Measurement of mucociliary transport velocity in the intact mucosa

A new method for measuring the velocity of the tracheal mucous transport rate in anesthetized dogs is described. The length of the trachea is determined with the bronchoscope as the distance between the larynx and the lower end of the trachea at the level of the carina. A small volume (0.04 to 0.1 ml) of albumin microspheres 5 mgm to 7 mum in diameter labeled with radioactive 99m technetium or 113m indium is deposited on the mucosal surface at the lower end of the trachea via a catheter placed in the inner channel of a fiberoptic bronchoscope. The movement of the microspheres towards the larynx is visualized and recorded using a scintallation camera (Picker Dyna Camera) with a large field of view (30 cm in diameter) for 30 to 60 minutes, depending upon the time required for the spheres to reach the top of the trachea. Polaroid pictures are made immediately and every minute thereafter until the activity reaches the larynx. The data are also recorded and stored on magnetic tape for subsequent analyses by computer. The length in millimeters divided by the time in minutes gives the transport velocity rate. The mean velocity was found to be 19.2 +/- 1.6 mm/min (+/- SE).