Bronchial inhalation challenge with ultrasonically nebulized saline; comparison to exercise-induced asthma

The airway response to ultrasonically nebulized sodium chloride of increasing concentration (0.9%, 2.5%, 5%, 10%, and 20%) was assessed in twenty asthmatic patients and five healthy subjects. Their response was compared to a standard exercise provocation test. Each concentration was inhaled for five minutes and the airway response was assessed by the measurement of the maximal expiratory flow volume curves. While only 65% of the patients developed significant bronchoconstriction to exercise, 90% had such response to inhaled sodium chloride of 20% or less. None of the healthy subjects showed any significant airway response. It is concluded that the inhalation of hypertonic sodium chloride is a sensitive method for the evaluation of airway hyperreactivity and can be used instead of the exercise provocation test in asthmatic patients.