Comparison of the effects of a 50% exchange-transfusion with albumin, hetastarch, and modified hemoglobin solutions

We compared the hemodynamic effects of replacing 50% of the blood volume of anesthetized rats with an equal volume of five solutions: human serum albumin (HSA), hetastarch, unmodified hemoglobin, diaspirin-crosslinked hemoglobin, and o-raffinose-crosslinked hemgolobin. Control rats were exchange-transfused with their own blood. HSA and hetastarch caused a severe reduction in systemic vascular resistance (SVR), hypotension, and acute renal failure immediately after the exchange-transfusion. Unmodified and diaspirin-crosslinked hemoglobins caused comparable and severe increases in SVR, whereas vasoconstriction induced by o-raffinose-crosslinked hemoglobin was minimal. The increased SVR induced by all hemoglobin solutions resolved over a 2-day period as the hemoglobin was cleared from plasma. Body weight was monitored for 5 days after the exchange transfusion as a measure of the relative long-term efficacy of the exchange solutions tested and increased substantially in control rats (that received blood). Rats that received both crosslinked hemoglobin solutions gained a comparable amount of weight as the control group. By contrast rats that received HSA, hetastarch and unmodified hemoglobin failed to gain weight or lost weight over the same period. In summary: i) HSA and hetastarch are relatively ineffective as resuscitative fluids when administered after the loss of a large volume of blood; ii) diaspirin-crosslinked hemoglobin causes severe vasoconstriction, comparable in intensity to that induced by unmodified hemoglobin; iii) o-raffinose-crosslinked hemoglobin induces minimal vasoconstriction; iv) the vasoactive effects of all hemoglobin solutions are reversible. We conclude, that of all solutions tested, both the short-and long-term effects of an exchange-transfusion with whole blood are most closely reproduced by an exchange with o-raffinose-crosslinked hemoglobin.