Crystalloids, colloids, blood, blood products and blood substitutes

The choice of fluid in a given clinical scenario relies on knowledge of the physiology and pharmacology of the fluid. A broad range of fluids are discussed in this article, with particular emphasis on problems associated with excess administration of 0.9% saline. Colloids, blood, blood products and blood substitutes are also discussed. Balancing the risks of allogenic blood transfusion for a patient and transfusion thresholds are considered. The potential of haemoglobin substitutes are still yet to be realized; however PolyHeme is currently in a phase 3 pre-hospital trauma trial.