Intraoperative use of IV ketamine bests dexmedetomidine for analgesia among those operated under spinal anesthesia: Study

Intravenous sedation administered alongside spinal anesthesia offers benefits such as prolonged spinal anesthesia duration and improved postoperative pain management. In a recent prospective randomized double-blind controlled trial, the study aimed to compare the effect of intravenous bolus and infusion of dexmedetomidine versus ketamine on postoperative analgesia in fracture femur patients operated under subarachnoid block. The study enrolled 75 patients aged 18–65 years, randomly divided into three groups to receive ketamine, dexmedetomidine, or saline (control group). Postoperative pain was evaluated using the numerical rating scale (NRS), duration of analgesia, and analgesic consumption.

The results showed that patients in the ketamine group had better postoperative analgesia with decreased pain on the NRS scale and reduced need for postoperative rescue analgesics. The duration of sensory block and motor block was prolonged in the ketamine group compared to the other two groups. The conclusion drawn from the study was that intraoperative use of intravenous ketamine was superior to dexmedetomidine for postoperative analgesia in fracture femur patients operated under subarachnoid block. The background of the study highlighted the limitations of postoperative analgesia in patients undergoing orthopedic surgery and the importance of effective pain management for postoperative rehabilitation and quality of life. Multimodal analgesia was emphasized as the standard of care for postoperative pain management.

The study design involved enrolling patients aged 18–65 years with fractured femurs and subjected to subarachnoid block. Dexmedetomidine and ketamine were administered intraoperatively, and postoperative outcomes were assessed, including pain scores, duration of analgesia, rescue analgesic consumption, and complications. The results indicated that ketamine was more effective than dexmedetomidine in providing postoperative analgesia, as evidenced by lower NRS scores and reduced need for rescue analgesics. This is consistent with previous studies on the analgesic efficacy of ketamine, also showing its effectiveness in prolonging the duration of analgesia and providing better postoperative pain relief. However, both drugs were found to be effective in postoperative pain management.

The study also highlighted the safety and efficacy of ketamine in terms of sedation, as it resulted in a lower Richmond Agitation Sedation Scale (RASS) score compared to dexmedetomidine. The duration of sensory and motor block was also prolonged in the ketamine group, further emphasizing its effectiveness in postoperative pain management. In conclusion, the study demonstrated that intraoperative use of intravenous ketamine was superior to dexmedetomidine for postoperative analgesia in fracture femur patients operated under subarachnoid block. The findings suggest the potential benefit of using ketamine for pain management in orthopedic surgeries, particularly for femur fractures under spinal anesthesia.

Key Points

- A prospective randomized double-blind controlled trial compared the effects of intravenous bolus and infusion of dexmedetomidine versus ketamine on postoperative analgesia in femur fracture patients operated under subarachnoid block.

- 75 patients aged 18–65 were randomly divided into three groups: ketamine, dexmedetomidine, and saline (control group). Pain was evaluated using the numerical rating scale (NRS), duration of analgesia, and analgesic consumption.

- Patients in the ketamine group had better postoperative analgesia with decreased pain on the NRS scale and reduced need for postoperative rescue analgesics. The duration of sensory and motor block was also prolonged in the ketamine group compared to the other two groups.

- The study highlighted the limitations of postoperative analgesia in orthopedic surgery patients and the importance of effective pain management for postoperative rehabilitation and quality of life. Multimodal analgesia was emphasized as the standard of care.

- Ketamine was found to be more effective than dexmedetomidine in providing postoperative analgesia, with lower NRS scores and reduced need for rescue analgesics. Both drugs were effective in postoperative pain management, but ketamine showed superiority.

- The study concluded that intraoperative use of intravenous ketamine was superior to dexmedetomidine for postoperative analgesia in fracture femur patients operated under subarachnoid block, suggesting the potential benefit of using ketamine for pain management in orthopedic surgeries, particularly for femur fractures under spinal anesthesia.

Reference –

Ather R, Nikhar SA, Kar AK, Durga P, Prasanna PL. Comparison of the effect of intraoperative dexmedetomidine versus ketamine on postoperative analgesia in fracture femur patients operated under subarachnoid block – A prospective randomized double‑blind controlled trial. J Anaesthesiol Clin Pharmacol 2024. DOI: 10.4103/joacp.joacp_67_23.