On vagal bronchoconstriction in asthmatic patients by nasal irritation

In 27 asthmatic patients a single cold stimulus into the nose resulted in a sudden increase of airway resistance, measured continuously by a forced-oscillation technique. The effect could be blocked by previous intrabronchial application of an anticholinergic drug. In laryngectomised patients, who no longer have a connection between the upper and the lower airways, a cold stimulus into the nose also caused bronchoconstriction. So the cold effect must be based on a reflex mechanism.