The comparative effects of elastase-induced emphysema on costal and crural diaphragm and parastermal intercostal muscle contractility

Chronically, hyperinflated human subjects with chronic obstructive pulmonary disease and animals with experimentally induced emphysema generate greater than expected levels of transdiaphragmatic pressure at high lung volume because of adaptive changes in the length-tension relationship of the costal diaphragm. The ability to lower intrathoracic pressure during inspiration depends on the mechanical action of all the inspiratory muscles acting in concert. However, the effect of chronic hyperinflation on the mechanical action of inspiratory muscles other than the costal diaphragm remains unknown