Nasal pressure-volume relationships determined with acoustic rhinometry

Partitioning of ventilation has been hypothesized to be related to nasal pressure-volume relationships, relationships that have been difficult to measure. Regional differences in nasal passage pressure-volume relationships are likely because the nasal valve and anterior turbinate are structurally different, but both are altered by agents that alter vascular tone. This study determined nasal volume-to-pressure ratio (NVPR) on six healthy nonsmoking subjects by measuring nasal volume by using acoustic rhinometry at pressures ranging between -14 and +14 cmH₂O on 3 days: baseline, after intranasal decongestion (oxymetazoline), and congestion (histamine). NVPR was lower in the nasal valve (0.07 ± 0.01 cm³/cmH₂O) than in the anterior portion of the turbinates (0.29 ± 0.05 cm³/cmH₂O; P < 0.005). Oxymetazoline decongestion decreased NVPR in the nasal valve by 23% and NVPR in the anterior portion of the turbinates by 47%. Histamine did not alter NVPR at either site. Nasal resistance changes correlated with changes in nasal valve and anterior turbinate volume. In summary, regional differences in nasal pressure-volume relationships exist and changes occur with pharmacologically induced vascular decongestion.