Thrombin activity during hemodialysis; evaluated by the fibrinopeptide a assay. A comparison between a high and a low heparin dose regime.

Ten patients participated in this study which evaluated the effect of two heparin dose regimes, a high dose regime (mean dose 6750 IU) and a low dose regime (mean dose 3750 IU), on the thrombin activity, achieved during a 4-hour-dialysis. The thrombin activity was measured by use of the FPA assay. Heparin was administered as bolus dose followed by a constant rate infusion which was discontinued 1.5–2 hours prior to the end of the dialysis. Both dose regimes inhibited thrombin activity equally effectively as long as heparin was administered. In the high dose regime, the FPA levels remained unchanged until the end of the dialyses in all patients. In the low dose regime, six patients had the same FPA values at the end of the heparin infusion and at the end of the dialysis. In the remaining four patients much higher FPA levels were achieved at the end of the dialysis. No serious bleeding or clotting complications occurred, and all dialyses were uneventful.