Effects of dezocine and oxycodone on remifentanil-induced hyperalgesia

Objective To evaluate the effects of dezocine and oxycodone in preventing remifentanil-induced hyperalgesia. Methods Forty-eight patients undergoing laparoscopic gynecological surgery under general anesthesia were randomly divided into three groups (16 patients in each group), respectively received treatment with dezocine (group D) or oxycodone (group O), or without treatment (group C). Fifteen minutes before the operation, patients in group D and group O were respectively injected intravenously with dezocine 0.09 mg/kg and oxycodone 0.09 mg/kg, respectively, while the equal volume of normal saline was administered in group C. Anesthesia was induced with a combination of 0.02 mg/kg midazolam, 0.3 mg/kg etomidate, 0.2 mg/kg cisatracurium, and 1 μg/kg remifentanil. Then, the patients were ventilated with laryngeal mask airway. During the operation, BIS in electroencephalography was maintained between 40 to 60 by adjusting the dosage of propofol. Remifentanil was injected at the speed of 0.2 μg·kg-1·min-1. After surgery, VAS score and Ramsay score were also calculated, and adverse effects, such as nausea, vomiting, and shivering were recorded. The thermal pain threshold was measured before and after surgery. Results Compared with the group C, the postoperative VAS scores were significantly decreased in both group D and group O (P 0.05). Conclusions Dezocine and oxycodone were both effective in preventing remifentanil-induced thermal hyperalgesia, and dezocine can cut down the incidence of shivering. Key words: Remifentanil; Hyperalgesia; Dezocine; Oxycodone