Recent reports confirm that the standard dose of enoxaparin in obese patients is often subtherapeutic, leading to a higher incidence of venous thromboembolism. All patients receiving subcutaneous enoxaparin 30 mg twice a day (b.i.d.) for venous thromboembolism prophylaxis were prospectively enrolled in this study. Trough antiXa levels were obtained and any level less than 0.1 IU/mL was considered subtherapeutic and the final dosage requirement was recorded. Body mass index (BMI), abdominal wall thickness, and fluid balance were collected. Thirty-four patients were prospectively enrolled in the study, 14 (50%) of which had a BMI >30. Sixty-five per cent of obese patients were initially nontherapeutic, compared with 53 per cent of the nonobese ( P = 0.73). However, elevated BMI ( P < 0.05) and abdominal wall thickness ( P < 0.05) correlated to an increased final dose required to attain an anti Xa ≥0.1 when not initially therapeutic, whereas fluid balance demonstrated no correlation ( P = 0.232). Subcutaneous enoxaparin dosing of 30 mg b.i.d. is not sufficient for the majority adult trauma patients in the intensive care unit, regardless of BMI. When enoxaparin 30 mg b.i.d. is initially subtherapeutic, obese patients may require a larger dose necessary to achieve necessary anticoagulation.
Does Obesity Predispose Medical Intensive Care Unit Patients to Venous Thromboembolism despite Prophylaxis? A Retrospective Chart Review
