Physical properties of sputum. VII. Rheologic properties and mucociliary transport.

Sputums from bronchitic patients were measured for viscosity and elastic recoil and then placed on an isolated frog pharyngeal palate to study the velocity of transport by beating mucosal cilia. Purulent sputum, as a group, demonstrated a higher viscosity and a lower elastic recoil, and was transported at a slower rate than mucoid samples of low viscosity and high recoil. Indigenous frog mucus, collected and reapplied to the palate, had the lowest viscosity, the highest elastic recoil, and the fastest transport rate. Thus, it was concluded that high elastic recoil and low viscosity represent the best rheologic combination for maximal velocity by a mucociliary system.