Sepsis involves an inflammatory response to infection, causing damage to organs, which may progress to shock and death.¹ Invading organisms breach defences; an inflammatory response occurs to contain the organism and repair tissue damage. Inflammatory mediators (e.g. histamine, kinins, leukotrienes, prostaglandins and complement) initiate vasodilatation, enhancing blood flow to the affected area. Increased capillary permeability permits defensive proteins, antibodies and clotting agents to trap and remove microbial toxins. The body may be successful in containing the infection or it may be overwhelmed, with the process becoming exaggerated, or dysregulated, failing to respond to inhibitory pathways, leading to organ damage, dysfunction or even death.

Sepsis, a major cause of distributive shock, affects millions worldwide. In developed countries the overall mortality from infection has decreased in the last 10 years, but one in four affected still die from sepsis or septic shock. In the UK an estimated 37 000 patients die from sepsis every year.¹ A further 65 000 people survive but suffer long-term physical and psychological complications.