**1. Introduction**

Sepsis and septic shock are one of the 10 causes of death worldwide, and the second cause in Intensive Care Unit. Moreover, in many septic patients (e.g., 40%), acute kidney injury rapidly develops, increasing the risk of mortality (from 50 to 80%) and the complications [1]. Despite the clinical importance of AKI during sepsis, many physiological aspects are not completely known, and its treatment is currently inadequate. Only recently, new studies have challenged the hemodynamic nature of AKI during sepsis, which may occur even if the renal blood flow (RBF) is maintained [2].

In the context of sepsis, considering as a dysfunctional immunological response, probably many pro-inflammatory mediators and endotoxin may interact with the kidney at different levels (tubular cells, mesangial cells, glomerular cells) and induce AKI [3]. The kidney itself may exacerbate this inflammatory response and cross talk with other organ (lung, heart) to induce a multiorgan failure [4]. This may occur also in the recent viremia Covid-19, in which an uncontrolled inflammatory response is described by many AA and septic shock with a multiorgan failure may ensue.

Extracorporeal blood purification, combining renal replacement therapy with the adsorption of many mediators, may be useful to modulate the septic immunological response and halt the renal cross talk with other organs.

Many devices are widely used, with different adsorbing capacity, but with inconclusive results [5].

The AN69-based oXiris membrane is modified with a positively charged charged polyimine ethylene layer capable of adsorbing negatively charged endotoxin molecules and IL6, IL10, and other mediators. Broman et al. have shown that Oxiris membrane may adsorb endotoxin and IL6 better than AN 69 st. in the first 24 h of treatment of patients with abdominal sepsis [6].

In this prospective study, we evaluated the changes of endotoxin during 76 h of CRRT in patients with different sources of sepsis. The changes of IL6, IL10, and procalcitonin are also studied, with the assessment of the coagulation in an attempt to confirm the effect of oXiris on endotoxin and other mediators in septic patients with AKI in a time period study longer than 24 h.
