Easy production of sterile, pyrogen-free dialysate.

Hemodialysis (HD) hypotension is frequently encountered during conventional acetate HD. Recently it has been suggested that monocytes that adhere to the dialysis membrane are also stimulated by endotoxins diffusing from the dialysate side. Stimulated monocytes, however, release interleukin-1, which mediates fever and hypotension through its action on the cyclo-oxygenase cascade. To prevent this endotoxin-induced stimulation of monocytes, a hemofilter with a polyamide membrane (FH 88, Gambro, Lund, Sweden, cut-off 20,000 daltons, surface area 2.0 m2) was interposed between the dialysate outlet of the HD machine and the dialyzer. The data obtained clearly show that the filtered dialysate was always pyrogen-free when tested with a limulus-amebocyte-lysate assay. In addition, in 80% of cases no bacteria were detected after the sterilizing filter. Almost no febrile episodes were observed when sterile dialysate was used.

Good biocompatibility of the polyamide hemofilter.

Chronic hemofiltration (HF) is now a well-established method, especially for elderly uremic patients and those suffering from cardiovascular problems. This is due to the fact that chronic HF offers superior treatment comfort with less hypotensive episodes, vomiting, muscle cramps and febrile reactions. Apart from the different blood purification techniques involved in chronic HF compared to hemodialysis (i.e. convection versus diffusion), it might well be that the better treatment comfort is attributable to a certain extent to the polyamide HF membrane used in our HF treatments. We studied different biocompatibility parameters and received the following data: (a) leukocytes and thrombocytes remained unchanged during a treatment session; (b) elastase increased slightly but there was no difference between the polyamide and polycarbonate membrane, and (c) arterial and venous concentrations of C5a and C3d remained almost unchanged. The superior treatment comfort and better vascular stability of HF over hemodialysis might also be due to the improved biocompatibility of the applied hemofilter as the polyamide membrane induces no changes in different biocompatibility parameters such as leukocytes, thrombocytes, C5a or C3d.

Performance and biocompatibility of a new hemodialysis membrane.

Performance studies and investigations of the biocompatibility of a new hemodialysis membrane were conducted in patients being chronically hemodialyzed. The investigated polycarbonate membrane revealed a very satisfying performance with regard to clearance values and the ultrafiltration rate. The biocompatibility studies showed a significant leukopenia and an increase of C5a, platelet factor 4 and granulocyte elastase. Thrombocytes and C3d remained unchanged. Long-term studies have to confirm whether or not the new membrane is more biocompatible, a suggestion which could be advanced, as no febrile episodes were observed during any treatment, a finding which is not typical for Cuprophan hemodialysis.