Abstract: A perfusion system for treating blood during a surgical procedure uses a flow control valve with first and second inlets and first and second outlets. A first intermediate line couples the first outlet to an air removal system. A second intermediate line couples blood from the air removal system to the second inlet. An arterial line carries treated blood from the second outlet back to the patient. The flow control valve has an open position and a recirculate position, wherein the first inlet is coupled to the first outlet when the flow control valve is in either the open position or the recirculate position. The second inlet is coupled to the second outlet and blocked from the first outlet in the open position. The second inlet is coupled to the first outlet and blocked from the second outlet in the recirculate position.