Use of EBPT in Critically Ill Patients With AKI and/or Multiorgan Failure: a Multicenter Prospective Observational Registry

The use of extracorporeal blood purification therapies (EBPT) is becoming increasingly widespread worldwide in everyday clinical practice, particularly in the critical care setting. For most of these treatments, the extracorporeal removal of inflammatory mediators (via enhanced transmembrane clearance and/or selective/un-selective adsorption of bacterial toxins or inflammatory mediators) is already well established in the literature. Unselective cytokine removal is the main rationale for the use of EBPT, and it might explain the effect of these treatments on multiorgan dysfunction in critically ill patients. Indeed, an increment in hemodynamic stability and an improvement in the multiorgan dysfunction scoring system of treated patients are consistently observed in most of the studies available in the literature. Nonetheless, most of the clinical trials aimed at exploring the effect of EBPT on patients' long-term outcomes have failed to demonstrate consistent results regarding 28 day- or hospital- mortality rates.

Interestingly, the post-hoc analysis of large databases suggests that a specific subpopulation of patients, who are likely to benefit more than others from EBPT, could be identified in clinical practice. As an example, press releases from the Euphrates trial suggest that a specific range of baseline endotoxin activity assay might correlate with a positive long-term outcome in patients treated with Toraymixin cartridges. Nowadays, a personalized approach to extracorporeal therapy has been advocated as the only strategy capable of maximizing the clinical effect of EBPT and their impact on patient outcomes (i.e. precision medicine).

The identification of clinical characteristics correlated with positive outcomes during EBPT allows the implementation of specifically designed trials, focused on a well-defined cluster of patients.

The implementation of a large database encompassing the clinical/biochemical characteristics of patients undergoing EBPT is thus widely hoped for to enable the identification of a cluster of patients with specific features who most benefit from these treatments.

Although it is well known that only a clinical trial can formally assess the effect of EBPT on a specific clinical outcome, several drawbacks pose practical limitations to the implementation of a clinical trial in the critical care setting for this purpose. First, most European countries (and particularly Italy) do not allow the enrollment and randomization of non-competent patients (as critically ill patients formally are), due to ethical issues. Second, clinical trials are associated with very high costs. Third, the quality of results and conclusions deriving from post-hoc analysis of randomized clinical trials (often underpowered) may be qualitatively similar to those obtained from a very large database of patients observed during treatments performed according to the routine clinical practice.