Abstract:
Nasal high flow therapy has been used clinically to increase the intubation period in patients requiring mechanical ventilation, however the mechanisms through which the therapy achieves this have not been investigated. Computational fluid dynamics has been used in this study to demonstrate the effect of the therapy on the gas concentrations within the apneaic human airway. The complexity of the human airway gives rise to an intricate flow field in which the turbulence and mixing of gas species is augmented by the application of nasal high flow therapy. The therapy was found to flush the airway with oxygen thereby removing the stagnant, CO2 rich gas via the nostrils and mouth and hence preventing CO2 build-up during apnea. These results explain the previously reported clinical observations and give confidence in the application of the therapy during anaesthetic procedures.