Which of the following is a result of air trapping during expiration in chronic bronchitis?

Air trapping during expiration in chronic bronchitis leads to the expansion of the thorax. In this condition, the air that cannot be expelled properly can lead to overinflation of the lungs. As air becomes trapped, it causes the lungs to remain inflated even during the breathing out phase, which results in a larger volume of air retained in the lungs than normal. This physical change forces the thoracic cavity to expand, impacting the overall structure and function of the respiratory system.

The expansion of the thorax is a compensatory response to maintain air exchange despite the underlying pathology of chronic bronchitis. Over time, as air trapping persists, this can lead to a barrel-chested appearance, contributing to changes in the shape of the thorax.

Understanding this process is crucial for grasping the effects of chronic bronchitis on pulmonary mechanics and the management of patients with this condition. The other options do not accurately reflect the physiological changes associated with air trapping; for instance, decreased lung compliance or increased elasticity would not typically coincide with the chronic inflammation and obstruction typical of bronchitis.