Purpose: We hypothesized that a high dose of dexmedetomidine (1 μg/kg/h) could reduce postoperative analgesic requirements of patients.
Methods: This was a prospective, randomized, double-blind, placebo-controlled study carried out in Tohoku University Hospital. Thirty-two patients who underwent open gynecological abdominal surgery were randomly divided into a control (group C) and a dexmedetomidine group (group D). In both groups of patients, an epidural catheter was put in position prior to the induction of anesthesia, and continuous epidural infusion was started using a patient-controlled epidural analgesia (PCEA) pump. During the induction of anesthesia, group D patients received a loading dose of dexmedetomidine (1 μg/kg over 10 min), followed by a continuous infusion at a rate of 1 μg/kg/h. The patients in group C received a volume-matched infusion of normal saline as placebo. Consumption of PCEA bolus (local anesthetics) during the first postoperative 24 h, postoperative pain scores, and side effects related to the use of dexmedetomidine were recorded.
Results: Dexmedetomidine (1 μg/kg/h) significantly reduced PCEA bolus consumption [15.9 ± 6.5 (group C) vs. 5.3 ± 5.0 ml (group D); P = 0.0001] and postoperative pain scores. The infusion of dexmedetomidine produced no serious side effects, such as hemodynamic changes.
Conclusions: Among this small patient cohort, perioperative infusion of dexmedetomidine (1 μg/kg/h) resulted in antinociception without severe side effects. These results suggest that this method could be of interest with respect to improving postoperative pain status.