Assessment of the safety and efficacy of fondaparinux as an anticoagulant in haemofiltraion in patients with acute renal failure

INTERVENTION: The active group will be given ondaparinux for anticoagulation for the first filter only during their course of haemofiltration. The decision to commence or cease haemofiltraion will remain with treating physician. CONDITION: Patients requiring haemofiltration for acute renal failure. PRIMARY OUTCOME: The study will evaluate the duration of filter patency using fondaparinux as an anticoagulant in haemofiltration and compare this to current standard haemofilter anticoagulation with enoxaparin. SECONDARY OUTCOME: To assess the incidence of complications, primarily bleeding, with fondaparinux compared to enoxaparin in this setting. INCLUSION CRITERIA: The study will be conducted in the Intensive Care Unit at The Royal Melbourne Hospital and will aim to include patients who fulfill the following criteria: 1.Adult patients admitted to the ICU with an expected stay of more than 48h. 2.Patients who require continuous renal replacement therapy. 3.Patients who consent or if the patient is incompetent, the next‐of‐kin who consent, to inclusion in the study.