Bronchoscopy is a procedure that allows veterinarian to examine your pets lungs and airway. It uses a thin, lighted tube called a bronchoscope. The tube is put through the mouth or nose and moved down the throat and into the airways. It helps diagnose and treat certain lung diseases. Bronchoalveolar lavage (BAL) is a procedure that is sometimes done during a bronchoscopy. It is also called bronchoalveolar washing. BAL is used to collect a sample from the lungs for testing. During the procedure, a saline solution is put through the bronchoscope to wash the airways and capture a fluid sample.