This method is used to remove pathogenic substances, including autoreactive antibodies, immune complexes, paraproteins, lipoproteins, and inflammatory mediators such as cytokines. Fluid replacement after PE maintains normal plasma volume and electrolyte concentrations. Plasma filters have a pore size of approximately 0.3��m and membrane area of 0.1�C0.8m [2]. Homogenization of sellekchem pore size has been sought to decrease cell leakage and hemolysis. The PE circuit includes the plasma filter, circuits for blood cells and plasma, equipment for plasma exchange (blood pump, plasma pump, hemadynamometer, plasma filtration manometer, trans-membrane-pressure (TMP) manometer, and an anticoagulant pump). A circuit for fluid replacement should be prepared when HD or hemodiafiltration is combined with PE.

The ideal replacement solution should maintain normovolemia and normal plasma electrolyte concentrations. The choice of replacement fluid includes crystalloids, semisynthetic colloids (hetastarch, gelatin, and dextrans), human albumin solutions, liquid stored plasma, fresh-frozen plasma (FFP), and cryoprecipitate. The replacement solutions most commonly used are liquid stored plasma and human albumin solution for the removal of some pathogenic substances. FFP infusion can cause hypocalcemia as a result of calcium chelation by sodium citrate, and alkalosis and sodium overload can also occur. The hypotensive effects of citrate-induced hypocalcemia can be minimized by administering calcium gluconate as a continuous intravenous infusion and monitoring serum calcium levels.

The treatment of choice for patients with AKI is combined plasmapheresis and HD to correct electrolyte abnormalities and provide renal support. A high flow volume may be needed when combining HD or hemodiafiltration with PE in patients undergoing long-term HD. When combining PE with HD in a serial circuit, a medical practitioner should monitor the procedure and stop it, if necessary, to prevent overfiltration at the HD side caused by decreased or obstructed blood flow at the PE side. Double-filtration plasmapheresis (DFPP) is a PE in which two filters with different pore sizes are used to separate toxic substances from plasma. The two-stage filtration allows the removal of albumin and its return into the blood circulation.

This feature provides the advantage of decreasing the need for replacement fluid and its associated complications, including allergic reaction and infection, that can occur with PE. Using DFPP also decreases the high cost associated with Brefeldin_A the replacement fluid [51]. Cryofiltration is a modification of DFPP that involves cooling the separated plasma at the plasma separator (first membrane) to gelatinize the proteins in the plasma, which are then ablated at the large-pore plasma component separator (second membrane) [52]. The gelatinized and ablated proteins form cryoglobulin or cryogel.