Pulmonary shunt

Question 1

what is a shunt?

Answer 1

mixed venous blood which enters the systemic arterial system **without passing through ventilated areas of the lung **(and therefore it is low O2 blood)

Question 2

what are examples of normal shunt?

Answer 2

• bronchial circulation
• coronary blood draining directly into the left ventricle

Question 3

what is ‘intrapulmonary shunt’?

Answer 3

• patient has normal perfusion but a lack of ventilation
• ie blood passes through the lungs but fails to take part in gas exchange

Question 4

in what conditions is intrapulmonary shunt a cause of?

Answer 4

• pulmonary shunt often occurs when alveoli fill with fluid
• main cause of** hypoxemia** (inadequate blood oxygen)
• also seen in **pulmonary oedema and pneumonia **

Question 5

what is anatomical shunt?

Answer 5

• anatomical shunting is when the blood supply to the lungs via the pulmonary arteries is returned via the pulmonary veins without passing through the pulmonary capillaries