ABSTRACT
This chapter provides the effects of inhaled bronchodilator medications and inhaled corticosteroids (ICS) on dyspnea as measured by multidimensional questionnaires and on tests of exercise performance and exertional dyspnea. ICSs may act acutely by direct inhibition of extraneuronal catecholamine transporter that may result in enhanced availability and action of norepinephrine with consequent greater bronchodilation. Bronchodilators reduce airway smooth muscle tone, thus improving airway conductance during both expiration and inspiration. Dyspnea is the most common symptom in chronic obstructive pulmonary disease (COPD) and is a major contributor to poor health status. Exercise testing, which includes both field tests and cardiopulmonary exercise tests, has increasingly been used in dyspnea assessment. Randomized controlled trials show that ICS treatment generally results in modest reductions in breathlessness in patients with COPD. Examination of peak expiratory flows measured by patients at home reveals that patients with COPD experience modest improvements in lung function within days of starting ICS therapy.
