Bolus ketamine does not decrease hyperalgesia after remifentanil infusion

Sahin A., CANBAY Ö., Cuhadar A., ÇELEBİ N., AYPAR Ü.

Pain Clinic, vol.16, no.4, pp.407-411, 2004 (Scopus) identifier

  • Publication Type: Article / Article
  • Volume: 16 Issue: 4
  • Publication Date: 2004
  • Doi Number: 10.1163/1568569042664413
  • Journal Name: Pain Clinic
  • Journal Indexes: Scopus
  • Page Numbers: pp.407-411
  • Keywords: Analgesics, Hyperalgesia, Ketamine, Remifentanil
  • Lokman Hekim University Affiliated: Yes


Background and aim: Several animal and human studies have proposed that acute tolerance to opioids might be manipulated by NMDA receptor antagonists. This study was designed to test the opioid-induced hyperalgesia produced by remifentanil, and to evaluate the effect of ketamine under these conditions. Methods: Forty-seven ASA 1-2 patients undergoing lumbar disc operation were randomly assigned into 3 anaesthetic regimens. The patients were not premedicated. After standard anaesthesia induction with propofol and vecuronium, group R and group K patients received a remifentanil infusion of 0.1 μg kg-1 min-1. Group K also received 0.5 mg kg-1 ketamine bolus before remifentanil infusion. Group S was the control group and equal volume of saline instead of remifentanil was infused throughout the operation. Groups R and S also received a bolus of the same volume of saline instead of ketamine by an anaesthesiologist blinded to the study. After the surgery under desflurane anaesthesia, patient-controlled analgesia with morphine was used in the postoperative care unit. Effective analgesia time, total morphine consumption, and visual analogue pain scores were noted at 15 min intervals during the first hour. Results: Age, sex, weight and height of the patients were similar. Remifentanil infusion time and effective analgesia time were similar in all groups. A significant decrease of morphine use was noted in all groups. Additionally, the groups showed a significant difference in VAS. VAS values were significantly lower in group S than in groups K and R. These values were similar groups R and K. Conclusion: Remifentanil infusion of 0.1 μg min-1 causes opioid-induced hyperalgesia in lumbar disc operations in the early postoperative period. Ketamine bolus of 0.5 mg kg-1 is insufficient to prevent this hyperalgesia.