Relation Between Mean Arterial Pressure and Renal Resistive Index in the Early Phase of Septic Shock

Inclusion Criteria: * adult patients (≥ 18 ans) * Admitted to the intensive care unit of Angers with * arterial hypotension requiring the etablishment of catecholamines * In a context of proven or suspected sepsis, whaterver the cause of this infection. * norepinephrine dose ⩾ 0.1µg/kg/min * After 2 hours of stabilization at 65 mmHg of mean arterial pressure Exclusion Criteria: * Pre-existing chronic renal failure (glomerular filtration rate \< 60 mL/min with MDRD) * Solitary kidney (anatomical or functional) * History of united or bilateral stenosis of the renal arteries * decision to stop or limit treatment * patient with an emergency indication of renal replacement therapy (severe hyperkalemia, severe metabolical acidosis with pH \<7.15, acute pulmonary edema due to fluid overload resulting in severe hypoxemia, serum urea concentration \> 40 mmol/l and oliguria/anuria \> 72 h.) * pregnant, lactating or parturient woman * patient deprived of liberty by judicial or administrative decision * patient with psychiatric compulsory care * patient subject to legal protection measures