Continuous hemofiltration improves hemodynamics in critically ill patients by removing cytokines from the plasma. The mechanism, however, remains to be clarified since recent studies show conflicting findings. The present study was therefore designed to evaluate hemodynamic changes and kinetics of tumor necrosis factor (TNF)alpha, interleukin (IL)1beta and IL6 in patients with septic shock and acute renal failure (ARF) undergoing continuous veno-venous hemofiltration (CWHF), over a 24-hour period.