Also known as block anesthesia, conduction anesthesia differs from general anesthesia in that it affects a specific part of the body and that patients may remain awake during the procedure. Conduction anesthesia is a comprehensive term which encompasses a variety of local and regional anesthetic techniques. While there is is a spectrum of complexity between simple local anesthetic infiltration and major regional blocks, such as the 'central neuraxial blocks' (spinal and epidural), the terms local anesthesia, regional anesthesia, and conduction anesthesia are often all used interchangeably.
Indications and applications
The aim of local or regional anesthesia is generally to induce local analgesia, that is, local insensitivity to pain, although other local senses may be affected as well. It allows patients to undergo surgical and dental procedures with reduced pain and distress. In many situations, such as cesarean section, it is considered safer and therefore preferred to general anesthesia. It is also used for relief of non-surgical pain and to enable diagnosis of the cause of some chronic pain conditions. Anesthetists sometimes combine both general and local anesthesia techniques.
Regional anesthesia is is anesthesia affecting a large part of the body, such as a limb or the lower half of the body. Regional anesthetic techniques can be divided into central and peripheral techniques. The central techniques include so called neuraxial blockade (epidural anesthesia, spinal anesthesia). The peripheral techniques can be further divided into plexus blocks such as brachial plexus blocks, and single nerve blocks. Regional anesthesia may be performed as a single shot or with a continuous catheter through which medication is given over a prolonged period, e.g. continuous peripheral nerve block (CPNB). Regional anesthesia can be provided by injecting local anesthetics directly into the veins of an arm (provided the venous flow is impeded by a tourniquet.) This is called intravenous regional techniques (Bier block).
Unlike a minor local anesthetic infiltration to allow a wound to be sutured, or a skin lesion to be excised, regional anesthesia may involve large doses of local anesthetic, or administration of the local anesthetic very close to, or directly into the central nervous system. Therefore there is a risk of complications from local anesthetic toxicity (such as seizures and cardiac arrest) and for a syndrome similar to spinal shock. Research suggests that this risk is rare, at less than 0.04%.
- localized prolonged anesthesia or paresthesia due to infection, hematoma, excessive fluid pressure in a confined cavity, and severing of nerves & support tissue during injection.
- systemic reactions such as depressed CNS syndrome, allergic reaction, vasovagal episode, and cyanosis due to local anesthetic toxicity.
- lack of anesthetic effect due to infectious pus such as an abscess.
Non-medical conduction anesthetic techniques
- Transcutaneous electrical nerve stimulation, which has been found to be ineffective for lower back pain, however, it might help with diabetic neuropathy.
- Pulsed radiofrequency, neuromodulation, direct introduction of medication and nerve ablation may be used to target either the tissue structures and organ/systems responsible for persistent nociception or the nociceptors from the structures implicated as the source of chronic pain.
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- New York School of Regional Anesthesia
- Anesthesia Books
- General information and tutorials in peripheral regional anesthesia
-  Free online manual of regional anaesthesia- John Hyndman
- Clinical Use of Peripheral Nerve Stimulators and The Neuromuscular Junction
- ESRA - The European Society for Regional Anaesthesia Congress