Heparin in Severe Sepsis

In Australia and New Zealand, around 5000 patients are admitted to Intensive Care Units (ICU) annually with severe infection (sepsis). Despite aggressive treatment, around 35% of these patients will not survive, making severe sepsis the most common non-cardiac cause of death in ICU patients. Even surviving patients often suffer a period of multiple organ failure. Most patients admitted to ICU receive heparin injections to prevent the formation of blood clots in the leg veins which can travel to the lungs, causing major breathing difficulties. Traditionally, the agent most commonly given to prevent blood clots was unfractionated heparin, but over the last decade, more purified forms of heparin (low and ultra-low molecular weight heparins) have become available. These more modern agents are replacing the traditional heparin for blood clot prevention because of reported increased effectiveness. Recent studies in animals, healthy humans and critically ill patients with severe sepsis have suggested that unfractionated heparin may have beneficial therapeutic effects in infection, additional to its action to prevent blood clots. These immune-active effects are related to molecular size and thus may be lost with the current trend to use purified heparin forms. If this is true, then this additional benefit may be lost as we change to more purified heparin forms. We aim to perform a pilot study to assess the feasibility of conducting a large multi-centre study to investigate whether unfractionated heparin is beneficial for patients with severe sepsis. If unfractionated heparin is shown to be beneficial in these patients, this would be a simple, cheap and widely applicable additional treatment for severe infection that could save lives world-wide, and be accessible in first to third-world environments.