Final answer:
Bronchoalveolar lavage (BAL) is useful for diagnosing lung infections, interstitial lung diseases, and malignancies by analyzing saline-washed fluid from the alveolar region for pathogens or abnormal cells. It is particularly valuable when non-invasive tests are inconclusive and is commonly performed by a pulmonologist.
Step-by-step explanation:
Bronchoalveolar lavage (BAL) is a diagnostic procedure that is most useful for identifying infections or diseases in the lungs, especially when conventional methods such as sputum examination fail to yield results. This technique involves washing out the alveolar region of the lung with a saline solution and then examining the retrieved fluid for the presence of pathogens, cancerous cells, or immune cells. The procedure is especially valuable in diagnosing conditions like pneumonia, interstitial lung diseases, and malignancies. In patients with suspected lung infections, the analysis of a BAL sample can reveal the organism responsible for the disease, as illustrated in Figure 14.15, which mentions microscopic examination facilitating the identification of the causative agent.
Additionally, BAL can be an important tool in investigating lung conditions in premature infants, or when evaluating the cause of unusual respiratory symptoms in individuals where non-invasive tests (like pulse oximetry) have not provided clear answers. It's also worth noting that due to its invasive nature, BAL is generally reserved for cases where it is expected to provide significant clinical benefit and is usually performed under the guidance of a pulmonologist.