Hemofiltration increases IL-6 clearance in early systemic inflammatory response syndrome but does not alter IL-6 and TNFα plasma concentrations

Abstract

Objective: To test the hypothesis that continuous hemofiltration increases interleukin-6 (IL-6) and tumor necrosis factor alpha (TNFα) clearances and results in decreased cytokine plasma concentrations independent of renal function in patients with early SIRS. Design: Prospective, controlled, randomized study. Setting: Intensive care units at a university hospital. Patients: 28 consecutive patients who fulfilled the criteria of the systemic inflammatory response syndrome (SIRS). Interventions: Patients with SIRS were randomly assigned to either a hemofiltration or a control group irrespective of renal function. In patients of the hemofiltration group an isovolemic hemofiltration was initiated directly after the diagnosis of SIRS and maintained for at least 48 h. Measurements and results: A significant (p < 0.001) increase in total IL-6 clearance (hemofiltrate + urine), but not in TNFα clearance, was observed with hemofiltration. However, the plasma concentrations of both cytokines remained unchanged. Hemodynamic variables did not change significantly. Conclusions: Continuous hemofiltration increases IL-6 plasma clearance but not TNFα clearance. However, hemofiltration failed to decrease plasma concentrations of TNFα and IL-6 and, therefore, cannot be used effectively for cytokine elimination in SIRS. Accordingly, beneficial effects occasionally reported with hemofiltration are unlikely to be expected due to elimination of IL-6 or TNFα.