ON COMPLEMENT NET GENERATION IN FAST HEMODIALYSIS - ARE HIGH BLOOD-FLOW RATES BIOINCOMPATIBLE

Arterial and venous concentrations of complement (C3a) and leukocyte c ount were determined in 17 patients during 201 hemodialysis sessions b y 12 different treatment modes executed in random order using cupropha n, hemophan, or polyamide membranes with small or large membrane areas and high blood flow (Qb) (400 mL/min) for 2 hours or low Qb (200 mL/m in) for 4 hours. With all membrane types, the number of leukocytes was significantly higher after 120 minutes of dialysis and by the end of treatment at high Qb compared with low Qb. C3a concentrations mu g/mL) in the arterial and venous blood lines were significantly higher duri ng cuprophan dialysis compared with hemophan and polyamide dialyses (P < 0.001). In addition, the net generation of C3a (mu g/min) was signi ficantly higher during hemodialysis with cuprophan compared with hemop han and polyamide (P < 0.001). After 2 hours at high Qb for each of th e three membranes, the net generation of C3a was significantly higher compared with low Qb (P < 0.05 for all comparisons). Possible reasons for the increase in the net generation of C3a (mu g/min) at high Qb ar e less protein deposition on the membrane at high Qb or the fact that the protein coat is stripped off in the dialyzer, thereby recreating a less biocompatible surface. Hemodialysis at high Qb may thus be less biocompatible than dialysis at low Qb. (C) 1995 by the National Kidney Foundation, Inc.