Hadzic's Regional Anesthesia > Part III. Clinical Practice of Regional Anesthesia > Section Seven. Intravenous Regional Blocks for the Upper & Lower Extremity > Chapter 41. Intravenous Regional Block for Upper & Lower Extremity Surgery Kenneth D. Candido, MD, Alon P. Winnie, MD

Intravenous Regional Block for Upper & Lower Extremity Surgery: Introduction

"The technique of intravenous regional anesthesia (IVRA) was first introduced by August Bier in 1908.¹ 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 Dr. 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 compartments.^2–4 After injecting the local anesthetic, Dr. 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 min, 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. Dr. Bier's conclusion was that two mechanisms of anesthesia were associated with his technique: peripheral infiltration block and conduction block. The technique, as originally described..."