Lung Volume Reduction in Patients with COPD: Physiological and Clinical Implications

Chronic obstructive pulmonary disease (COPD) currently ranks as the fourth cause of death in the United States and it is an increasingly important health problem for the rest of the world [1-3]. Its prevalence has increased as overall mortality from myocardial infarction and cerebro-vascular accident, the two organ system affected by the same risk factor (namely cigarette smoking), have decreased. Although preventable and treatable, once diagnosed and symptomatic COPD is progressive and in some patients leads to disability usually due to dyspnea, at a relatively early age (6th or 7^th decade) [4,5]. Limitation to airflow occurs as a consequence of destruction of lung parenchyma or to alterations in the airway itself. One of the most important consequences is the development of static and dynamic hyperinflation with important clinical consequences such as dyspnea with exercise and decreased survival. This chapter integrates the pathologic changes of COPD with the known adaptive and maladaptive consequences of those changes. These factors should help us understand the rationale behind the therapeutic strategies aimed at decreasing lung volume and addressing the complications of patients with COPD.