Airways hyperresponsiveness and the effects of lung inflation

Lung inflation has a beneficial effect on the airways of healthy subjects. It acts as a bronchoprotector, that is to prevent bronchoconstriction, and as a bronchodilator, in that it reverses bronchial obstruction. The broncho protective effect of deep inspiration is more potent than the bronchodilato ry one, and the two phenomena appear to advocte different mechanisms. Asthm atics and rhinitics with airways hyperresponsiveness show an impairment in bronchoprotection induced by deep breaths, whereas the bronchodilatory effe ct, although reduced, is still effective. The lack of the bronchoprotective effect of deep inspiration may contribute to the development of airways hy perresponsiveness. The mechanisms through which lung inflation exerts its b eneficial role in healthy subjects, and the factors impairing such an effec t in those with airways hyperresponsiveness, are currently under investigat ion. Copyright (C) 2001 S. Karger AG, Basel.