Ketamine has demonstrated analgesic effects in subanesthetic doses, besides the maintenance of stability of physiological parameters. The study aimed to evaluate the cardiorespiratory effects and the post operative analgesia of ketamine via epidural route, intravenous continuous infusion or association of both, in dogs submitted to femoral osteosynthesis. Twenty-five healthy bitches were randomly assigned to four groups: CEP (2mg kg-1 of ketamine associated with lidocaine 2% via epidural route), CIV (lidocaine 2% via epidural route and 1mg kg-1 of ketamine IV, followed by IV continuous infusion of 100µg kg min-1 of ketamine), CIVEP (epidural anesthesia identical to CEP and ketamine infusion as in CIV) and CON (epidural anesthesia with lidocaine 2%). HR, RR, SAP, MAP, DAP and T°C, sensitive blockade time and post operative analgesia measured with visual analog scale were evaluated. There was an increase in HR in CIV and decrease of this parameter in CEP. Arterial pressures kept within physiological values and differences in RR and T°C were not observed. The anesthetic blockade time was augmented in the groups which received epidural ketamine, differing significantly in relation to the control. The time for rescue analgesia did not differ between the groups. It can be concluded the administration of ketamine via epidural route, intravenous continuous infusion or the association of both promoted cardiorespiratory stability during the operative period; however, it was not able to extend the duration of post operative analgesia in dogs submitted to femoral osteosynthesis.
post operative pain; multimodal analgesia; ketamine; dogs
