TY - JOUR T1 - Long-acting inhaled bronchodilators in COPD: how many drugs do we need? JF - European Respiratory Journal JO - Eur Respir J SP - 190 LP - 191 DO - 10.1183/09031936.05.00054905 VL - 26 IS - 2 AU - P. M. A. Calverley Y1 - 2005/08/01 UR - http://erj.ersjournals.com/content/26/2/190.abstract N2 - Bronchodilators remain the mainstay of chronic obstructive pulmonary disease (COPD) management and are recommended for the treatment of symptomatic patients at all stages of this disease 1. For many years studies of these drugs focussed on changes in forced expiratory volume in one second (FEV1) or, occasionally, forced vital or slow vital capacity, believing that these robust and reproducible end-points were a legitimate surrogate for the changes in symptomatology, which were the real interest of patients and clinicians alike. By the 1990s, this comfortable assumption had been challenged when it became clear that individual improvement in exercise capacity and breathlessness were not closely related to changes in the magnitude of these spirometric indices 2. This stimulated research into the determinants of exercise performance and dyspnoea in COPD, and why spirometry was of so little help in predicting symptomatic improvement. A range of mechanisms have been identified and have recently been reviewed 3. Principal among these is the change in end-expiratory lung volume (EELV) during exercise in COPD patients. When healthy subjects exercise, EELV is reduced helping to keep the operating lung volumes on the steeper part of the pressure-volume relationship. COPD patients with tidal expiratory flow limitation must either allow EELV to rise 4, or try to overcome flow limitation at their initial lung volume an unsatisfactory strategy which limits exercise performance 5. Most patients with more severe disease adopt for the former approach which allows them to exercise longer, but at the cost of increasing difficulty in breathing as … ER -