Perspective

Intravenous (IV) regional anesthesia was introduced by Bier in 1908. As illustrated in Figure 9-1, in the initial description a surgical procedure was required to cannulate a vein, and both proximal and distal tourniquets were used to contain the local anesthetic in the venous system. After its introduction, the technique fell into disuse until the less toxic amino amides became available in the mid-20th century. This technique can be used for a variety of upper extremity operations, including both soft tissue and orthopedic procedures, primarily in the hand and forearm. The technique has also been used for foot procedures with a calf tourniquet.

Figure 9-1. Early Bier block: surgical technique.

Placement

Anatomy

The only anatomic detail necessary for clinical use of the IV regional block is identification of a peripheral vein; one must be cannulated in the involved extremity.

Position

The patient should be resting supine on the operating table with an IV tube already established in the nonsurgical arm. The involved arm should be extended on an arm board near available supplies (Fig. 9-2).

Figure 9-2. Intravenous regional block: equipment.

Needle Puncture

Before placement of the IV catheter in the operative extremity, a tourniquet, either double or single, should be placed around the upper arm of the patient. An IV cannula is then inserted in the operative extremity, as distally as possible, most commonly in the dorsum of the hand (Fig. 9-3). There are two methods for exsanguinating the venous blood from the operative extremity. The traditional technique requires the wrapping of an Esmarch bandage from distal to proximal (Fig. 9-4). When the Esmarch bandage is not available or the patient is in too much pain to allow its placement, another method is to raise the arm for 3 to 4 minutes to allow gravity to exsanguinate the operative upper extremity (Fig. 9-5). After the blood has been exsanguinated from the upper extremity, the tourniquet is inflated. If a double tourniquet is used, only the upper tourniquet is inflated. Recommendations for tourniquet inflation pressures range from 50 mm Hg above systolic blood pressure with a wide cuff, to a cuff pressure double the systolic blood pressure, to 300 mm Hg regardless of blood pressure. Until more information is available, I caution against using pressures greater than 300 mm Hg during upper extremity block.

Figure 9-3. Intravenous regional block: distal IV site.

Figure 9-4. Intravenous regional block: venous exsanguination with Esmarch bandage.

Figure 9-5. Intravenous regional block: venous exsanguination by gravity.

If an Esmarch bandage has been used, the elastic bandage is then unwrapped, and in the average adult 50 mL of 0.5% lidocaine without a vasoconstrictor is injected. Onset of the block usually occurs within 5 minutes, and the block is effective for procedures lasting as long as 90 to 120 minutes. This time limit is due to tourniquet time constraints rather than to diminution of the local anesthetic effect. The IV cannula is removed before preparation for operation. The block persists as long as the cuff is inflated and disappears shortly after deflation.

Potential Problems

The principal disadvantage of IV regional anesthesia is that physicians unfamiliar with treating local anesthetic toxicity may use the technique when appropriate resuscitation measures are not available. Although some workers report successful use of IV regional anesthesia for lower extremity surgery, especially if a calf tourniquet is used for foot surgery, its use is not widespread. During upper extremity use, a considerable number of patients complain about tourniquet pressure even when a double tourniquet is used, and this is often the clinically limiting feature of this technique. Appropriate use of IV sedatives is important for patient comfort.

Pearls

Figure 9-6 illustrates the two complementary theories of how IV regional anesthesia produces block. The figure conceptualizes local anesthetic entering the venous system and producing block by blocking the peripheral nerves running with the venous structures. It also outlines a theory that may be complementary—that is, the local anesthetic leaves the veins and blocks small distal branches of peripheral nerves. It is likely that both of these theories are operative. If IV regional anesthesia is to be used successfully, all members of the operating team should understand the importance of tourniquet integrity because the most significant problems with the technique involve unintentional deflation of the tourniquet.

Figure 9-6. Intravenous regional block: potential mechanism(s) of action.