Comparative efficacy of three common treatments for equine recurrent airway obstruction

Objective - evaluate horses with acute airway obstruction using three treatment regimens: tapering doses of dexamethasone (DEX), environmental modification (ENV), and a combination of both treatments (DEX + ENV) by analyzing clinical parameters, pulmonary function testing, bronchoalveolar lavage fluid (BALF) cytology and BALF cell expression of the cytokines IFN-? and IL-4 Animals - 6 horses with recurrent airway obstruction (RAO) Procedures - Clinical examination, pulmonary function test, and collection of BALF prior to treatment and during 22 day treatment period Hypothesis - Alterations in clinical parameters, pulmonary function and airway inflammation in acute equine RAO will return to remission values by treating with DEX, ENV or DEX + ENV Results - All horses demonstrated clinical disease, reduced pulmonary dynamic compliance (Cdyn) and an increased maximum change in pleural pressures (?Pplmax) when in a challenge environment. All treatments improved clinical parameters, ?Pplmax and Cdyn. BALF cytology during an RAO crisis demonstrated neutrophilic inflammation. ENV or DEX + ENV resulted in a significant decrease in airway neutrophilia that was maintained throughout the treatment period. In contrast, treatment with DEX caused a reduction in airway neutrophilia initially followed by a rebound neutrophilia as the period between administrations of dexamethasone (0.05mg/kg) was increased to 72 hours. The rebound neutrophilia was not accompanied by equivalent deterioration in clinical parameters or pulmonary function. Conclusions - Environmental modification is important in the management of RAO horses. Treatment of clinical RAO with a decreasing dosage protocol of corticosteroids in the absence of environmental modification results in the persistence of airway inflammation without recrudescence of clinical disease.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Veterinary Medical Sciences

Department dc:contributor.department

Veterinary Medical Sciences

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2009

Author dc:creator

• Lee, Laura Caryn

Committee members dc:contributor.committeemember

• Zimmerman, Kurt L.
• Witonsky, Sharon G.
• Buechner-Maxwell, Virginia A.

• Pulmonary Function Testing
• Airway Inflammation
• Asthma
• Equine Recurrent Airway Obstruction (RAO)
• Equine Heaves
• Allergy
• Dexamethasone
• Environmental Modification
• Airway Neutrophilia
• Bronchoalveolar Lavage Fluid

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en_US

Dc Identifier Other

etd-07102009-190004

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/76818