Hydroxyethyl Starch
Hydroxyethyl starch is a synthetic colloid prepared from chemically modified branched glucose polymers. Veterinary formulations differ in molecular size, degree of hydroxyethyl substitution and concentration. Its principal clinical application is short-term intravascular volume expansion in selected hypovolemic patients. Veterinary evidence has not established a consistent outcome advantage over other resuscitation fluids.
Group
Synthetic colloid volume expander
Mechanism of Action
Hydroxyethyl starch molecules increase plasma colloid osmotic pressure while they remain within the vascular compartment. This favors intravascular water retention and plasma-volume expansion, potentially supporting venous return and cardiac output. Polymer size and substitution influence enzymatic breakdown, renal elimination and persistence. The volume effect also depends on endothelial permeability and distribution of starch molecules outside the circulation.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Small-volume resuscitation | Reference only | IV | 5 mL/kg, followed by reassessment. | |
| Volume resuscitation | Reference only | IV | 5-15 mL/kg, reassessing response. | |
| Colloid infusion | Reference only | IV | 10-20 mL/kg/day (approximately 0.4-0.8 mL/kg/hour). Daily maximum stated as 33-50 mL/kg; cumulative maximum 70 mL/kg over 4 days. These exposure caps require an individualized fluid plan. | |
| Hetastarch shock resuscitation | Reference only | IV | 6% HES 450/0.7: 10-20 mL/kg, reassessing frequently. | |
| Hetastarch oncotic support | Reference only | IV | 1-2 mL/kg/hour as needed, with total no greater than 20 mL/kg/24 hours; a continuous rate cannot run unrestricted for a full day. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Volume resuscitation | Reference only | IV | 2-5 mL/kg, reassessing response. | |
| Colloid infusion | Reference only | IV | 5-10 mL/kg/day (approximately 0.2-0.4 mL/kg/hour). | |
| Hetastarch shock resuscitation | Reference only | IV | 6% HES 450/0.7: 5-10 mL/kg; deliver slowly and reassess. | |
| Hetastarch oncotic support | Reference only | IV | 1-2 mL/kg/hour as needed, with total no greater than 10 mL/kg/24 hours. |
Horses
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Volume resuscitation | Reference only | IV | Bolus 8-10 mL/kg. | |
| Colloid infusion | Reference only | IV | 0.5-1 mL/kg/hour. | |
| Hetastarch volume or oncotic support | Reference only | IV | Adults: 8-10 mL/kg/day or a 3-10 mL/kg volume-replacement dose; do not exceed 10 mL/kg/day. Hypooncotic hydrated horses: 0.5-1 mL/kg/hour, subject to the same daily limit. Foals needing rapid support: 3-5 mL/kg with crystalloids. |
Birds
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Hetastarch resuscitation | Reference only | IV, IO | 3-5 mL/kg over 10 minutes for one or two boluses. Reassess circulation between doses. |
Indications
- Selected short-term intravascular volume expansion in veterinary patients with acute hypovolemia or hypovolemic shock; evidence of improved clinical outcomes is uncertain.
Contraindications
- Known kidney disease
- Coagulopathy or active haemorrhage
Interactions
- Compatibility depends on the particular fluid formulation.
Adverse effects
- Coagulation and platelet dysfunction
- Kidney injury and volume overload
Toxicity
Discontinue if bleeding or renal injury develops; provide supportive treatment and reassess fluid strategy.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| VetStarch 6% tetrastarch 130 kDa tetrastarch; preserve molecular identity. Fluid-volume regimens are readable only. | Injection | 6 g / 100 mL | IV |
| Hespan 6% hetastarch HES 450/0.7 In 0.9% sodium chloride; formulation differs from tetrastarch. | Injection | 6 g / 100 mL | IV |
| Voluven 6% tetrastarch HES 130/0.4 In 0.9% sodium chloride; fluid-volume protocol only. | Injection | 6 g / 100 mL | IV |
Monitoring and Administration
Prefer the lowest effective exposure and reassess after each small bolus. The supplied material favours 6% low-molecular-weight tetrastarch over more persistent high-molecular-weight products.
Monitor blood pressure, volume status, renal parameters and haemostasis. Amylase can rise for 2-3 days.
Starch types and concentrations are not interchangeable. Keep the original sterile package intact.
Alternative avian protocols describe 10-15 mL/kg over 20-40 minutes, followed by 1-2 mL/kg/hour or repeated doses; these can conflict with the stated 20 mL/kg/day maximum. Do not combine them into an uncapped plan. Small-volume protocols pair hypertonic saline 3-5 mL/kg with hetastarch 3-5 mL/kg, followed by reassessed crystalloid/colloid increments.
A healthy-llama study used 15 mL/kg and increased colloid osmotic pressure for up to 96 hours, with haemodilution and modest coagulation-test changes; no administration route is specified for a general llama regimen. HES carries no oxygen and cannot replace red cells. Do not use turbid, brown or precipitated solutions; avoid freezing. Hextend must not share an administration set with blood.