Objective—To determine tracheal mucociliary clearance
rate (TMCCR) by use of a standard protocol in
healthy anesthetized cats and to determine the effect
of theophylline on TMCCR in healthy anesthetized
Animals—6 healthy cats.
Procedure—Cats were anesthetized with propofol,
and a droplet of the radiopharmaceutical technetium
Tc 99m macroaggregated albumin was placed endoscopically
at the carina. Dynamic acquisition scintigraphic
imaging was performed, using the larynx as
the end point. The TMCCR was determined by measuring
the distance the droplet traveled by frame rate.
Each cat was imaged 6 times as follows: 3 times following
placebo administration and 3 times following
the administration of sustained release theophylline
(25 mg/kg, PO). Serum theophylline concentrations
were assessed during imaging to ensure therapeutic
Results—The TMCCR in healthy adult cats anesthetized
with propofol was 22.2 ± 2.8 mm/min.
Tracheal mucociliary clearance rate in cats receiving
theophylline was 21.8 ± 3.5 mm/min. Theophylline
administration did not significantly alter TMCCR.
Conclusion and Clinical Relevance—Theophylline
has been shown to increase TMCCR in humans and
dogs. In our study, we determined TMCCR in healthy
anesthetized cats and found that it was not accelerated
by the administration of theophylline. (Am J Vet