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 research aimed to compare the severity of mucous accumulation in the respiratory tract to cytology findings in horses with recurrent airways obstruction (RAO) and inflammatory airway disease (IAD). The study involved 96 horses with RAO, 139 with IAD, and 10 controls, with all subjects undergoing both clinical and endoscopic examinations.

Study Procedure

• The researchers performed a detailed endoscopic examination of each horse’s lower respiratory tract, focusing on the lower three-quarters of the trachea and the tracheal bifurcation.
• They measured the amount of mucous accumulation in these areas and assessed any thickening of the tracheal septum.
• Tracheal aspirates (TA) and broncho-alveolar lavage fluid (BALF) were collected from each horse.
• The collected samples were then analyzed cytologically, with particular attention to the percentages of different cell types present.

Findings & Oversight

• Among horses with RAO and IAD, a positive correlation was found between the percentage of neutrophils, a type of white blood cell, and the accumulation of discharge in the respiratory tract.
• In the IAD group, the study found a negative correlation between the percentage of eosinophils, another type of white blood cell, and the accumulation of mucus.
• However, no specific relationship was found between tracheal septum thickening and the percentages of either neutrophils or eosinophils, suggesting that thickening may be a separate issue or occur independently of these factors.

The findings from this study enhance the understanding of airway diseases in horses, and potentially aid in improving diagnostic processes and medical treatments in the future.