What is the primary purpose of the cardioplegia delivery system during CPB?

• A. Provide oxygen to blood
• B. Deliver cardioplegic solution to arrest the heart
• C. Pump blood through the circuit
• D. Monitor oxygen saturation

Answer: (B)

The cardioplegia delivery system exists to perfuse the heart with a specialized solution that arrests the heart and protects the myocardium during CPB. This cardioplegic solution, usually high in potassium, induces diastolic arrest so the heart stops beating, which lowers its metabolic demand and helps preserve heart muscle while the aorta is cross-clamped. The delivery can be antegrade through the aortic root or retrograde via the coronary sinus to ensure even distribution, and it is typically delivered at a controlled temperature to maximize protection. Repeated dosing or continuous delivery may be used depending on the case.

Oxygen delivery is handled by the oxygenator, not the cardioplegia system, the pump circulates blood through the circuit, and monitoring oxygen saturation is done by the patient monitoring equipment.