Effect of Intravenous Dexmedetomidine in patients undergoing Total Knee Arthroplasty on post operative analgesic requirement

Pain, either acute or chronic, is one of the most common reasons why patients seek medical help. Pain is a multifactorial and complex process that is defined as ‘‘an unpleasant sensory and emotional experience associated with actual or potential tissue damage” . A prospective cohort study was conducted in Germany comparing 179 surgical procedures in 50,523 patients, which showed that the 40 procedures with the highest pain scores included 22 orthopaedic procedures on the extremities. Patients who undergo Total knee arthroplasty (TKA) are associated with a significant postoperative pain which sometimes can be underemphasized. This in turn affects the recovery of the patient, early mobilization and rehabilitation. Therefore, an adequate approach for pain management is extremely important to reduce the morbidity and improve recovery.

Many drugs have been used to provide adequate and effective post operative analgesia, including local anesthetics such as lidocaine and bupivacaine, opioids such as morphine and α2- adrenergic receptor agonists such as clonidine. However, none of these agents are free from limitations such as the need for special equipment and monitoring or the risk of complications which may cause a delay in the discharge process.

Dexmedetomidine is a highly selective, specific, and potent α2-adrenergic receptor agonist. It possesses anxiolytic, sedative, analgesic and sympatholytic properties. Many studies have demonstrated that dexmedetomidine can significantly decrease pain scores and postoperative diclofenac sodium, major opioid consumption and can improve the duration of the analgesic effect in patients undergoing knee arthroscopy. Furthermore, the incidence of postoperative delirium and postoperative nausea and vomiting (PONV) decreases with the use of dexmedetomidine therapy. It has also been shown that dexmedetomidine prolonged the duration of spinal anaestheisa and improved post-surgical analgesia.

This study aims to evaluate the analgesic effect of intravenous dexmedetomidine and its effectiveness in reducing the postoperative consumption of non-steroidal anti-inflammatory drugs and opioid analgesics.