The use of hetastarch for plasma expansion

The use of colloids in hypo-oncotic individuals to increase plasma volume has been shown to have distinct and consistent advantages compared with the use of crystalloid fluids. Colloids increase plasma colloid oncotic pressure, whereas crystalloids decrease it, an effect that can be extremely detrimental in individuals with low basal plasma colloid oncotic pressure. Increasing plasma volume in hypo-oncotic individuals without inducing large increases in interstitial water content is difficult when crystalloid fluids are used. However, colloids have much better plasma volume expansion ability without the induction of concurrent increases in interstitial water content, even in hypooncotic individuals. Review of the literature indicates that hetastarch is an extremely safe colloid for acute and long-term use in humans and dogs. Its excellent safety record probably is attributable to its structural analogy to the natural compound glycogen. The lack of availability of a substance analogous to human 5% serum albumin and the scarcity of plasma in veterinary medicine leaves hetastarch as the safest option of available colloids. Its ability to increase plasma volume and colloid oncotic pressure is equal to or better than dextran 70 and 5% albumin and is clearly better than plasma or whole blood. Increases in plasma volume and colloid oncotic pressure usually last approximately 48 hours after a single injection, but the duration of increases significantly after multiple infusions. Contraindications to its use include heart failure and oliguric renal failure, because of its excellent ability to increase plasma volume, and the presence of von Willebrand's disease, because of its ability to significantly lower all components of Factor VIII-related complex in humans.