Exhaled nitric oxide in pediatric patients with respiratory disease.

Measurement of nitric oxide (NO) levels in exhaled air from the upper and lower airways is currently used as a non-invasive marker of inflammation in respiratory diseases. Assessment of NO exhaled from the lower air respiratory tract is considered to be a quick method for confirmation and control of asthma in patients as well as an estimation of treatment efficiency. The main aim of this study was to determine differences between levels of exhaled nitric oxide (fractional exhaled NO; FeNO) in patients with respiratory disease as measured by an electrochemical analyzer. Measurements were taken in 352 pediatric patients aged 4-17 with cystic fibrosis (CF) (n = 43), asthma (n = 69), allergic rhinitis (AR) (n = 70), asthma and AR (n = 128) and non-diseased children (n = 42) recruited from the Allergology Outpatient Department, Provincial Hospital No 2, Rzeszów. The second objective of this study was to assess any correlations between FeNO and clinical parameters of patients. The level of FeNO in patients with CF was normal when compared with control subjects (10.8 ± 2.9 versus 11.4 ± 6 ppb). We found significantly higher FeNO in patients with asthma (26.6 ± 15.3 ppb, p < 0.001), AR (18.4 ± 9.6 ppb, p < 0.01) as well as in patients with both asthma and AR (43.3 ± 31.1 ppb, p < 0.001) when compared to healthy children. Statistical analysis revealed a positive correlation between FeNO and age, height and weight of control subjects, and height in children with AR. FeNO was independent of sex, BMI, spirometry and blood results as well as the type of residence in control children and subjects with CF, asthma, AR and combined asthma and AR. In conclusion, we found normal levels of FeNO in children with CF and elevated levels in patients with asthma, AR and combined asthma and AR as compared to control subjects. Due to conflicting data, there is still a need for additional research, especially related to regarding factors that affect FeNO levels in respiratory disease.