No abstract

Epidural anesthesia is a locoregional anesthetic technique that provides analgesia and muscle relaxation in the-retroumbilical region. The combination of opioids and local anesthetics increased the intensity and duration of analgesia by causing immediate motor and sensory nerve blockade, and improved recovery after surgery. The objective was to comparatively evaluate the trans- and postoperative cardiorespiratory and analgesic effects of epidurally administered tramadol, ropivacaine and tramadol-ropivacaine combination in dogs undergoing elective ovariohysterectomy. The effect of isoflurane concentration was also evaluated. This study was performed on 24 female mongrel dogs, pre-medicated with chlorpromazine (0.5 mg kg-1, IV) and, anesthetized with propofol and isoflurane. The dogs were randomly divided into three groups. The first group receveid epidural tramadol (2 mg kg-1, GT group), the second group received ropivacaine (1.5 mg kg-1, GR group), and the third group received a tramadol-ropivacaine combination at the above-mentioned doses (GTR group). At pre-defined time points, classified into pre-, trans-, and postoperative periods, cardiorespiratory variables and analgesia were analyzed for a period of up to 420 min following epidural anesthesia. The check analgesia was check of approximately 105, 217 and 382 minutes, in GR, in GT and GTR respectively, and no cardiovascular and respiratory depression. The drugs used in this study are considered safe and effective for ovariohysterectomy due to the cardiorespiratory stability and trans-operative analgesia provided by them. However, the combination of ropivacaine and tramadol ensured a greater reduction in the inhaled anesthetic dose and better analgesia during in the postoperative period.

RESUMO.-[Comparação da infusão continua intravenosa de tramadol e de tramadol-lidocaína-cetamina no requerimento de sevofluorano em cães.] O objetivodeste estudo foi comparar a influência da infusão contínua intravenosa do tramadol isolado e associado com lidocaína e cetamina, na concentração alveolar mínima de sevofluorano (CAMsevo) em cadelas submetidas à ovariosalpingohisterectomia. Foram utilizados 28 animais saudáveis de várias raças e idades, divididos aleatoriamente em dois grupos de acordo com a infusão adminstrada: TRA (tramadol) ou TLK (tramadol, lidocaína e cetamina). A medicação pré-anestésica foi realizada com acepromazina e midazolam, em seguida, a anestesia foi induzida com propofol e mantida com sevofluorano. Quinze minutos após a indução, os pacientes receberam um bolus do tratamento, com a infusão continua iniciada logo em seguida, sendo 1,3mg/kg/ hora de tramadol, associado ou não a 3mg/kg/hora de lidocaína e 0,6mg/kg/hora de cetamina, diluidos em uma bolsa The objective of this study was to compare the influence of continuous intravenous infusion of tramadol alone, or tramadol combined with lidocaine and ketamine, on minimum alveolar concentration of sevoflurane (MACsevo) of dogs undergoing an ovariohysterectomy (OHE). We used 28 healthy dogs of various breeds and age, randomly divided into two groups according to the infusion given: TRA (tramadol alone) or TLK (tramadol, lidocaine and ketamine). The patients were premedicated with acepromazine and midazolam, and then anesthesia was induced with propofol and maintained with sevoflurane. Fifteen minutes after induction, the patients received their loading dose of treatment. Then, the continuous infusion was then set to 1.3mg/kg/hour of tramadol with or without 3mg/kg/ hour of lidocaine and 0.6mg/kg/hour of ketamine, diluted in a 500mL bag of saline solution at an infusion rate of 10mL/kg/hour. The Dixon method was chosen to determine the MACsevo and a skin incision was used as a noxious stimulus. An unpaired Student's t-test was used to identify statistically significant differences between the treatments. These differences were considered significant when p<0.05. The MACsevo of the TRA group was 1.22±0.15 vol% and the MACsevo of the TLK group was 0.85±0.22 vol%. We conclude that TLK infusion decreased the MACsevo by 30.22% compared to tramadol alone, demonstrating that the combination of drugs was effective in reducing MACsevo in dogs.INDEX TERMS: Tramadol, tramadol-lidocaine-ketamine, sevoflurane, dogs, analgesia, anesthesia, inhalant, MAC.