Abstract: Objective To study the impact of different kinds of mechanical circulation support devices on plasma free hemoglobin(FHb). Methods From Mar. 2004 to Dec. 2005, 20 patients received mechanical circulation support in Fu Wai Hospital, who were divided into 4 groups according to the different type of supporting devices. 9 got extracorporeal membrane oxygenation (ECMO) treatment, 8 received BVS5000 left ventricular support, 2 got MEDOS left ventricular support and 1 received AB5000 left ventricular support. Random control group included 9 cardiotomy patients after CPB supporting and 9 patients with offpump coronary artery bypass grafting during the same period. Parameters such as FHb, Tbil, Dbil, Cr and BUN were monitored throughout the supporting term. The results were compared according to the different types of mechanical circulation support devices. Results The elevation of FHb caused by CPB could be decreased to normal within 1d. However, in BVS5000 group, the elevated FHb level decreased to normal till 2 days later. The others mechanical circulation support devices such as ECMO, MEDOS, AB5000 elevated the FHb throughout the whole supporting period. Compared with those in ECMO group, the patients in BVS5000 group had obviously lower level of FHb since the third day after the beginning of supporting. In patients who got ECMO treatment, there was a trend that the elevation degree of FHb was lower in those with support flow rate less than 2.5 L/min. For most patients got devices support, there was also an elevation of Tbil and BUN level during the supporting period. Conclusion Mechanical circulation support devices, such as ECMO, BVS5000, MEDOS and AB5000, can cause red cell destruction in acceptable level. BVS5000 has much smaller impact on cell destruction than others do in postoperative patients.