Hemodynamic and metabolic alterations associated with intravenous infusion of a combination of adenosine triphosphate and magnesium chloride in conscious horses.

The study examines the metabolic and hemodynamic changes occurring in horses following the intravenous (IV) infusion of a mixture of magnesium chloride and adenosine triphosphate, as well as determining a maximum safe infusion rate.

Study Design and Methods

• The study was conducted on six adult female horses.
• An IV infusion of ATP-MgCl2 was administered to all horses, beginning at a rate of 0.05 mg of ATP per kg of body weight per minute. This rate was increased in increments of 0.05 mg/kg/min at 10-minute intervals until reaching a rate of 1.0 mg/kg/min.
• Data was collected prior to the infusion, at the end of each infusion rate, and at 15-minute intervals for an hour after stopping the infusion.

Measurements Taken

• Hemodynamic variables such as heart rate, cardiac output, cardiac index, stroke volume, systemic and pulmonary arterial pressures, and systemic and pulmonary vascular resistances were either measured or calculated.
• Several other factors including arterial blood gas tensions, complete blood count (CBC), plasma biochemical profiles, and urine volume and specific gravity were also evaluated.
• Clinical signs of disease and certain behavior changes, like appetite and levels of activity, were also monitored.

Results

• The IV infusion of ATP-MgCl2 led to a significant increase in cardiac output and pulmonary hypertension, while systemic vascular resistance decreased.
• The extent of these changes depended on the rate of infusion.
• The maximum safe infusion rate was determined to be 0.3 mg/kg/min. Beyond this, all horses exhibited signs such as lethargy, reduced appetite, apparent abdominal discomfort and increased sweating.
• Changes in urine volume and specific gravity, as well as in hematologic, biochemical and arterial blood gas parameters, were observed during and after the infusion.

Conclusion

• The researchers concluded that intravenous administration of the ATP-MgCl2 combination induced various metabolic and hemodynamic changes in healthy adult horses. Even though these changes were observed, they did not seem to cause any significant detrimental effects to the horses’ health.