Acute limited normovolemic hemodilution: A method for avoiding homologous transfusion

Preoperative normovolemic hemodilution was introduced for clinical application by Messmer and co‐workers. Preoperative blood withdrawal of 1,500–2,000 ml by an isovolemic exchange with colloids or crystalloids (3 times the volume of blood withdrawn), in order to maintain a constant circulating volume, is offset by an adequate increase of cardiac output and an unchanged systemic oxygen transport capacity despite a decreased oxygen content. Patients lose fewer red cells and more plasma intraoperatively. The retransfusion of autologous blood follows in the reverse order of collection after hemostasis is restored. The procedure is a safe and feasible method, which is not beset with the logistical problems of autologous blood predeposit and has the added advantage that fresh autologous blood is available at once for retransfusion. Provided that the contraindications are observed, the technique helps to reduce or even avoids the risks of homologous blood transfusion. The need for stored blood can be reduced by 20% to 90%, depending on the surgical procedure.