Avaliação dos efeitos cardiorrespiratórios da dexmedetomidina isolada e associada à morfina em cadelas submetidas à ovariossalpingohisterectomia eletiva sob anestesia geral inalatória / Evaluation of cardiorespiratory effects of dexmedetomidine isolated and associated with morphine in bitches submitted to elective ovariossalpingohisterectomy under general inhalation anesthesia

ABSTRACT

Background: Elective ovariossalpingohysterectomy is one of the most accomplished surgeries in veterinary practice, presenting moderate degree of pain. Aiming at balanced anesthesia, α2-agonists have been increasingly used, with dexmedetomidine being characterized by its sympatholytic, sedative, analgesic properties and synergism with opioids, benzodiazepines and other drugs. The objective of this study was to evaluate the effects of dexmedetomidine alone and associated with morphine under the cardiovascular, respiratory and body temperature variables in the pre and trans-operative periods in bitches submitted to elective ovariossalpingohisterectomy under general inhalation anesthesia.Materials, Methods & Results: Sixteen bitches were used in this study, which were submitted to elective ovariossalpingohisterectomy, all of which were clinically healthy based on clinical and hematological results. The animals were randomized into two groups, in which intramuscular dexmedetomidine alone and 5 µg/kg (DG) and 0.3 mg/kg morphine (GDM). In both groups, anesthesia was induced with propofol administered and maintained with isoflurane diluted in 100% oxygen administered through a calibrated vaporizer and appropriate anesthetic system based on the weight of the animal and kept under spontaneous ventilation. After stabilization of the patient, the surgical procedure started, which lasted 45 min. The parameters evaluated were heart rate (HR), respiratory rate (ƒ), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), body temperature (TºC), expired isoflurane concentration , partial carbon dioxide gas pressure (ETCO2 ) and oxygen saturation in hemoglobin (SatO2 ), which were measured before and after the application of preanesthetic medication and at specific surgical times[...]