HELP apheresis in the treatment of sepsis.

Heparin induced extracorporeal lipoprotein fibrinogen precipitation (HELP) is an established procedure for removal of low-density lipoprotein (LDL) cholesterol, lipoprotein (a), and fibrinogen in patients with severe hypercholesterolemia. In vitro studies revealed that HELP also removes endotoxin, tumor necrosis factor alpha (TNF-alpha) and C-reactive protein (CRP). With the intention to treat, we applied this procedure to 4 patients with severe gram-negative sepsis with highly elevated endotoxin blood levels. Nine treatments were performed, 6 using the standard HELP precipitating buffer and 3 without addition of heparin to the precipitating buffer. Heparin was omitted from the precipitating buffer to avoid fibrinogen depletion in patients at risk (low fibrinogen, postoperative). The average processed plasma volume was 3,386 ml in the standard and 2,963 ml in the modified treatment. Mean reductions (%) in plasma solute concentrations were (standard/ modified procedure) as follows: endotoxin, 50/57; TNF-alpha, 25/5; CRP, 49/55; fibrinogen, 49/6; total cholesterol, 38/5; and apolipoprotein B (Apo B), 41/2. Both treatment modalities were equally effective in removing endotoxin and CRP. With the modified precipitation buffer, fibrinogen was not removed. To further simplify the extracorporeal treatment, we have designed a closed-loop circuit with 2 adsorbers in series, one for removal of TNF-alpha (dextran sulfate modified cellulose) and the other for removal of endotoxin (DEAE-cellulose). In vitro evaluation confirmed very efficient endotoxin and TNF-alpha removal from plasma. This system is very simple, operates at physiological pH, and uses adsorbers already in clinical use for other purposes.