Effects of antitussive agents administered before bronchoalveolar lavage in horses.
OBJECTIVE
To determine whether treatment of horses with antitussive agents before bronchoalveolar lavage (BAL) reduces the frequency and intensity of the cough reflex during BAL.


METHODS
8 healthy horses.


METHODS
Standard BAL was performed on each horse weekly for 6 weeks. Detomidine was used as a general sedative, and various antitussive agents were evaluated for their suitability to suppress undesirable coughing. Treatments administered prior to BAL consisted of saline (0.9% NaCl) solution (control treatment), codeine, butorphanol tartrate, glycopyrrolate, lidocaine hydrochloride (final concentration, 0.33%), and lidocaine hydrochloride at a final concentration of 0.66% (lidocaine 0.66%). Frequency and intensity of coughing were digitally recorded throughout the BAL procedure. The volume of BAL fluid collected was measured, and the fluid was cytologically examined to assess potential effects of the medications on composition.


RESULTS
Coughing frequency was significantly reduced after intratracheal administration of lidocaine 0.66%. Moreover, intratracheal administration of lidocaine 0.66% or IV administration of butorphanol resulted in a significant reduction in the intensity of coughing episodes. All other treatments failed to significantly suppress coughing frequency and intensity, compared with results for the saline treatment. Glycopyrrolate caused obvious adverse clinical effects. Treatments did not influence the volume of BAL fluid collected nor composition of the fluid.


CONCLUSIONS
Intratracheal administration of lidocaine (final concentration, 0.66%) proved to be the most reliable method to reduce frequency and intensity of coughing in horses during BAL.
Westermann
Cornélie M
CM
Department of Equine Science, Faculty of Veterinary Medicine, Utrecht University, PO Box 80152, 3508 TD, Utrecht, The Netherlands.
Laan
Tamarinde T
TT
van Nieuwstadt
Roel A
RA
Bull
Sarah
S
Fink-Gremmels
Johanna
J
D000818:Animals; D000996:Antitussive Agents / Q000494:pharmacology*; D018893:Bronchoalveolar Lavage / Q000009:adverse effects / Q000662:veterinary*; D002077:Butorphanol / Q000494:pharmacology; D003061:Codeine / Q000494:pharmacology; D003371:Cough / Q000517:prevention & control / Q000662:veterinary*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D006024:Glycopyrrolate / Q000494:pharmacology; D006736:Horses / Q000502:physiology*; D008012:Lidocaine / Q000494:pharmacology
D000996:Antitussive Agents; D008012:Lidocaine; D002077:Butorphanol; D003061:Codeine; D006024:Glycopyrrolate