**2. Methods**

#### **2.1 Study design**

Non-interventional, observational, multicenter, prospective study.

#### **2.2 Study cohort**

The setting was a 11-bed secondary referral medical-surgical intensive care unit (ICU) at the Aurelia Hospital in Rome, Italy, and the 15-bed Cardiothoracic Intensive Care at the European Hospital in Rome. All patients were treated according to the normal ICU protocol and current severe sepsis guidelines [7].

The study population consisted of patients with sepsis/septic shock defined by Sepsis 3 conference with AKI, defined by KDIGO criteria. (Sepsis 3 Kdigo) Inclusion criteria were also considered: Endotoxin activity assay ≥0.6 and/or IL6 ≥ 150 pg/mL, noradrenaline infusion, MAP, and P/F ratio < 200 with mechanical ventilation or NIV. Patients with an age < 18 years 80 > and/or being pregnant, if present chronic renal failure (or previous treatment with CRRT), endotoxin or interleukins in the normal range, Glasgow Coma Score (GCS) < 8 due to hemorrhagic or ischemic events, and the need of extracorporeal membrane oxygenation (ECMO) were not eligible to receive CRRT and Oxiris treatment.

#### **2.3 Study procedure**

After receiving consent, Oxiris filter (Baxter, Il\_USA) was assembled on the Prismaflex System or Prismamax (Il\_USA), and CRRT was started on CVVHDF mode.

All treatments were performed by the same experienced nurses under the supervision of the investigators. Vascular access was obtained with use of doublelumen venous catheters through echographic visualization of femoral or Iinternal giugular vein. The circuit was prepared according to the manufacturer's guidelines
