Multiple breath washout (MBW) using sulfur hexafluoride – Proof of concept in COPD

Saur, Daniel; Roth, Katharina; Borggrefe, Martin; Kaden, Jens J.; Michels, Julia; Saur, Joachim

doi:10.1183/13993003.congress-2016.pa3440

Cited by 4 publications

(2 citation statements)

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“…In early stages, IOS parameters outperformed conventional spirometry when differentiating heavy smokers with normal lung function as well as early-stage COPD 46 20 . Even in absence of spirometric obstruction, LCI was already pathologically altered 22 . Differences in FRC as measured by plethysmography and MBW were described previously in patients with obstructive lung disease 39,47,48 .…”

Section: Discussionmentioning

confidence: 99%

Feasibility and clinical applications of multiple breath wash-out (MBW) testing using sulphur hexafluoride in adults with bronchial asthma

Lenz

Schäfer

Gawlitza

et al. 2020

Sci Rep

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Ventilation heterogeneity is frequent in bronchial asthma and can be assessed using multiple breath wash-out testing (MBW). Most data is available in paediatric patients and using nitrogen as a tracer gas. We aimed to evaluate sulphur hexafluoride (SF 6) MBW in adult asthmatics. Spirometry, wholebody plethysmography, impulse oscillometry and SF 6-MBW were prospectively performed. MBW parameters reflecting global (lung clearance index, LCI), acinar (S acin) and conductive (S cond) ventilation heterogeneity were derived from three consecutive wash-outs. LCI was calculated for the traditional 2.5% and an earlier 5% stopping point that has the potential to reduce wash-out times. 91 asthmatics (66%) and 47 non-asthmatic controls (34%) were included in final analysis. LCI 2.5 and Lci 5 were higher in asthmatics (p < 0.001). Likewise, S acin and S cond were elevated (p < 0.001 and p < 0.01). Coefficient of variation was 3.4% for LCI 2.5 and 3.5% for LCI 5 in asthmatics. Forty-one asthmatic patients had normal spirometry. ROC analysis revealed an AUC of 0.906 for the differentiation from non-asthmatic controls exceeding diagnostic performance of individual and conventional parameters (AUC = 0.819, p < 0.05). Sf 6-MBW is feasible and reproducible in adult asthmatics. Ventilation heterogeneity is increased as compared to non-asthmatic controls persisting in asthmatic patients with normal spirometry. Diagnostic performance is not affected using an earlier LCI stopping point while reducing wash-out duration considerably. Disease control is the primary goal of asthma therapy being linked to absence of symptoms and exacerbations 1. Regrettably, up to half of the patients are poorly controlled 2,3. Despite therapeutic advances, numbers remained fairly unaltered during the last decade. The clinical and pathophysiological explanations associated with poor disease control are heterogenous. In general, more severe disease is related to more frequent exacerbations, health care contacts 3 and symptoms 4. Lung function is also impaired in severe disease indicated by a lower forced expiratory volume in one second (FEV 1) and lower forced vital capacity (FVC) 3. Both parameters represent rather central sites of obstruction. However, involvement of peripheral airways is common in the majority of asthmatic patients 5. This holds true across the whole spectrum of severity 6 and may be a consequence of several influencing factors. These include inflammation, wall thickening, smooth muscle hypertrophy, and mucus 7-10. However, changes in the lung periphery are still often missed by commonly used techniques such as spirometry. Impulse oscillometry (IOS) is an inexpensive non-invasive technique to measure airway resistance. It was shown to identify small airway obstruction 11 , the related characteristics of disease control 12,13 and response to

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Section: Discussionmentioning

confidence: 99%

Feasibility and clinical applications of multiple breath wash-out (MBW) testing using sulphur hexafluoride in adults with bronchial asthma

Lenz

Schäfer

Gawlitza

et al. 2020

Sci Rep

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“…MBW yielded promising results for the determination of ventilation heterogeneity in patients with COPD. Lung clearance index (LCI) is already elevated even in the absence of spirometric obstruction [16]. Both techniques may therefore provide additional information when assessing lung function impairment in patients with PH.…”

