The impact of fraction of exhaled nitric oxide measurements in patients with asthma exacerbation

BACKGROUND Fraction of exhaled nitric oxide measurements (FENO) is accessible, a fast, non- invasive, highly repeatable test for determining eosinophilic airway inflammation. PURPOSE The objective of this prospective study is to determine the structure of FENO measurements in patients with asthma exacerbation and characteristics of asthma with FENO as a good indicator of asthma exacerbation. METHODS This study included 92 patients with asthma exacerbation, aged from 17 to 83 years. Patients were distributed into 3 groups with respect to FENO range: FENO > 50 ppb, FENO between 25 and 50 ppb , FENO < 25 ppb. Analyses by age, sex, form of asthma, presence of acute respiratory failure (ARF), rhinitis and treatment were conducted. Mean values of FENO, FEV1, PEF, T.I. were calculated. The results with mean FENO, FEV1, PEF, T.I. values were compared between 3 groups: FENO > 50ppb, FENO < 25 ppb and control group of 27 healthy adults. Results: 34 patients (37 % of all) were in FENO > 50 ppb group; 17 females, 17 males. Allergic asthma was found in 19 patients (56 %), 2 patients (6 %) had ARF, asthma with rhinitis was found in 8 patients (24 %). 33 patients (36 % of all) were in the FENO < 25 ppb group; 25 females (76 %), 8 males (24 %). 23 patients (70 %) suffered from nonallergic asthma, ARF was found in 6 patents (18 %), and asthma with rhinitis in 2 patients (6 %). Compared to patients with FENO values higher than 50 ppb, the results showed statistically significantly lower FEV1 and PEF values in patients with FENO < 25 ppb(p < 0.005) and in healthy adults (p = 0.000). CONCLUSIONS There are differences in sex, form of asthma, presence of rhinitis, burden of asthma and treatment between patients with FENO > 50 ppb and FENO < 25 ppb.