Total and partial blood exchange in the rat with hemoglobin prepared by crystallization.

Hemoglobin, prepared by crystallization, has been used as a blood substitute in total (91 to 93%) and partial (70 to 76%) blood replacement studies. Exchange transfusions have been carried out in laboratory animals to a total blood replacement of 91 to 93 per cent with hemoglobin or with albumin solutions. When albumin was used, all animals died at approximately ten minutes after transfusion was completed, whereas all animals transfused with hemoglobin survived for five hours and displayed normal activity during this time. In these studies the plasma half-disappearance time of hemoglobin was 3.5 hours and body distribution of 51Cr-labeled hemoglobin, as a percentage of initial levels, has shown six per cent in the kidney, six per cent in the liver, 10.5 per cent in the marrow and 13 to 14 per cent in the urine at three hours after transfusion. Survival was obtained with all animals transfused with hemoglobin or albumin solutions to a partial blood replacement of 70 to 76 per cent. However, the oxygen capacity of the circulating fluid in the hemoglobin transfused animals was about three times greater than that found in the corresponding albumin-transfused controls. Values of hemoglobin, hematocrit, platelets, and P50 returned to normal pretransfusion levels within five to seven days.