The influence of asthma and COPD exacerbation on exhaled nitric oxide (FENO)

Exhaled nitric oxide is a marker of airway inflammation and it is significantly decreased by glucocorticosteroid therapy, especially in patients with asthma. Aim of the study: evaluation of changes in FENO in asthma and COPD exacerbation. Materials and methods: 17 patients with acute asthma and 19 patients with an exacerbation of COPD were enrolled to the study. FENO (chemiluminescence, on-line, restricted breath technique measurement in accordance with the ATS recommendations) was performed for five consecutive days following admission to hospital. Results of the following additional blood investigations: peripheral white blood cell count, ESR, C-reactive protein level, arterial blood gases, spirometry or peak expiratory flow were also analyzed. Results: The average value of FENO on admission was 41.5 &plusmn; 10.7 ppb (95% CI: 18.8 - 64.2 ppb) asthma patients and 28.6 &plusmn; 5.4 ppb (95% CI: 17.4 - 40.0 ppb) in COPD patients. In asthma patients a significant decrease of FENO on the third day of therapy was observed (41.5 vs. 26.1 ppb, p < 0.05). We found a positive correlation between FENO on admission and the peripheral blood eosinophil count. In COPD patients a significant decrease of FENOon the 4th day was noted (28.6 vs. 17.5 ppb, p < 0.05). FENO in both groups was higher than that of 19 healthy volunteers previousty studied in oun laboratory (14.1 &plusmn; 4.7 ppb; 95%CI: 11.8 &plusmn; 16.4 ppb). Conclusions: Exacerbations of asthma and COPD are associated with an increased FENO. FENO measurement is a useful tool in the assessment of treatment efficacy. Exhaled nitric oxide may indicate the intensity of allergic inflammation in patients with asthma