Effect of hydroxyethyl starch infusion on colloid oncotic pressure in hypoproteinemic horses.

This research evaluates the use of hydroxyethyl starch (HES) in horses with low protein blood levels, assessing its impact on colloid oncotic pressure, an essential factor in fluid balance. The study establishes a significant oncotic effect persisting for 24 hours post HES infusion, though the predictive model used did not account for HES’s oncotic impact.

Objective of the Research

• The main goal of this study was to determine the influence of hydroxyethyl starch (HES) on the colloid oncotic pressure (pi) during the fluid resuscitation of hypoproteinemic horses. Hypoproteinemia refers to an unusually low level of protein in the blood.
• The study also sought to assess the practicality of direct and indirect methods for determining pi, before and after HES infusion.

Research Methods

• The prospective clinical study involved 11 horses suffering from hypoproteinemia.
• The horses were administered IV infusions of a 6% HES solution at 8 to 10 milliliters per kilogram of the horse’s body weight during fluid resuscitation.
• Blood samples were collected to establish plasma measured colloid oncotic pressure, total plasma protein, and albumin concentrations. Plasma globulin concentration was calculated as the difference between total plasma protein and albumin concentrations.
• Using a previously developed nomogram for horses, colloid oncotic pressure derived from albumin and globulin (piA + G) was calculated.

Results of the Study

• The results showed concurrence between pi measured directly from plasma (pi meas) and the value calculated using albumin and globulin (piA + G) prior to HES ingestion. However, such concurrence was absent following HES intake.
• After HES infusion, the mean pi meas was raised significantly and stayed elevated above the baseline for 6 hours.
• Conversely, mean values for total plasma protein and albumin concentrations, along with piA + G, declined notably from baseline and remained low for 24 hours.
• Discrepancies between mean pi meas and piA + G post HES ingestion were noticeable for the same 24 hours.

Conclusions of the Research

• The research concluded that plasma pi meas and piA + G values align in blood samples taken from hypoproteinemic horses immediately before HES infusion.
• However, the predictive nomogram did not accommodate the oncotic influence of HES.
• When comparing pi meas to piA + G post HES infusion, a significant oncotic effect appeared to last for 24 hours in the study horses. These results could have practical implications for the emergency treatment of hypoproteinemia in horses.

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