Thrombogenicity testing of central venous catheters in vitro

To date there have been no standard methods for assessing the thrombogenici ty of centre,venous catheters, A procedure for testing the thrombogenicity of intravenous lines such as the silver-impregnated catheter by continuous blood flow in vitro nas therefore developed. For this test, fresh blood,was drawn from healthy human donors and anticoagulated with sodium citrate (1: 9), All material tested (catheter tubes with and without silver manufacture d in the same ,way, polethylene tubes and tubes with potentially thrombogen ic material),were perfused through their lumen with anticoagulated blood fo r up to 31 hours. Blood samples were collected at different times from the test system at sites before and after the perfusion of the test catheters, The hemoglobin concentration, erythrocyte, leukocyte and thrombocyte counts and markers for thrombin activation (thrombin-antithrombin III-complex, F1 +2-prothrombin fragments) and for hyperfibrinolysis (d-dimers),were determi ned. No thrombin activation, or signs of hyperfibrinolysis were detected in any material tested. Polyethylene tubes were found to cause hemolysis? as shown by a decrease in hemoglobin content from 15 g% to 4.5 g%, Tecothane(c ircle times) tubes with and,without silver did not induce hemolysis.