Abstract
Characteristics of solute removal and biocompatibility were clinically compared among three kinds of membrane hemodialyzers with minimum activating capacity for complement, and comparable in vitro clearance of urea. Ten patients with chronic renal failure who had undergone hemodialysis (HD) three times a week for more than one year were enrolled in this study. These patients were dialyzed using three kinds of dialyzer membranes, Hemophan (H), cellulose di-acetate (CA), and polymethylmethacrylate (PMMA) in a crossover method under HD conditions that were similer except for dialyzer membrane. Testing of HD included evaluation of clearance and reduction rate of small molecular substances (urea nitrogen, UN; creatinine, Cr ; uric acid, UA ; and phosphate, iP) ; and changes of blood cell counts ; beta-thromboglobulin (β-TG) ; thromboxane B2; 6-keto-prostaglandin F1α; granulocyte elastase-αl proteinase inhibitor complex (G-elastase) ; celite activated coagulation time (CCT) ; and fibrinopeptide A (FPA) . Although the clearance and reduction rates of UN, Cr and UA did not differ among the three membranes, those of iP were significantly lower with PMMA than with CA or H, and the clearance of iP was maximum with H. HD with H induced a greater decrease of leucocytes, than with CA and a higher venous/arterial ratio of β-TG than CA or PMMA. HD with H prolonged CCT less than HD with PMMA, and increased FPA more than CA or PMMA. The largest increase in G-elastase was observed in HD with PMMA. Strongly negative, and relatively positive membrane charges were reported in PMMA and H, respectively. It is well known that positive membrane charge is an activating stimulus for platelets. The results thus suggest that elimination of negatively charged iP decreased in HD with PMMA and increased with H membrane because of membrane charges, and that coagulation cascade was stimulated during HD with H, possibly because its positive membrane charge activated platelets and adsorbed negatively charged heparin.
