[The role of nonspecific nasal reactivity in the evaluation of induced bronchial hyperreactivity].

The excitation of the irritant receptors in the upper respiratory tract may result in reflex bronchoconstriction. Does the raised reactivity of the nasal mucus membrane--the place of the first contact with respiratory irritants--play an important role in the expression of IBH? The level of NNR and the existence of relation between NNR and IBH have been assessed in 32 healthy subjects and 28 workers exposed to irritants with respiratory disorders. Nonspecific nasal provocation was performed by spraying of doubled concentrations of histamine solution in saline (0.03-16 mg/mL) in both nostrils in three minute intervals. The reaction was monitored by measurement of nasal peak inspiratory flow, nasal resistance, nasal forced expiratory volume in first second and nasal forced expiratory mid-flow. The level of NNR was expressed as provocation concentrations of histamine solution that produced significant change of all four measured parameters. Nonspecific bronchial provocation with histamine was performed by the modified method of Chai H. et al. The criterion for hyperreactivity was PC20FEV1 less than or equal to 8 mg/mL of histamine. There was statistically no significant correlation between NNR and IBH.