Instrumentation of exercising thoroughbreds to determine blood gas tensions and acid-base status.

The study presents a method to regularly collect arterial blood samples from horses during exercise to observe changes in blood gas levels and acid-base balance. The researchers used a specially designed device and procedural method, and highlighted signs of low oxygen levels and excessive acid in the blood of the tested horses.

Introduction and Methodology

• This research is focused on monitoring the blood gas tensions (oxygen and carbon dioxide pressures) and acid-base status (pH balance) in exercising horses.
• To do this, the researchers built a custom device, using easily obtained medical supplies and hardware. The purpose of this device was to allow multiple arterial blood samples to be drawn manually on demand.
• In the experiment, the right carotid arteries (major blood vessels in the neck) of five horses were surgically elevated. This surgical procedure allowed for the direct cannulation, or insertion of a tube, into the artery for blood sampling.

Experiment and Findings

• The experiment involved galloping each horse on a 1.6-kilometer test track at a speed of approximately 500 meters per minute.
• The rider of each horse would activate the sampling device at every 0.4-kilometer mark on the track to collect arterial blood samples.
• Each horse underwent 10 test gallops. For every test run and every sampling mark, a mean and standard error (statistics to understand data variability) were calculated.
• These calculations included those performed on both pre-exercise and post-exercise blood samples.

Conclusions

• The research findings reveal that horses exercised under the conditions described exhibit signs of acidemia and hypoxia — conditions characterized by an excess of acid in the blood and low levels of oxygen, respectively.
• This could have implications in understanding and improving horse health and performance, particularly in racing and work environments.