Heparin in Severe Sepsis

INTERVENTION: Blinded study of low‐dose intravenous unfractionated heparin (UFH) (control) compared to subcutaneous fondaparinux (intervention) in patients with severe sepsis. Fondaparinux: an injection of fondaparinux 2.5mg in 0.5ml of saline for injection will be administered subcutaneously daily for 7 days commencing within 24 hours of onset of severe sepsis. For blinding purposes, a continuous infusion of normal saline will also be required at the same time as the control arm. Duration of the study is 7 days in both arms. CONDITION: Severe sepsis PRIMARY OUTCOME: All cause mortality Survivial from severe sepsis. SECONDARY OUTCOME: Adverse events related to drug safety, particularly bleeding episodes, monitored daily. Death from all causes Death in Intensive Care Unit (ICU) ICU and hospital length of stay The need for and duration of organ support(inotropic/vassopressor/mechanical ventilation) measured daily whilst in ICU. INCLUSION CRITERIA: 1. Diagnosis of severe sepsis 2. Patients able commence study treatment within 24 hours of fulfilling inclusion criteria. 3. Informed consent obtained from the patient or next of kin/legal surrogate.