Page 637 - The Veterinary Care of the Horse

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Figure 15.2 Endoscopic examination of a horse

Tracheal wash

The endoscope can be used to collect respiratory secretions for bacteriology and cytology
(examination of the cells under a microscope).

PROCEDURE

A long, sterile catheter is inserted into the biopsy channel of the endoscope and advanced part
of the way along the channel. The endoscope is introduced into one nostril and carefully

guided through the larynx and into the trachea. The catheter is then pushed in further so it
protrudes from the end of the endoscope and is positioned at the lowest point of the trachea.

If there is a pool of discharge, this may be sucked up through the catheter with a syringe. If a
sample cannot be obtained in this way, 50–100 ml of warmed sterile saline is introduced via
the catheter. This runs down the wall of the trachea and washes epithelial cells, discharges

and bacteria from the lining of the airway. The fluid pools at the entrance to the chest and this
can be retrieved through the catheter. The scope is then withdrawn.

EXAMINATION OF THE SAMPLES