The technique of intravenous regional anesthesia (IVRA) was first introduced by August Bier in 1908.1 IVRA essentially consists of injecting local anesthetic solution into the venous system of an extremity that has been exsanguinated by compression and/or gravity and isolated from the central circulation by means of a tourniquet. Procaine in concentrations of 0.25% to 0.5% was injected through an intravenous cannula placed between two Esmarch bandages used as tourniquets to divide the arm into proximal and distal compartments in Bier’s original technique.2-4 He noted two distinct types of anesthesia. The first was an almost immediate onset of “direct” anesthesia between the two tourniquets. An “indirect” anesthesia distal to the distally placed tourniquet was noted after a delay of 5 to 7 minutes. This technique was eventually renamed the Bier block.
Bier performed dissections of the venous system of the upper extremity in cadavers after injecting methylene blue. He was able to determine that the “direct” anesthesia was the result of the local anesthetic agent bathing bare nerve endings in the tissues. The “indirect” anesthesia was most probably due to the local anesthetic agent being transported into the substance of the nerves via the vasa nervorum where a conduction block is affected. Bier’s conclusion was that there were two mechanisms of anesthesia associated with his technique: a peripheral infiltration block and a conduction block.
The only major modification of Bier’s technique in the past 100 years has been the development of the double tourniquet technique in current clinical practice.5-7 The Bier block is appropriate for brief surgical procedures of the upper or lower extremity. The technique has certainly gained its greatest acceptance for use in the upper extremity as tourniquet problems and safety issues seem to arise more frequently when IVRA is undertaken in the lower extremity.
The Bier block is a procedure that has found utility as a treatment adjunct for patients suffering from complex regional pain syndromes (CRPS; formerly known as reflex sympathetic dystrophy [RSD] or sympathetically maintained pain) as an alternative to repeated sympathetic blocks. Chemical sympathectomy using IVRA with agents such as guanethidine or bretylium may last up to 5 days as compared to local anesthetic blocks that typically provide analgesia lasting only hours.
ANATOMY AND PATHOPHYSIOLOGY
Lidocaine is the most commonly used local anesthetic agent for IVRA in the United States. Prilocaine is more routinely chosen in Europe. Prilocaine is metabolized to orthotoluidine, an oxidizing compound capable of converting hemoglobin to methemoglobin. This is usually only of concern when the dose of prilocaine is greater than 600 mg. Lower extremity IVRA using volumes up to 100 mL does not approach this dosage.
The usual dose of lidocaine to administer is approximately 3 mg/kg. This is a relatively large dose in terms of potential systemic toxicity. Systemic toxic reactions can and do occur due ...