In search of balanced anesthesia: analyzing the effects of various injectible drug combinations in selected domestic animals

The lecture explored the use of balanced anesthesia in veterinary practice. The basic principles of anesthesis and background on studies on the use of tietamine-zolazepam for balanced anesthesia in both domestic and wild animals is first discussed. The results of several studies local done on anesthetic combinations in three domestic animal species focusing on the duration of various phases of anesthesia, the cardiorespiratory effects of these anesthetic combinations, and their effects on the electrocardiogram where then analyzed in detail. The base anesthethic used was tiletamine-zolazepam since this has susperseded ketamine as the anesthetic of choice in domstic animals is with the classification of ketamine as a schedule 2 regulated drug . Studies in cats have shown that the addition of xylazine significantly prolongs the effect of tiletamine-zolazepam but the addition of ketamine to tiletamine and xylazine also resulted in significant depression of the heart rate, respiratory rate and temperature. Higher doses of tiletamine-zolazepam when combined with zylazine also resulted to a greater degree of depression of the heart rate, respiratory rate and temperature. Higher doses of tiletamine-zolazepam when combined with zylazine also resulted to a greater degree of depression of vital signs. However, the use of propofol maybe a better anesthetic combination although respiratory rates and temperature also dipped with this combination. The Sp02 levels tended to remain abov 90 on average in all the combinations used suggesting adequate tissue oxygenation. In dogs, tiletamine-zolazepam alone tends to result to a 'stormy' recovery since tiletamine is metabilized more slowly than zolaszepam. Thus, it is important to produce a balanced anesthesia that would result to smoother recoveries. Romifidine has been shown to prolong the duration of tiletamine-zolazepam anesthesia although it is also resulted in depression of vital signs except when only half the recommended dose of tiletamine-zolazepam is used. ECG abnormalities when only half the recommended dose of tiletamine-zolazepam is used. ECG abnormalities were also observed. In goat, tiletamine-zolaspam alone did not result to the production of anelgesia. Combining tiletamine-zolazepam with xykazine has been shown to result in decreased cortisol levels 30 minutes after administration which is interpreted to mean that there is an adequate pain relief. However, the decrease is cortisol level is significantly lower when ketamine-xylazine combination is used leading one to concluded that this combination produces better antinociception. Although xylazine does prolong the duration of action tiletamine-zolazepam and ketamine, this also results to prolonged recovery times. Cardiorespiratory depression is also present and there is a tendency towards the production of arrhythmias.