8.10: Local Anesthetics: Clinical Application as Intravenous Regional Anesthesia
Intravenous regional anesthesia or the Bier block technique is used to anesthetize a specific limb or extremity. It uses exsanguinated or blood-drained vessels to transport local anesthetics or LAs to the peripheral nerve trunks. Lidocaine without vasoconstrictors like epinephrine is most commonly used for this technique. Other drugs used are prilocaine, ropivacaine, and chloroprocaine. Bupivacaine is not recommended for this technique due to its high cardiac toxicity.
One of the advantages of the Bier block technique is its rapid onset of action. Anesthesia is achieved within five minutes after the injection, allowing for efficient pain control during procedures. Additionally, the procedure can be performed on an outpatient basis, avoiding the need for general anesthesia and its associated risks. The technique requires minimum additional equipment and can be done in a simple clinical environment.
However, its use is limited to certain areas, like the arm. Other disadvantages include the quick return of pain after tourniquet deflation and high systemic toxicity on premature tourniquet release. Contraindications of this technique include hypersensitivity to local anesthetics, deep vein thrombosis or impaired limb perfusion, hypertension, open wounds, and significant limb injuries.
