Hemofiltration treatment for sepsis: is it time for controlled trials?

While the use of hemofiltration to treat septic shock has potential benefits, the existing studies are difficult to compare because of their variety of inclusion criteria. The concept is to remove the various mediators of severe sepsis and septic shock, such as cytokines and eicosanoids, so that acute renal failure and the resultant multi-organ failure and possible death can be delayed or prevented. The dilemmas include: (a) hemofiltration cannot distinguish between these pro-inflammatory mediators as they are of similar molecular weights, and thus it is difficult to determine which one or combination should be eliminated for the best hemodynamics; (b) timing of the hemofiltration to remove a particular cytokine may make a difference in patient outcome; (c) the most efficacious convection rate of ultrafiltration has not been determined yet; (d) since these mediators quickly saturate the membrane, it should be frequently changed, and thus biocompatibility, availability and costs are added issues; (e) the choice of buffer is different according to the diagnosis of these critically ill patients. Before designing clinical trials, further experimentation is necessary to explore these problems.