The effects of hypohydration on central venous pressure and splenic volume in adult horses.

In plain language, this research studies the relationship between hydration levels in adult horses and central venous pressure (CVP), a measure of blood volume. The research concludes that as horses become dehydrated, their CVP reduces in proportion.

Experimental Approach

• This study conducted experiments on 10 healthy adult horses that were part of the university’s teaching herd.
• The horses underwent the installation of a central venous catheter so that readings of Central Venous Pressure (CVP) could be taken using water manometry, a method for measuring pressure.
• To induce hypohydration (dehydration), the horses were denied water and administered a drug called Furosemide periodically over a span of 36 hours. Furosemide is a diuretic, which increases urine production, causing the horse to lose more water and become dehydrated.

Monitoring Method

• The horses’ weight, CVP, vital signs, packed cell volume (PCV, a measure of the concentration of red blood cells in the blood), total protein (TP), and serum lactate levels were monitored at the start of the experiment and then every six hours.
• The target for induced dehydration was a 5% decrease in body weight.
• The volume of the spleen, an organ that can hold a reservoir of blood, was estimated using ultrasound imaging at the start and end of the volume depletion period.
• A statistical technique called linear regression analysis was used to assess the relationship between CVP and other clinical parameters and the degree of body weight loss over time.

Findings

• The research found significant correlations between decline in body weight and measures of CVP, suggesting as the horses lost water weight, the blood volume in the body also decreased.
• Furthermore, they found associations between volume depletion (dehydration) with increased total protein levels, increased serum lactate levels, and decreased spleen volume, suggesting that hydration is an important factor in maintaining normal physiology and organ function in the horse.
• However, CVP changes did not have a significant relationship with vital signs or packed cell volume (PCV), indicating that these factors are not as sensitive to hydration changes as is CVP.

Conclusion

• The researchers concluded that monitoring CVP could be useful in the clinical evaluation of a horse’s hydration status. This finding will contribute to the overall understanding of how hydration status in horses affects their central venous pressure and could potentially influence veterinary medical practices.