Comparison of effects of intraoperative esmolol and ketamine infusion on acute postoperative pain after remifentanil-based anesthesia in patients undergoing laparoscopic cholecystectomy

Abstract

Background: Remifentanil is a short-acting drug with a rapid onset that is useful in general anesthesia. Recently, however, it has been suggested that the use of opioids during surgery may cause opioid-induced hyperalgesia (OIH). Researchers have recently reported that esmolol, an ultra-short-acing β1 receptor antagonist, reduces the postoperative requirement for morphine and provides more effective analgesia than the administration of remifentanil and ketamine. Hence, this study was conducted to determine whether esmolol reduces early postoperative pain in patients who are continuously infused with remifentanil for anesthesia during laparoscopic cholecystectomy.

Methods: Sixty patients scheduled to undergo laparoscopic cholecystectomy were randomly divided into three groups. Anesthesia was maintained with sevoflurane and 4 ng/ml (target-controlled infusion) of remifentanil in all patients. Esmolol (0.5 mg/kg) was injected and followed with a continuous dosage of 10 µg/kg/min in the esmolol group (n = 20). Ketamine (0.3 mg/kg) was injected and followed with a continuous dosage of 3 µg/kg/min in the ketamine group (n = 20), while the control group was injected and infused with an equal amount of normal saline. Postoperative pain score (visual analog scale [VAS]) and analgesic requirements were compared for the first 6 hours of the postoperative period.

Results: The pain score (VAS) and fentanyl requirement for 15 minutes after surgery were lower in the esmolol and ketamine groups compared with the control group (P < 0.05). There were no differences between the esmolol and ketamine groups.

Conclusions: Intraoperative esmolol infusion during laparoscopic cholecystectomy reduced opioid requirement and pain score (VAS) during the early postoperative period after remifentanil-based anesthesia.

Keywords: Esmolol; Hyperalgesia; Ketamine; Postoperative pain; Remifentanil; Sevoflurane.

Fig. 1

Pain score (visual analog scale) measured for 1 hour in the recovery room. Data are the mean ± SD. The esmolol group and the ketamine group appeared to have especially reduced scores compared with the control group for the first 15 minutes, with no differences between the esmolol and ketamine groups (^*P < 0.05, ^†P < 0.05).

Fig. 2

Postoperative fentanyl requirement in the recovery room. Data are the mean ± SD. The fentanyl requirement at 5 minutes and 15 minutes after surgery in the esmolol group and the ketamine group was less than in the control group, as was the total amount of fentanyl administered during the first hour after surgery in the recovery room (^*P < 0.05, ^†P < 0.05). There was no difference between the esmolol and ketamine groups.

Fig. 3

Pain score (visual analog scale) from 1 hour to 6 hours after surgery. Data are the mean ± SD. No statistical differences were observed between the three groups (P > 0.05).