Effects of long-term hemofiltration on circulating mediators and superoxide production during continuous endotoxin administration

Background: The purpose of this study was to test whether continuous hemofiltration eliminates cytokines and eicosanoids, or stimulates granulocyte function. Methods: Nineteen pigs were divided into a control group (n = 7), a hemofiltration group (n = 7), and an extracorporeal circuit only group (n = 5). All animals received the same amount of intravenous endotoxin and resuscitation fluid. Zero-balanced hemofiltration was started 30 minutes after initiation of endotoxemia and continued throughout the experiment. Plasma endotoxin, tumor necrosis factor-α, eicosanoids, superoxide production, and other physiologic parameters were measured before challenge and at scheduled intervals thereafter. Results: Eicosanoids were filtered but plasma concentrations were not reduced. Tumor necrosis factor- α was not filtered or adsorbed. There were no significant differences between groups in any measured parameters. Conclusion: Continuous hemofiltration could not efficiently remove tumor necrosis factor-α or eicosanoids. Also, continuous hemofiltration did not stimulate production of the proinflammatory mediators measured, nor improve respiratory distress.