How to perform a transtracheal aspirate in horses for diagnosis of lower respiratory tract disease.

The research article discusses the method and importance of performing a transtracheal aspirate in horses, primarily to diagnose lower respiratory tract diseases like pneumonia.

Objective and Scope of the Research

• The primary objective of the study is to outline the procedure and indications for conducting a transtracheal aspirate in horses. The procedure is particularly useful when there is a suspicion of pulmonary or other lower respiratory tract diseases in the subject.
• The authors used a healthy university-owned horse for demonstrating the procedure, along with images from clinical case samples from the University of Illinois Veterinary Teaching Hospital.

Procedure for Transtracheal Aspiration

• The procedure begins by restraining the horse and sedation with detomidine or xylazine for easier restraint, and butorphanol is administered to minimize coughing.
• The ventral neck of the horse is prepared aseptically, and the site planned for puncture is anesthetized with lidocaine. This site is located proximal to the bifurcation of the sternocephalicus.
• Two to three 30-mL syringes are filled with saline aseptically, and a stab incision is made with a No. 15 blade to the depth of the trachea.
• A trocar is then advanced between the tracheal rings, the stylet removed, and the aspiration catheter is advanced through the trocar to the level of the proximal horizontal trachea.
• 30 mL of Sterile saline is infused rapidly, and suction is applied to the syringe while slowly withdrawing the catheter until fluid is retrieved.
• Finally, the catheter and trocar are withdrawn, and the incision site is dressed with antimicrobial ointment or a light bandage.

Results and Conclusion

• The fluid samples are collected in a plain tube for bacteriologic culture and EDTA for cytology. Notably, the visual appearance of a purulent effluent is a confirmation of severe pneumonia.
• The authors conclude that conducting a transtracheal aspirate is minimally invasive yet supremely useful. It provides valuable information on the health status of the respiratory tract of the horse, it informs treatment decisions and helps in appropriate selection of antimicrobials for horses suspected to have lower respiratory tract diseases.