Evaluation of xylazine and ketamine for total intravenous anesthesia in horses.

The research paper describes the evaluation of the use of xylazine and ketamine for intravenous anesthesia in horses. The study examined different combinations of these drugs administered to horses, and observed the effects on their heart rate, blood pressure, and other cardiopulmonary measurements, as well as their response to pain and recovery times.

Objective of the Study

The main goal of this study was to assess the effectiveness and safety of using xylazine and ketamine, two common veterinary anesthetics, as intravenous anesthetics for horses. The risk factors, recovery time, and overall physical impact on the horses were evaluated.

Experimental Design

• The study was conducted using eight horses as experimental subjects.
• The anesthetic induction was administered in four separate instances using three different substances: xylazine, guaifenesin, and ketamine at predetermined doses.
• Thereafter, the horses underwent one of the six treatment regimes, with varying dosage infusion rates of xylazine and ketamine.
• The treatments differed by doses (35, 90, 120, and 150 microg/kg/min), substances used (either xylazine (X) or ketamine (K)) and oxygen levels.

Data Collection and Observations

• Cardiopulmonary measurements were used to monitor the physiological response of the horses during the anesthesia period.
• The horses’ responses to a harsh electrical stimulus were observed at three varying intervals after induction.
• The durations to achieve sternal recumbency (lying down on their sternum) and standing were recorded. The quality of sedation, induction, and recovery were also observed and evaluated subjectively by the research team.

Results

• The study found that heart rate and cardiac index were higher, and total peripheral resistance was lower in certain treatment groups (K150-(O2) and X35 + K120-air).
• Mean arterial pressure was found to be highest in the X35 + K120-air group and the lowest in the K150-(O2) group.
• The duration for recovery, marked by the time to reach sternal recumbency and standing, varied between different treatment groups. It was shortest for horses in the K150-(O2) group and longest for those in the X70 + K90-(O2) group.

Conclusion

The paper concludes that infusions of xylazine and ketamine may be utilized, along with oxygen support, for maintaining 60 minutes of anesthesia in healthy adult horses. This sheds light on effective medications and anesthesia processes for equine health and surgery.