Nasobronchial relationship after cold air provocation

Provocation with cold air in the nose causes broncho-obstruction while warm air causes bronchodilation in patients with asthma, but not in healthy sub jects. These findings have suggested the existence of a nasobronchial refle x. The present study aimed to block this effect and evaluate the mechanisms underlying the effect on lung function after cold stimulation of the nose. Lung function, as measured with specific conductance and forced expiratory flow, was reduced after cold stimulation of the nose, but this effect coul d not be blocked by anesthetizing the nose or by inhaling an anti-cholinerg ic drug before the provocation. These results confirm the presence of a nas obronchial relationship, but not of a nasobronchial reflex.