How is a culture obtained for the diagnosis of acute respiratory distress syndrome (ARDS)?

Updated: Mar 27, 2020
  • Author: Eloise M Harman, MD; Chief Editor: Michael R Pinsky, MD, CM, Dr(HC), FCCP, FAPS, MCCM  more...
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Answer

An alternative means of obtaining a culture is by means of a protected specimen brush, which is passed through the bronchoscope into a segmental bronchus. Subsequently, the brush is cut off into 1 mL of sterile nonbacteriostatic saline. Culture of 1000 organisms is considered significant.

Analysis of the types of cells present in the BAL fluid may be helpful in the differential diagnosis of patients with ARDS. For example, the finding of a high percentage of eosinophils (>25%) in the BAL fluid is consistent with the diagnosis of acute eosinophilic pneumonia. The use of high-dose corticosteroids in these patients may be lifesaving.

A high proportion of lymphocytes may be observed in acute hypersensitivity pneumonitis, sarcoidosis, or cryptogenic organizing pneumonia (COP). Red blood cells and hemosiderin-laden macrophages may be observed in pulmonary hemorrhage. Lipid-laden macrophages are suggestive of aspiration or lipoid pneumonia.


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