Effect of a syringe aspiration technique versus a mechanical suction technique and use of N-butylscopolammonium bromide on the quantity and quality of bronchoalveolar lavage fluid samples obtained from horses with the summer pasture endophenotype of equine asthma.

This study examined two techniques of obtaining bronchoalveolar lavage (BAL) fluid from horses with summer pasture equine asthma and the influence of the drug N-butylscopolammonium bromide (NBB) on the process. The results indicated that the syringe aspiration method led to better sample quantity and caused less trauma compared to the mechanical suction method, while the use of NBB didn’t affect the procedure.

Research Methodology

• Eight horses diagnosed with the summer pasture endophenotype of equine asthma were used for this study. All the procedures performed were bilateral, meaning they were done on both the right and left lung sites.
• BAL was carried out with a flexible videoendoscope that was manoeuvred through either the left or right nasal passage.
• Two fluid retrieval techniques were used in the study: gentle syringe aspiration and mechanical suction with a pressure-regulated wall-mounted suction pump. The methods were alternated in each lung site.
• NBB was used for premedication in one of the two procedures performed for each horse, with a 21-day interval between the operations.
• The BAL fluid samples obtained were evaluated in terms of volume, total cell count, differential cell count, RBC count, and total protein concentration.

Results and Observations

• The syringe aspiration method resulted in significantly higher quantities of BAL fluid (an average volume increase of 40mL or approximately 7.5% yield). It also reduced the total RBC count (with a mean decrease of 142 cells/μL) compared to the mechanical suction method.
• There wasn’t any difference in the BALF nucleated cell count and the differential cell count between the two BAL methods used.
• The application of NBB did not influence the retrieval of BAL fluid in any noticeable manner.

Implications and Future Research

• This study posits that using syringe aspiration for collecting BAL fluid could increase yield and decrease trauma in horses at a higher risk of bronchoconstriction and bronchiolar collapse. This could lead to less discomfort for the horses during the procedure and more optimal sample volumes for the researchers.
• However, the role of NBB and other bronchodilators in BAL procedures calls for further investigation. Though no significant effects of NBB were observed in this study, future research might determine whether it or another bronchodilator can enhance the sample collection process or benefit the horses in other ways.