Research Output per year
Nasal high flow (NHF) therapy is used to treat a variety of respiratory disorders to improve patient oxygenation. A CO2Â washout mechanism is believed to be responsible for the observed increase in oxygenation. In this study, experimentally validated Computational Fluid Dynamics simulations of the CO2 concentration within the upper airway during unassisted and NHF assisted breathing were undertaken with the aim of exploring the existence of this washout mechanism. An anatomically accurate nasal cavity model was generated from a CT scan and breathing was reproduced using a Fourier decomposition of a physiologically measured breath waveform. Time dependent CO2Â profiles were obtained at the entrance of the trachea in the experimental model, and were used as simulation boundary conditions. Flow recirculation features were observed in the anterior portion of the nasal cavity upon application of the therapy. This causes the CO2Â rich gas to vent from the nostrils reducing the CO2Â concentration in the dead space and lowering the inspired CO2 volume. Increasing therapy flow rate increases the penetration depth within the nasal cavity of the low CO2Â concentration gas. A 65% decrease in inspired CO2Â was observed for therapy flow rates ranging from 0 to 60Â LÂ min−1 supporting the washout mechanism theory.
- Breathing therapy
- CO washout
- Computational fluid dynamics
- Nasal cavity
- Non-invasive ventilation
Fabrication of rigid and flexible refractive-index-matched flow phantoms for flow visualisation and optical flow measurementsGeoghegan, P. H., Buchmann, N. A., Spence, C. J. T., Moore, S. & Jermy, M. C., May 2012, In : Experiments in Fluids. 52, 5, p. 1331-1347 17 p.
Research output: Contribution to journal › Article