What happens to the thickness of respiratory membrane in a patient with pulmonary edema?

In pulmonary edema, the thickness of the respiratory membrane increases. This is because the fluid that leaks into the alveoli from the capillaries causes the alveolar walls to become thicker and stiffer. The increased thickness of the respiratory membrane makes it more difficult for oxygen to diffuse from the alveoli into the blood, which can lead to hypoxemia.