Transtracheal Aspiration in Cats

Transtracheal aspiration (TTA), also called a transtracheal wash (TTW), is the insertion of a catheter into the trachea and upper airway to collect fluid lavaged from the lower airways. This technique is most commonly performed in dogs.

A variant of the technique, employed in cats, is to intubate the airway of the anesthetized animal with a sterile endotracheal tube, and to obtain a fluid sample from the lower airway via this tube. The fluid can be collected directly from the endotracheal tube or from a catheter inserted through it. This procedure is also sometimes referred to as bronchoalveolar lavage (BAL).

What Does Transtracheal Aspiration Reveal?

Transtracheal aspiration is performed as a diagnostic aid to help determine the cause of coughing or other abnormal respiratory signs that can be caused by some form of acute or chronic bronchitis, pneumonia, and other forms of lower airway disease. It is often possible to identify bacterial, parasitic, fungal, and allergic causes of pulmonary disorders. The technique is less helpful in identifying disorders caused by viruses or tumors.

Analysis of fluid samples can help to determine the prognosis for recovery from smoke inhalation and chemical injuries of the airway.

How is Transtracheal Aspiration Performed?

In cats, under anesthesia, a sterile endotracheal tube is inserted into the trachea. An intravenous catheter is inserted into the endotracheal tube and threaded into the lower airway. A syringe containing sterile saline or an electrolyte solution is attached to the catheter. The solution is injected into the airway and the fluid is then aspirated (suctioned) back into the catheter. The fluid is then be analyzed under a microscope.

Is the Procedure Painful?

Because the procedure is performed under anesthesia, there is little pain involved. There may be some mild discomfort following the procedure.

Is Sedation or Anesthesia Required?

The endotracheal technique is performed while the cat is under the influence of a short-acting anesthetic.