What effect does elevating the head and chest have on a patient with pulmonary edema?

Elevating the head and chest of a patient with pulmonary edema is beneficial for several physiological reasons. This positioning takes advantage of gravity, which helps to decrease the venous return to the heart, potentially reducing the preload in patients with heart failure or fluid overload. As a result, this can reduce the amount of fluid that may be present in the alveoli and improve gas exchange.

Additionally, elevating the upper body facilitates improved lung expansion. When a patient is in an upright position or has the head of the bed elevated, the diaphragm can work more effectively. This is because the diaphragm has more room to move downward as compared to a supine position. Improved diaphragm efficiency translates into better ventilation and oxygenation, which is critical in patients experiencing pulmonary edema, as the condition limits oxygen exchange due to fluid accumulation.

Thus, the choice indicating that elevating the head and chest improves lung expansion and diaphragm efficiency accurately reflects the positive physiological effects of this positioning in managing pulmonary edema.