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

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posted on 2019-09-23, 16:36 authored by Marcia Soares, Matthew Richardson, James Thorpe, John Owers-Bradley, Salman Siddiqui
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.


Supported by grants from and National Institute for Health Research (NIHR) Leicester Biomedical Research Centre: Respiratory Theme, the East Midlands Comprehensive Clinical Research Network and EU FP7 AirPROM project (grant agreement no. 270194) and an unrestricted grant from the Chiesi Onulus Foundation (Validation of Particle in Exhaled Air (PEx) as a Novel Matrix for Non-Invasive Detection of Small Airways Disease in Asthma). The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health.



Scientific Reports, 2019, volume 9, Article number: 2130

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/Organisation/COLLEGE OF LIFE SCIENCES/School of Medicine/Department of Infection, Immunity and Inflammation


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