A procedure in which cells are taken from the inside of the airways that lead to the lungs. A bronchoscope (a thin, tube-like instrument with a light and a lens for viewing) is inserted through the nose or mouth into the lungs. A mild salt solution is washed over the surface of the airways to collect cells, which are then looked at under a microscope. Bronchial washing is used to find infections. It may also help find cancer or changes in cells that may lead to cancer.