Peri operative haemorrhage following cardio Pulmonary Bypass may occur in 5 to 10% of cardiac surgical interventions.

Treatment of such complication often necessitates various combinations therapeutic intervention including allogenic blood products administration, drug use and/or surgical intervention. All are expensive treatment and decision making is guided by patient clinical status and biological tests of the haemostatic function.

A key point is the time frame of the clinical process. Therapeutic choices have to be done as fast as possible to minimize bleeding consequences on patient haemodynamic and physiological status. Conventional coagulation test results availability time usually exceed 45' after blood drawing. In such situation, the results may not reflect precisely the coagulation system current state. This downside is often counterbalanced by clinicians empirical choices preceding lab test results knowledge that may conduct to inappropriate treatment, blood product overuse and undue expense.

Viscoelastic point of care test may compensate for the limitations of conventional coagulation tests. In perioperative haemorrhage, faster and more precise information about haemostatic function may help for more accurate therapeutic choices.

The IMOTEC study aims to compare haemorrhage management following cardiac surgery using conventional blood coagulation tests or thrombo-elastogaphic point of care test.

Primary endpoint is a cost utility analysis of the technology and secondary endpoints include blood component transfusion, postoperative bleeding , thoracic re-intervention, postoperative infection (any cause), organ failure, in hospital length of stay and death.

The research is a real life, prospective, single blinded stepped wedge randomized study.

Inclusion after informed consent of adult patient having cardio-vascular surgical procedure using cardiopulmonary bypass and meeting inclusion criterion "bleeding".

After meeting inclusion criterion patients are managed either using conventional blood coagulation tests or using thrombo-elastometry POC test and predefined therapeutic interventions described in a specific algorithm.

Other elements of patient clinical management follow usual center standard care .

Follow up of EQ-5D and clinical evaluations are performed at one , 6 and 12 months after inclusion.

Pre-Inclusion Criteria:

• Adult patients over 18 years old scheduled for elective or urgent cardiac surgery using cardiopulmonary bypass .
• Patient informed written consent (non-opposition to data use) or person of trust or family member information .

Inclusion Criteria:

Blood Coagulation test sampling indication for intra or post-operative bleeding defined as follow:

1. intra-operative post CPB bleeding; evaluation more than 10min after heparin reversal by protamin.

   • Clinically significant bleeding judged on surgeon and anesthesiologist consensual point of view
   • Sternal closure delay
   • Chest tube bleeding exceeding 50ml in 10min or more than 1ml/kg in 30min (2ml/kg/h)

2. Postoperative period , evaluation in post operative care environment after 30min stabilization period

   • Chest tube bleeding exceeding 50ml in 10min or more than 1ml/kg in 30min (2ml/kg/h)
   • Patient requiring surgical re-exploration for diagnosed or suspected pericardial effusion or surgical site bleeding requiring surgical hemostatic intervention

Exclusion Criteria:

• Known congenital bleeding disorder
• Redo surgery for patient previously included in the study
• Implantation of Cardiac support device, Extra Corporeal Membrane Oxygenation (ECMO) Extra Corporeal Life support (ECLS), uni or bi-ventricular artificial hearts.
• Indication for post-CPB ECMO or ECLS
• blood transfusion refusal
• pregnant women
• patients under 18 years old
• Adult patient under guardianship, trusteeship or safeguard justice