<qa>  What is the bronchoalveolar lavage?- c bronchoalveolar lavage. This 15- to 30-minute procedure is done in the intensive care unit. The mouth, nasal passages, throat and airways are numbed with lidocaine and a thin flexible tube is passed through the nose into the lung airways. Samples of cells and secretions are obtained by rinsing lavage the airways with salt water. The fluid is analyzed for infection, inflammatory cells and inflammatory chemicals. 