Med Eng Phys. 2021 Nov;97:1-9. doi: 10.1016/j.medengphy.2021.09.004. Epub 2021 Sep 16.
Medical engineering & physics
Rutger H J Hebbink, Rob Hagmeijer
PMID: 34756332 DOI: 10.1016/j.medengphy.2021.09.004
Spirometry is a gold standard to assess lung function, and to identify respiratory impairments seen in obstructive lung diseases. The method is used for periodic monitoring, but it only provides snapshot information, and it requires forceful exhalation which is associated with limited reliability and repeatability. Several studies indicate that tidal flow-volume curves measured by pneumotachography or plethysmography can also be used to assess lung function. These methods avoid the forced manoeuvre, but are complex to set up or sensitive to movement. In the present work we address the long-standing problem of the unavailability of an easy-to-use and accurate method for monitoring tidal breathing frequently or even continuously. We show that pressure recordings from a nasal cannula can be accurately converted into scaled flow-volume curves by means of an algorithm that continuously calibrates itself. The method has been validated by feeding realistic healthy and unhealthy breathing patterns to anatomically correct 3D-printed upper airways of an infant and an adult, and by comparing the imposed flow-volume curves to the pressure-derived flow-volume curves. The observed very high level of accuracy opens the route towards remotely monitoring patients with chronic lung diseases.
Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.
Keywords: Flow-volume curves; Nasal cannula; Obstructive lung diseases; Tidal spirometry
