Cardiovascular and pulmonary effects of hetastarch plus hypertonic saline solutions during experimental endotoxemia in anesthetized horses.

This research investigates the effects of a type of therapy known as small-volume resuscitation, using a saline solution and a substance called Hetastarch, on horses induced with endotoxemia. The findings indicate that this method of treatment did not improve the negative responses observed when the condition was induced in the animals, therefore the beneficial value of this therapy in real-world conditions remains uncertain.

Objective and Methods of the Study

• The study aimed to understand the impact of small-volume resuscitation using a hypertonic saline solution (HSS) and Hetastarch (HES) on artificially induced endotoxemia in horses under anesthesia. Endotoxemia is a condition that results from the presence of endotoxins (toxins released by bacteria when they die) in the blood. It can lead to septic shock, a life-threatening complication.
• Eighteen healthy horses were divided into three groups for the study, and they were all anesthetized using halothane. The endotoxemia was induced by administering 50 microg/kg of Escherichia coli endotoxin intravenously.
• The horses were then treated with three different solutions – a balanced polyionic crystalloid solution (control), a large amount of the same balanced solution (ISO), or a combination of HSS and HES (HSS-HES). The objective was to assess the effects of these treatments on various indicators of cardiopulmonary function in the context of endotoxemia.

Results of the Study

• The result of the study showed that cardiac output (the amount of blood the heart pumps) increased significantly from the baseline in all groups after being given endotoxin. However, only in the ISO group did the mean central venous pressure increase significantly.
• Mean pulmonary artery pressure increased from the baseline in horses treated with isotonic fluids and the HSS-HES combination. However, the HSS-HES treatment did not affect the cardiac output, systemic vascular resistance (resistance that must be overcome to pump blood through the circulatory system), mean arterial pressure, blood lactate concentrations, or arterial oxygenation.
• This essentially indicated that the combination of HSS-HES did not noticeably improve the negative reactions associated with endotoxemia in horses.

Conclusions

• The study concluded that the use of HSS-HES as a method for small-volume resuscitation failed to alleviate the harmful hemodynamic responses related to endotoxemia in horses.
• Despite the tested approach being advocated as a beneficial therapy for endotoxemia in horses, this study found that its clinical value remains unconfirmed as it didn’t yield desired improvements for the specific conditions tested.