Studies of transnasal pressure and airflow values in a Japanese population

The proportions of subjects who attained transnasal pressure and flow values of different magnitudes during spontaneous nasal breathing at rest were determined. Several co-ordinate points on transnasal pressure: flow curves generated by 77 (34 M, 43 F) healthy Japanese subjects aged 15-65 years were examined. By posterior rhinomanometry the proportion approximated 100% at Brom's radii R1 and R2 and 80-90% at 0.25 l/sec flow and at 0.5 cm H2O (50 Pa) pressure when both nasal cavities were patent. When one nasal cavity was occluded the results were 100% at radius R1 and 80-90% at radius R2 and 0.5 cm H2O (50 Pa) pressure. By anterior rhinomanometry, the proportion approximated 100% at radius R1 and 0.5 cm H2O (50 Pa) pressure and was quite high at radius R2 and 1.0 cm H2O (100 Pa) pressure. Pressure and flow are more representative at points where the pressure: flow curve includes the turbulent flow component than at radius R1 and 0.5 cm H2O (50 Pa) pressure. Calculation of total nasal resistance from unilateral resistances at 1.0 cm H2O (100 Pa) appears a suitable compromise and this point is recommended for a Japanese population.