E03 - An In-Hospital Clinical Trial Assessing Nebulized Lidocaine Compared to Saline for Treatment of Equine Asthma.

Background: Corticosteroids are the mainstay of pharmacologic treatment for equine asthma (EA), but may have adverse effects in metabolically unstable horses. Recent pilot studies support the use of nebulized lidocaine as an alternative treatment option.
Hypothesis: Nebulized lidocaine will improve clinical parameters and decrease airway inflammation associated with EA.
Animals: 20 client-owned horses diagnosed with EA.

Methods: A randomized, blinded, in-hospital study compared the effects of 1mg/kg 4% lidocaine (n=10) nebulized twice daily via Flexineb™ over 4 days to saline control (n=10). Clinical examination, endoscopy, lung function, bronchoalveolar lavage cytology, and inflammatory markers in blood and epithelial lining fluid (ELF) were compared between treatment groups using univariate analyses, based on data normality

Results: Neither lidocaine nor saline nebulization resulted in significant improvement of any of the assessment parameters between day 0 and 4. Comparing effects between treatment groups, horses undergoing saline nebulization showed a significantly greater decrease in ELF interferon-γ (P = 0.015) and tissue necrosis factor-α (P = 0.034) compared to lidocaine treated horses.
Conclusions and Clinical Importance: Nebulized lidocaine did not show efficacy as an alternative treatment for EA in this study, but a longer duration of treatment may be necessary. The significant changes in cytokine levels may help elucidate the immunology of EA.