”Bronchoalveolar lavage cytology findings in horses during stabling period”

The aim of this study was to evaluate the BAL-technique (bronchoalveolar lavage) as diagnostic criteria. Sixteen horses with a history of RAO/IAD (Recurrent Airway Obstruction/Inflammatory Airway Disease). “Diseased” horses came from different stables, were investigated under stabling period, and had a “normal” control horse (that had no history of respiratory disease) recruited from the same stable, and examined on the same day. All horses received detailed clinical and respiratory examination, including auscultation following rebreathing, and blood sample analysis for white and red blood cell parameters, plasma fibrinogen, arterial blood gases partial pressures (PaO2 and PaCO2) and pH. Additionally, each had upper and lower airway endoscopy, and bronchoalveolar lavage and bronchial biopsies under endoscopic guidance. Data collection for the clinical history included detailed information on, for example, stabling and stage of training. Disease criteria were a history of chronic cough with no fever while stabled and that the horses had not received medical treatment under one month prior investigation. The results of this initial phase of examination showed that not only horses with history of RAO/IAD have inflammatory changes in BALF, but also several “normal” control horses with no history of clinical signs show degrees of inflammatory changes in their airways. Additionally, several horses with a clear history of RAO/IAD had normal BAL cytology, suggesting a confounding effect of stable environment on BAL studies. Recent research support our findings, where clinically healthy horses housed in a stable environment can show lavage changes suggestive of IAD (Gerber et al, 2003). Thus, use of BAL alone as gold standard for RAO/IAD must be questioned