Dexmedetomidine alone or combined with morphine for epidural anesthesia in bitches undergoing elective ovariohysterectomy

• Grant number: 19/04534-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2019
• End date: July 31, 2020
• Field of knowledge: Agronomical Sciences - Veterinary Medicine
• Principal Investigator: Beatriz Perez Floriano
• Grantee: Andressa Rodrigues de Souza
• Host Institution: Centro Universitário Faculdades Integradas de Ourinhos. Fundação Educacional Miguel Mofarrej. Ourinhos , SP, Brazil

Abstract

Local anesthesia provides better intraoperative analgesia and lesser use of general anesthetics. Epidural anesthesia is indicated due to its low cost, easy execution and safety. To date, no studies addressing epidural dexmedetomidine without local anesthetics or combined with opioids were found. Therefore, the purpose of this study is to assess analgesia provided by the combination of epidural dexmedetomidine and morphine in bitches undergoing elective ovariohysterectomy. Twenty-four bitches will be used and allocated into three groups: GD, dexmedetomidine 2 µg/kg; GM, morphine 0.1 mg/kg; and GDM, dexmedetomidine and morphine at the same doses. All groups will be diluted in saline to the final volume of 0.36 mL/kg. Variables heart rate (HR), respiratory rate (FR) and systolic blood pressure (SAP) will be recorded prior to epidural anesthesia (MB), after the epidural injection (MAP), at surgical incision (MIC), at the first ovarian pedicle clamping (MP1), at the second pedicle clamping (MP2), at uterine stump clamping (MCU), at the beginning of abdominal cavity closure (MIS) and at the end of skin closure (MFS). At each time point, rescue analgesia comprised of fentanyl 2 mg/kg will be given IV if nociception corresponding to a 20% increase of the variables. At the end of the study, data will be analyzed using ANOVA for repeated measures followed by Tukey test or Friedman followed by Dunn test. The association between the number of rescue analgesia boluses and the anesthetic protocols will be assessed using chi-square test or Fisher's exact test. All analyses will be performed under 5% significance.