Total intravenous anaesthesia in ponies using detomidine, ketamine and guaiphenesin: pharmacokinetics, cardiopulmonary and endocrine effects.

The study explores the effects of a combination of detomidine, ketamine, and guaiphenesin on anaesthesia in ponies, including its pharmacokinetics and physiological and endocrine effects. The findings suggest a mild cardiorespiratory depressive effect, altered sugar levels in blood, and changes in blood constituents, with no changes in certain plasma substances. Plasma substance concentration changes suggest a suppression in steroid production. Stable levels of ketamine and guaiphenesin were reached during infusion, with ketamine levels adequate for pain relief during surgeries. However, a stable detomidine concentration wasn’t achieved. On average, it took the ponies about 68 minutes to fully revive from the anaesthesia, with no adverse events noted during the post-anaesthetic recovery.

Set Up and Aim of the Study

• The research involved eight ponies where a concoction of detomidine, ketamine and guaiphenesin was administered intravenously to work as an anaesthetic during surgical proceedings.
• The main goal of this experiment was to investigate pharmacokinetics, cardiorespiratory effects, and endocrine influences of these anaesthetics.

Cardiorespiratory Effects

• The anaesthetic blend caused mild cardiorespiratory depression, translating into lower heart and respiratory rates than normal, which is often acceptable in anaesthetic protocols.
• Further, a reduction in haematocrit was observed, representing a decrease in the ratio of the volume of red cells to the total volume of blood.
• However, hyperglycaemia was noted, indicating an increase in the blood glucose levels during the period of anaesthesia.

Endocrine Effects

• Despite the perceived anticipation that the anaesthetic components could alter some plasma substances like opioids, pituitary peptides, and catecholamines, no significant changes were detected in these parameters.
• Nonetheless, the concentration of cortisol in the plasma decreased while plasma 11-deoxycortisol levels increased, illustrating a suppression of steroidogenesis, the process of creating steroids that are essential for various bodily functions.

Pharmacokinetics

• Steady-state concentrations of ketamine and guaiphenesin were achieved during the infusion period, which is important in maintaining a stable and reliable depth of anaesthesia.
• In contrast, attaining a steady-state concentration of detomidine wasn’t met, which could impact the effectiveness and safety of the anaesthesia.
• Notably, the ketamine levels achieved were ample to offer sufficient pain relief for surgical operations.

Recovery

• The ponies took an average of 68 minutes to recover to a standing position after the administration of the anaesthesia, and the recovery process was smooth, with no complications being noted during this period.