Pharmacokinetics of Enoxaparin in Intensive Care Patients

Inclusion Criteria: * Body Mass Index between 18-30 kg/m2 * Critically ill patients requiring intensive care and pharmacological thromboprophylaxis * Expected to remain in the ICU for at least 72 h * Written informed consent obtained from the patient or his/her legal representative. Exclusion Criteria: * Other indications for anticoagulant therapy than thromboprophylaxis * Intracranial haemorrhage or central neurosurgical operation within three months prior to the admission * Disseminated intravascular coagulation (DIC) according to the international society on Thrombosis and Haemostasis criteria * Known heparin induced thrombocytopenia (HIT), or hypersensitivity to enoxaparin or heparin * Treatment with enoxaparin or any other low-molecular weight heparin (LMWH) or heparin within 24 hours prior to ICU admission. If patient has received thromboprophylactic dose of LMWH within 24-72 hours before ICU admission inclusion can be done if measured anti-factor Xa level is \<0.1 IU/ml at the time of admission * Any long-term anticoagulant medication, expect low-dose aspirin * Major bleeding within the last week unless definitively treated * Blood platelet count \<50, P-thromboplastin time (TT) \<40% , international normalized ratio (INR) \>1.7 * Glomerular filtration rate less than 50 ml/min/1.73 m2 estimated from serum creatinine by applying Cockcroft-Gault equation or chronic dialysis * HIV, hepatitis B virus, or hepatitis C virus infection * Pregnancy