Selection of the Optimal Dose of Dexmedetomidine and its Cardiovascular Effects when used as Part of Combined Anesthesia for Surgical Correction of Kyphosis in Dogs

The development, clinical and instrumental characterization, and evaluation of the effectiveness of various schemes of combined general anesthesia in dogs are important problems in veterinary surgery. The effects of varying doses of dexmedetomidine in combination with tiletamine–zolazepam and isoflurane have not been studied in the surgical treatment of dogs with kyphosis. We aimed to evaluate the changes in the functional characteristics of the cardiovascular system and the clinical effectiveness of intramuscular administration of dexmedetomidine (Dex) at doses of 5, 7.5, and 10μg/kg followed by intravenous administration of tiletamine–zolazepam and isoflurane inhalation for anesthesia in dogs with kyphosis. The study involved 60 dogs with kyphosis, with an anesthetic risk group of categories I or II according to the ASA (American Society of Anesthesiologists) classification and without anomalies of the cardiovascular system. All dogs were randomly divided into equal 3 groups: Dex 5, Dex 7.5, and Dex 10. Intravenous administration of tiletamine–zolazepam (induction) in dogs with kyphosis and inhalation of isoflurane (maintenance of anesthesia) did not cause changes in the heart rate, or systolic, diastolic or mean arterial blood pressure compared with baseline values. Combined dexmedetomidine–tiletamine–zolazepam–isoflurane anesthesia is highly effective and safe in the surgical correction of kyphosis in sick dogs. Dexmedetomidine intramuscularly administered at a dose of 5.0- 7.5μg/kg is the optimal premedication for examining or performing the surgical correction of spinal pathologies in dogs.