This thesis evaluated the use of intravenous lidocaine to treat the bradycardia associated with the administration of the sedative dexmedetomidine in canine anesthetic protocols. Research Beagle dogs were assigned to three different groups in a randomized crossover design that involved the administration of intravenous dexmedetomidine in different modalities of the anesthetic protocol. In two groups, dexmedetomidine was administered to dogs while awake and in the third group while anesthetized with isoflurane.After receiving dexmedetomidine, dogs were given intravenous lidocaine as a bolus 30 minutes later, followed by a second bolus and a constant rate infusion 20 minutes after the first bolus, in one of the awake groups and the anesthetized group. The other awake group received the lidocaine bolus and constant rate infusion 5 minutes after the dexmedetomidine.Intravenous lidocaine increased heart rate in awake and anesthetized dogs pretreated with intravenous dexmedetomidine. Additional benefits from lidocaine administration included an increase in cardiac index and a decrease in systemic vascular resistance.iii
DEDICATIONIn Memoriam of my grandparents Ieda Hainzenreder and João de Mesquita.Foremost, I would like to thank my supervisor, Dr. Alexander Valverde, for opening the doors for me, for being resolute, tireless and for his guidance during my program. I would also like to thank all the anesthesia faculties I had the opportunity to work with and absorb some of their knowledge, but specially to Drs. Andrea Sanchez, Carolyn Kerr and Melissa Sinclair for the personal and professional support along these three years.