title: Comparison of effects of intraoperative nefopam and ketamine infusion on managing postoperative pain after laparoscopic cholecystectomy administered remifentanil.
abstract: BACKGROUND
  Although intraoperative opioids provide more comfortable anesthesia and reduce the use of postoperative analgesics, it may cause opioid induced hyperalgesia (OIH). OIH is an increased pain response to opioids and it may be associated with N-methyl-D-aspartate (NMDA) receptor. This study aimed to determine whether intraoperative nefopam or ketamine, known being related on NMDA receptor, affects postoperative pain and OIH after continuous infusion of intraoperative remifentanil.
  
  
  METHODS
  Fifty-four patients undergoing laparoscopic cholecystectomy were randomized into three groups. In the nefopam group (N group), patients received nefopam 0.3 mg/kg at the induction of anesthesia followed by a continuous infusion of 0.065 mg/kg/h. In the ketamine group (K group), patients received ketamine 0.3 mg/kg at the induction of anesthesia followed by a continuous infusion of 3 µg/kg/min. The control group did not received any other agents except for the standard anesthetic regimen. Postoperative pain score, first time and number of demanding rescue analgesia, OIH and degrees of drowsiness/sedation scale were examined.
  
  
  RESULTS
  Co-administrated nefopam or ketamine significantly reduced the total amount of intraoperative remifentanil and postoperative supplemental morphine. Nefopam group showed superior property over control and ketamine group in the postoperative VAS score and recovery index (alertness and respiratory drive), respectively. Nefopam group showed lower morphine consumption than ketamine group, but not significant.
  
  
  CONCLUSIONS
  Both nefopam and ketamine infusion may be useful in managing in postoperative pain control under concomitant infusion of remifentanil. However, nefopam may be preferred to ketamine in terms of sedation.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Gwangju Christian Hospital, Gwangju, Korea.
authors.forename: Sung Kwan
authors.initials: SK
authors.lastname: Choi
authors.affiliation: Department of Anesthesiology and Pain Medicine, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Myung Ha
authors.initials: MH
authors.lastname: Yoon
authors.affiliation: Department of Anesthesiology and Pain Medicine, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Jung Il
authors.initials: JI
authors.lastname: Choi
authors.affiliation: Department of Anesthesiology and Pain Medicine, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Woong Mo
authors.initials: WM
authors.lastname: Kim
authors.affiliation: Department of Anesthesiology and Pain Medicine, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Bong Ha
authors.initials: BH
authors.lastname: Heo
authors.affiliation: Department of Anesthesiology and Pain Medicine, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Keun Seok
authors.initials: KS
authors.lastname: Park
authors.affiliation: Department of Anesthesiology and Pain Medicine, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Ji A
authors.initials: JA
authors.lastname: Song
keywords: Hyperalgesia; Ketamine; Nefopam; Postoperative pain