New time-saving predictor algorithm for multiple breath washout in adolescents

Grønbæk, Jonathan Kjær; Hallas, Henrik Wegener; Arianto, Lambang; Pedersen, Knud Erik; Thomsen, Arne; Chawes, Bo; Bisgaard, Hans

doi:10.1038/pr.2016.57

Cited by 9 publications

(5 citation statements)

References 15 publications

(17 reference statements)

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“…Moreover, the part of expiration that the tracer gas concentration is determined from is more critical in patients with CF or PCD, as mentioned earlier. Therefore, in accordance to similar studies [ 23 , 24 ], our analysis suggests that it is essential to include measurements from subjects with lung disease in software/algorithm validation studies, as those measurements are more sensitive to small changes in the analysis process.…”

Section: Discussionsupporting

confidence: 78%

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Comparison of different analysis algorithms to calculate multiple-breath washout outcomes

et al. 2018

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Lung clearance index (LCI) is the main outcome of the multiple-breath washout (MBW) test. Current recommendations for LCI acquisition are based on low-grade evidence. The aim of this study was to challenge those recommendations using alternative methods for LCI analysis.Nitrogen MBW measurements from school-aged children, 20 healthy controls, 20 with cystic fibrosis (CF) and 17 with primary ciliary dyskinesia (PCD), were analysed using 1) current algorithms (standard), 2) three alternative algorithms to detect with higher precision the end of MBW testing and 3) two alternative algorithms to determine exhaled tracer gas concentrations. LCI values, intra-test repeatability, and ability to discriminate between health and lung disease were compared between these methods.The analysis methods strongly influenced LCI (mean±sd overall differences (%) between standard and alternative analysis methods: −4.9±5.7%; range: −66–19%), but did not improve intra-test variability. Discrimination between health and disease was comparable as areas under the receiver operator curves were not greater than that from standard analysis.This study supports current recommendations for LCI calculation in children. Alternative methods influence LCI estimates and hamper comparability between MBW setups. Alternative algorithms, whenever used, should be carefully reported.

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Section: Discussionsupporting

confidence: 78%

“…The intra-test variability in LCI values was chosen to measure the robustness of different algorithms, as previously described [ 24 , 26 ]. Despite the high quality of the recordings, intra-test variability was widely scattered, which possibly facilitates comparison to clinical testing situations.…”

Section: Discussionmentioning

confidence: 99%

Comparison of different analysis algorithms to calculate multiple-breath washout outcomes

et al. 2018

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“…For both tracer gases, several adaptions to the measurement protocols have been proposed, including reduction of total measurements or earlier cut-offs for terminating the washout. [44][45][46][47] Moreover, closed-circuit SF 6 -MBW was shown to effectively reduce wash-in times. 15 We therefore calculated reference values for an earlier 5% stopping point reducing washout times considerably by 24%.…”

Section: Discussionmentioning

confidence: 99%

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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“…LCI is defined as a number of times lung turn overs (as represented by FRC) have to turn over to the clear the lungs from nitrogen (N 2 ). LCI (LCI 2.5 ) reflects N 2 washout until 1/40 th of the starting N 2 end-tidal concentration (cet), i.e., 2.5% and LCI 5 reflects N 2 washout until 1/20 th of the starting N 2 concentration (Cet), i.e., 5% [49][50][51][52][53]. So, the sicker the child is, the more air it must breathe to clear its lungs from the tracer gas.…”

Section: Introductionmentioning

confidence: 99%