The control of anti-coagulation in acute dialyses with sensitive laboratory parameters

In seven patients who had to be dialysed between four and 13 times due to acute renal failure, low molecular weight heparin (LMWH) Fragmin was used for anticoagulation. According to dose-finding studies, 80-90 U kg-1 body weight of LMWH as a single bolus were administered initially, producing dose-related levels of 0.3-1.5 anti-factor Xa U ml-1 in plasma. Apart from the anti-Xa activity in the plasma, the thrombin anti-thrombin III complex (TAT complex) and a fibrin degradation product (D-dimer) were measured as parameters of a coagulation activation. A sufficient anti-coagulation during dialysis was supposed to exist at a normal range (5.0 micrograms l-1 or below) of TAT complex. Pathological TAT concentrations at the end of dialysis indicated the requirement of an increased dose for the next dialysis. These concentrations reflected a need for more heparin if, for example, inflammation, indicated by increasing C-reactive protein levels (CRP), occurred. The increase of TAT complex and D-dimer during dialysis showed a good agreement (p less than 0.001). Due to a single bolus application before dialysis, one measurement of TAT at the end of the dialysis was sufficient. The determination of the TAT complex concentration enabled a heparinization better adapted to the clinical situation of intensive-care patients undergoing acute dialyses, so that the coagulation system was not additionally activated by the extracorporeal circulation.