Measurement of Lung Tissue Viscous Resistance Using Gases of Equal Kinematic Viscosity

Abstract

The original expression for respiratory resistance devised by Rohrer was shown to be inadequate to explain the changes which occur when the subject breathes a gas of different density and viscosity from air. The kinematic viscosity ([image]) of the gas breathed affects the distribution of turbulence in the respiratory tract and consequently alters the respiratory resistance. Respiratory resistance in normal subjects breathing air was compared with that on gas mixtures of the same kinematic viscosity as air, and the tissue viscous resistance calculated by extrapolating to conditions of zero density and viscosity-Tissue viscous resistance was found to constitute about 30% -40% of the total respiratory resistance during quiet breathing in normal adult males.