Bleeding after intermittent or continuous r-hirudin during CVVH

Objective:To demonstrate bleeding complications encountered in patients after cardiac surgery on continous venovenous haemofiltration (CVVH) treated with continuous versus intermittent r-hirudin for heparin-induced thrombocytopenia (HIT) type II. Design: Case description. Setting: Cardiothoracic intensive care unit at a university hospital. Patients: 5 consecutive patients with proven HIT type II on CVVH after major cardiac surgery. Interventions: Recombinant hirudin (r-hirudin) was given continuously at a dose of 0.01 mg/kg per h in three patients or in repeated bolus administration of 0.05 mg/kg in two patients. Measurements and results: Since the ecarin clotting time assay was not available at that time to monitor hirudin effects on coagulation, the activated partial thromboplastin time (normal range 26-38 s, target range 50-60 s) was used. The continuously treated patients suffered from major bleeding complications. Therefore, the regimen was changed to repeated bolus administration, reducing the incidence of bleeding complications probably due to a threefold diminished cumulative hirudin dose per day in comparison to continuous administration. Conclusions: If ecarin clotting time, the most suitable monitor for hirudin activation, is not available, we would prefer to give r-hirudin in repeated boluses to avoid major bleeding complications in cardiac surgery patients on CVVH.