Longitudinal course of clinical lung clearance index in children with cystic fibrosis

Frauchiger, Bettina Sarah; Binggeli, Severin; Yammine, Sophie; Spycher, Ben D.; Krüger, Linn; Ramsey, Kathryn; Latzin, Philipp

doi:10.1183/13993003.02686-2020

Cited by 36 publications

(51 citation statements)

References 46 publications

(61 reference statements)

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“…The lung clearance index (LCI), which is derived from multiple breath nitrogen washout (MBNW), is a sensitive parameter in early CF lung disease and is increasingly used to assess lung function in stable condition periods as well as during PEx [ 6 , 7 , 8 , 9 ]. It might be an alternative and more useful indicator than FEV 1 to estimate treatment response in the growing number of children and young adults with CF who have spirometry within the normal range.…”

Section: Introductionmentioning

confidence: 99%

Lung Clearance Index in Children with Cystic Fibrosis during Pulmonary Exacerbation

Walicka‐Serzysko¹,

Postek²,

Milczewska³

et al. 2021

JCM

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(1) Background: Pulmonary exacerbation (PEx) is one of the main factors affecting the quality of life and life expectancy in patients with cystic fibrosis (CF). Our study aimed to evaluate the change in selected pulmonary function parameters, including lung clearance index (LCI), in patients with CF diagnosed with PEx. (2) Methods: We enrolled 40 children with CF aged 6–17. They performed spirometry and multiple breath nitrogen washout (MBNW) tests during a stable condition period at the beginning and the end of intravenous antibiotic treatment. (3) Results: LCI increased by 65% and FEV1 decreased by ≥10% in 40% of patients with CF during PEx. An absolute change in LCI between a stable condition period and PEx was 1.05 (±1.92) units, which corresponds to a relative change of 11.48% (±18.61) of the baseline. The relative decrease in FEV1 was −9.22% (±12.00) and the z-score was −0.67 (±1.13). After the PEx treatment, FEV1 increased by 11.05% (±9.04) on average, whereas LCI decreased by 1.21 ± 1.59 units on average, which represented 9.42% ± 11.40 compared to the value at the beginning of PEx. (4) Conclusions: The change in LCI captures a higher proportion of events with functional impairment than FEV1 in school-age children with CF.

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Section: Introductionmentioning

confidence: 99%

Lung Clearance Index in Children with Cystic Fibrosis during Pulmonary Exacerbation

Walicka‐Serzysko¹,

Postek²,

Milczewska³

et al. 2021

JCM

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“…LCI averaged across three visits provided even stronger association with death or LTX compared to a single LCI value. Clinically important events such as ABPA or pulmonary exacerbations contribute to LCI variability and may therefore influence the predictive capacity of LCI [34,35]. In our study, LCI, but not FEV 1 , was predictive of death or LTX in younger individuals and individuals with mild CF lung disease.…”

Section: Association Of Lung Function With Respiratory Disease Outcomesmentioning

confidence: 47%

Association of lung clearance index with survival in individuals with cystic fibrosis

