An experimental model of gas dispersion and uptake at the bronchial wall

Dispersion and uptake of gas boli of a range of solubilities was examined in lung airway models; first a straight tube, then a four generation network. Airway liquid lining was simulated with gelatin. The bolus dispersion was determined from the first three moments of the concentration profile measured at two positions down-stream. The disruption of the flow by the bifurcations significantly reduces the dispersion of an insoluble gas, compared to that predicted in an equivalent network of parallel straight tubes. Retention of gas in the wall increases with solubility causing increased bolus dispersion and decreased average speed. For highly soluble gases this process dominates and the effect of bifurcations becomes less significant.