Adequate thromboprophylaxis in critically ill patients

Venous thromboembolism is a relatively frequently occurring complication in critically ill patients admitted to the ICU despite prophylactic treatment with subcutaneous low molecular weight heparin. Several studies show that critically ill patients have significantly lower plasma anti-factor-Xa activity levels compared to control patients after administration of subcutaneous heparin. Robinson and colleagues show in this issue of Critical Care dose-dependent but relatively low levels of anti-factor Xa activity at increasing doses of enoxaparin. Anti-factor Xa levels thought to be required for adequate thromboprophylaxis are observed only at doses of enoxaparin that are one and a half times higher than the conventional dose (40 mg).