TY - CHAP M1 - Book, Section TI - Chronic Obstructive Pulmonary Disease A1 - Jameson, J. Larry A1 - Fauci, Anthony S. A1 - Kasper, Dennis L. A1 - Hauser, Stephen L. A1 - Longo, Dan L. A1 - Loscalzo, Joseph PY - 2020 T2 - Harrison's Manual of Medicine, 20e AB - Chronic obstructive pulmonary disease (COPD) is a syndrome characterized by chronic airflow obstruction. COPD includes emphysema (lung parenchymal destruction), chronic bronchitis (chronic cough and phlegm production), and small airway disease (fibrosis and destruction of small airways) in varying combinations in different pts. The presence of airflow obstruction is determined by a reduced ratio of the forced expiratory volume in 1 s (FEV1) to the forced vital capacity (FVC). Among individuals with a reduced FEV1/FVC ratio, the severity of airflow obstruction is determined by the level of reduction in FEV1 (Table 133-1): ≥80% is stage I, 50–80% is stage II, 30–50% is stage III, and <30% is stage IV. Pts who do not meet these classic thresholds for airflow obstruction may have emphysema, chronic bronchitis, and respiratory symptoms suggestive of COPD. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessmedicine.mhmedical.com/content.aspx?aid=1167067242 ER -