THE INFLUENCE OF DIALYZER GEOMETRY ON BLOOD-COAGULATION AND BIOCOMPATIBILITY

The influence of dialyzer geometry on blood coagulation, heparin requi rement and complement activation was studied in fourteen chronic hemod ialysis patients. Each patient was dialyzed with two different cuproph an dialyzers, hollow fiber GF 120 M and parallel plate Lundia IC5N. Bo th dialyzers had a wall thickness of 11 mum, surface area of 1.2 m2 an d both were sterilized with ethylene oxide. Heparin doses were individ ually titrated. The mean heparin dose was 6089 +/- 988 U. Platelet cou nt decreased from 218 x 10(9)/l to 193 x 10(9)/l and from 235 x 10(9)/ l to 197 x 10(9)/l respectively (hollow fiber/plate dialyzer, ns). The number of leucocytes decreased at 15 min after start of dialysis by 5 6% and 61% (hollow fiber/plate dialyzer, ns). The heparin requirement, measured as prolongation of whole blood activated coagulation time af ter identical doses of heparin, were the same in hollow fiber and plat e dialysis sessions. The arterial fibrinopeptide A concentrations incr eased during dialysis from 5.4 to 7.1 nmol/l and 8.5 to 9.6 nmol/l res pectively (hollow fiber/plate dialyzer, ns). The residual blood volume in the hollow fiber dialyzers was 1.3 +/- 1.1 ml and in the plate dia lyzers 1.5 +/- 0.9 ml (ns). C3a activation, indicated by a marked arte rio-venous difference, was observed at 15 min after start of dialysis with hollow fiber as well as plate dialyzers. The arterio-venous diffe rence was less pronounced at the end of dialysis. There were no differ ences in C3a activation between hollow fiber and plate dialyzers at an y timepoint. It is concluded that dialyzer geometry does not significa ntly influence platelet count, blood coagulation, heparin requirement or complement activation.