Bioimpedance monitoring of airway inflammation in asthmatic allergic children.

BACKGROUND: Asthma in childhood is characterized by chronic inflammation. Measurement of bioimpedance (BI) is a non-invasive way of detecting airway inflammation. The aim was to compare BI with exhaled nitric oxide (eNO) and lung function evaluations in asthmatic allergic children while not exposed to offending allergens. METHODS: 22 asthmatic children allergic to house dust mites have been enrolled while residents at high altitude in an environment free of house dust mites. They were evaluated at T0 after allergen exposure at home, at T1 and at T2 after 1 and 4 months of allergen avoidance, respectively. RESULTS: eNO decreased from 32.21 +/- 5.70 ppb at T0 to 21.92 +/- 4.36 ppb at T1, after one month at high altitude (p = 0.038), without a further decrease at T2. Data in electrical activity showed a significant decrease in conductivity of lower airways between T0 (48.53 +/- 3.53 microA) and T1 (42.08 +/- 3.47 microA) (p = 0.023). deltaB parameter (difference between conductivity of lower respiratory tract and average yield) showed significant decrease from T0 (20.75 +/- 2.64 microA), and T1 (12.84 +/- 2.52 microA) (p < 0.01), but no further decrease at T2. No difference in lung function parameters was observed. CONCLUSION: Allergen avoidance regimen modifies inflammatory parameters in allergic asthmatics. Evaluation of extracellular bioelectrical conductivity seems to represent a promising non-invasive method to assess airway inflammation.