Kurz

Ramsey

Rodriguez

et al. 2021

Preprint

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BackgroundLung clearance index (LCI) quantifies global ventilation inhomogeneity, a sensitive biomarker of airway function in cystic fibrosis (CF) lung disease.ObjectivesWe examined the association of LCI with the risk of death or lung transplantation (LTX) in individuals with CF.MethodsWe performed a retrospective analysis in a cohort of individuals with CF aged ≥ five years with available LCI and FEV1 measurements between 1980 and 2006. Outcome was time until death or LTX. We applied Cox proportional hazard regressions using the earliest available LCI and FEV1 values and adjusted for demographic and clinical variables. For sensitivity analyses, we used the mean of the first three LCI and FEV1 measurements, stratified the cohort based on age, and investigated individuals with normal FEV1.ResultsIn total, 237 individuals with CF aged mean (range) 13.9 (5.6–41.0) years were included. This time-to-event analysis accrued 3813 person-years, 94 (40%) individuals died or received LTX. Crude hazard ratios [95% CI] were 1.04 [1.01–1.06] per one z-score increase in LCI and 1.25 [1.11–1.41] per one z-score decrease in FEV1. After adjusting LCI and FEV1 mutually in addition to sex, age, BMI and the number of hospitalisations, hazard ratios were 1.04 [1.01-1.07] for LCI, and 1.12 [0.95-1.33] for FEV1. Sensitivity analyses yielded similar results and using the mean LCI strengthened the associations.ConclusionsIncreased ventilation inhomogeneity is associated with greater risk of death or LTX. Our data support LCI as novel surrogate of survival in individuals with CF.TAKE HOME MESSAGELung clearance index (LCI) is a measure of global ventilation inhomogeneity which increases early during the course of Cystic Fibrosis (CF) lung disease. This study shows that LCI is predictive of death or lung transplantation in individuals with CF.Study registration numberNCT04016194

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“…We included experimental data from gas mixture measurements and mass spectrometry (Eco Medics AG, Duernten, Switzerland). We characterized the impact of the developed correction functions on MBW outcomes with data from healthy children 16 and children diagnosed with CF (Swiss Cystic Fibrosis Infant Lung Development (SCILD) cohort) 6,17 . The Ethics Committee of the Canton of Bern, Switzerland approved the study protocol (PB_2017-02139).…”

Section: Methodsmentioning

confidence: 99%

“…For this, we re-analysed 357 MBW measurements of 85 healthy controls (HC, mean age: 11.1y, SD: 3.8y, range: 6-17.8y) and 62 subjects diagnosed with cystic fibrosis (CF, mean age: 9.5y, SD: 3.5y, range: 4-17.3y) from previous studies 6,16 (OLS Table 2 for details). We included study visits with at least two acceptable, quality controlled N 2 -MBW measurements, in accordance with recent consensus guidelines 20 .…”

Section: Methodsmentioning

confidence: 99%

Correction of measurement error in a commercial multiple-breath washout device

Wyler¹,

Oestreich²,

Frauchiger³

et al. 2021

Preprint

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Rationale: Nitrogen multiple breath washout (N2MBW) is an established technique to assess functional residual capacity (FRC) and ventilation inhomogeneity in the lung. Accurate gas sensors are essential for the appropriate calculation of clinical outcomes. Objectives: We investigated the accuracy of oxygen and carbon dioxide sensors used for the indirect measurement of nitrogen in the Eco Medics Exhalyzer D N2MBW device and characterized the impact of potential sensor errors on FRC and the lung clearance index (LCI). Methods: Technical gas mixtures and mass spectrometry were used to evaluate sensor accuracy. We assessed the impact of potential sensor errors and correction on FRC and LCI in a dataset of healthy children and children with cystic fibrosis using custom analysis software. Results: We found a systematic error in the gas sensors of the Exhalyzer D device involving inadequate correction for the cross sensitivity between the oxygen and carbon dioxide sensors. This error results in an overestimation of expired nitrogen concentration, and consequently FRC and LCI outcomes. Breath-by-breath correction for this sensor error non-systematically reduced mean (SD) FRC by 8.9 (2.2)% and LCI by 11.9 (4.0)%. It also resulted in almost complete disappearance of the tissue nitrogen signal at the end of the measurement. Conclusions: An error in the cross sensitivity correction between the oxygen and carbon dioxide gas sensors of the Exhalyzer D device leads to an overestimation of FRC and LCI. Correction of this error is possible but needs to be applied breath-by-breath by re-analysing the measurements in an updated software version.

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Longitudinal course of clinical lung clearance index in children with cystic fibrosis

Cited by 36 publications

References 46 publications

Lung Clearance Index in Children with Cystic Fibrosis during Pulmonary Exacerbation

Lung Clearance Index in Children with Cystic Fibrosis during Pulmonary Exacerbation

Association of lung clearance index with survival in individuals with cystic fibrosis

Correction of measurement error in a commercial multiple-breath washout device

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