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Effects of theophylline on tracheal mucociliary clearance rates in healthy cats

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  • 1 Department of Veterinary Internal Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4.
  • | 2 Department of Clinical Sciences, University of Montreal, St-Hyacinthe, QC, Canada, J2S 7C6.
  • | 3 Department of Veterinary Internal Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4.
  • | 4 Veterinary Anesthesia, Radiology, and Surgery, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4.
  • | 5 Western College of Veterinary Medicine, the Department of Nuclear Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4.
  • | 6 Western College of Veterinary Medicine, the Department of Nuclear Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4.
  • | 7 Department of Nuclear Medicine, Queen Elizabeth II Health Sciences Centre, Halifax, NS, Canada, B3J 3K4.
  • | 8 Western College of Veterinary Medicine, the Department of Nuclear Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4.
  • | 9 Veterinary Anesthesia, Radiology, and Surgery, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4.
  • | 10 Department of Anesthesia, University of Florida, Gainesville, FL, 32610-0126.
  • | 11 Royal University Hospital, College of Pharmacy and Nutrition,University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4.

Abstract

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 cats.

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 concentrations.

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 Res 2002;63:1320–1322)

Abstract

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 cats.

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 concentrations.

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 Res 2002;63:1320–1322)