Pharmacokinetics of Enoxaparin in Intensive Care Patients

Plasma Anti-FXa Concentration After Continuous Intravenous Infusion and Subcutaneous Dosing of Enoxaparin for Thromboprophylaxis in Critically Ill Patients

To evaluate the pharmacokinetics of the thromboprophylactic agent enoxaparin in critically ill patients by comparing plasma anti-factor Xa activity when enoxaparin is administered either as a continuous intravenous infusion or subcutaneous bolus once daily.

To investigate possible ongoing coagulation by coagulation markers during antithrombotic therapy with standard doses of enoxaparin

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