In complete bypass, intercardiac venous return is significantly contributed by which veins?

• A. Bronchial veins
• B. Pulmonary arteries
• C. Coronary arteries
• D. Portal veins

Answer: (A)

In complete bypass, the heart is not pumping, so venous blood from thoracic tissues must be redirected into the bypass circuit. The intercardiac venous return refers to the venous blood that needs to reach the right-sided heart circulation to be drained by the CPB setup. Bronchial veins are part of the thoracic venous drainage; they channel blood from the bronchial tree and other nearby thoracic structures into the systemic venous system that ultimately feeds the CPB reservoir. Because this thoracic venous network contributes to what returns to the right heart via the systemic veins, it is a significant source of intercardiac venous blood during bypass.

In contrast, the pulmonary arteries carry blood away from the heart to the lungs (not venous return to the circuit), the coronary arteries supply the heart muscle (arterial, not venous return), and portal veins drain the GI portal system (not thoracic intercardiac drainage).