Current international guidelines suggest a restrictive transfusion strategy, setting that Hb level at 7 g/dl is a reasonable threshold. However, the idea of having only one threshold for all the patients has been challenged by authors, suggesting a more liberal strategy for certain cases. At the moment, there is no other parameter considered accurate enough to be taken into consideration for transfusion strategy management.

This study is to use ScVO2, a current, easily accessible parameter, before blood transfusion in order to stratify its indication after cardiac surgery.

Monocentric, randomised, single blind study (patient not aware of the group assignments) Patient inclusion will be made in ICU if the physician decides to perform blood transfusion according to standard transfusion strategy to treat a postoperative anemia (Hb<9g/dL).

Every patient will go through randomization to be placed in one of the two groups of the study: either the one whose transfusion strategy is adjusted by the pretransfusion ScvO2 (group ScvO2), or the control group.

Our main objective is to evaluate the impact of a new transfusion strategy founded on guidelines, but provided ScvO2 is less than 65%, on the incidence of red blood cells transfusion for anemia early after cardiac surgery.

Currently, the rate of transfusion of cardiac surgery patients is approximately 50%. The decision to transfuse is based on the hemoglobin (Hb), the transfusion threshold from 7 to 9 g / dL seems to be reasonable, based on clinical parameters, as well as patient history, as the degree of coronary stenosis . Several randomized studies have shown that a restrictive transfusion strategy was superior to a liberal strategy.

ScvO2 is a parameter reflecting the balance between transport O2 and O2 in tissue consumption, which Hb is one of the determinants. It requires that a levy on central venous used frequently for such patients. ScvO2 could make better account of the actual tolerance of anemia that the only value of Hb and the patient's clinical characteristics.

We therefore hypothesize that ScvO2 can help with the decision of RBC transfusions after heart surgery.

Primary and secondary endpoints Principal: To assess the value of ScvO2 threshold (65%) in the restrictive transfusion strategy on the incidence of transfusion after cardiac surgery.

secondary:

• Assess the impact of transfusion strategy based on ScvO2 on the number of transfused patients at D28
• Assess the impact of transfusion strategy based on ScvO2 on the number of cells transfused concentrates.
• Assess the impact of transfusion strategy based on ScvO2 on mortality or incidence of disease events such as cardiac complications, renal, respiratory or neurological dysfunction in the immediate aftermath of surgery.

Inclusion Criteria:

• Age over 18 years
• Patients admitted to intensive care after heart surgery
• Anemic patient (Hb < 9 g/dL)
• Patient with a central venous catheter in the territory SVC

Exclusion Criteria:

• Patient with acute bleeding defined as a postoperative bleeding over 1000 ml in 12 hours or the need for a recovery operation for hemostasis or the transfusion of blood units over 4
• Patient with severe sepsis or septic shock criteria defined by the Surviving Sepsis compaign