HEMOGLOBIN BLOOD SUBSTITUTES IN EXTENDED PREOPERATIVE AUTOLOGOUS BLOOD DONATION - AN EXPERIMENTAL-STUDY

Background. The risks of homologous blood transfusion have stimulated interest in developing possible alternatives. In this study we examine d the efficacy of using a hemoglobin-derived blood substitute to augme nt and extend preoperative autologous blood donation. Methods. In an o vine model, two experimental groups (n = 6 each) of animals donated ei ther 45% or 80% or more of calculated blood volume, which was replaced with a polymerized bovine hemoglobin solution. Two control groups (n = 6 each) either did not donate or donated 45% of calculated blood vol ume, which was replaced with a 6% hetastarch solution. Twenty-four hou rs after blood donation, sheep underwent a measured surgical stress wi th standardized intraoperative blood loss; donated blood was reinfused . Results. Extended autologous blood donation and replacement with thi s blood substitute were efficacious in supporting oxygen consumption; there was no systemic toxicity. After the postoperative replacement of autologous blood, animals that donated 80% or more of red cell mass e xhibited overall blood conservation with a final hematocrit of 25.7% /- 3.6%, compared with 20.5% +/- 2.0% (p < 0.05) and with 21.5% +/- 1. 1% (p < 0.05) in both control groups. Conclusions. This study suggests that the benefits of a blood substitute can be combined with autologo us blood donation to (1) safely increase the amount of autologous bloo d donated while supporting oxygen consumption, (2) avoid the need for advanced preoperative donation, and (3) decrease the need for homologo us blood transfusion.