Chest
ORIGINAL RESEARCHASTHMAExhaled Nitric Oxide and Exhaled Breath Condensate pH in Severe Refractory Asthma
Section snippets
Subjects
Subjects were recruited from an open cohort of patients with asthma who were under medical follow-up care in the asthma clinics of the First and Second Respiratory Medicine University Departments in Athens, Greece. The diagnosis of asthma was established according to Global Initiative for Asthma guidelines.1 The diagnosis of SRA was established according to American Thoracic Society criteria.2 Twenty-nine patients with SRA were recruited. All were receiving high doses of ICS (> 1.2 μg
pH and FeNO Values in the Three Study Groups
Subjects' characteristics are summarized in Table 1. The EBC pH in patients with SRA was significantly lower than in patients with moderate asthma and healthy subjects (7.22 ± 0.08 vs 7.36 ± 0.06 vs 7.72 ± 0.1, respectively; P < .0001), (Fig 1A, Table 1). FeNO levels were significantly higher in patients with SRA than in patients with moderate asthma and healthy subjects (43 [18.5-72.5] vs 25 [17–38] vs 12 [9.5–19], respectively; P < .0001) (Fig 1B, Table 1).
Inflammatory Cells in Induced Sputum
Patients with SRA had significantly
Discussion
In this study, different cutoff values of FeNO in patients with SRA identified those with predominant sputum eosinophilia and neutrophilia. Those with sputum eosinophilia had elevated FeNO levels despite high-dose steroid treatment, whereas those with sputum neutrophilia had low FeNO levels regardless of the concomitant presence of eosinophilia. EBC pH could not identify the cellular profiles in SRA; however, it had a better prognostic performance for the eosinophilic profile in moderate asthma.
Acknowledgments
Author contributions: Dr Tseliou: contributed to the performance of the FeNO and pH measurements and sputum induction and processing.
Dr Bessa: contributed to the performance of the FeNO and pH measurements and sputum induction and processing.
Dr. Hillas: contributed to the performance of sputum induction and processing.
Dr Delimpoura: contributed to the performance of the FeNO and pH measurements and sputum induction and processing.
Dr Papadaki: contributed to the performance of the FeNO and pH
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