Effect of the combination of two bronchodilators on breathlessness in patients with chronic obstructive pulmonary disease. A crossover clinical trial.

Background: Dyspnea is the major limiting symptom for patients with chronic obstructive pulmonary disease (COPD). This study was designed to investigate the impact of the combination of two bronchodilators on perception of dyspnea in these patients.

Methods: Twenty patients with moderate to severe COPD (age was [mean +/- standard deviation (SD)] 64 +/- 7 years, FEV1/FVC ratio was 45 +/- 11%) were randomized in a crossover, double-blind, placebo-controlled clinical trial to receive two puffs of either ipratropium bromide plus salbutamol (IB+S), IB+placebo (P), S+P, or P+P through metered dose inhalers (MDIs) daily over a 2-week period for each combination.