Oxygen carrying capacity of totally artificial red cell substitute--liposome embedded heme--in hemorrhagic beagle dogs

Liposome embedded heme (L/H) was produced by embedding synthesized lipid-heme in liposomes. The oxygen carrying capacity of this totally artificial oxygen carrier was evaluated in dogs. Under controlled ventilation, 30ml/kg of blood was drawn. Thirty minutes after bleeding, 30mg/kg of the L/H solution was intravenously injected in group I (n = 6) and the same volume of normal saline solution was injected in group II (n = 7). No transfusion was performed in group III (n = 7). In group I, mixed venous O2 tension (PvO2), O2 transport (TO2) and O2 consumption (VO2) increased significantly compared with those observed before injection of the L/H (p < 0.05). PvO2 kept higher level compared with group II until 90 minutes after injection of the L/H (p < 0.05). Following the L/H injection, TO2 by the dogs' Hb was 187ml/min and that by the L/H was 43ml/min. VO2 from the dogs' Hb was 51ml/min and that from the L/H was 16ml/min. Thus TO2 by the L/H provided 19% of the total TO2 and VO2 from the L/H provided 24% of the total VO2. Thus, this exchange transfusion experiment show that the L/H has ability as an oxygen carrier to bind and to transport oxygen to the tissues.