Exhaled breath condensate pH in infants and children with acute and recurrent wheezy bronchitis

Abstract

The analysis of exhaled breath condensate (EBC) is a promising new method to measure airway inflammation. So far only limited data exist about methodological issues of EBC sampling in infants and young children. We evaluated 18 children with acute wheezy bronchitis (median age 24.3 months (min-max: 4-89.9)), 54 children with recurrent wheezy bronchitis (median age 52.5 months (7.2-94.8)), and 32 healthy controls (median age 49.6 months (25.3-67.8)). EBC was sampled with a modified commercially available EBC-sampler, pH was measured after deaeration. EBC volume was significantly correlated to age (r = 0.56, P < 0.001). EBC pH was significantly decreased in all patients compared to the healthy controls (acute wheezy bronchitis 7.87 (7.16-8.19), P = 0.003, recurrent wheezy bronchitis 7.86 (6.95-8.39), P = 0.002, and healthy controls 8.04 (7.81-8.87), respectively). There were no significant differences of the EBC pH between the disease groups. When divided into different subgroups, an influence of inhaled steroid treatment was found with steroid-naive recurrent wheezers having significantly lower EBC pH levels compared to healthy controls (7.80 (6.95-8.37), P = 0.018), but not so steroid treated (7.94 (7.24-8.39), P = 0.055). Both, recurrent wheezers with or without a positive allergy test had significantly lower EBC pH compared to healthy controls (7.91 (6.95-8.37), P = 0.007 and 7.82 (7.32-8.39), P = 0.005, respectively). This study indicates that EBC can be collected with a modified commercially available EBC sampler in infants and young children. Further studies need to be performed to evaluate the relevance and meaning of pH differences of EBC in this age group.