POSTURE AND NASAL PATENCY - EVALUATION BY ACOUSTIC RHINOMETRY

Nasal passage geometry was measured by acoustic rhinometry in 8 health y medical students (5 males and 3 females, 21-29 years old; mean age 2 4 years) after 6 min in different postures of head and body. The minim um cross-sectional area (A-min) and volume between the nostril and 7 c m posteriorly were measured on both sides. When changing from sitting to horizontal the total airway dimension (i.e., the sum of A-min for t he two sides) decreased by about 16% (Mean +/- SD = 0.19 +/- 0.14 cm2) , and when standing up it increased by about 12% (0.14 +/- 0.13 cm2). A-min seemed more sensitive than volume to detecting postural changes. Including the variation between the cavities, the coefficient of vari ation (CV = SD/Mean) for area was 24.8 +/- 6.7 and for volume 22.4 +/- 6.4 for the 8 subjects. For the total nasal airway passage the corresp onding figures were 12.9 +/- 3.9 and 10.9 +/- 5.5. These figures are c onsiderably higher than for subjects measured only in the sitting posi tion under comparable circumstances. In conclusion, our findings indic ate a composite response of the nasal cavity mucosa to both systemic ( hydrostatic) and local conditions, probably induced by vascular and cu taneous reflexes. These factors must be taken into account in studies of environmental, clinical, and pharmacological conditions.