| Budget Amount *help |
¥3,910,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥210,000)
Fiscal Year 2007: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2006: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2005: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Research Abstract |
The present study was performed to clarify the effect of blood exchange with liposome-encapsulated hemoglobin (LEH) on oxygen metabolism. Fifteen New Zealand White rabbits were anesthetized with pentobarbital sodium and randomly divided into three groups (n=5, each) based on the materials of blood substitute : LEH group with LEH suspension ([Hb]=6g/dL in saline containing 3% alubumin), RBC group with shed blood diluted 1:1 with saline containing 3% alubumin, and Plasma group with saline containing 3% alubumin without hemoglobin. After baseline measurements, 9mL/kg of circulating blood was withdrawn in 150sec and the identical amount of blood substitute was subsequently infused in 150sec. This procedure was repeated eight times in 5-min cycles for 40min to achieve blood exchange at approximately 90% of total circulating blood. Hemodynamics and oxygen metabolism parameters were measured at 60, 90, 120min after the beginning of blood exchange. Rabbits were subjected to stepwise cardiac tamponade to reduce oxygen delivery (DO_2) thereafter. The oxygen consumption (VO_2)/DO_2 relation was analyzed by the dual line method. Mean values of [Hb] after blood exchange in groups LEH, RBC, and Plasma were 5.7g/dL, 6.0g/dL, and 1.2g/dL, respectively. Mean arterial pressure, heart rate, and cardiac output in groups LEH and RBC at 60, 90, and 120min did not significantly differ from the corresponding baseline values. All animals in Plasma group died by 120min due to circulatory shock. After blood exchange, DO_2 values for groups LEH and RBC were reduced by approximately 50%, but VO_2 values remained consistent in comparison with the baseline values. In the VO_2/DO_2 relation, the slope of the supply-dependent line for LEH group (y=0.69x+1.8) was not significantly different from that for RBC group (y=0.68x+2.3). These results indicate that LEH is a potent blood substitute with respect to the ability of tissues to extract oxygen even in case of massive transfusion.
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