Gas mixing in the pulmonary airways

Abstract

The traditional Bohr model subdivides the pulmonary airways into two serial gas mixing compartments: a nonmixed conducting airway or dead space compartment and a well-mixed alveolar compartment. Experimental as well as theoretical evidence indicates that some mixing does occur in the dead space compartment by a combination of axial convection and radial diffusion. And although this mixing may only play a minor role during normal respiration in a normal lung, it is an important factor in high frequency (low tidal volume) assisted ventilation and in lung pathologies where the diffusion cross-section of the respiratory zone is reduced.