Tidal changes in respiratory resistance are sensitive indicators of airway obstruction in children

Czövek, Dorottya; Shackleton, Claire; Hantos, Zoltán; Taylor, Kate; Kumar, Anushma; Chacko, Archana; Ware, Robert S.; Makan, Gergely; Radics, Bence; Gingl, Zoltán; Sly, Peter D.

doi:10.1136/thoraxjnl-2015-208182

Cited by 53 publications

(63 citation statements)

References 39 publications

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“…It is worthwhile to note that one device (MostGraph-02) was tested in both impulse and pseudo-random signal modes and the results were basically similar. The current study does not address the marked nonlinearities present in the upper airways and flow-limiting bronchial segments, causing large intra-breath fluctuations in R rs and X rs [31][32][33][34][35], a factor potentially affecting the device-subject interaction and hence the device performance. However, new modalities of oscillometry that widen the utility of this method in lung function testing [33,34] and monitoring [36], impose further requirements over the accuracy of mean R rs and X rs .…”

Section: Discussionmentioning

confidence: 99%

Comparison of oscillometry devices using active mechanical test loads

et al. 2019

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Noninvasiveness, low cooperation demand and the potential for detailed physiological characterisation have promoted the use of oscillometry in the assessment of lung function. However, concerns have been raised about the comparability of measurement outcomes delivered by the different oscillometry devices. The present study compares the performances of oscillometers in the measurement of mechanical test loads with and without simulated breathing.Six devices (five were commercially available and one was custom made) were tested with mechanical test loads combining resistors (R), gas compliances (C) and a tube inertance (L), to mimic respiratory resistance (R rs ) and reactance (X rs ) spectra encountered in clinical practice. A ventilator was used to simulate breathing at tidal volumes of 300 and 700 mL at frequencies of 30 and 15 min −1 , respectively. Measurements were evaluated in terms of R, C, L, resonance frequency ( f res ), reactance area (A X ) and resistance change between 5 and 20 or 19 Hz (R 5-20(19) ).Increasing test loads caused progressive deviations in R rs and X rs from calculated values at various degrees in the different oscillometers. While mean values of R rs were recovered acceptably, some devices exhibited serious distortions in the frequency dependences of R rs and X rs , leading to large errors in C, L, f res , A X and R 5-20(19) . The results were largely independent of the simulated breathing.Simplistic calibration procedures and mouthpiece corrections, in addition to unknown instrumental and signal processing factors, may be responsible for the large differences in oscillometry measures. Rigorous testing and ongoing harmonisation efforts are necessary to better exploit the diagnostic and scientific potential of oscillometry. @ERSpublicationsThe clinical utility of oscillometry is limited by the lack of standardisation of devices. This study tested six oscillometers, and reveals very different performances at higher mechanical impedances observed in children and adults with lung disease. http://bit.ly/317sfjHCite this article as: Dandurand RJ, Lavoie J-P, Lands LC, et al. Comparison of oscillometry devices using active mechanical test loads.

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Section: Discussionmentioning

confidence: 99%

Comparison of oscillometry devices using active mechanical test loads

et al. 2019

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“…EFL T is a condition that occurs only when the combination of lung function impairment and amplitude of expiratory flows overcome a threshold, which means that subtle changes in lung function, too small to overcome the threshold, may not affect ΔX8. Whether other indices of the within‐breath impedance analysis may reveal more subtle changes in lung function, independently of EFL T , needs to be further investigated.…”

Section: Discussionmentioning

confidence: 99%

Within‐breath changes in respiratory system impedance in children with cystic fibrosis

