Inhalation of Hypertonic Saline As a Bronchial Challenge in Children with Mild Asthma and Normal Children

The response to bronchial challenge with ultrasonically nebulized 4.5% saline was compared to the response to histamine and isocapneic hyperventilation in a group of children with mild asthma and control subjects. Challenge with 4.5% saline was found to have an accuracy of approximately 80%, compared to 90% for histamine and 80% for hyperventilation. The challenge test was well tolerated by all children. Increasing the dose of 4.5% saline delivered to the children by use of a nebulizer with a higher output improved the accuracy of challenge with 4.5% saline to approximately 90%. This finding suggests that the nebulizer output is an important determinant of the accuracy of bronchial challenge with 4.5% saline. Bronchial challenge with 4.5% saline appears to be a promising addition to the tests of bronchial responsiveness in children, but further studies, particularly documenting the reproducibility and the relationship to clinical asthma, are needed before it can replace the current standard tests.