Basic Mechanisms of Hemoadsorption: Incumbency for Better Clinical Utility

BACKGROUND: The term adsorption is defined as the process in which molecules accumulate in the interfacial surface layer of a solid. The solid material is the sorbent, and the substance in the adsorbed state is called adsorbate. The basic principles and mechanisms involved in hemoadsorption include flow dynamics, chemical characteristics of synthetic materials, adsorption isotherms, mass transfer zone, and the Vroman effect. The development of devices and materials for hemoadsorption started in the 1970s, where activated charcoal coated in a plastic case was used as a sorbent for patients with drug overdose. Further developments of adsorbent materials led to the creation of several cartridges, which are now available for clinical use and are deployed for a myriad of purposes. Indications for hemoadsorption include sepsis, intoxication, drug overdose, acute kidney injury, rhabdomyolysis, cytokine release syndromes, acute liver failure, antibody-mediated autoimmune diseases, and uremia. SUMMARY: Herein, we aimed to describe the mechanisms involved in the adsorptive process and explore the singular properties of the commercially available devices for hemoadsorption. KEY MESSAGES: The devices deployed to adsorption are cartridges or filters. In cartridges, blood or plasma interacts with polymers in the form of beads, powder, flakes, granules, or a mesh of fibers. In filters, blood is exposed to a synthetic membrane in the form of hollow fibers. In research, clinical practice, and education, it is essential to specify the device and the adsorbent material used for hemoadsorption, since their properties and targets may vary entirely. Nephrologists and intensivists should be familiarized with the mechanisms and principles of hemoadsorption as these treatments are now being routinely applied.