hetastarch

Hetastarch, or hydroxyethyl starch (HES), is a synthetic colloid prepared by hydroxyethylation of starch, typically derived from amylopectin. It is used intravenously as a plasma volume expander to treat hypovolemia when crystalloids alone are insufficient or rapid intravascular volume replacement is needed.

Two main forms exist: older, higher-molecular-weight hetastarch with greater viscosity and longer intravascular persistence, and newer, lower-molecular-weight hydroxyethyl starch preparations designed to reduce persistence and coagulopathy. Hydroxyethylation slows degradation by amylase, prolonging intravascular retention; molecular weight and substitution level influence duration of effect and safety. After administration, HES remains largely intravascular but is eventually excreted renally or metabolized.

Indications include acute management of hypovolemia due to surgery, trauma, or fluid losses, particularly when rapid volume expansion is needed and risk of fluid overload from crystalloids is a concern. It is not a substitute for blood products and is not indicated in certain conditions.

Safety concerns: HES can impair coagulation and increase bleeding risk, particularly at higher molecular weights or substitutions. It is associated with an increased risk of acute kidney injury, including the need for renal replacement therapy, in some patient populations. Hypersensitivity reactions and rare anaphylactoid responses have been reported. Because of these risks, many guidelines limit or advise against its use in critically ill patients, those with sepsis or renal impairment, and in ongoing resuscitation.

Regulatory status: International authorities have restricted the use of HES, with warnings on labeling and temporary or permanent withdrawal of certain formulations in several regions. In practice, many clinicians reserve HES for specific, carefully monitored situations and prefer crystalloids or albumin when volume expansion is required.