Cytological evaluation of tracheal aspirate and broncho-alveolar lavage fluid in comparison to endoscopic assessment of lower airways in horses with recurrent airways obstruction or inflammatory airway disease

The aim of the present study was to compare the grade of discharge accumulation in the tracheal lumen, area of tracheal bifurcation, main bronchi and the tracheal septum thickness with the cytology of the tracheal aspirate (TA) and broncho-alveolar lavage fluid (BALF) in horses with recurrent airways obstruction and inflammatory airway disease from those horses. This study was conducted on 96 horses with RAO, 139 horses with IAD and 10 control horses. In all the horses, both clinical and endoscopic examinations were performed. During endoscopy, a score of mucus accumulation was estimated in 3/4 lower of the trachea and in the tracheal bifurcation. In addition, thickening of the tracheal septum was also assessed; tracheal aspirates and broncho-alveolar lavage were performed. An estimate of cell percentage was done in TA and BALF samples. In horses suffering from RAO and IAD, there was a positive correlation between the percentage of neutrophils and the accumulation of discharge, and in the IAD group, there was a negative correlation between the percentage of eosinophils and the accumulation of discharge. There was no correlation between tracheal septum thickening and the percentage of neutrophils and/or eosinophils.