TY - CHAP M1 - Book, Section TI - Principles and Applications of Cardiopulmonary Exercise Testing A1 - Weber, Karl T. A1 - Newman, Kevin P. A2 - Grippi, Michael A. A2 - Elias, Jack A. A2 - Fishman, Jay A. A2 - Kotloff, Robert M. A2 - Pack, Allan I. A2 - Senior, Robert M. A2 - Siegel, Mark D. Y1 - 2015 N1 - T2 - Fishman's Pulmonary Diseases and Disorders, 5e AB - Cardiopulmonary exercise (CPX) testing draws on the recognition that the thorax represents a metabolic gas transport unit, the function of whose requisite components – diaphragm, heart, lungs, rib cage, and corresponding skeletal muscles – is to transport O2 to and CO2 from metabolizing tissues. Unit O2 and CO2 transport must adjust to physiological and pathophysiological stresses that augment the body's consumption of oxygen (V̇O2) and carbon dioxide production (V̇CO2). During strenuous levels of muscular work, for example, V̇O2 may rise eightfold, accompanied by increased V̇CO2. Cardiovascular or ventilatory disease can disrupt the unit's functional integrity. With severe disease, an abnormality in respiratory gas transport may be apparent at rest, when the body's O2 requirements are modest. Resting function is preserved with less severe expressions of disease, but abnormal respiratory gas transport becomes apparent when the unit is stressed by an elevation in V̇O2. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessmedicine.mhmedical.com/content.aspx?aid=1122358097 ER -