The role of airflow in mucous transport in the trachea

The role of airflow in mucous transport in the respiratory tract was studied. Seven mongrel dogs were tracheostomised at the caudal end of the neck, and the following two procedures were performed. In procedure (1), a small radiopaque plastic disc was placed on the mucous membrane of the right side wall of the trachea through the tracheostoma, which was then closed to let the dog breathe through the normal respiratory tract. Roentgenograms of the trachea were taken three times at 5-min intervals. Procedure (2) was designed to eliminate airflow from around the disc. A canula was placed in the trachea through the tracheostoma to bypass airflow, and the disc was placed on the mucous membrane slightly more proximal than the cannula. The transport rate was 11.1 +/- 4.1 mm/min (mean +/- S.D.) in procedure (1) and 5.4 +/- 2.7 mm/min in procedure (2), which showed a significant difference. The present results seem to indicate an important role of airflow in mucous transport in the trachea.