Transfusion Savings in Heart Surgery: Impact of Individual Strategy by Erythropoietin and Metabolic Adjustment (ScvO2)

Preoperative anemia is the most common haematological abnormalities in cardiac surgery affecting 20 to 40% of patients and is becoming increasingly prevalent due to an ageing population with more chronic diseases.Preoperative anemia is independently associated with increased risk of adverse outcome following cardiac surgery but also implies blood transfusions which, associated with anemia, increase significantly perioperative cardiac morbidity and mortality. Therefore, strategies of blood conservation to optimize anemia and to minimize transfusion have been developped in the concept of the Blood Patient Management (BPM). To correct anemia, intravenous iron has been shown to be an effective treatment with increase hemoglobin (Hb) level in the perioperative period. It is now established that intravenous iron, as ferric carboxymaltose (Ferinject) is better tolerated compared to oral supplementation with better stimulation of erythropoiesis and,consequently, higher Hb levels. Based on promising results in the orthopedic surgery patients, the use of recombinant human erythropoietin (EPO) has also been proposed in cardiac surgery. Secondly, because even one red blood cells products (RBC) compromises postoperative outcome, guidelines suggest to adopt restrictive threshold of Hb levels to decide RBC transfusion. However, beyond the fact that RBC transfusion correct Hb level, the final goal of blood transfusion is to improve oxygen delivery to hypoxemic tissue. In this respect, the relevance of the use of a Hb threshold to guide transfusion have been questioned. Venous oxygen saturation (SvO2) and ScvO2 (central oxygen venous saturation), global parameters of tissue oxygenation, in stable hemodynamic and respiratory conditions, may be an relevant marker of anemia tolerance. Recently, the investigators demonstrated the lack of benefit in terms of ScvO2 increase during erythrocyte transfusion if ScvO2 was \> 65%. In order to reduce exposure to transfusion, the management of anemia with EPO and perioperative intravenous FCM associated with the use of ScvO2 could be interesting to both improve Hb levels and reduce RBC transfusion.