Hydroxyethyl starch

Hydroxyethyl starch (HES/HAES) is a nonionic starch derivative. It is one of the most frequently used blood plasma substitutes under the trade names Hespan by B. Braun Medical Inc. and Voluven by Fresenius Kabi. It is also used in oil drilling.

Therapeutic use

An intravenous solution of hydroxyethyl starch is used to prevent shock following severe blood loss caused by trauma, surgery, or some other problem. It increases the blood volume, allowing red blood cells to continue to deliver oxygen to the body.

Contraindications

• This product should not be used in people who are hypersensitive or allergic to hydroxyethyl starch.
• Patients with kidney failure not related to low blood volume and patients on dialysis should avoid this product in high doses which are used for volume expansion.
• Use of hydroxyetyl starch with normal saline in its preparation is contraindicated in people with severe increases in blood levels of sodium or chloride.
• Patients with bleeding inside the head should not use this product.

Pharmacokinetics

The elimination depends on molar substitution degree. Molecules smaller than the renal threshold (60–70 kDa) are readily excreted in the urine while the larger ones are metabolized by plasma α–amylase before the degradation products are renally excreted.

Adverse effects

Anaphylactoid reactions: hypersensitivity, mild influenza-like symptoms, bradycardia, tachycardia, bronchospasm and non-cardiogenic pulmonary edema.

Decrease in hematocrit and disturbances in coagulation. May be associated with covering the use of anabolic steroids/EPO for endurance athletes.

HES derivatives with a higher molecular weight (200 kDa) have been demonstrated to have increased rates of acute renal failure and need for renal replacement therapy and to decrease long-term survival when used alone in cases of severe sepsis compared with Ringer Lactate solution (Brunkhorst 2008). This study specifically used 10% HES with 0.45-0.55 substitution grade and molecular weight of 200 kDa (Hemohes). It also used a regimen without any crystalloids and was critized for its study design. The same effects have not been observed with HES 130kDa/0.4.