Abstract

Measurement of fractional exhaled nitric oxide (FENO) in asthmatic patients not only reflects airway inflammation but also can be used as a loss-of- control marker in asthma and as a tool for monitoring the effectiveness of anti-inflammatory medications. The aim of this study was to determine the mean level of FENO in stable asthmatics and factors affecting the FENO levels.
We included 118 stable asthmatics (aged 42.9±11.7 years) with a mean FEV 1 83.6±18.1 % and mean FENO level 14.4±1.1 ppb. There was no significant difference between the mean FENO levels of asthmatics when grouped for the presence of atopy, chronic sinusitis, allergic rinitis and aspirin intolerance. Male asthmatics had significantly higher levels of FENO (19.6±2.6 ppb) when compared to the females asthmatics (12.8±1.1 ppb) (p<0.01). Current smokers had significantly lower levels of FENO(8.2±1.1 ppb) when compared to non-smokers (18.5±2.1 ppb) (p<0.05).
When we grouped the patients according to the severity of asthma, mean levels FENO were significantly higher in severe persistent asthmatics. There was no significant difference between the FENO levels of patients receiving different antiasthmatic drugs. We found a positive correlation between the mean duration of asthma and the FE NO levels.
We can conclude that FE NO levels can reflect the degree of inflammation in asthmatics and are affected by smoking status, severity and duration of asthma.