This study evaluates if improvement of renal resistive index when mean arterial pressure increase (at 65 mmHg to 85 mmHg) in early phase of septic shock is predictive of better renal survival.

Learned societes (survival sepsis campaign and ESICM) are currently recommending a mean arterial pressure (MAP) target at 65 mmHg in septic shoc with a potential increase to 85 mmHg in patients with medical history of arterial hypertension.

A high renal resistive index on the first day of septic shock was associated with acute renal failure more frequently on the 5th day. A decrease in the renal resistance index was also objectified during the increase in MAP.

The main objective of this trial is to study the relationship between the improvement of the resistance index during a test of increase in average blood pressure during septic shock and the improvement of renal function

In this interventional monocenter trial, we will measure the renal resistive index after stabilization of the MAP at 65 mmHg for two hours, then after 2 hours of stabilization at 85 mmHg. This part allows us to define the patients "responding" to the renal resistive index (improvement of the resitive renal index when the MAP increases).

Then, patients will be randomized into two groups :

• first group with a MAP target at 65 mmHg
• second group with a MAP target at 85 mmHg. There will be a stratification on the responder character to the renal resistance index.

Finally, we will assess renal function on the 7th day (with the assessment of serum creatinine and the change of stage of the KDIGO classification)

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

Data will be shared upon reasonable request. Only de-identified data will be shared. Any data collected during the study may be shared. The protocol will be shared initially. Other documents may be shared at a later date upon request (e.g., the CRF to allow a collaborator to select the data they wish to access). The recipients of the data will be researchers. The data will be available for any purpose deemed relevant by the study investigator, based on a protocol provided by the requester, after verification of the obtaining of regulatory approvals, including the favorable opinion of an ethics committee.

The data will be shared after signing a negotiated data transfer agreement ( data access agreement), for the duration specified in the agreement.

The data will be made available via secure transfer (sharing platform approved by the university hospital: BlueFiles or Oodrive).