A blood pump-oxygenator system comprises a blood pump, oxygenator, blood flow inlet, and blood flow outlet forming a circuit operable as a cardiopulmonary bypass system for extracorporeal processing of the patient's blood, wherein the first blood pump conveys blood through the circuit from the patient into the blood flow inlet, through the oxygenator and out of the blood flow outlet back into the patient. The system further comprises a recirculation loop between the blood flow inlet and blood flow outlet that accommodates the first blood pump and oxygenator, wherein the first blood pump circulates at least part of the blood in the circuit through the recirculation loop such that blood passes through the oxygenator multiple times and is repeatedly subject to exchange of O.sub.2 and CO.sub.2 within the oxygenator. A valve between the recirculation loop and blood flow outlet controls an amount of blood flowing through the recirculation loop.

A blood pump-oxygenator system for increasing perfusion and oxygen level in a patient comprises a blood flow inlet and outlet forming a circuit operable as a cardiopulmonary bypass system for extracorporeal processing of blood, a first blood pump and first oxygenator. The first blood pump conveys blood through the circuit from the patient into the blood flow inlet, through the first oxygenator and out of the blood flow outlet back into the patient. The system further comprises a second blood pump and second oxygenator. The second blood pump conveys blood through the circuit from the patient into the inlet, through the second oxygenator and out of the outlet back into the patient. A pump control unit controls the first and second pumps to increase or decrease blood flow rate through the respective oxygenator to vary a ratio of flow rates of blood through the first and second oxygenators.