[The effect of inhaled anticholinergic drug on dyspnea and on the physiologic function of respiratory system in patients with chronic obstructive pulmonary disease].

The mechanism underlying the relief of the sensation of dyspnea during exercise following the inhalation of anticholinergic drug in patients with chronic obstructive pulmonary disease (COPD) has not been fully elucidated. We examined pulmonary function, static respiratory pressure, and dyspneic sensations during exercise before and after the inhalation of oxitropium bromide (OTB) in 14 male patients with COPD. FEV1 and FVC were increased after the inhalation of OTB, whereas RV and the ratio of RV to TLC were decreased after inhalation. Maximum inspiratory pressure (PImax) was significantly increased after the administration of OTB. Dyspneic sensation during exercise, measured as a Borg scale slope (BSS, delta BS/ delta Vo2) were reduced after the inhalation of OTB. There were significant correlations among BSS, PImax and RV/TLC. These results suggest that a reduction in air trapping after the inhalation of OTB may enhance the ability of the to diaphragm generate pressure at a given neural input, resulting in a reduced sensation of dyspnea during exercise in patients with COPD.