Airway responses to hypertonic saline, exercise and histamine challenges in bronchial asthma

The airway responses to histamine, exercise and ultrasonically nebulized hypertonic saline have been compared in ten asthmatic patients. The responses to hypertonic saline were not significantly different when the same volume of aerosol was given in a single dose or in 10 l aliquots, suggesting that the challenge is cumulative. The variability of the response to hypertonic saline challenge was not significantly different from that of exercise challenge. Response to hypertonic saline correlated significantly with exercise (r = 0.68, p less than 0.05) and with histamine response (r = 0.74, p less than 0.02), but the correlation between exercise and histamine was not statistically significant (r = 0.15, p greater than 0.1). These findings suggest that exercise-induced asthma has a closer relationship to bronchial responsiveness to hypertonic saline aerosol than it does to non-specific reactivity demonstrated by histamine challenge.