Blood, Electrolytes, and Intravenous Infusions
2-9
2-9. CRYSTALLOID AND COLLOID SOLUTIONS
The nature of injectable crystalloid and colloid solutions determines their ability to be absorbed by the cells or to remain in the circulatory system.
a. Crystalloid Solutions. Crystalloid solutions contain small molecules that pass freely through cell membranes and vascular system walls. These solutions are useful as fluid expanders and are stored at room temperature. The crystalloid solutions are a useful source for electrolytes and a temporary source of fluid volume. They flow out of the vascular system rather quickly. Lactated Ringer's is an example of a crystalloid solution.
b. Colloid Solutions. The colloid solution contains molecules that are frequently very complex and much larger than those in the crystalloid solutions. A solution that contains protein is colloidal. The colloidal solutions are needed when a solution is required to remain in the vascular system. Colloid solutions generally require refrigeration and can be stored for a limited period. Whole human blood U.S.P. and Hetastarch are examples of colloid solutions.
