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 FE(NO) 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. FE(NO) (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 FE(NO) on admission was 41.5+/-10.7 ppb (95% CI: 18.8-64.2 ppb) asthma patients and 28.6+/-5.4 ppb (95% CI: 17.4-40.0 ppb) in COPD patients. In asthma patients a significant decrease of FE(NO) on the third day of therapy was observed (41.5 vs 26.1 ppb, p < 0.05). We found a positive correlation between FE(NO) on admission and the peripheral blood eosinophil count. In COPD patients a significant decrease of FE(NO) on the 4th day was noted (28.6 vs 17.5 ppb, p < 0.05). FE(NO) in both groups was higher than that of 19 healthy volunteers previously studied in our laboratory (14.1+/-4.7 ppb; 95% CI: 11.8+/-16.4 ppb).
Conclusions: Exacerbations of asthma and COPD are associated with an increased FE(NO). FE(NO) 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.