Washout as a Lung Function Test in Cystic Fibrosis. A Cystic Fibrosis Foundation Workshop Report

et al. 2015

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“…From the semi-log plot of mean expired concentration (as a percent of initial concentration) versus TO we derived: 1) LCI, as the TO value corresponding to the intercept between the semi-log plot of mean expired concentration and the 1/0.40th initial concentration level; 2) Curv, as unity minus the ratio of two regression slopes, where the regression slope in the denominator is that determined in the range TO=0 and TO=LCI/2 and in the numerator that between TO=LCI/2 and TO=LCI [12]. From the plot of normalised phase III slope (normalised by mean expired concentration) versus TO, we derived indices of acinar and conductive (Sacin, Scond) ventilation heterogeneity, as well as two modified indices (Sacin*, Scond*) for use in patient groups such as CF where ventilation heterogeneity is so marked that Scond becomes invalid [22]. Finally, we determined Fowler dead space volume of the first breath (VDF) in order to assess its potential impact on LCI when exploring the relationship between LCI, which is an overall index of ventilation heterogeneity, and its potential determinants (Sacin, Scond).…”

Section: Mbw Testmentioning

confidence: 99%

Transfer factor, lung volumes, resistance and ventilation distribution in healthy adults

et al. 2015

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Monitoring of chronic lung disease requires reference values of lung function indices, including putative markers of small airway function, spanning a wide age range.We measured spirometry, transfer factor of the lung for carbon monoxide (TLCO), static lung volume, resistance and ventilation distribution in a healthy population, studying at least 20 subjects per sex and per decade between the ages of 20 and 80 years.With respect to the Global Lung Function Initiative reference data, our subjects had average z-scores for forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC of −0.12, 0.04 and −0.32, respectively. Reference equations were obtained which could account for a potential dependence of index variability on age and height. This was done for (but not limited to) indices that are pertinent to asthma and chronic obstructive pulmonary disease studies: forced expired volume in 6 s, forced expiratory flow, TLCO, specific airway conductance, residual volume (RV)/total lung capacity (TLC), and ventilation heterogeneity in acinar and conductive lung zones.Deterioration in acinar ventilation heterogeneity and lung clearance index with age were more marked beyond 60 years, and conductive ventilation heterogeneity showed the greatest increase in variability with age. The most clinically relevant deviation from published reference values concerned RV/TLC values, which were considerably smaller than American Thoracic Society/European Respiratory Society-endorsed reference values. @ERSpublications We present reference equations for median and variability of most lung function indices, in the age range 20-80 years http://ow.ly/SsZFW

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“…diffuse panbronchiolitis [11] and primary acquired pulmonary alveolar proteinosis [12], how a specific treatment of the peripheral lung zones is reflected in the response of the MBW-derived index of acinar ventilation heterogeneity. We also showed how the identification of conductive and acinar components of ventilation heterogeneity can be hampered by the severity of the lung disease, for instance in adult CF patients [13,14]. We showed that a combination of a large LCI value and a highly curvilinear washout curve, often observed in adult CF patients, is suggestive of ventilation heterogeneity between relatively large lung units [13].…”

Section: Introductionmentioning

confidence: 99%

“…These large-scale ventilation heterogeneities could potentially mask the more peripheral component of ventilation heterogeneity. Hence, we explored in a dedicated study [14] how the currently accepted MBW indices of conductive and acinar ventilation heterogeneity could be adapted to accurately represent ventilation heterogeneity at various lung depths, even in patients with severe lung disease.…”

Section: Introductionmentioning

confidence: 99%

Evidence of an Acinar Response following Treatment for Exacerbation in Adult Patients with Cystic Fibrosis

et al. 2014

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Background: Treating acute infectious exacerbations in cystic fibrosis (CF) patients with intravenous antibiotic therapy leads to variability in lung function and the ventilation distribution response. Part of the variable lung clearance index (LCI) response could be associated with the variable peripheral effects of intravenous antibiotic administration. Objectives: We explored to what extent the peripheral lung zones of CF patients could contribute to lung function improvements following treatment for infectious exacerbations. Methods: Over a 1-year period, 15 adult CF patients admitted for acute exacerbations were recruited. Lung function and multiple breath washout (MBW) tests were performed on the day of admission and at discharge. From the MBW test, we obtained acinar and conductive indices of ventilation heterogeneity and LCI. Results: The mean age (±SD) was 26 ± 5 years. Upon admission, the FEV₁ was 54 ± 16% predicted and the LCI was 181 ± 26% predicted. After treatment, the average FEV₁ increased to 61 ± 20% predicted (p < 0.001) and the LCI decreased to 173 ± 28% predicted (p = 0.042). The change in LCI was associated with a change in acinar (ρ = +0.54; p = 0.039) but not in conductive ventilation heterogeneity (p > 0.1). Conclusions: In CF patients in whom an improvement in LCI was obtained after treatment for an acute infectious exacerbation, this was paralleled by a decrease in acinar ventilation heterogeneity.

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Acinar and conductive ventilation heterogeneity in severe CF lung disease: Back to the model

Cited by 38 publications

References 19 publications

Multiple-Breath Washout as a Lung Function Test in Cystic Fibrosis. A Cystic Fibrosis Foundation Workshop Report

Multiple-Breath Washout as a Lung Function Test in Cystic Fibrosis. A Cystic Fibrosis Foundation Workshop Report

Transfer factor, lung volumes, resistance and ventilation distribution in healthy adults

Evidence of an Acinar Response following Treatment for Exacerbation in Adult Patients with Cystic Fibrosis

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