Oxygen Carrying Capacity of Totally Synthetic Oxygen Carrier-Lipidheme-Microsphere-

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Totally synthetic oxygen carrying substance (artificial red cell) was produced by covering clinically available fat droplets (triglyceride microsphers) with synthetic lipidhemes. Thus fat droplets were used as vehicles of lipidhemes as oxygen carrier. The size of this artificial red blood cell substitute is 103 <plus-minus> 29nm. Specific gravity, viscosity and osmotic pressure were very similar to that of human blood. In vitro study its oxygen binding was reversible and fast, the P50 was 40mmHg. Half life time in blood was 10-13 hourExchange transfusion in beagles upto 60% of circulating blood volume showed that oxygen transport to the tissue by this red blood substitute was about 50ml/min which corresponded about 40% of total oxygen transport. Oxygen consumption from this oxygen carrier was 25ml/min which corresponded about 25% of total oxygen consumption. In exchange transfusion upto 80%, it was difficult to keep beagles alive because of pulmonary edema due to severe hypoalbuminemia. To continue experiment it was necessaty to use total cardiopulmonary bypass. Another idea is to produce artificial oxygen carrier which has oncotic pressure. We are now producing this kind of material by using albumin in which lipidhemes are embedded. As perfusate albumin was mandatory to increase colloid oncotic pressure to this lipidheme microsphere. Albumin which has colloid oncotic pressure, is used as vehicles of lipid heme as oxygen carrier.