Equine Tracheal Wash Catheter. Transtracheal wash is a very useful diagnostic tool in the treatment of lower respiratory disease in horses. The Tracheal Wash kit provides a convenient and easy method to obtain high quality diagnostic samples. The procedure is simple to perform under light sedation with a small local block over the lower third of the neck. Sterile. 15g cannula and 16g needle, Catheter Length 55cm.