Continuous Lidocaine Infusion in Thyroid Surgery Using Intraoperative Neurophysiological Monitoring

Thyroid surgery is a common procedure for the treatment of thyroid tumors, nodules and other related lesions. During this procedure, intraoperative neurophysiological monitoring is used to protect the recurrent laryngeal nerves. For the nerve monitor to work properly, a reduced muscle relaxant dosage is indicated. The main objectives of the anesthesiologist are maintaining deep sedation, analgesia and immobilization during surgery, as well as enhance post-operative recovery. Reduced muscle relaxant use during surgery poses the risk of inadequate immobilization during the operation, which may result in serious surgical complications. Intravenous bolus administration of fentanyl is currently the most popular method to maintain the depth of anesthesia during such operations. However, the side effects include intraoperative hypotension, bradycardia, and postoperative nausea and vomiting. The ultra-short acting remifentanil may be appropriate for inhibiting the bucking reflex during surgery, but the risk of opioid-induced hyperalgesia and opioid tolerance after surgery has been reported. In recent studies, intravenous lidocaine has been shown to increase the depth of anesthesia and provide analgesia, with no muscle relaxing effect. The aim of this study is to examine the depth of anesthesia, surgical operating conditions, and the recovery profile with the use of a continuous lidocaine infusion.