The effect of decongestion on nasal airway patency and airflow

Abstract

Nasal decongestant reduces blood flow to the nasal turbinates, reducing tissue volume and increasing nasal airway patency. This study maps the changes in nasal anatomy and measures how these changes affect nasal resistance, flow partitioning between superior and inferior cavity, flow patterns and wall shear stress. High-resolution MRI was applied to capture nasal anatomy in 10 healthy subjects before and after application of a topical decongestant. Computational fluid dynamics simulated nasal airflow at steady inspiratory flow rates of 15 L.min$$^{-1}$$ - 1 and 30 L.min$$^{-1}$$ - 1 . The results show decongestion mainly increases the cross-sectional area in the turbinate region and SAVR is reduced (median approximately 40$$\%$$ % reduction) in middle and lower parts of the cavity. Decongestion reduces nasal resistance by 50$$\%$$ % on average, while in the posterior cavity, nasal resistance decreases by a median factor of approximately 3 after decongestion. We also find decongestant regularises nasal airflow and alters the partitioning of flow, significantly decreasing flow through the superior portions of the nasal cavity. By comparing nasal anatomies and airflow in their normal state with that when pharmacologically decongested, this study provides data for a broad range of anatomy and airflow conditions, which may help characterize the extent of nasal variability.

Asymmetrical nasal high flow ventilation improves clearance of CO2 from the anatomical dead space and increases positive airway pressure

“…Nasal decongestants may affect NHF therapy by changing nasal resistance, but this was not addressed in this current investigation. A study using high-resolution magnetic resonance imaging and computational flow dynamics in healthy subjects found that decongestants increased the averaged cross-sectional area of the nasal cavity by a factor of 1.4 and halved the nasal resistance ( 37 ). This may again affect the magnitude but not the mechanism of clearance with asymmetrical flow.…”

Effects of decongestion on nasal cavity air conditioning efficiency: a CFD cohort study

“…The image acquisition protocol and the translation of magnet resonance images (MRI) to 3D virtual airway surfaces were the same as in previously published work. 20 The ethical approval was granted by the National Health Service Health Research Authority NRES Committee South East Coast-Surrey with reference number 06/Q0602/18. Informed consent was obtained from each of the subjects included in this study.…”

“…The ow computations were performed for inspiratory owrates at 15 and 30 using the methodology as described more fully in previous work; brie y a mass ow inlet was speci ed at a far-removed external domain inlet and a pressure outlet condition was speci ed at an extended nasopharyngeal outlet. 20 There are 4 million total CFD polyhedral volume cells for each CFD simulation, and each simulation has 7 prism layers near the airway wall to L. min −1 account for both high ow and temperature gradient. The total thickness of prism layer is 0.3 mm, and rst layer is 0.01 mm with a stretch factor of 1.7 to allow a smooth transition of cells in between.…”

“…More detailed mesh scenes can be found in the previous study on nasal air ow distribution in this cohort. 20 Results using our model for heat and water transfer are compared with previous in-vivo measurements in the results section.…”

Numerical and Experimental Analysis of Drug Inhalation in Realistic Human Upper Airway Model

“…The human nose serves as the initial conduit for inhaled air while also conditioning, filtering, and sensing the inhaled volume [ 1 ]. The lungs’ exposure to the external environment causes them to be highly vulnerable to infectious and toxic agents in the ambient air [ 2 ].…”