Bronchial Responsiveness to Inhaled Nonisotonic Solutions in Children with Asthma with Exercise-Induced Broncho-Obstruction

The purpose of the present study was to assess the relation between bronchial responsiveness (BR) to exercise and inhaled nonisotonic solutions in children with asthma with exercise-induced broncho-obstruction (EIB). We investigated BR to exercise, inhaled, ultrasonically nebulized 4.5% saline (HS), and distilled water (UNDW) by bronchoprovocation challenges in 41 children with asthma, 6 to 15 year olds, with documented EIB. Bronchial responsiveness, as measured by a decrease in pulmonary function with various stimuli, was noted in 36 (87.8%) of children when challenged by HS and only 6 (14.6%) with UNDW. A positive correlation was noted between bronchial responsiveness to exercise and HS (r = 0.34323; p < 0.025), whereas no correlation was noted between exercise and UNDW (r = 0.02626; p > 0.05). Bronchial responsiveness to HS, and not UNDW, may mimic the response to exercise in children with asthma with EIB. It is a possible that responsiveness to exercise may have similar with hypertonic and different from hypotonic stimuli mechanisms or pathways leading to bronchoconstriction in children with asthma with EIB.