Hydroxyethyl starch

A synthetic colloid used as a plasma volume expander

Hydroxyethyl starch (HES) is a synthetic, non-ionic starch derivative used as a plasma volume expander. It is commonly used in intravenous therapy to treat or prevent hypovolemia when crystalloids alone are not sufficient.

Structure and Composition

Hydroxyethylstärke

Hydroxyethyl starch is derived from amylopectin, a component of starch, which is modified by the addition of hydroxyethyl groups. This modification increases the solubility and stability of the starch in solution. The degree of substitution and the pattern of hydroxyethylation affect the pharmacokinetics and pharmacodynamics of the compound.

Mechanism of Action

HES works by increasing the osmotic pressure in the blood vessels, which helps to draw fluid into the intravascular space, thereby expanding the plasma volume. This is particularly useful in situations where rapid volume expansion is necessary, such as in shock or sepsis.

Clinical Uses

Hydroxyethyl starch is used in various clinical settings, including:

• Surgery: To maintain adequate blood volume during and after surgery.
• Trauma: As part of the resuscitation fluids in trauma patients.
• Sepsis: To manage severe sepsis and septic shock.

Adverse Effects

Hydroxyethylstarch ball-and-stick

The use of HES has been associated with several adverse effects, including:

• Coagulopathy: HES can interfere with blood clotting mechanisms, increasing the risk of bleeding.
• Renal impairment: There is evidence that HES can cause or worsen kidney injury, particularly in critically ill patients.
• Anaphylactoid reactions: Although rare, some patients may experience allergic reactions to HES.

Regulatory Status

Due to concerns about safety, particularly regarding kidney function and bleeding risks, the use of HES has been restricted or banned in some countries. Regulatory agencies have issued warnings and guidelines to limit its use to specific patient populations.

Alternatives

Alternatives to HES include other colloids such as gelatin and albumin, as well as crystalloids like saline and Ringer's lactate. The choice of fluid depends on the clinical scenario and patient-specific factors.

Related Pages

• Intravenous therapy
• Colloid
• Crystalloid
• Hypovolemia
• Sepsis

File:Hydroxyethyl starch (HES-HAES).jpg

Hydroxyethyl starch (HES-HAES)