The glycocalyx is a layer of proteins and complex sugars covering the endothelium of vessels. Its role as capillary filtration control is important. In case of alteration of the glycocalyx, experimental models and some clinical studies show an increased capillary leak responsible for interstitial edema. The analysis of glycocalyx in routine care is important to guide volume expansion. Indeed, the literature provides evidence about the poor prognosis of excess water and its impact on organ. This analysis challenge is to justify filling solution of choice according to the characteristic of this capillary leakage.

Extra corporeal circulation and aortic clamp induce ischemia-reperfusion damages.

Vascular damages are represented by first glycocalyx, a layer of endovascular vessel proteoglycans, responsible for fluid permeability and secondly by nitro oxygen liberation responsible for vascular tonus.

The investigators suppose that both functions are impaired after cardiac surgery.

Inclusion Criteria:

• cardiac surgery

Exclusion Criteria:

• auricular fibrillation
• endocarditis
• aortic dissection
• end stage chronic renal disease

All patients going for cardiac surgery enrolled for 48 hours after surgery.