title: Modeling the pharyngeal pressure during adult nasal high flow therapy.
abstract: Subjects receiving nasal high flow (NHF) via wide-bore nasal cannula may experience different levels of positive pressure depending on the individual response to NHF. In this study, airflow in the nasal airway during NHF-assisted breathing is simulated and nasopharyngeal airway pressure numerically computed, to determine whether the relationship between NHF and pressure can be described by a simple equation. Two geometric models are used for analysis. In the first, 3D airway geometry is reconstructed from computed tomography images of an adult nasal airway. For the second, a simplified geometric model is derived that has the same cross-sectional area as the complex model, but is more readily amenable to analysis. Peak airway pressure is correlated as a function of nasal valve area, nostril area and cannula flow rate, for NHF rates of 20, 40 and 60 L/min. Results show that airway pressure is related by a power law to NHF rate, valve area, and nostril area.
authors.affiliation: Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand. Electronic address: h.kumar@auckland.ac.nz.
authors.forename: Haribalan
authors.initials: H
authors.lastname: Kumar
authors.affiliation: Fisher and Paykel Healthcare Limited, Auckland, New Zealand.
authors.forename: Callum J T
authors.initials: CJ
authors.lastname: Spence
authors.affiliation: Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.
authors.forename: Merryn H
authors.initials: MH
authors.lastname: Tawhai
mesh_terms: D057785:Catheters; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008297:Male; D008955:Models, Cardiovascular; D009296:Nasal Cavity / Q000000981:diagnostic imaging; D010614:Pharynx / Q000000981:diagnostic imaging / Q000502:physiology*; D011312:Pressure; D011859:Radiography; D012119:Respiration; D012138:Respiratory Therapy / Q000379:methods*; D014054:Tomography; D055815:Young Adult