I of this three-part Continuing Education Series discussed fluid dynamics and the distribution of administered fluids in various fluid compartments of the body in health and disease. This part discusses the characteristics of various natural and synthetic colloids that are available in veterinary medicine. The clinical effects of a colloid depend largely on its molecular size and its half-life in blood.
Some colloids have unusual properties that are useful for treating specific cases.
For example, dextran 40 coats red blood cells and platelets and may be helpful in treating patients in hypercoagulable states. Medium-range hydroxyethyl starches might actually plug endothelial gaps that occur in diseases that lead to the systemic inflammatory response syndrome. Some patients are best managed with a combination of natural and synthetic colloids as well as crystalloids. Part III of this series will discuss the proper administration of colloids.