Infusion fluids fall into two categories: crystalloids and colloids. Crystalloid solutions are plasma volume expanders that contain crystals such as electrolytes like sodium and potassium. These crystals are capable of fully dissolving into solution and allow the solution to move through membranes. Crystalloid solutions are mainly used to increase the intravascular volume when it is reduced. Some crystalloid solutions are used in specific circumstances to replace electrolyte losses or glucose as indicated. Crystalloids are typically used to replace fluids loss with hemorrhage, dehydration, and fluid loss due to surgery.
Colloids are gelatinous solutions with large molecules that act as plasma volume expanders. Particles in the colloid solution are too large to pass a semipermeable membrane, such as capillary membranes and stay in the intravascular spaces longer than crystalloids. Fluids in the colloid group are albumin, dextran, and hetastarch. These fluids are typically used to maintain circulating fluid volume after blood loss from trauma or surgery. Colloid administration is prone to increased risk of side effects.
It is important for all nurses to understand fluids, their properties and proper use and side effects of administration. Print and use this resource as a quick reference guide!