Premium
What is normal nasal airflow? A computational study of 22 healthy adults
Author(s) -
Zhao Kai,
Jiang Jianbo
Publication year - 2014
Publication title -
international forum of allergy and rhinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.503
H-Index - 46
eISSN - 2042-6984
pISSN - 2042-6976
DOI - 10.1002/alr.21319
Subject(s) - airflow , medicine , rhinomanometry , vorticity , anatomy , turbulence , nose , mechanics , vortex , physics , thermodynamics
Background Nasal airflow is essential for the functioning of the human nose. Given individual variation in nasal anatomy, there is yet no consensus what constitutes normal nasal airflow patterns. We attempt to obtain such information that is essential to differentiate disease‐related conditions. Methods Computational fluid dynamics (CFD) simulated nasal airflow in 22 healthy subjects during resting breathing. Streamline patterns, airflow distributions, velocity profiles, pressure, wall stress, turbulence, and vortical flow characteristics under quasi–steady state were analyzed. Patency ratings, acoustically measured minimum cross‐sectional area (MCA), and rhinomanometric nasal resistance (NR) were examined for potential correlations with morphological and airflow‐related variables. Results Common features across subjects included: >50% total pressure drop reached near the inferior turbinate head; wall shear stress, NR, turbulence energy, and vorticity were lower in the turbinate than in the nasal valve region. However, location of the major flow path and coronal velocity distributions varied greatly across individuals. Surprisingly, on average, more flow passed through the middle than the inferior meatus and correlated with better patency ratings ( r = −0.65, p < 0.01). This middle flow percentage combined with peak postvestibule nasal heat loss and MCA accounted for >70% of the variance in subjective patency ratings and predicted patency categories with 86% success. Nasal index correlated with forming of the anterior dorsal vortex. Expected for resting breathing, the functional impact for local and total turbulence, vorticity, and helicity was limited. As validation, rhinomanometric NR significantly correlated with CFD simulations ( r = 0.53, p < 0.01). Conclusion Significant variations of nasal airflow found among healthy subjects; Key features may have clinically relevant applications.