Efferent methods of therapy for critical illness

Abstract

Extracorporeal blood purification is intended to eliminate dysregulation of the immune system. The concept of extracorporeal therapy is based on the nonspecific clearance of inflammatory mediators and triggers, which attenuates the systemic expression of inflammatory mediators. The main types of extracorporeal therapy are hemoadsorption and plasma exchange. Hemoadsorption is used primarily as an adjuvant treatment for septic shock and other severe inflammatory conditions, including severe forms of COVID-19 with cytokine storm.
 Reliable data demonstrating the benefit of hemoadsorption in critically ill patientsis is limited. Recommendations for the use of hemoadsorption devices are often based on incomplete data or questionable interpretations of available data. Given the lack of evidence for the benefit of hemoadsorption in the treatment of severe inflammation, sepsis, liver failure and rhabdomyolysis, its routine use in clinical practice is not justified until the mechanisms underlying these findings are fully elucidated.
 Plasma replacement is a potentially life-saving invasive extracorporeal blood purification procedure that replaces plasma with a substitute fluid (saline, albumin solution, fresh frozen plasma, or a combination of these) with the risk of side effects and complications. There is still uncertainty regarding the timing, type of plasma exchange, volume and frequency of plasma filtration. Although plasma replacement is considered to be relatively safe, there is still insufficient evidence to support its inclusion in sepsis treatment protocols.
 Reports of the use of extracorporeal methods in the treatment of patients with severe refractory systemic inflammation provide evidence of decreased levels of inflammatory biomarkers, improved hemodynamic parameters, and decreased organ failure. However, according to the results of randomized clinical trials, extracorporeal therapy does not affect clinical outcomes, and in some even increases mortality. To clarify the effectiveness of extracorporeal therapy, it is necessary to study the mechanisms of interaction of the devices used with target and non-target blood components and large-scale randomized controlled trials assessing the ability of this therapy to improve clinical outcomes.