LABORATORY CONTROL OF MINIMAL HEPARINIZATION DURING HEMODIALYSIS IN PATIENTS WITH A RISK OF HEMORRHAGE

For patients undergoing dialysis with a high risk of haemorrhage there is no standardized procedure for anticoagulation during extracorporea l circulation. Minimal heparinization with a dose equivalent to half t hat used for chronic haemodialysis was employed in 49 patients (125 ha emodialyses) performed after operative interventions (83.3%), after ha emorrhagic events (5.2%) and after invasive investigations (11.5%). Us ing a biocompatible membrane and a low molecular weight heparin (bolus dose 500-1300 U; continuous infusion 100-400 U) it was possible to co mplete haemodialysis in 74 cases (Group 0) without clots appearing in the venous bubble trap of the tubing system. In 30 cases (Group 1) onl y small clots were detected at the end of haemodialysis, and in 13 cas es (Group 2) larger clots (exceeding a diameter of 1 cm) were found. I n eight cases (Group 3) partial or complete clot formation occurred in the tubing. No haemorrhagic complications were observed. Anti-Xa acti vity, thrombin-antithrombin III complex (TAT) and D-dimer were determi ned before haemodialysis, 2 h after the start of haemodialysis and on completion of the procedure. The anti-Xa activities ranged between < 0 .2 and 0.56 U/ml. In contrast, at 2 h there were significant differenc es (P < 0.05) in the TAT concentrations between Group 0 and the other groups, as well as between Group 1 and Groups 2 and 3. Significant dif ferences (P < 0.05) in D-dimer levels occurred only at the end of haem odialysis. Minimal heparinization in haemodialysis is a practicable al ternative in patients with a high risk of haemorrhage and extended coa gulation monitoring is helpful in adjusting heparin dosage.