Abstract

"Background: The six minute walk test (6MW) elicits dynamic hyperinflation (DH) in severe COPD patients, which can be evaluated by reductions in inspiratory capacity (IC). Although IC is currently used to determine the effects of bronchodilators on DH during exercise tests on a cycle ergometer, its usefulness during a walking test has not been evaluated. Aim: To study the acute effects of ipratropium bromide (IB) on forced expiratory volume at l second (FEV1) and IC at rest and on DH during exercise assessed by the 6MW. Subjects and methods: Fifteen stable COPD patients were randomly allocated in a double-blind, placebo-controlled, crossover fashion to 2 treatment periods using a single dose of nebulized IB 500 mg or placebo. Spirometry, including IC, and 6MW were measured at baseline and after IB and placebo. IC was also measured 15 min after exercise. Dyspnea, oxygen saturation (SpO2) and heart rate were assessed at the end of exercise. Results: After IB, 8/15 patients exhibited a clinically significant increase in IC (