Usefulness of Exhaled NO in the Differential Diagnosis Acute Eosinophilic Pneumonia and Bacterial Pneumonia

Acute eosinophilic pneumonia (AEP) is diagnosed by cell count analysis of bronchoalveolar lavage fluid. However, the performance of bronchoscopy is not easy for patients with AEP, because they usually have hypoxia. Exhaled nitric oxide (FeNO) is usually elevated in the patients with eosinophilic inflammation such as asthma, but there is no previous studies FeNO in the patients with AEP. Investigators hypothesized that FeNO elevated significantly in patients with AEP, and FeNO can be used as non-invasive diagnostic method in patients who are clinically suspected with AEP, especially when the performance of bronchoscopy is difficult.