A new roentgenographic method for estimating mucous velocity in airways.

A new roentgenographic method is described for the estimation of mucous velocity in airways. Radiopaque discs of teflon mixed with bismuth trioxide were deposited in the trachea, and their motion was observed by a fluoroscopic image intensifier. Simultaneous measurements of disc movement were obtained by a previously reported cinebronchofiberscopic method and by the roentgenographic method in 6 anesthetized dogs. Mean +/- SD tracheal mucous velocity was 8.5 +/- 7.3 mm per min by the roentgenographic method, and 7.6 +/- 7.1 mm per min by the cinebronchofiberscopic method. Discrepancies between the 2 methods for individual disc velocities could be accounted for by the cumulative errors of both methods. The roentgenographic method was also used in 7 normal volunteers who did not have topical anesthesia of the tracheobronchial tree. The discs were blown through the inner channel of a bronchofiberscope, the tip of which was located just above the vocal cords. Placement of the discs on the tracheal mucosa generally did not produce coughing. Tracheal mucous velocity ranged from 7.4 to 19.4 mm per min as estimated from videotape recordings of the image intensifier images. There was no consistent difference in velocity between the erect or supine position, or after topical anesthesia with lidocaine.