NMDA Antagonist: ketamine for balanced analgesia in the perioperative period. What is the preferential route?

ABSTRACT

This study aimed to investigate whether intraoperative sub-anesthetic doses of ketamine could represent an efficient constituent of balanced analgesia and which is the preferential route of administration, either systemic [intravenous] or epidural. Fifty patients scheduled for upper abdominal operations under combined epidural/general anesthesia were included in the study. Before skin incision, all patients received an epidural bolus, followed by an infusion of continuous bupivacaine/fentanyl/clonidine mixture. They were randomly assigned to receive No ketamine [group 1]; i.v. ketamine at a bolus dose of 0.25 mg/kg, followed by an infusion of 0.125 mg/kg/h [group 2]; i.v. ketamine 0.5 mg/kg and followed by an infusion of 0.25 mg/kg/h [group 3]; epidural ketamine 0.25 mg/kg and 0.125 mg/kg/h [group 4] or 0.5 mg/kg and 0.25 mg/kg/h [group 5]. All i.v. And epidural anesthesia stopped at the end of surgery and the patients were connected to i.v. Morphine patient-controlled analgesia [PCA] device. The study supported the theory that sub-anesthetic doses of i.v. ketamine [0.5 mg/kg bolus, followed by 0.25 mg/kg/h] given during anesthesia are useful adjuvant in perioperative-balanced analgesia. Moreover, they showed that the systemic route is the preferential route