Zannin

Nyilas

Ramsey

et al. 2019

Pediatric Pulmonology

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Background The aim of this study was to assess within‐breath respiratory system impedance by the forced oscillation technique (FOT) in children with cystic fibrosis (CF) and relate it to the underlying lung disease. Methods Thirty‐three children with CF (median [range] age 12.0 [6‐17] years) underwent FOT at 8 Hz during tidal breathing, multiple breath nitrogen washout (LCI), spirometry (FEV1), body plethysmography (RV/TLC), and magnetic resonance imaging (MRI). FOT outcomes included: mean inspiratory, expiratory, and whole breath resistance (R8INSP, R8EXP, R8TOT) and reactance (X8INSP, X8EXP, X8TOT), and the differences between X8INSP and X8EXP (ΔX8). Morphological changes were evaluated by MRI using CF‐specific morphological scores. Spearman correlation was performed to examine the correlation between FOT indices and other parameters. Results FEV1 was negatively correlated with R8EXP (r = −0.52, P = 0.002) and ΔX8 (r = −0.55, P = 0.001), and positively correlated with and X8EXP (r = 0.56, P < 0.001). RV/TLC was positively correlated with R8EXP (r = 0.43, P = 0.013), and ΔX8 (r = 0.54, P = 0.001) and negatively correlated with X8EXP (r = −0.54, P = 0.001). We found poor correlation between FOT parameters and LCI and no correlation between FOT parameters and MRI scores. Conclusion In children with CF, changes in within‐breath FOT parameters are consistent with peripheral obstruction and dynamic airway compression, while they are not associated with ventilation heterogeneities and morphological alterations.

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“…Longitudinal changes in some respiratory function (RF) tests have previously been described 5 but the relationship between RF and polysomnography (PSG) findings has not been extensively researched in SMA, particularly in younger children, some by this study group. 6,7 Need for respiratory assessment has become more relevant with the improved availability of NIV and newer disease-modifying medications such as Nusinersen.…”

Section: Introductionmentioning

confidence: 99%

Relationship between respiratory function and need for NIV in childhood SMA

Kapur

Deegan

Parakh

et al. 2019

Pediatric Pulmonology

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BackgroundSpinal muscular atrophy (SMA) causes progressive respiratory muscle weakness but respiratory function (RF) in those using noninvasive ventilation (NIV) is not well described.ObjectiveTo describe RF in childhood SMA and assess differences between those using and not using NIV.MethodsA cross‐sectional study of childhood SMA assessed polysomnography (PSG), spirometry, forced oscillation technique (FOT), lung clearance index (LCI), sniff nasal inspiratory pressures, peak cough flow, maximal inspiratory and expiratory pressure, and NIV use and indication.ResultsTwenty‐five children (median age [interquartile range], 8.96 [5.63] years; 10 F) with SMA 1 (n = 3), 2 (n = 15), and 3 (n = 7) were recruited. Spirometry and FOT testing was feasible in children as young as 3 years. Ten (40%) required NIV, 5 for sleep‐disordered breathing (SDB), and 5 initiated during lower respiratory tract infection (LRTI). Children requiring NIV were older (median, 10.52 vs 5.67 years; P < .02) with more abnormal forced vital capacity (FVC) z‐score (−5.70 vs −1.39, P < .02), Rsr8 z‐score (1.97 vs 0.50, P = .04), and LCI (8.84 vs 7.34, P = .01). Two had normal RF and SDB. For FVC z‐score less than −2.5 and LCI greater than 7.5, the odds ratio for NIV was 10.70 (95% confidence interval [CI], 1.39‐82.03) and 2 (95% CI, 0.40‐10.31), respectively. All children with LCI greater than 8 used NIV. FVC z‐score and LCI are associated with maximum transcutaneous carbon dioxide on PSG (r = 0.43, P < .001).ConclusionNIV is common in SMA. Normal RF does not exclude SDB. Children with more abnormal FVC and LCI should be considered at risk of starting NIV during/following an LRTI.

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Tidal changes in respiratory resistance are sensitive indicators of airway obstruction in children

Abstract: New lung function measure ΔR is able to detect airway obstruction with high sensitivity and specificity and is suitable for use in lung function testing in young children.

Cited by 53 publications

References 39 publications

Comparison of oscillometry devices using active mechanical test loads

Comparison of oscillometry devices using active mechanical test loads

Within‐breath changes in respiratory system impedance in children with cystic fibrosis

Relationship between respiratory function and need for NIV in childhood SMA

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