Coagulation, oncotic and haemodilutional effects of a third-generation hydroxyethyl starch (130/0.4) solution in horses.

The research provides insight into the use and effects of a specific type of hydroxyethyl starch, tetrastarch (130/0.4), on the clotting, oncotic and haemodilutional functions in horses. Different dosages were tested, revealing potential changes in coagulation and improvement in colloid osmotic pressure despite being within normal reference ranges.

Objective and Methodology

In this experiment, the use and effects of a special type of synthetic colloid, hydroxyethyl starch or HES (namely tetrastarch (130/ 0.4)), were examined in horses. The compound has the potential for rapid plasma volume expansion and in providing oncotic support. The focus of the study was to understand more about its effects on coagulation, the process of clot formation and dissolution in blood.

• The researchers used a randomised crossover experiment set-up involving six healthy pony mares.
• Three treatment groups were established with the ponies receiving tetrastarch at three different doses: 10, 20, and 40 ml/kg body weight (bwt).
• There was a two-week washout period followed by extensive monitoring which included measurements at baseline, immediately after infusion and several time intervals up to 96 hours post-infusion. This allowed for the assessment of packed cell volume, plasma total solids, colloid osmotic pressure (COP), platelet count and thromboelastography (TEG).

Findings

• All TEG variables remained within the normal reference ranges across the three treatment groups. This indicates that the compound’s use did not have harmful effects on the coagulation process or clot formation and dissolution.
• However, there were noteworthy changes when tetrastarch was administered at the highest dose (40 ml/kg bwt). Here, it resulted in a prolonged K-time at 6 hours post infusion and a decreased maximum amplitude at several points of measurement post-infusion. Although still within the acceptable range, these changes suggest an impact on the coagulation process in horses.
• Furthermore, the administration of tetrastarch increased mean COP values above baseline across all treatment groups. An increase in COP values implies an improvement in the movement of fluid between blood vessels and tissues, which aids volume expansion and oncotic support — a beneficial effect.

Conclusion

The study provides evidence that tetrastarch (130/0.4) shows potential for use in veterinary medicine as a synthetic colloid for resuscitation and oncotic support within particular dosages. While slight changes in coagulation were noted for the highest dose, they were still within acceptable reference ranges. The research provides valuable insight and adds to existing literature about the use and safety of HES for treatment purposes in horses.