Hydroxyethyl starch
Encyclopedia
Hydroxyethyl starch is a nonionic starch
derivative
. It is one of the most frequently used volume expander
under the trade names Hespan by B. Braun Medical Inc. and Voluven or Volulyte by Fresenius Kabi.
loss caused by trauma
, surgery
, or some other problem. It increases the blood volume
, allowing red blood cell
s to continue to deliver oxygen
to the body. During 2010/11 a large number of research papers associated with a single author were retracted for ethical reasons and this may have an impact on clinical guidelines referring to HES preparations prepared before this date.
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.
Decrease in hematocrit and disturbances in coagulation. One liter of 6% solution (Hespan) reduces factor VIII
level by 50% and will prolong aPTT.
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 criticized for its study design. The same effects have not been observed with HES 130kDa/0.4. It has been recommended that, since medium-MW HES solutions may be associated with harm, these solutions should not be used routinely for patients with septic shock.
Starch
Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store...
derivative
Modified starch
Modified starch, also called starch derivatives, are prepared by physically, enzymatically, or chemically treating native starch, thereby changing the properties of the starch. Modified starches are used in practically all starch applications, such as in food products as a thickening agent,...
. It is one of the most frequently used volume expander
Volume expander
A volume expander is a type of intravenous therapy that has the function of providing volume for the circulatory system. It may be used for fluid replacement.-Physiology:...
under the trade names Hespan by B. Braun Medical Inc. and Voluven or Volulyte by Fresenius Kabi.
Therapeutic use
An intravenous solution of hydroxyethyl starch is used to prevent shock following severe bloodBlood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
loss caused by trauma
Physical trauma
Trauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death...
, surgery
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
, or some other problem. It increases the blood volume
Blood volume
Blood volume is the volume of blood in the circulatory system of an individual.-Humans:A typical adult has a blood volume of approximately between 4.7 and 5 liters, with females generally having less blood volume than males....
, allowing red blood cell
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...
s to continue to deliver oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
to the body. During 2010/11 a large number of research papers associated with a single author were retracted for ethical reasons and this may have an impact on clinical guidelines referring to HES preparations prepared before this date.
Contraindications
- This product should not be used in people who are hypersensitive or allergicAllergyAn Allergy is a hypersensitivity disorder of the immune system. Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. A substance that causes a reaction is called an allergen. These reactions are acquired, predictable, and rapid...
to hydroxyethyl starch. - Patients with kidney failure not related to low blood volume and patients on dialysisDialysisIn medicine, dialysis is a process for removing waste and excess water from the blood, and is primarily used to provide an artificial replacement for lost kidney function in people with renal failure...
should avoid this product in high doses which are used for volume expansion. - Use of hydroxyethyl starch with normal saline in its preparation is contraindicated in people with severe increases in blood levels of sodiumSodiumSodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
or chlorideChlorideThe chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...
. - Patients with intracranial bleeds should not use this product.
Pharmacokinetics
Different types of hydroxyethyl starches are typically described by their average molecular weight, typically around 130 to 200 kDa (bearing in mind that there will be a range of different-sized molecules in any given solution); and their degree of molar substitution (what proportion of the glucose units on the starch molecule have been replaced by hydroxyethyl units), typically around 0.35 to 0.5. A solution of hydroxyethyl starch may further be described by its concentration in % (i.e. grams per 100ml). So for example, one commercially available hydroxyethyl starch (Voluven) is described as 6% HES 130 / 0.4.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
Amylase
Amylase is an enzyme that catalyses the breakdown of starch into sugars. Amylase is present in human saliva, where it begins the chemical process of digestion. Food that contains much starch but little sugar, such as rice and potato, taste slightly sweet as they are chewed because amylase turns...
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. One liter of 6% solution (Hespan) reduces factor VIII
Factor VIII
Factor VIII is an essential blood clotting factor also known as anti-hemophilic factor . In humans, Factor VIII is encoded by the F8 gene...
level by 50% and will prolong aPTT.
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
Pentastarch
Pentastarch is a subgroup of hydroxyethyl starch, with five hydroxyethyl groups.It is sold under the name Pentaspan and used for fluid resuscitation. It is considered a plasma expander because it remains primarily intravascular after infusion....
). It also used a regimen without any crystalloids and was criticized for its study design. The same effects have not been observed with HES 130kDa/0.4. It has been recommended that, since medium-MW HES solutions may be associated with harm, these solutions should not be used routinely for patients with septic shock.