[In vitro and in vivo study of a hemoglobin solution used as a blood substitute].

In vitro studies of a stroma free haemoglobin solution of human origin (Wx B 8326, Warner-Lambert) in comparison with fresh and stored low DPG whole human blood, was undertaken with regard to the fixation. of oxygen. Such an hemoglobin solution was shown to exhibit a high affinity for oxygen and a low Bohr effect (assessed from the delta log Po2/delta pH ratio). The specific effect of Co2 (assessed from the delta log Po2/delta log. Pco2 ratio) appeared to be increased as compared to fresh whole blood. This hemoglobin solution was tested as a blood substitute in two in vivo experimental situations: exsanguino transfusion on rabbits (n = 6) and closed-chest extracorporeal circulation on dogs (n = 6). In order to evaluate the part taken by the tested Hb solution in arterial O2 carrying capacity and in O2 delivery, two ratios were calculated: arterial plasmatic O2 content/arterial circulating blood O2 content and arterio-venous plasmatic O2 difference/arterio-venous circulating blood O2 difference. These two ratios amounted 28,2 +/- 2,5% (rabbits) and 47,0 +/- 6% (dogs) for the arterial O2 carrying capacity and 13,8 +/- 3,0% (rabbits) and 25,8 +/- 5,0% (dogs) for the tissular O2 delivery. Among the properties of the tested stroma free hemoglobin solution its low contribution to the tissular O2 delivery, its high affinity for oxygen, its low Bohr effect and its short half-life as compared to whole blood are not favouring its use in clinical practice.