Hypo-osmolar aerosol induces hyperventilation in chronic non-asthmatic rhinitics

Abstract

The effect of a hypo-osmolar aerosol on transcutaneous O 2 and CO 2 time course ( PtcO 2, PtcCO 2) was investigated in subjects affected by chronic non-atopic rhinitis, without any history of asthmatic symptoms and no airways hyper-responsiveness. Twelve normal subjects and 12 subjects affected by chronic idiopathic rhinitis, who had normal responsiveness to both hypo-osmolar aerosol and methacholine challenge as measured by the decrease in FEV 1 (mean FEV 1 decrease=5% and PC 20 > 16 mg, respectively) were studied. By means of a transcutaneous mono-electrode, it was possible to study the time course of PtcO 2 and PtcCO 2 during and after a 5-min inhalation of ultrasonically nebulized distilled water (output 2 ml/min −1). A significant decrease in PtcCO 2 and increase in PtcO 2 were observed during the challenge in rhinitics as compared with normal subjects [maximum decrease and maximum increase expressed as mean value (± sd) were −22% (± 6·9) and +12·6% (± 7·2), respectively]. No significant changes in either PtcCO 2 and PtcO 2 were observed after the test. The results of this study suggest that patients affected by idiopathic chronic rhinitis with absence of bronchial hyper-responsiveness may present a hyperventilatory response to the inhalation of hypo-osmolar aerosol; the mechanism of such a response might be due to an upregulation of the irritant receptors of the upper airways.