Measurement duration impacts variability but not impedance measured by the forced oscillation technique in healthy, asthma and COPD subjects

Watts, Joanna C.; Farah, Claude S.; Seccombe, Leigh M.; Handley, Blake M.; Schoeffel, Robin E.; Bertolin, Amy; Carroll, Jessica; King, Gregory G.; Thamrin, Cindy

doi:10.1183/23120541.00094-2015

Cited by 16 publications

(18 citation statements)

References 14 publications

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“…Longer acquisitions are likely to be more challenging in younger paediatric populations. In healthy adults and adults with asthma or COPD, within-session variability also decreased as acquisition duration increased from 16 s, 30 s and 60 s [97]. Additionally, there were small but statistically significant differences in mean R rs or X rs , between triplicate measurements of 16 s, 30 s and 60 s, in healthy adults or those with asthma or COPD [97].…”

Section: Duration Of Acquisitionmentioning

confidence: 84%

“…The number of technically acceptable measurements used to determine a mean value will affect the variability of the test. Work in adults suggests that two technically acceptable measurements result in the same mean resistance and reactance values as three or more replicate measurements, regardless of measurement duration [97]. There is no comparable information of the effect of the number of replicates in children.…”

Section: Minimum Number Of Technically Acceptable Replicate Measurementsmentioning

confidence: 99%

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Technical standards for respiratory oscillometry

King

Bates

Berger³

et al. 2019

Eur Respir J

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420

496

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Oscillometry (also known as the forced oscillation technique) measures the mechanical properties of the respiratory system (upper and intrathoracic airways, lung tissue and chest wall) during quiet tidal breathing, by the application of an oscillating pressure signal (input or forcing signal), most commonly at the mouth. With increased clinical and research use, it is critical that all technical details of the hardware design, signal processing and analyses, and testing protocols are transparent and clearly reported to allow standardisation, comparison and replication of clinical and research studies. Because of this need, an update of the 2003 European Respiratory Society (ERS) technical standards document was produced by an ERS task force of experts who are active in clinical oscillometry research.The aim of the task force was to provide technical recommendations regarding oscillometry measurement including hardware, software, testing protocols and quality control.The main changes in this update, compared with the 2003 ERS task force document are 1) new quality control procedures which reflect use of “within-breath” analysis, and methods of handling artefacts; 2) recommendation to disclose signal processing, quality control, artefact handling and breathing protocols (e.g. number and duration of acquisitions) in reports and publications to allow comparability and replication between devices and laboratories; 3) a summary review of new data to support threshold values for bronchodilator and bronchial challenge tests; and 4) updated list of predicted impedance values in adults and children.

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Section: Duration Of Acquisitionmentioning

confidence: 84%

Section: Minimum Number Of Technically Acceptable Replicate Measurementsmentioning

confidence: 99%

Technical standards for respiratory oscillometry

King

Bates

Berger³

et al. 2019

Eur Respir J

Self Cite

420

496

View full text Add to dashboard Cite

show abstract

“…The forced oscillation technique (FOT) is used to noninvasively assess the mechanical properties of the respiratory system (5,31,47,65). Recently, it has been demonstrated that FOT can be used to identify lung derecruitment (16,35,36) and a surrogate measure of airway closure (critical volume) (35).…”

Section: Introductionmentioning

confidence: 99%

Early onset of airway derecruitment assessed using the forced oscillation technique in subjects with asthma

