Combined Ketamine-Tramadol Subcutaneous Wound Infiltration for Multimodal Postoperative Analgesia: A Double-Blinded, Randomized Controlled Trial after Renal Surgery

BACKGROUND Pain is an important consideration after renal surgery. A multimodal approach to postoperative pain management could enhance analgesia by risking fewer side effects after surgery. OBJECTIVES The aim of this study was to evaluate the clinical efficacy of the subcutaneous infiltration of ketamine and tramadol at the incision site to reduce postoperative pain. METHODS Sixty-four patients between 18 and 80 years old who were scheduled for elective renal surgery were enrolled in a double-blind randomized controlled study. At the end of the surgery, patients were divided into four groups with 16 patients in each group: the saline group, who were treated with 10 mL of saline solution; the K group, who were treated with 1 mg/kg etamine in 10 mL of saline solution; the T group, who were treated with 1 mg/kg tramadol in 10 mL of saline solution; and the K/T group, who were treated with 0.5 mg/kg ketamine with 0.5 mg/kg tramadol in 10 mL of saline solution. In each group, the solution was infiltrated subcutaneously at the incision site. The postoperative pain scores and rescue analgesic consumption of the patients in each group were recorded for 24 hours and compared. The primary goal of the study was to compare the results of patients treated with a combined ketamine and tramadol subcutaneous wound infiltration, patients treated with a tramadol subcutaneous wound infiltration, and patients treated with a ketamine subcutaneous wound infiltration. RESULTS Sixty-four patients were enrolled in the study. Pain intensity and cumulative meperidine consumption were significantly lower in the K/T group (27 mg; 95% confidence interval, 25.2 - 53.2) in comparison with the group that received a saline infusion during the first 24 hours after surgery (P < 0.001). The sedation score of the K, T, and K/T groups were significantly higher than the saline group (P < 0.001). CONCLUSIONS The combined subcutaneous infiltration of ketamine and tramadol at the incision site produces better analgesia and an opioid-sparing effect during the first 24 hours when compared with the control group and the groups that received a subcutaneous infiltration of only ketamine or tramadol.