The technique of bronchoalveolar lavage. A guide to sampling the terminal airways and alveolar space

Bronchoalveolar lavage (BAL) provides a means of recovering cells and biochemical substances directly from the alveoli in patients with numerous pulmonary diseases. It is also useful in diagnosing opportunistic infections in immunocompromised patients. Upper airway contamination of BAL specimens is the chief liability. In diffuse lung disease, the bronchoscope is usually positioned in the middle lobe; when focal lung disease is present, the bronchoscope is placed in the area of greatest roentgenographic involvement. Sterile saline is instilled and recovered for analysis. Most side effects are related to endoscopic technique, location and extent of lavaged lung area, and the volume and temperature of instilled fluid.