[Compensation for bleeding in a surgical milieu. Importance of normovolemic hemodilution. Apropos of 25 cases].

In order to get round blood supply difficulties, 25 patients undergoing hemorrhagic interventions (blood loss average of 1,500 ml) were subjected to the techniques of normovolemic hemodilution. Preoperatively a volume of 1,080 ml of blood was taken in every patient (a total of 271 in all patients together); the blood was simultaneously replaced by 1,300 ml of macromolecules (modified fluid gelatin polymer and/or low molecular weight dextran according to disponibility). Two thirds of the taken amount are transfused to the patients preoperatively immediately after surgical hemostasis has been achieved or when the hematocrit is about 20%; the last third is administered in the immediate postoperative period. The economy of blood realised by this technique is considerable (119 units of homologous blood). The rationale depends on two essential particularities: on one hand, the diminution of blood loss since at a hematocrit of 25% the loss is only 50% of the globular mass which would have disappeared at normal hematocrit; on the other hand, the compensation of hemorrhage by transfusion of fresh autologous blood, eliminating homotransfusion reactions. The main hematocrit obtained 24 hours after transfusion is about 34%. Thus, economy of blood and rheological advantages (amelioration of microcirculation, increase of capacity of oxygen transport, increase of tissular oxygenation) must induce physicians to reexamine their behaviour in transfusion strategy and compensation of hemorrhage because the optimal hematocrit in normovolemy is of about 30%.