Effectiveness of combining plasma exchange and continuous hemodiafiltration (combined modality therapy in a parallel circuit) in the treatment of patients with acute hepatic failure.

Plasma exchange has gained widespread acceptance as an effective mode of blood purification in patients suffering from acute hepatic failure. However, it is still undetermined whether a single use of plasma exchange is capable of removing inflammatory cytokines completely or of preventing the development of citrate toxicity inherent with fresh frozen plasma. To clarify these issues we developed combined plasma exchange and continuous hemodiafiltration (CHDF) modality in which CHDF is performed in an opposite direction to plasma exchange. This study was designed to assess the effectiveness of combined modality therapy. Fifteen patients with acute hepatic failure were treated with plasma exchange (plasma exchange group) or plasma exchange and CHDF (plasma exchange + CHDF group), and various biochemical parameters were determined before and after treatment. Although citrate levels increased significantly after treatment compared with pretreatment levels in both the plasma exchange group and the plasma exchange + CHDF group, the percentage of the increase in citrate levels was significantly higher in the plasma exchange group than in the plasma exchange + CHDF group. Bilirubin levels were significantly lower after treatment in both the plasma exchange and plasma exchange + CHDF groups. There were no significant differences in tumor necrosis factor-alpha levels before and after treatment in the plasma exchange group, but they were significantly lower after treatment in the plasma exchange + CHDF group. Interleukin-6 (IL-6) levels increased significantly after treatment in the plasma exchange group, but there were no significant differences in the IL-6 levels before and after treatment in the plasma exchange + CHDF group. Interleukin-8 levels increased significantly after treatment in the plasma exchange group while decreasing significantly after treatment in the plasma exchange + CHDF group. These results indicate that combining plasma exchange and CHDF in a parallel circuit is an effective modality for suppressing the elevation of blood citrate levels and for removing inflammatory cytokines. This finding may have important implications for the development of an effective treatment for patients with acute hepatic failure.