Abnormalities on ventilation/perfusion lung scans induced by bronchoalveolar lavage.

Studies were performed before and at varying times after lavage in 10 normal volunteers to assess whether bronchoalveolar lavage results in significant abnormalities on ventilation/perfusion lung scans and chest x-rays. Abnormal lung scans were obtained in six subjects, interpretable as intermediate (three scans), low (one scan) and very low (two scans) probability for pulmonary emboli. Defects varied from multisegmental to subsegmental in size, while chest x-rays were normal in all but one. Both the extent and frequency of defects tended to decrease with time; 24 hr after bronchoalveolar lavage only one of four subjects had a minimally abnormal scan. It is recommended that ventilation/perfusion lung scanning be delayed at least 24 hr following bronchoalveolar lavage to avoid problems in interpretation of defects which may merely be the result of the lavage.