Efficacy of low molecular weight heparin in a canine model of thromboplastin-induced acute disseminated intravascular coagulation

The aim of this study was to test the efficacy of different dosages of low molecular weight heparin (LMWH) in acute DIC which was induced in anaesthetised dogs by 4 h infusions of a canine lung thromboplastin extract. In all animals during the first 2 h, development of acute DIC was characterised by decreasing fibrinogen concentrations, platelet numbers, factor V- and antithrombin activities. Two hours after starting the thromboplastin infusion, intravenous LMWH treatment in different dosages started in groups 2 and 3 to achieve plasma levels between 0.27+/-0.01 and 0.36+/-0.02 anti-FXaUml(-1) or 0.62+/-0.08 and 0.90+/-0.07 antiFXaUml(-1) (mean+/-SD), respectively, during the time period of parallel administration of thromboplastin and LMWH (group 1=control; 4 dogs/group). In this time period, changes in factor V activity and fibrinogen concentration did not differ between group 2 and the control group. This was in contrast to group 3. The results of this study indicate that an efficacious interruption of the consumption reaction in cases of severe canine DIC requires high plasma heparin levels.