Intrapulmonary shunting refers to

A pulmonary shunt often occurs when the alveoli fill with fluid, causing pas of the lung to be unventilated although they are still perfused. Intrapulmonary shunting is the main cause of hypoxemia (inadequate blood oxygen) in pulmonary edema and conditions such as pneumonia in which the lungs become consolidated Ref: guyton and hall textbook of medical physiology 12 edition page number:333,334,335