ABSTRACT

Section of Pulmonary and Critical Care Medicine, Dartmouth Medical School, Dartmouth-Hitchcock

Medical Center, Lebanon, New Hampshire, U.S.A.

I. Introduction

The most important benefits of bronchodilator medications in patients with chronic

obstructive pulmonary disease (COPD) are relaxation of bronchial smooth muscle,

which increases lung function and improves lung emptying during tidal breathing. For

a long time the major outcome measure to evaluate the efficacy of a bronchodilator

has been forced expiratory volume in one second (FEV

). However, the goals of treating

COPD have shifted from improving physiological measures to improving clinical

outcomes. There are several reasons for this paradigm shift. First, the individual patient is

interested primarily in being able to breathe easier with activities, have a better quality of

life, and avoid respiratory tract infections. Second, studies have demonstrated that

bronchodilator reversibility (i.e., the acute changes in FEV

after inhalation of albuterol

or ipratropium) does not predict the clinical benefits of long-acting bronchodilators as

experienced directly by the patient (1,2). Moreover, studies have demonstrated that

improvements in breathlessness and exercise tolerance are more importantly related to

enhanced lung emptying rather than the magnitude of the increase in expiratory airflow.

Third, there is no current evidence that bronchodilator therapy slows the progression of

the disease as traditionally measured by the changes in FEV