Pathophysiology of Pertpheral Airways in Chronic Obstructive Pulmonary Disease

点击翻译按钮获取中文摘要

AbstractWe studied the effective sites of airway response to atropine and fenoterol aerosols and to the intravenous injection of aminophylline in patients with stable and spontaneous asthma, by the simultaneous assessment of respiratory resistance (Rrs) and anatomic dead space (V_D). Central airway response was determined by V_D, and overall response was determined by Rrs. Peripheral airway response was inferred from Rrs when the change in V_D was slight. Atropine (4 mg/m1) or fenoterol (0.4 mg/ml) was continously inhaled during tidal breathing for 5 min. Inhalation of both atropine and fenoterol increased Grs (reciprocal of Rrs) (p|0.01) with a simultaneous increase in V_D (P|0.01) in the patients with stable and spontaneous asthma. Fenoterol increased Grs more than did atropine at an equivalent increase in V_D in patients with spontaneous asthma (p|0.05). Intravenous injection of aminophylline (250 mg) had no effects on either Grs or V_D in patients with stable asthma, but it significantly increased Grs (P|0.01) without change in V_D in patients with spontaneous asthma. These results suggest that the predominant sites of bronchodilation induced by inhaled atropine are the central airways, and those induced by intravenous injection of aminophylline are the peripheral airways, and that inhaled fenoterol dilates both the central and peripheral airways in asthmatic subjects. Differences among clinically used bronchodilators on the effective sites may be considered in the treatment of bronchial asthma.