Pulmonary vascular pressures of strenuously exercising thoroughbreds after administration of flunixin meglumine and furosemide.

This research study explores the impact of administering two different drugs, flunixin meglumine and furosemide, on the pulmonary pressures of thoroughbred horses during strenuous exercise. The study concludes that furosemide helps to reduce the increase in pulmonary capillary blood pressure during intense exercise, but this outcome appears not to be reliant on prostaglandin production.

Research Study Objectives and Methods

The study aimed to determine whether the reduction of the increase in pulmonary capillary blood pressure during high-intensity exercise, caused by the administration of furosemide, is mediated through the release of prostaglandins.

• Eight healthy, thoroughbred horses which were exercise-trained were selected for the study.
• The horses were studied on three different occasions applying the following treatments:
• Injection of saline solution
• Injection of furosemide alone (250 mg, intravenous, 4 hours before exercise)
• Injection of flunixin meglumine (1.1 mg/kg, intravenous, every 8 hours for 3 days) along with furosemide (250 mg, intravenous, 4 hours before exercise)
• The horses were subjected to resting and high-intensity exercising environments, specifically incremental-step exercise on a treadmill. The high-intensity workload involved running at 14.5m/s on a 5% uphill incline.
• Measurements of right atrial and pulmonary vascular pressures were collected both at rest and during exercise.

Findings

Findings of the study revolved around the changes in mean pulmonary capillary blood pressure:

• At rest and during the high workload stage, the mean pulmonary capillary blood pressure following the administration of furosemide alone was not significantly different from that after the administration of both flunixin meglumine and furosemide.
• However, these values were significantly lower than the mean pulmonary capillary blood pressures reported after the administration of the saline solution.

Conclusions

The research concluded that although furosemide does help mitigate the increase in pulmonary capillary blood pressure during strenuous exercise, the mechanisms do not appear to be facilitated by prostaglandin production. The study helps to enhance understanding and the development of more efficient drug application techniques to manage the physiological responses of horses during strenuous exercise.