Multimodal Analgesia With Ketamine or Tramadol in Combination With Intravenous Paracetamol After Renal Surgery

BACKGROUND: Opioids are generally the preferred analgesic agents during the early postoperative period. OBJECTIVES: The present study was designed to assess and compare the multimodal analgesic effects of ketamine and tramadol in combination with intravenous acetaminophen after renal surgery. PATIENTS AND METHODS: This randomized, double-blinded, clinical trial was conducted on 80 consecutive patients undergoing various types of kidney surgeries in Sina hospital in Tehran in 2014 - 2016. After extubation, the patients were randomly assigned to receive intravenous paracetamol (1 gr) plus tramadol (0.7 mg/kg) (PT group) or paracetamol (1 gr) plus ketamine (0.5 mg/kg) (PK group) within ten minutes. Pain severity was assessed by the visual analog scale (VAS), and the level of agitation was assessed by the Ramsey sedation scale (RSS). Morphine consumption was assessed within the first six hours after drug injection, and hemodynamic parameters were assessed at 5, 10, and 20 minutes after infusion, at the time of transfer from recovery to the ward, and also at one and six hours after transfer to the ward. RESULTS: Postoperative pain scores were significantly lower in the PK group than in the PT group during all study time points. The mean dose of morphine needed at recovery in the PK group was lower compared with the PT group (0.47 ± 0.94 mg versus 1.50 ± 1.35 mg/P = 0.001). The level of agitation based on the RSS score was significantly lower in the PK group than in the PT group at 10 and 20 minutes after drug administration. The total postoperative complication rate in the PK group was lower than in the PT group (20% versus 53.3%, P = 0.007). In this regard, catheter bladder discomfort was more frequent in the PT group than in the PK group (43.3% versus 3.3%, P < 0.001). CONCLUSIONS: The combination of intravenous paracetamol 1 gr and ketamine 0.5 mg/kg resulted in an overall reduction in pain scores, decreased postoperative analgesic requirements, and lower agitation score compared with intravenous paracetamol 1 gr and tramadol 0.7 mg/kg for patients undergoing renal surgery.