Hemodynamic Optimisation Guided With Transcranial Doppler in Septic Shock

Randomized, controlled, prospective trial, including ICU patients with Sepsis or septic Shock, at the early phase. patients will be randomized in 2 groups regarding the hemodynamic management and catecholamin doses: * Group 1: standard hemodynamic goals and catecholamin infusion to achieve: mean arterial pressure \> or equal to 65 mmHg and diastolic arterial pressure \> ou equal to 50 mmHg within the first 60 minutes. * Group 2: personalized hemodynamic goals and catecholamin infusion until normal transcranial doppler: IP\<1,2.