Avaliação da analgesia pós-operatória da dexmedetomidina isolada e associada à morfina quando utilizada na medicação pré-anestésica em cadelas submetidas à ovariosalpingohisterectomia eletiva / Evaluation of postoperative analgesia of dexmedetomidine alone or associated to morphine as premedicants in bitches undergoing ovariosalpingohisterectomy

ABSTRACT

Background: Elective ovariossalpingohysterectomy is a common surgery that causes mild to moderate pain. Aiming at the treatment of pain in these patients, analgesia should be balanced from pre-anesthetic, transoperative and postoperative medication, with-2-agonists and opioids being commonly used, especially dexmedetomidine that has sedation, relaxation muscle and analgesia.The aim of the present study was to evaluate the postoperative analgesic efficacy of dexmedetomidine alone and associated withmorphine when used in the preanesthetic medication of bitches submitted to elective ovarian oysterectomy using the modifiedGlasgow pain scale and the Melbourne pain scale.Materials, Methods & Results: Twenty bitches were used in this study, all of them submitted to ovarian oysterectomy, and were clinically healthy according to laboratory and clinical exams. During the experiment, bitches were randomly distributed into two groups,which received preanesthetic medication (MPA) with 5 μg/kg dexmedetomidine alone (GD) or associated with 0.3 mg/kg morphine(GDM) intramuscularly (IM). In both groups, anesthetic induction with dose-effect propofol was performed and maintained withisoflurane diluted in 100% oxygen administered through a calibrated vaporizer and appropriate anesthetic system based on the weightof the animal and maintained on spontaneous ventilation. After stabilization of the patient the surgery was started, which lasted 45min. The bitches were evaluated by the Modified Glasgow Scale (GSM), the Melbourne Scale (MS) and the Dobbins Sedation Scale(DS), previously administered MPA (T0) and the others performed in 1h (T1), 2h (T2), 4h (T3), 8h (T4), 12h (T5) and 24h (T6) afterextubation. If the GSM score was greater than the value of 3.3 an analgesic rescue of 0.5 mg/kg of morphine intramuscularly would beadministered. An increase in the scoring of pain scales in both groups can be observed from the T1, with significant difference only ofthe...