Expiratory reactance abnormalities in patients with expiratory dynamic airway collapse: a new application of impulse oscillometry

Fielding, David; Travers, Justin; Nguyen, Phan; Brown, Michael G.; Härtel, Günter; Morrison, Stephen

doi:10.1183/23120541.00080-2018

Cited by 8 publications

(5 citation statements)

References 39 publications

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“…Dynamic collapse of the central airways (EDAC) shows similar reactance patterns to EFL reported here, although R20 was numerically lower in COPD patients versus COPD + EDAC (0.33 versus 1.07 cmH20/L/s) [29]. Hence, it is likely that EFL is a continuous process that can occur throughout the airways.…”

Section: Discussionsupporting

confidence: 63%

“…R 20 is considered to be a measure of proximal airway resistance [ 28 ] and was similar between those with and without EFL (0.36 and 0.39 kPa·L −1 ·s −1 , respectively; p=0.49). Expiratory dynamic airways collapse (EDAC) shows similar reactance patterns to EFL reported here, although R 20 was numerically lower in COPD patients versus COPD + EDAC (0.33 versus 1.07 cmH 2 O·L −1 ·s −1 ) [ 29 ]. Hence, it is likely that EFL is a continuous process that can occur throughout the airways.…”

Section: Discussionmentioning

confidence: 79%

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Expiratory flow limitation in a cohort of highly symptomatic COPD patients

et al. 2022

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The question addressed by the studySmall airway collapse during expiration, known as expiratory flow limitation (EFL), can be detected using oscillometry and is associated with worse clinical outcomes in chronic obstructive pulmonary disease (COPD).This study investigated the prevalence of EFL in a cohort of highly symptomatic patients, evaluated clinical and lung function characteristics of patients with EFL and studied the repeatability of EFL over 6 months.Materials/patients and methodsSeventy patients were recruited. Clinical characteristics and lung function metrics were collected at baseline and 6 months. Impulse oscillometry (IOS) was used to detect presence of EFL. Patients were defined as EFLHigh (ΔX5 ≥0.28 kPa L s−2); EFLIntermediate (ΔX5 0.1–0.27 kPa L s−2) and EFLNone (ΔX5 <0.1 kPa L s−2).ResultsEFLHigh was present in 47.8% of patients at baseline. ΔX5 showed excellent repeatability over 6 months (rho=0.78, p<0.0001, ICC=0.88), with the best repeatability observed in EFLNone and EFLHigh patients (ICC=0.77 and 0.65 respectively). Compared to EFLNone patients, EFLHigh had a higher BMI, worse health-related quality of life and increased peripheral airway resistance. EFLIntermediate was more variable over time with less severe physiological impairment.Answer to the questionOverall, these data indicate that EFLHigh is a common, and relatively stable, component of disease pathophysiology in highly symptomatic COPD patients. EFLHigh was also associated with worse quality of life and obesity.

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Section: Discussionsupporting

confidence: 63%

Section: Discussionmentioning

confidence: 79%

Expiratory flow limitation in a cohort of highly symptomatic COPD patients

et al. 2022

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“…19 This is due to loss of lung structure leading to obstruction resulting in wide spread airway closure. 93 In the example in Figure 4, the oscillogram and oscillometry parameters of a subject with symptomatic COPD GOLD Stage IV, Grade D, with a heterogeneous distribution of emphysema by quantitative CT scan (LAA <-950 HU ¼ 11%) very severe ventilatory inhomogeneity with an A X of 85 cmH 2 O. L À1 and a Z-score above 7 assuming proper cheek support and BMI < 40. High BMI can affect the frequency dependence likely indicative of obesity causing peripheral airway closure and hence, heterogeneity.…”

Section: Copd With Emphysemamentioning

confidence: 99%

Applications of oscillometry in clinical research and practice

Lundblad

Siddiqui

Bossé

et al. 2019

Canadian Journal of Respiratory, Critical Care, and Sleep Medic

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Oscillometry is gaining in clinical use and while there is an increased interest in the technique, there is paucity in the understanding of its possibilities and limitations. Oscillometry has seen extensive use in research over several decades, but only recently is the technique being adopted in clinical practice; hence, there is a need to educate the novel users. The goal of the mini symposium arranged in San Diego in 2018 was to discuss the principles of oscillometry, showcase some of the recent ongoing research using this technique and to demonstrate how oscillometry may be used in clinical practice. It was concluded that oscillometry has several advantages over spirometry, most notably, with novel data being shown, its sensitivity allowing early detection of small airways disease not possible with spirometry and it can be used in subjects who have difficulties performing forced maneuvers such as preschool children, the elderly and subjects with handicaps. The site of respiratory pathology can be reflected by the various parameters generated by oscillometry and thus help with both disease diagnosis and localization. While the interpretation of oscillometry parameters and translating them into meaningful pathological correlates is still evolving, it is likely that oscillometry will soon be at the forefront of both pulmonary clinical practice and research. R ESUM EL'oscillom etrie est de plus en plus utilis ee en contexte clinique, mais malgr e l'int erêt accru pour cette technique, la compr ehension de ses possibilit es et de ses limites est encore insuffisante. Pendant plusieurs d ecennies, l'oscillom etrie a largement et e utilis ee dans la recherche, mais l'adoption de cette technique dans la pratique clinique est encore r ecente, de sorte qu'il est n ecessaire de former les nouveaux utilisateurs. Le but de ce mini symposium qui s'est tenu a San Diego en 2018 etait de discuter des principes de l'oscillom etrie, de pr esenter les plus r ecentes etudes utilisant cette technique et de d emontrer comment elle peutêtre utilis ee dans la pratique clinique. Il a et e d etermin e que l'oscillom etrie pr esentait plusieurs avantages par rapport a la spirom etrie notamment, comme le d emontrent de nouvelles donn ees, sa sensibilit e qui permet la d etection pr ecoce de la maladie des petites voies a eriennes, ce que la spirom etrie ne peut pas faire, ainsi que le fait qu'elle puisseêtre utilis ee aupr es de sujets qui eprouvent de la difficult e a effectuer des manoeuvres forc ees comme les enfants d'âge pr escolaire, les personnesâg ees et les personnes atteintes d'un handicap. L'emplacement de la pathologie respiratoire peut se refl eter dans les divers param etres produits par la spirom etrie, ce qui peut contribuer a diagnostiquer la maladie et a la localiser. Bien que l'interpr etation des param etres de l'oscillom etrie et leur traduction dans des corr elats pathologiques significatifs continue d' evoluer, l'oscillom etrie sera vraisemblablement a l'avant-plan de la pratique clinique et de la recherche pulmonair...

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“…In this regard, RI has also been seen in a cohort of adult subjects with bronchoscopically demonstrated tracheobronchomalacia. 5 These large changes in airway size would predominate at lower frequencies, that is, those at which RI is seen (Figure 1), and could cause the reactance curve to assume a less exponential negative direction. However, while models that might increase inertance may cause reactance to fall less rapidly at low frequencies, no theoretical models support our observation of reactance inversion.…”

Section: Discussionmentioning

confidence: 99%