Fraction of Exhaled Nitric Oxide in Patients With Acute Eosinophilic Pneumonia

Background Acute eosinophilic pneumonia (AEP) is an idiopathic disease characterized by pulmonary eosinophilia. Because the fraction of exhaled nitric oxide (Feno) is a surrogate of eosinophilic inflammation, we evaluated the levels, changed treatments, and the diagnostic role of Feno in patients with AEP. Methods Between June 2010 and March 2011, we prospectively enrolled patients at the Armed Forces Capital Hospital who had pulmonary infiltrates and a febrile illness and who were clinically suspected to have AEP. We measured Feno twice at the initial visit (pretreatment) and 2 weeks after the initial measurement (posttreatment). Results A total of 60 subjects were enrolled, and 31 were given a diagnosis of AEP. The pretreatment Feno levels of the patients with AEP were significantly higher than those of the patients without AEP (median, 48 parts per billion [ppb] [range, 10-138] vs 14 ppb [range, 5-41]; P P = .21) Conclusions The Feno level was significantly higher in patients with AEP than in those without AEP. Feno measurement can be used as a diagnostic tool to differentiate patients with AEP from those without AEP. Trial Registry ClinicalTrials.gov; No.: NCT01152424; URL: www.clinicaltrials.gov