Assessment of the effect of ketamine in combination with remifentanil on postoperative pain

Abstract

Background and objectives: The combination of ketamine and remifentanil seems to be associated with better analgesia and duration. The aim of this study was to evaluate whether a ketamine- remifentanil combination promotes improved postoperative analgesia.

Methods: Prospective, randomized, double blind study of 40 patients undergoing video laparoscopic cholecystectomy. Anesthesia was performed with remifentanil, propofol, atracurium, and 50% oxygen. Group 1 (GI) patients received remifentanil (0.4 mcg.kg(-1).min(-1)) and ketamine (5 mcg.kg(-1).min(-1)) and Group 2 (G2) received remifentanil (0.4 mcg.kg(-1).min(-1)) and saline solution. Morphine 0.1 mg.kg(-1) was administered at the end of the procedure, and postoperative pain was treated with morphine via PCA. We evaluated the severity of postoperative pain by a numerical scale from zero to 10 during 24 hours. We registered the time to the first analgesic supplementation, amount of morphine used in the first 24 hours, and adverse effects.

Results: There was a decrease in pain severity between extubation and other times evaluated in G1 and G2. There was no significant difference in pain intensity between the groups. There was no difference between G1 (22 ± 24.9 min) and G2 (21.5 ± 28.1 min) regarding time to first dose of morphine and dose supplement of morphine consumed in G1 (29 ± 18.4 mg) and G2 (25.1 ± 13.3 mg).

Conclusion: The combination of ketamine (5 mcg.kg(-1).min(-1)) and remifentanil (0.4 mcg.kg(-1).min(-1)) for cholecystectomy did not alter the severity of postoperative pain, time to first analgesic supplementation or dose of morphine in 24 hours.

Keywords: Analgesia; Cholecystectomy; Ketamine; Piperidines/remifentanil.; Postoperative Period.