The vast majority of acutely ill patients admitted into the intensive care unit require volume expansion at some stage of their stay. Patients suffering from haemorrhage, extended trauma or severe dehydration are obvious candidates. Septic, traumatized and even postoperative patients also develop exudation of plasma into the inflamed areas. Patients with sepsis may develop generalized alterations of the endothelial barrier, resulting in diffuse capillary leak and generalized oedema. This accumulation of extravascular fluid may contribute to the development of cellular hypoxia and multiple organ failure