The clinical use of BAL in patients with pulmonary infections.

In immunocompetent patients with community acquired pneumonia, as well as in the immunocompetent host with nosocomial pneumonia, a calculated therapy can be initiated without prior invasive diagnostic procedure. This kind of patient management, however, is not warranted in immunocompromised or immunodeficient patients, in whom an exact diagnosis and the identification of the organism causing pneumonia is of utmost importance to select the correct therapeutic regime. If less invasive techniques like blood cultures were not successful in establishing the diagnosis, or the results from other procedures such as sputum induction were nondiagnostic, it is necessary to obtain specimens from the lower respiratory tract. These specimens can be taken using transtracheal aspiration, fibreoptic bronchoscopy, transthoracic needle puncture, or open lung biopsy. Such invasive procedures may also be necessary in the immunocompetent host, if therapy for a community acquired pneumonia or nosocomial pneumonia have failed and less invasive procedures are not likely to identify the cause of the disease. As experience during the past years has shown, taking microbiological samples by protected brush, bronchoalveolar lavage and/or transbronchial lung biopsy are methods which combine a low rate of side-effects and a sufficient diagnostic yield when used in this context [222-224]. Also bronchoalveolar lavage alone is a sensitive method to establish the diagnosis of infection of the lower respiratory tract caused by bacteria [222, 223], mycobacteria [225], viruses [226) and other opportunistic infections of the lung (e.g. Pneumocystis carinii pneumonia) [227, 228] (summary in table 1).