Evaluation of Total Intravenous Anesthesia by Ketamine-Xylazine Constant Rate Infusion in Dogs: A Novel Preliminary Dose Study

Abstract

Background and Aims: The use of ketamine-xylazine for total intravenous anesthesia (TIVA)
by constant rate infusion (CRI) has not been well-documented in literature. The present study
aimed to define the optimal dosage of ketamine-xylazine for TIVA in dogs and its effects on
physiological body parameters.
Materials and Methods: Twenty mongrel dogs were randomly assigned to four treatment protocols (n=5): A (0.5 mg kg-1, ketamine+ 0.25 mg kg-1, xylazine and 0.6 mg kg-1 h-1, ketamine+0.3
mg kg-1 h-1, xylazine ), B (5 mg kg-1, ketamine+0.5 mg kg-1, xylazine and 10 mg kg-1 h-1, ketamine+1 mg kg-1 h-1, xylazine), C (2 mg kg-1, ketamine+0.5 mg kg-1 xylazine and 5 mg kg-1 h-1,
ketamine+0.5 mg kg-1 h-1 xylazine), and D (2 mg kg-1 ketamine+1 mg kg-1 xylazine and 10 mg
kg-1 h-1, ketamine+1 mg kg-1 h-1 xylazine) for induction and maintenance of anesthesia, respectively.
Results: The anesthesia was deep in protocols B, C, and D (pedal reflex of grade=0), but
light in the protocol A (pedal reflex of grade=3). Animals in both protocols B and C showed
paddling and tonic clonic convulsions. All the protocols recorded a non-significant increase
in the body temperature but; a significant decrease in the respiratory rate. There was a nonsignificant decrease in the heart rate in protocols A and C; while a non-significant increase was
recorded in protocols B and D.
Conclusion: The protocol D could be considered as the optimal dosage of ketamine-xylazine
for TIVA by CRI in dogs, with minimal effects on vital body parameters, for extended surgical
interventions.