Ketamine as an Adjuvant in Lidocaine Intravenous Regional Anesthesia

Abstract

Ketamine delays and minimizes intraoperative tourniquet pain when added to lidocaine-based intravenous regional anesthesia (IVRA). It is unclear if adding ketamine to the IVRA injectate is more efficacious compared with systemic administration. This study compares intraoperative tourniquet pain, postoperative analgesia, and side effects of systemic versus IVRA ketamine during outpatient hand surgery. We conducted a randomized, double-blind, systemic control study of 40 patients undergoing hand surgery using lidocaine IVRA. In group IVRA, 0.1 mg/kg ketamine in 1 mL of normal saline was added to the IVRA lidocaine, and 1 mL of normal saline was administered via a peripheral IV line. In group systemic, 1 mL of normal saline was added to the IVRA syringe, and 0.1 mg/kg ketamine in 1 mL of normal saline was administered via a peripheral intravenous line. Ten minutes after proximal tourniquet inflation, the distal tourniquet was inflated, and the proximal tourniquet deflated. Tourniquet pain was measured every 10 mins. Need for intraoperative opioids was recorded. Recovery room pain scores, analgesic needs, and sedation scores were compared. Patients were contacted 24 hrs after surgery and reported their analgesic consumption, satisfaction scores, and the occurrence of any unpleasant psychologic effects. Groups IVRA and systemic were comparable in demographic and surgical parameters. There were no differences between groups in intraoperative tourniquet pain scores, intraoperative fentanyl requirements, recovery room pain or sedation scores, postsurgical analgesic needs, or patient satisfaction scores. In comparison to systemic administration, there is no selective benefit to adding ketamine to the IVRA injectate.