Hemodynamic effects of exchange transfusions with liposome-encapsulated hemoglobin.
The ability of liposome-encapsulated hemoglobin (LEH) to sustain life in rats at hematocrits 45% below lethal levels was demonstrated by virtually total exchange transfusions. All control animals (transfused with 7% albumin in Erilyte) died at a mean hematocrit of 5.35%, with corresponding oxygen-carrying capacity of 2.65 ml/100 ml. All LEH animals survived with a final RBC hematocrit of 2.96% and an oxygen-carrying capacity of 7.05 ml/100 ml. LEH animals maintained normal blood pressures and essentially normal cardiac output, while control animals failed to do so. Systemic vascular resistance of control animals at 78% exchange was reduced to 33% of baseline, while of LEH animals at 92% exchange, to 80% of baseline. In-vitro measurements were made of LEH and RBC suspension viscosity as a function of shear rate, suspension concentration, and lipid membrane composition. The viscous behavior of the LEH suspensions was non-Newtonian and nearly the same as suspensions of natural RBC prepared similarly, though LEH suspensions had slightly higher viscosity.
D000818:Animals; D001794:Blood Pressure; D001802:Blood Substitutes / Q000627:therapeutic use*; D001809:Blood Viscosity; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output; D004912:Erythrocytes / Q000502:physiology; D005078:Exchange Transfusion, Whole Blood; D005260:Female; D006400:Hematocrit; D006439:Hemodynamics; D006454:Hemoglobins / Q000502:physiology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008081:Liposomes; D010100:Oxygen / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains; D014655:Vascular Resistance
D001802:Blood Substitutes; D006454:Hemoglobins; D008081:Liposomes; D002245:Carbon Dioxide; D010100:Oxygen