Acute hemodynamic effects of furosemide administered intravenously in the horse.

This research studied the effects of intravenously giving the drug furosemide to horses. It found that this procedure led to immediate significant changes in various heart and circulation measures, increased urine production, and increased levels of total serum protein and packed cell volume, although these last measurements and a few others did not return to normal levels within the observation period. The effect of this drug appears to be temporary and related to the reduced plasma volume cause by increased urination.

Objective of the Research

• The objective of this research was to study the acute hemodynamic effects of intravenously administered furosemide on horses. Furosemide is a commonly used diuretic that helps eliminate excess fluid from the body. The researchers were interested in understanding how the administration of this drug affects different cardiovascular parameters and urinary production in horses.

Key Findings of the Research

• The researchers discovered that the intravenous administration of furosemide led to a significant decrease in several cardiovascular indices including right atrial pressure, pulmonary arterial pressure, pulmonary arterial wedge pressure, cardiac output, and stroke volume.
• Concurrently, there was a noticeable increase in the total systemic vascular resistance and heart rate.
• Meanwhile, the administration did not cause any significant alterations in the mean arterial pressure.
• Along with these hemodynamic changes, an increase in urine production was observed. This was accompanied by an increase in packed cell volume (the volume fraction of red cells in blood) and total serum protein levels.

Conclusion of the Study

• The effects observed after the administration of furosemide were mostly transitory, as most variables returned to their baseline levels within 105 minutes post-injection. Nevertheless, a few variables such as cardiac output, stroke volume, packed cell volume, and total solids did not return to their normal levels within the said timeframe.
• The researchers concluded that the effects of intravenously administered furosemide in horses are temporary and likely dependent on the decrease in plasma volume caused by diuresis (increased urination). Therefore, furosemide’s action mechanism in horses is mainly through inducing a diuretic effect that leads to lowered plasma volume.