<P> Local anesthetic nerve block (local anesthetic regional nerve blockade, or often simply nerve block) is a short - term nerve block involving the injection of local anesthetic as close to the nerve as possible for pain relief . The local anesthetic bathes the nerve and numbs the area of the body that is innervated by that nerve . The goal of the nerve block is to prevent pain by blocking the transmission of pain signals from the surgical site . The block provides pain relief during and after the surgery . The advantages of nerve blocks over general anesthesia include faster recovery, monitored anesthesia care vs. intubation with an airway tube, and much less postoperative pain . </P> <P> Local anesthetics act on the voltage - gated sodium channels that conduct electrical impulses and mediate fast depolarization along nerves . Local anesthetics also act on potassium channels, but they block sodium channels more . </P> <P> Lidocaine preferentially binds to the inactivated state of voltage - gated sodium channels, but has also been found to bind potassium channels, G protein - coupled receptors, NMDA receptors, and calcium channels in vitro . The duration of the block is mostly influenced by the amount of time the anesthetic is near the nerve . Lipid solubility, blood flow in the tissue, and presence of vasoconstrictors with the anesthetic all play a role in this . A higher lipid solubility makes the anesthetic more potent and have a longer duration of action; however, it also increases the toxicity of the drug . </P> <P> Local anesthetic toxicity is indicated by numbness and tingling around the mouth, metallic taste, or ringing in the ears . Additionally, this may lead to seizures, arrhythmias, and may progress to cardiac arrest . This reaction may stem from an allergy, excessive dose, or intravascular injection . Other complications include nerve injury which has an extremely low rate of 0.029 - 0.2% . Some research even suggests that ultrasound lowers the risk to 0.0037% . The use of ultrasound and nerve stimulation has greatly improved practitioners' ability to safely administer nerve blocks . Nerve injury most often occurs from ischaemia, compression, direct neurotoxicity, or needle laceration, and inflammation . </P>

Local anesthetic therapeutic effect to block nerve conduction