Systemic effects of a prolonged continuous infusion of ketamine in healthy horses.

The research paper investigates the systemic effects of administering ketamine over a prolonged period of time in healthy horses.

Objective and Methodology of the Research

• The overall aim was to determine the impact of prolonged continuous rate infusion (CRI) of ketamine on parameters such as gastrointestinal transit time, fecal weight, vital health parameters, gastrointestinal borborygmi (a rumbling noise made by movement of fluid and gas in the intestines), and behavior scores in adult horses.
• The experiment involved seven adult Thoroughbred or Thoroughbred cross horses, all of which had permanently implanted gastric cannulae (leveraged for administering medicine directly into the stomach).
• The research design was a non-blinded trial with random assignment to one of two crossover designed treatments. Horses were subjected to ketamine treatment or were given a lactated Ringer’s solution as a placebo.
• Pre-treatment, all horses received two hundred 3 x 5 mm plastic beads via nasogastric tube. These beads were used to monitor gastrointestinal transit time.
• Various parameters were recorded at different intervals over a period ranging from a minimum of 34 hours to a maximum of 96 hours. The parameters recorded every two hours include vital parameters, behavior scores, fecal weights, and bead retrieval, while the borborygmi scores were documented every six hours.

Results and Conclusions

• No significant differences were found between the ketamine and placebo treatments in regards to vital signs or gastrointestinal borborygmi.
• However, a significant increase was observed in behavior score during the ketamine infusion, indicating changes in the horse’s behavior in response to the ketamine infusion.
• Ketamine also caused a significant delay in the passage of the ingestible beads (25, 50, and 75% respectively). This is indicated by longer hours needed for the passage of the same percentages of beads in ketamine-treated horses compared to those in placebo-treated ones.
• A significant decrease was observed in the fecal weight during the ketamine infusion, reflecting potential changes in digestion or gastrointestinal function.
• In conclusion, continuous ketamine infusion appeared to delay gastrointestinal transit time in healthy horses, without impacting other vital parameters. This finding is useful for managing pain in hospitalized horses, and further studies could extend understanding of ketamine’s impact on equine health.