Nasal flow, volumes, and minimal cross sectional areas in asthmatics.

Background: The Unified Airways hypothesis suggests an involvement of the upper airways in asthma. Critical parameters of the nasal airway can be quantified objectively with acoustic rhinometry (AR) and peak nasal inspiratory flow (PNIF).

Objective: We aimed to investigate nasal airway patency in asthmatics compared to non-asthmatic controls. Nasal volume, cross sectional area and flow were measured using acoustic rhinometry (AR) and peak nasal inspiratory flow (PNIF) in 87 asthmatics and 93 non-asthmatic controls before and after decongestion with xylometazoline. Nasal congestion index (NCI) was calculated, and allergy status was assessed by skin prick test or specific IgE.

Results: We found significantly smaller minimum cross sectional area and nasal cavity volume in asthmatics than controls, and the cross sectional area is at its minimum at 2-3 cm from the nasal orifice in both groups. AR and PNIF measurements are not different in allergic and non allergic subjects in either group. The effect of xylometazoline is not significantly different between the 2 groups with regard to AR, but there is a significant improvement in PNIF for the asthmatics when assessed by the NCI.

Conclusion: The present study demonstrates a significantly smaller nasal airway when assessed by minimum cross sectional area and nasal cavity volume in asthmatics than controls, and these findings apply to asthmatics and controls irrespective of allergy status.