SALMETEROL REDUCES DYSPNEA AND IMPROVES LUNG-FUNCTION IN PATIENTS WITH COPD

Study objective: To investigate the short-term effects of inhaled salm eterol on the perception of dyspnea and lung function in patients with COPD. Design: Double-blind, crossover, randomized trial comparing inh aled salmeterol and inhaled placebo over 4 h. Setting: Pulmonary funct ion laboratory at university medical center. Patients: Sixteen patient s with symptomatic COPD and at least 200-mL increase in FEV1 after inh alation of two puffs (180 mu g) of albuterol. Interventions: Visit 1 w as used for familiarization. At visits 2 and 3 (2 to 3 days apart), pa tients inhaled either two puffs of salmeterol (42 mu g) or placebo. Me asurements and results: Lung function and dyspnea were measured at 0.5 , 2, and 4 h after inhalation of the study medication. Dyspnea was mea sured by the -5 to +5 category scale at rest and by the 0 to 10 catego ry-ratio scale while breathing through inspiratory resistances of 5, 1 5, and 30 cm H2O/L/s. Age was 66+/-8 years (mean+/-SD). FEV1 was 0.97/-0.331 (51+/-13% predicted). There were significantly higher values f or FEV1 and FVC (at all time periods) and lower values for functional residual capacity (at all time periods) and residual volume (at 4 h) w ith salmeterol than with placebo. There were significantly lower dyspn ea ratings on the -5 to +5 category scale (p=0.03 at 2 h and p=0.02 at 4 h) and for the mean dyspnea scores during resistive breathing with salmeterol compared with placebo (p=0.002). Conclusions: Inhaled salme terol reduced dyspnea, increased airflow, and reduced hyperinflation o ver 4 h in patients with symptomatic COPD.