PT - JOURNAL ARTICLE AU - O'Donnell, D. E. AU - Laveneziana, P. TI - Physiology and consequences of lung hyperinflation in COPD AID - 10.1183/09059180.00010002 DP - 2006 Dec 01 TA - European Respiratory Review PG - 61--67 VI - 15 IP - 100 4099 - http://err.ersjournals.com/content/15/100/61.short 4100 - http://err.ersjournals.com/content/15/100/61.full SO - EUROPEAN RESPIRATORY REVIEW2006 Dec 01; 15 AB - Lung hyperinflation commonly accompanies expiratory flow limitation in patients with chronic obstructive pulmonary disease (COPD) and contributes importantly to morbidity and an impoverished quality of life. It is not surprising, therefore, that lung hyperinflation has become an important therapeutic target in symptomatic COPD patients. Acute dynamic increases in lung hyperinflation under conditions of worsening expiratory flow limitation and increased ventilatory demand (or both) can seriously stress cardiopulmonary reserves in patients with more advanced disease. The present understanding of the physiological mechanisms of dynamic hyperinflation during exacerbations of COPD and during physical activity continues to grow, together with an appreciation of its negative mechanical and sensory consequences. In this brief overview, definitions and measurement of lung hyperinflation during rest and exercise will be discussed and its potential clinical importance will be considered. The focus will mainly be on current concepts of the mechanisms of air trapping and its role in inducing respiratory discomfort and activity limitation in COPD.