Bier Block Limitations

Bier block, also known as “Intravenous Regional Anesthesia” or “IVRA” was invented by August Bier in 1908 and has been most commonly used for short duration procedures of the upper extremity distal to the elbow. A Bier block is performed by inserting a small gauge IV as distal in the operative extremity as possible. Next, the arm is elevated and exsanguinated with an Esmarch. A proximal tourniquet is then applied to the upper extremity and inflated ideally to 50-100mmHg above the patient’s systolic BP although it is more common to simply inflate to 250mmHg. A distal tourniquet can also be placed for longer duration procedures. Relatively high doses of local anesthetic are then injected through the IV catheter. Lidocaine is most commonly used; 15-20mL of 2% lidocaine is a fairly standard dose. The IV catheter is then removed and blockade of distal nerves is achieved via diffusion of local anesthetic across the vascular bed. Other minor mechanisms of anesthesia include diffusion of local anesthetic into local tissues, tissue acidosis, hypothermia and ischemia.

Limitations of Bier block include the short-duration of the blockade (~30 minutes), tourniquet pain, potential for local anesthetic toxicity particularly if the tourniquet is deflated within 30 minutes of the block, and severe pain immediately after tourniquet deflation. Complications from wash-out of local metabolites are possible albeit rare given the relatively short tourniquet time. Inability to obtain IV access also limits use of Bier blocks. Relative contraindications include local tissue infection, arteriovenous malformations of operative extremity, sickle cell disease and local anesthetic allergy.