Apheresis of plasma compounds as a therapeutic principle in severe sepsis and multiorgan dysfunction syndrome

During sepsis there is an increase in the plasma content of several compounds, e.g., bacterial toxins, cytokines, cell debris, free hemoglobin and myoglobin. In blood, these compounds activate various cascade systems, which in large amounts or in more vulnerable patients lead to a disseminated intra-vascular coagulopathy (DIC) with multiorgan dysfunction syndrome (MODS) and death, despite conventional intensive care unit therapy. Therapeutic attempts to reverse these conditions have so far been of limited benefit. These effects have mainly been focused on lowering the blood concentration of single substances such as tumor necrosis factor. By the use of low-and high-flux hemodialysis filters, usually only small amounts of these substances are removed. By the use of plasmapheresis or plasma exchange, the extent of removal is considerably increased. The efficacy varies between the techniques (centrifugation vs. filtration or adsorption) and has also different influences on e.g. the complement system. This report describes these techniques and the therapeutical possibilities given by them. In small trials, blood or plasma exchange has been used as rescue therapy in critically ill patients with a progressive MODS and DIC. A survival of about 80% of the patients has been reported in these studies and the use of combined therapy will be discussed. Controlled trials are required in this field.