Section: Introductionmentioning

confidence: 99%

Small Airway Disease in Pulmonary Hypertension—Additional Diagnostic Value of Multiple Breath Washout and Impulse Oscillometry

Gawlitza

Kunstler

Schäfer

et al. 2018

JCM

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Airways obstruction is frequent in patients with pulmonary hypertension (PH). Small airway disease (SAD) was identified as a major contributor to resistance and symptoms. However, it is easily missed using current diagnostic approaches. We aimed to evaluate more elaborate diagnostic tests such as impulse oscillometry (IOS) and SF6-multiple-breath-washout (MBW) for the assessment of SAD in PH. Twenty-five PH patients undergoing body-plethysmography, IOS and MBW testing were prospectively included and equally matched to pulmonary healthy and non-healthy controls. Lung clearance index (LCI) and acinar ventilation heterogeneity (Sacin) differed significantly between PH, healthy and non-healthy controls. Likewise, differences were found for all IOS parameters between PH and healthy, but not non-healthy controls. Transfer factor corrected for ventilated alveolar volume (TLCO/VA), frequency dependency of resistance (D5-20), resonance frequency (Fres) and Sacin allowed complete differentiation between PH and healthy controls (AUC (area under the curve) = 1.0). Likewise, PH patients were separated from non-healthy controls (AUC 0.762) by D5-20, LCI and conductive ventilation heterogeneity (Scond). Maximal expiratory flow (MEF) values were not associated with additional diagnostic values. MBW and IOS are feasible in PH patients both providing additional information. This can be used to discriminate PH from healthy and non-healthy controls. Therefore, further research targeting SAD in PH and evaluation of therapeutic implications is justified.

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Multiple breath washout (MBW) testing using sulfur hexafluoride: reference values and influence of anthropometric parameters

Maros

Roth

Hermanns

et al. 2021

Thorax

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BackgroundMultiple breath washout (MBW) using sulfur hexafluoride (SF6) has the potential to reveal ventilation heterogeneity which is frequent in patients with obstructive lung disease and associated small airway dysfunction. However, reference data are scarce for this technique and mostly restricted to younger cohorts. We therefore set out to evaluate the influence of anthropometric parameters on SF6-MBW reference values in pulmonary healthy adults.MethodsWe evaluated cross-sectional data from 100 pulmonary healthy never-smokers and smokers (mean 51 (SD 20), range 20–88 years). Lung clearance index (LCI), acinar (Sacin) and conductive (Scond) ventilation heterogeneity were derived from triplicate SF6-MBW measurements. Global ventilation heterogeneity was calculated for the 2.5% (LCI2.5) and 5% (LCI5) stopping points. Upper limit of normal (ULN) was defined as the 95th percentile.ResultsAge was the only meaningful parameter influencing SF6-MBW parameters, explaining 47% (CI 33% to 59%) of the variance in LCI, 32% (CI 18% to 47%) in Sacin and 10% (CI 2% to 22%) in Scond. Mean LCI increases from 6.3 (ULN 7.4) to 8.8 (ULN 9.9) in subjects between 20 and 90 years. Smoking accounted for 2% (CI 0% to 8%) of the variability in LCI, 4% (CI 0% to 13%) in Sacin and 3% (CI 0% to 13%) in Scond.ConclusionSF6-MBW outcome parameters showed an age-dependent increase from early adulthood to old age. The effect was most pronounced for global and acinar ventilation heterogeneity and smaller for conductive ventilation heterogeneity. No influence of height, weight and sex was seen. Reference values can now be provided for all important SF6-MBW outcome parameters over the whole age range.Trial registration numberNCT04099225.

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Multiple breath washout (MBW) using sulfur hexafluoride – Proof of concept in COPD

Cited by 4 publications

References 0 publications

Feasibility and clinical applications of multiple breath wash-out (MBW) testing using sulphur hexafluoride in adults with bronchial asthma

Feasibility and clinical applications of multiple breath wash-out (MBW) testing using sulphur hexafluoride in adults with bronchial asthma

Small Airway Disease in Pulmonary Hypertension—Additional Diagnostic Value of Multiple Breath Washout and Impulse Oscillometry

Multiple breath washout (MBW) testing using sulfur hexafluoride: reference values and influence of anthropometric parameters

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