Astımlı Hastalarda Ekshale Nitrik Oksit Konsantrasyonun Önemi ve Ölçümünü Etkileyen Faktörler

Abstract

Measurement of exhaled nitric oxide (FeNO) concentration is a simple, reproducible, and noninvasive means of identifying the extent of airway inflammation and disease control in asthma. Accuracy of FeNO measurements depends on certain host-related factors such as atopy, sex, diet, and environmental factors such as ambient conditions and measurement technique. In this study, we aimed to assess the correlation between FeNO levels, disease control, host related factors and environmental factors in asthma. For this purpose, we enrolled 40 asthmatics and 20 controls; measured FeNO, serum ECP, total IgE, blood eosinophilia; and performed spirometry both on a relatively less polluted a summer day with a repeat procedure14 days later and on a polluted winter day. Difference between these timepoints in terms of Peak Expiratory Flow (PEF) was calculated for asthmatics. No association between FeNO levels, host factors and air pollution was found in asthmatics; however, there was a significant increase in FeNO with increasing air pollution in normal subjects. There was an insignificant reduction in FeNO levels in active smokers as compared to exsmokers and nonsmokers both in asthmatics and controls. Atopic asthmatics had significantly higher FeNO levels than those with no atopy (p=0.022). Initial blood eosinophilia correlated with FeNO levels (p=0.008). These results suggest that asthmatics with high FeNO levels should be investigated for the presence of atopy and low FeNO levels (<25ppb) have a high positive predictive value for asthma control.