Intravenous regional anesthesia (IVRA) provides anesthesia to either the upper or lower extremity by means of local anesthetic introduction into a peripheral vein. Alternatively named the Bier block, this anesthetic is contraindicated for procedures requiring muscle paralysis, blockade of individual nerves, or prolonged surgical duration. Developed in 1908 by Dr August Bier, the Bier block remains popular due to its ease of use, reliability, and low incidence of complications. It is useful in short, modestly invasive procedures such as carpel tunnel release and ganglionectomy. The duration of the block is predicated on the duration of tourniquet inflation, limiting toxicity risk from longer acting agents; however, tourniquet discomfort precludes Bier blocks for longer procedures. When employed carefully, the Bier block is a safe and reliable method of producing anesthesia.
Application of the Bier block requires several steps that ultimately exsanguinate the extremity followed by delivery of local anesthetic into the exsanguinated vascular space. An IV cannula is placed in an extremity that the Bier block is not being performed on for administration of adjunctive medications. An IV cannula is also placed distally in the procedure limb. Next, a double tourniquet with clearly designated proximal and distal tourniquets is placed on the operative extremity proximal to the surgical site. The extremity is elevated above the level of the heart for 1 minute, allowing for passive evacuation of blood. Then, an Esmarch bandage is applied to the limb in a spiral fashion, starting distally, to actively remove remaining blood from the vascular space. The double tourniquet is tested with the distal tourniquet first inflated followed by the proximal tourniquet to 50–100 mmHg above systolic blood pressure. Once the function is verified, the distal tourniquet is deflated. The Esmarch bandage is removed and local anesthetic given to the operative extremity. Typically, 12–15 mL of preservative-free 2% Lidocaine HCL or 30–50 mL of preservative-free 0.5% Lidocaine HCL is slowly administered in adult patients. After injection, the IV cannula is removed from the operative extremity.
Surgical anesthesia typically occurs immediately but may take up to 5 minutes. After 20–30 minutes the patient may experience tourniquet pain; with pain, the distal tourniquet can be inflated followed by deflation of the proximal cuff. This technique is applied within 40–60 minutes of surgical anesthesia and is less painful as the distal cuff tightens on an anesthetized portion of the extremity. Upon surgical completion, the distal cuff is deflated for 10 seconds followed by reinflation for 1 minute. This slowly releases local anesthetic into circulation, minimizing toxicity risk. After 1 minute, the cuff can be deflated completely and the tourniquet removed.
Nearly all local anesthetics are used for IV regional anesthesia. Lidocaine is the most commonly used local anesthetic with the fewest side effects. A maximum of 3 mg/kg is generally considered safe since epinephrine is not used. Additionally, preservative-free solution prevents ...