Cardiorespiratory effects of a tiletamine/zolazepam-ketamine-detomidine combination in horses.

The research article explores the effects on heart and lung function in horses when given a specific combination of anesthetic drugs, namely tiletamine/zolazepam, ketamine, and detomidine (TZKD). The aim of the study was to evaluate the safety and effectiveness of this combination in causing short-term anesthesia in horses.

Methods

• The study was conducted on 8 healthy adult horses, all of which were prepared for the monitoring of heart and lung function, as well as acid-base balance and electrolyte levels.
• Each horse was administered xylazine, a sedative, about 10 to 15 minutes before being given the TZKD combination to induce a state of lying down voluntarily and temporarily losing the ability to move (recumbency).
• The heart and lung parameters, acid-base balance, and electrolyte levels were measured at 5-minute intervals for about 30 minutes or more following anesthesia administration.

Results

• All horses reacted to the TZKD combination almost immediately (within 1 minute), showing a mean recumbency duration of 40 minutes. All horses managed to regain their standing position after one or two attempts.
• The level of anesthesia and pain reduction was deemed satisfactory in all horses.
• It was noted that administering xylazine led to reductions in respiratory rate, heart rate, cardiac output, the rate of increase of right ventricular pressure, and rate pressure product. However, carbon dioxide partial pressure (PaCO2), right atrial pressure, and peripheral vascular resistance saw an increase. Essentials such as blood temperature, oxygen pressure (PO2), blood pH (pHa), bicarbonate (HCO3-), packed cell volume (PCV), total solids, sodium (Na), and potassium (K) values remained unchanged.
• Following the administration of the TZKD combination, right atrial pressure and PaCO2 increased, whereas PaO2 decreased when compared to the values after giving xylazine. But, the remaining parameters didn’t significantly deviate from the values obtained after xylazine administration.

Conclusions

• The research concluded that intravenous (IV) administration of the TZKD combination induces short-term anesthesia in horses.
• The advantage of this combination is the small quantity required for administration. It also minimally depresses cardiorespiratory function. Plus, the quality of induction and maintenance of anesthesia, as well as recovery from anesthesia, is high with this combination. The duration of the drug effect is also satisfying.