The aim of the present study is to verify whether the earlier association of vasopressin and norepinephrine, in patients in septic shock, determines variations in terms of use of renal function replacement techniques in the first 7 days of hospitalization in Intensive Care, compared to patients in whom vasopressin is added only when norepinephrine reaches a higher dose.

The aim of the present study is to verify whether the earlier association of vasopressin and norepinephrine, in patients in septic shock, determines variations in terms of use of renal function replacement techniques in the first 7 days of hospitalization in Intensive Care, compared to patients in whom vasopressin is added only when norepinephrine reaches a higher dose. The study is aimed at patients admitted to the ICU with a diagnosis of septic shock on admission or in the first 24 hours of admission.

Patients will be divided and randomized in a 1:1 ratio through a computer-generated scheme, when the dose of norepinephrine administered is ≥ 0.25 mcg/kg/min, into the following groups:

• Group A: when the norepinephrine dosage is equal to or greater than 0.25 mcg/kg/min in the absence of adequate MAP (Mean arterial pressure >65 mmhg), vasopressin infusion will be associated with the standard dosage of 0.3UI/min.
• Group B (control): the infusion of vasopressin at a dosage of 0.3 IU/min will be associated if norepinephrine exceeds the dosage of 0.5 mcg/kg/min in the absence of adequate MAP.

Inclusion Criteria:

• patients suffering from septic shock hospitalized in an intensive setting
• patients over 18 years and under 80 years of age
• patients within 24 hours of clinical diagnosis, and requiring, in this time window, a norepinephrine dosage equal to or greater than 0.25 mcg/kg/min according to the patient's ideal weight (IBW)
• patients capable of expressing informed consent to treatment.

Exclusion Criteria:

• patients in the absence of consent to participate in the study and to the processing of personal and particular data;
• patients under 18 years of age or over 80 years of age;
• patients who died within the first 24 hours of admission to the ICU;
• patients requiring a norepinephrine dosage lower than 0.25 mcg/kg/min in the first 24 hours of hospitalization in the ICU;
• patients with recent acute coronary syndrome (within the previous 7 days);
• patients with allergy/intolerance to the drugs used in the study or to any component of the study drug including excipients;
• pregnant patients;
• breastfeeding individuals;
• patients who need to start renal replacement treatment within 24 hours of admission to the ICU for dialysis emergencies that cannot be deferred;
• patients with a history of end-stage renal failure or already undergoing dialysis treatment (CKD stages 4 and 5, with glomerular filtration < 30 ml/min);
• single kidney patients;
• patients with bilateral renal hypoplasia;
• patients undergoing kidney transplant;
• patients undergoing haemoperfusion with an adsorbent cartridge for bacterial endotoxin.

An expert nephrology consultant has been included among the investigators to assess the need for CRRT according to KDIGO criteria, and he will be blinded to the subject allocation. In addition, the physicians who will perform ultrasound evaluation will be blinded to the subject allocation, in order to reduce the potential bias of overestimating the efficacy of the study treatment.