Effect of infusion of equine plasma or 6% hydroxyethyl starch (600/0.75) solution on plasma colloid osmotic pressure in healthy horses.

The research article investigates the impacts of two different intravenous treatments – equine plasma and 6% hydroxyethyl starch solution, on the osmotic pressure of plasma and other health indicators in horses. The study finds that both solutions similarly increase plasma osmotic pressure for up to 48 hours, though the starch solution has more pronounced and long-lasting effects on other clinical variables.

Objective and Methodology

• The aim of the research was to contrast the effects of similar volumes of equine plasma and a 6% hydroxyethyl starch solution (otherwise known as hetastarch) when intravenously administered to horses, on multiple clinicopathologic variables and, particularly, on Plasma Colloid Osmotic Pressure (pCOP).
• The study group consisted of six healthy mare horses. The approach taken was a randomized crossover study, where each horse was treated with either the hetastarch or the plasma, then given the alternate treatment after 18 months. All infusions had a volume of 10 mL per kg of the horse’s weight.

Procedure

• Important clinicopathologic variables and pCOP were measured before the administration of the solutions (baseline), right after administration, and then at intervals up to 96 or 120 hours post-infusion.
• Times for blood coagulation parameters – prothrombin and activated partial thromboplastin, were also measured before and at 2 and 8 hours after each treatment.

Results

• The mean starting pCOP for both the hetastarch and plasma treatments was around 19.4 mm Hg.
• Both treatments ended up similarly increasing pCOP from the baseline for around 48 hours, with the most significant increases hovering around 2.2 mm Hg.
• However, hetastarch infusions caused decreases in Hematocrit (Hct) and hemoglobin, total protein, and albumin concentrations, which lasted for periods from 72 to 120 hours after the infusion. The most significant decreases registered went up to 8.8% for Hct, 3.2g/dL for hemoglobin, 1.2g/dL for total protein, and 0.6g/dL for albumin.
• Infusions of equine plasma also caused decreases in hemoglobin concentration and Hct for around 20 and 24 hours, but with maximum changes of only 1.5g/dL and 6.6% correspondingly. They also increased total solids concentration for around 48 hours with a maximum change of 0.6g/dL.
• Both treatments had minor effects on platelet counts and coagulation times.

Conclusions and Clinical Relevance

• Ultimately, both hetastarch and plasma infusions comparably increased pCOP in healthy horses for around 48 hours.
• However, hetastarch induced greater and more persistent changes in other clinicopathologic variables.
• The results suggest that both types of infusions can be effective for managing osmotic pressure, but careful consideration needs to be given to the broader impacts of hetastarch on clinical pathologies.