Characterizing human nasal airflow physiologic variables by nasal index

Area of Science:

• Anatomy
• Physiology
• Biophysics

Background:

• Nasal index (NI) variations are linked to climate adaptation.
• The relationship between NI and nasal airflow dynamics requires further investigation.

Purpose of the Study:

• To investigate the association between nasal index (NI) and airflow variables using computational fluid dynamics (CFD).
• To explore how NI influences nasal resistance (NR), wall shear stress (WSS), and heat flux (HF).

Main Methods:

• CFD modeling was employed on 16 subjects with normal nasal anatomy.
• Airflow simulations were performed under constant inspiratory pressure.
• Correlations between NI and NR, WSS, and HF were analyzed.

Main Results:

• Nasal resistance (NR) showed weak associations with NI across different nasal regions (R(2)=0.26 and R(2)=0.12).
• NI explained 38-52% of the variability in nasal wall shear stress (WSS) and heat flux (HF).
• Stronger correlations between HF, WSS, and NI were observed for NI < 80 compared to NI > 80.

Conclusions:

• A significant relationship exists between nasal index and nasal heat flux and wall shear stress.
• Nasal index is a less significant predictor of nasal resistance.
• The findings are particularly pronounced in individuals with a nasal index below 80.