++
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 by Dr. Bier, remains
essentially unchanged in modern practice for the past 95 years, except for
the introduction of the double-tourniquet preparation used in current
clinical practice5–7 (Figure 41–1).
++
++
Bier block can be used for brief surgical procedures or manipulations of
the upper or lower extremity. However, the technique found its greatest
acceptance for use for the upper extremity because tourniquet problems and
other safety issues seem to arise more frequently when IVRA is used on the
lower extremities. Bier block is also a procedure that has found utility as
a treatment adjunct for patients suffering from complex regional pain
syndromes (CRPS) (formerly know as reflex sympathetic dystrophy, or
sympathetically maintained pain) as an alternative to repeated sympathetic
blocks. In this regard, IVRA has been shown to decrease neurogenic
inflammation, a phenomenon possibly associated with CRPS, with little
impairment of sensory function, at least when mepivacaine is the local
anesthetic chosen for the block. Sensibility to cold is significantly
decreased 10 and 30 min after the block, even with a reduction in the skin
temperature on the blocked side.8 Chemical sympathectomy
using IVRA with agents such as guanethidine or bretylium may last up to
5 days, as compared with local anesthetic blocks, which typically provide
analgesia lasting only several hours. Quantitative sensory testing before
and after such blocks has demonstrated that it ...