RT Book, Section A1 Candido, Kenneth D. A1 Tharian, Anthony R. A1 Winnie, Alon P. A2 Hadzic, Admir SR Print(0) ID 1141732237 T1 Intravenous Regional Block for Upper and Lower Extremity Surgery T2 Hadzic's Textbook of Regional Anesthesia and Acute Pain Management, 2e YR 2017 FD 2017 PB McGraw-Hill Education PP New York, NY SN 9780071717595 LK accessanesthesiology.mhmedical.com/content.aspx?aid=1141732237 RD 2024/03/29 AB The technique of intravenous regional anesthesia (IVRA), or “Bier block,” was first introduced in 1908 by the German surgeon August Bier.1 A Bier block essentially consists of injecting local anesthetic solutions into the venous system of an upper or lower extremity that has been exsanguinated by compression or gravity and that has been isolated by means of a tourniquet from the central circulation. In Bier’s original technique, the local anesthetic procaine in concentrations of 0.25% to 0.5% was injected through an intravenous cannula, which had been placed between two Esmarch bandages utilized as tourniquets to divide the arm into proximal and distal components.2,3,4after injecting the local anesthetic, Bier noted two distinct types of anesthesia: an almost-immediate onset of “direct” anesthesia between the two tourniquets and then, after a delay of 5 to 7 minutes, an “indirect” anesthesia distal to the distally placed tourniquet. By performing dissections of the venous system of the upper extremity in cadavers after injecting methylene blue, Bier was able to determine that the direct anesthesia was the result of local anesthesia bathing bare nerve endings in the tissues, whereas the indirect anesthesia was most probably due to local anesthesia being transported to the substance of the nerves via the vasa nervorum, where a typical conduction block occurs. Bier’s conclusion was that two mechanisms of anesthesia were associated with this technique: peripheral infiltration block and conduction block. The technique, as originally described by Bier, remains essentially unchanged in modern practice for the past 106 years, except for the introduction of the pneumatic-type double-tourniquet preparation used in current clinical practice5,6,7 (Figure 21–1).