Nilsen

Thien

Thamrin

et al. 2019

Journal of Applied Physiology

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Derecruitment of air spaces in the lung occurs when airways close during exhalation and is related to ventilation heterogeneity and symptoms in asthma. The forced oscillation technique has been used to identify surrogate measures of airway closure via the reactance (Xrs) versus lung volume relationship. This study used a new algorithm to identify derecruitment from the Xrs versus lung volume relationship from a slow vital capacity maneuver. We aimed to compare two derecruitment markers on the Xrs versus volume curve, the onset reduction of Xrs (DR1vol) and the onset of more rapid reduction of Xrs (DR2vol), between control and asthmatic subjects. We hypothesized that the onset of DR1vol and DR2vol occurred at higher lung volume in asthmatic subjects. DR1vol and DR2vol were measured in 18 subjects with asthma and 18 healthy controls, and their relationships with age and height were examined using linear regression. In the control group, DR1vol and DR2vol increased with age ( r2 = 0.68, P < 0.001 and r2 = 0.71, P < 0.001, respectively). DR1vol and DR2vol in subjects with asthma [76.58% of total lung capacity (TLC) and 56.79%TLC, respectively] were at higher lung volume compared with control subjects (46.1 and 37.69%TLC, respectively) ( P < 0.001). DR2vol correlated with predicted values of closing capacity ( r = 0.94, P < 0.001). This study demonstrates that derecruitment occurs at two points along the Xrs-volume relationship. Both derecruitment points occurred at significantly higher lung volumes in subjects with asthma compared with healthy control subjects. This technique offers a novel way to measure the effects of changes in airways/lung mechanics. NEW & NOTEWORTHY This study demonstrates that the forced oscillation technique can be used to identify two lung volume points where lung derecruitment occurs: 1) where derecruitment is initiated and 2) where onset of rapid derecruitment commences. Measurements of derecruitment increase with age. The onset of rapid derecruitment was highly correlated with predicted closing capacity. Also, the initiation and rate of derecruitment are significantly altered in subjects with asthma.

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“…(iii) Finally, differences in the acquisition time between the IOS and TremoFlo may have introduced bias. However, a previous study by Watz et al ., concluded that FOT data were minimally impacted by acquisition duration in asthmatic subjects and healthy volunteers 12 .…”

Section: Discussionmentioning

confidence: 99%

Comparison of Forced and Impulse Oscillometry Measurements: A Clinical Population and Printed Airway Model Study

Soares

Richardson

Thorpe

et al. 2019

Sci Rep

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The use of commercialised forced oscillation (FOT) devices to assess impedance in obstructive diseases such as asthma has gained popularity. However, it has yet to be fully established whether resistance and reactance measurements are comparable across different FOT devices, particularly in disease. We compared two commercially available FOT devices: Impulse Oscillometry (IOS) and TremoFlo FOT (Thorasys) in a) clinical adult population of healthy controls (n = 14), asymptomatic smokers (n = 17) and individuals with asthma (n = 73) and b) a 3D printed CT-derived airway tree model resistance, as well as a 3 L standardised volume reactance. Bland-Altman Plots and linear regressions were used to evaluate bias between the devices. Resistance measurements at both 5 and 20 Hz were numerically higher with IOS compared to FOT, with evidence of small and statistically significant proportional systematic bias and a positive Bland-Altman regression slope at both 5 and 20 Hz. In contrast, the IOS device recorded reactances that were less negative at both 5 Hz and 20 Hz and significantly smaller reactance areas when compared to TremoFlo. Larger statistically significant proportional systematic biases were demonstrated with both reactance at 5 Hz and reactance area (AX) between the devices with a negative Bland-Altman regression slope. The printed airway resistance and standardised volume reactance confirmed the observations seen in patients. We have demonstrated that the impulse oscillation system and TremoFlo FOT demonstrate comparative bias, particularly when comparing airway reactance in patients. Our results highlight the need for further standardisation across FOT measurement devices, specifically using variable test loads for reactance standardisation.

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Measurement duration impacts variability but not impedance measured by the forced oscillation technique in healthy, asthma and COPD subjects

Cited by 16 publications

References 14 publications

Technical standards for respiratory oscillometry

Technical standards for respiratory oscillometry

Early onset of airway derecruitment assessed using the forced oscillation technique in subjects with asthma

Comparison of Forced and Impulse Oscillometry Measurements: A Clinical Population and Printed Airway Model Study

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