Low-dose heparin thromboembolism prophylaxis

In their article on low-dose heparin thromboembolism prophylaxis, Owings and Blaisdell 1 cited decreased levels of antithrombin III in severely injured patients as a reason for the failure of therapy with low-dose heparin. If this hypothesis holds true, then increasing the dose of unfractionated heparin, which would counteract the reduced bioavailability, or administering a product with predictable bioavailability such as low-molecular-weight heparin (LMWH) should be equally efficacious. The authors mention that the primary problem with the use of LMWH is the inability to document the effect of a given dose except through measurement of ex vivo antifactor Xa activity. Clinical evidence is mounting that LMWH is an option for thromboembolism prophylaxis in high-risk patients without routine laboratory study monitoring. 2 The antifactor IIa and Xa response differs with LMWH preparations. Therefore, these preparations should be evaluated individually for clinical efficacy. The conclusions drawn in this literature review are not consistent