| Research Abstract |
We evaluated the effects of liposome encapsulated homoglobin Neo Red Cell (NRC) on irreversible homorrhagicshock. and as a perfusate for partial and total cardiopulmonary bypass. [Homorrhagic shock] Methods : Eight beagles (body weight ; 10-13kg) were used. Blood was removed from the arteries at a rate of 30 ml/min to induce hemorrhagic shockbringing the systolic pressure lower than to 60 mmHg. After 30 minutes steady state without any treatment NRC was transfused at the same rate. This replacement repeated more than three times. To maintained the circulation satisfactory, the animal needed the 1.5 times amount of NRC transfusion to blood loss. After blood exchange, the cardiac index did not increase and vascular resistance did not decrease in spite of low viscosity NRC (less than 1/3 of that of whole blood) transfusion. In this situation, NRC increased the oxygentransport efficiency (OTE) averaged from 32.2 to 43.1%, compensated the reduction of cardiac output and contributed the incr
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easing the oxygenconsumption. On the other hand, red blood cell did not increase the OTE more than 15% and did not supply oxygen to peripheral tissue satisfactory. On severe hemorrhagic shock, even if transfused low viscosity NRC,vascular resistance did not decrease and cardiac output did not increase. However, NRC compensated reduction of cardiac output by increasing its oxygen transport efficiency and satisfied the oxygen demand. [Partial cardiopulmonary bypass (PCPB)] Nonpulsatile PCPB was made in 10 adult mongrel dogs weighing 9-11 kg at 37 Cusing a rollerpump. The perfusate was 500ml NRC,500 ml hydroxyethylstarch (HES), 40 ml/L Meylon, AND 3 ml/kg mannitol (20%) on NRC group (6 animals). The perfusate was 1000 ml HES,40 ml/L Meylon, and 3 ml/kg mannitol (20%) on controlgroup (4 animals). PCPB was continued for hour. Vascular resistance (RV) in NRC group decreased less than 1/4 of VR in control group. This change suggests that, the viscosity of which is lower than that red blood cells (RBC). NRC delivered oxygen more than two times of that of RBC.NRC reduced vascular resistance, increased cardiac output, and showed excellentoxygen transport ability. NRC is suitable as perfusate for both PCPB.[Total cardiopulmonary bypass (TCPB)] The TCPB was started after removal of 57.1-73.3% of autologous blood and continued for 7 hours. During TCPB using NRC,the vascular resistance (VR) decreased to 1/4 of VR when red blood cells (RBC) were used. This change suggests that NRC,the viscosity of which is lower than that of RBC,reduced the load on the circulation system. The oxygen volume delivered by NRC was higher than that delivered by RBC,resulting in a greater oxygen consumption with NRC.During TCPB,the serum LDH level was lower than that using RBC.So we concluded that NRC compensated for the reduction in the oxygen transport ability, which is a disadvantage of dilution TCPB,and further increased the circulation of dijution TCPB,and further increased the circulation improvin Less
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