WHAT IS A BIER BLOCK?
This block is done using a large blood pressure cuff on the affected extremity. An IV is started in the affected extremity. The extremity is elevated, and wrapped tightly with an elastic wrap. This forces most of the blood above the cuff. The cuff is inflated and then the medication is injected into the IV. This medicine is absorbed by the nerve endings in the area below the cuff. This medicine is a combination of local anesthetic (numbing medicine) and a medication to slow or stop the pain impulses sent from your painful extremity. The goal of this is to reduce your pain. You will have an IV started and be connected to a BP and EKG monitor.
This block is used to treat sympathetically mediated pain in either the hand, arm, foot, or leg. It is most beneficial to pain below the knee or elbow. This type of pain is often diagnosed as Reflex Sympathetic Dystrophy (RSD).
This block can be safely performed as an outpatient at the PCC. Complications are rare, however there are potential risks with any block. These include:
Failure to do either of the above will require rescheduling your procedure.
If, after
you are home you have questions, these will be answered at your next
appointment. Please write them down to help you remember when you see
your doctor. If there are urgent questions or problems, such as a rash or
an IV site that does not heal, you should call the pain program and ask to speak
to the nurse, or leave a message for your doctor. If you believe that
your problem is an emergency, please go to the nearest emergency room and have
the physician contact one of our staff physicians.
Intravenous Regional Block (Bier Block)
Overview
General considerations
Intravenous
regional anesthesia was originally introduced by the German surgeon August K.
G. Bier in 1908; thus the name, "Bier block". Dr. Bier described a
complete anesthesia and motor paralysis after intravenous injection of prilocaine into a previously exsanguinated
limb. The resultant anesthesia is produced by direct diffusion of the local
anesthetic from the vessels into the nearby nerves. The technique was
reintroduced into clinical practice using lidocaine as a local anesthetic in
mid-1960s. Since its reintroduction, intravenous regional anesthesia is one of
the most commonly used regional anesthesia techniques in the
Regional anatomy
Peripheral
nerve endings of the extremities are nourished by small blood vessels.
Injection of a local anesthetic solution into a venous system results in
diffusion of the local anesthetic into the nerve endings with the consequent
development of anesthesia. This holds true for as long as the concentration of
the local anesthetic in the venous system remains relatively high. As it will
be apparent in the technique description, it is imperative that before the
injection, the venous system is exsanguinated to
prevent dilution of local anesthetic
Distribution of medication
Intravenous
regional block results in anesthesia of the entire extremity below the level of
the tourniquet. The duration of the anesthesia and analgesia are limited by the
duration tourniquet.
Patient positioning
The
patient is in the supine position with the arm to be blocked elevated to
achieve passive exsanguination. This is a crucial
step and care should be taken to allow 1-2 minutes for passive return of blood
to the dependent levels. An intravenous line is started on the side opposite to
be blocked before the block procedure.
Equipment
The standard regional anesthesia tray is prepared with the following
equipment:
A
double-cuff tourniquet with in-line valves
TIPS:
Technique
A
tourniquet is placed on the proximal arm of the extremity to be blocked. We use
a "double cuff" to increase the reliability of the technique and help
reduce the tourniquet pressure pain. Attention should be paid to generously
wrapping the arm at the tourniquet site with a soft cloth to prevent discomfort
on application of the tourniquet and skin bruising at the sites where the
tourniquet may pinch the unprotected skin.
The
tourniquet should be well secured and fastened to prevent its inadvertent
slipping or opening with consequent loss of anesthesia and/or toxic reactions
due to the access of the injected local anesthetic to the central circulation.
Prior to proceeding, it is of utmost importance to check the functionality of
the tourniquet by briefly inflating both tourniquet cuffs and squeezing the
inflated cuffs and observing that there are no leaks and that the pressure
raises with the squeezes.
TIPS:
A
small IV intravenous catheter (e.g, 22-gauge) is
introduced in the dorsum of the patient's hand of the arm to be anesthetized.
The catheter should be firmly taped in place to prevent its dislodgment during
the exsanguination with the Esmarch
or the injection procedure. The arm is then elevated and at least for 1 minute
to allow passive exsanguination, which occurs as the
large veins are emptied into the more proximal circulation. Then, a 5" Esmarch is applied systematically from the finger tips to
the distal cuff. The methodical application of the Esmarch
requires an assistant to properly hold the arm in the upright position and some
skill for proper application. The Esmarch should be
always slightly stretched before applying the next turn-wrap around the
extremity.
TIP: The proper and
methodical application of the Esmarch and
completeness of the exsangunation as the blood is
being squeezed from the vascular beds into the proximal circulation are the
most important steps to take to ensure a high success rate with this technique.
Once
the Esmarch is applied, the following maneuvers are
undertaken to complete the exsanguination of the
extremity:
The
cuffs should be inflated to a pressure of 100 mm Hg above the systolic blood
pressure, or at least 300 mm Hg. The Esmarch is then
unwrapped and the extremity is checked for color (pale skin) and arterial
occlusion (absence of the radial pulse).
TIP: Inadequate occlusion of
the arterial blood flow by the tourniquets can result in venostasis
and venous engorgement of the extremity, occasionally,
this makes it difficult to operate.
The
extremity is then lowered and the local anesthetic is slowly injected through
the previously inserted IV catheter.
Choice of local
anesthetic
Lidocaine
is the most commonly used drug for intravenous regional anesthesia. Most
authors recommend a larger volume of dilute solution of local anesthetic (e.g.,
50 mL of 0.5% lidocaine). However, some prefer a smaller volume
of a concentrated drug (e.g., 12-15 mL of 2%
lidocaine) because the dilution and drawing of the drug in multiple syringes is
time consuming and not necessary. In addition, smaller volumes are easier to
inject and simpler to prepare.
Several
other local anesthetic solutions and additives are reported to result in a
slight prolongation of analgesia such as, bupivacaine
0.25%, ropivacaine 0.2%, meperidine,
tramadol, ketorolac and clonidine. In the
case of CRPS, the medication of choice is bretylium.
Unfortunately, bretylium is no longer readily available
and therefore, clonidine seems to be used more frequently.
Block Dynamics and Perioperative Management
The
onset of anesthesia with this technique is within 5 minutes. The patient will
typically report "pins and needles" in the extremity. However, this
sign is almost always missed in our practice because we routinely administer
small doses of midazolam (2-4 mg IV) to ensure the
patient's comfort during the procedure. Most patients will invariably report
pressure at the site of the tourniquet after 30-45 minutes; sometimes even
earlier. When the discomfort becomes trouble-some and requires significant
additional sedation and analgesics, the distal cuff over the
anesthetized extremity is inflated and the proximal cuff is deflated.
This provides immediate relief of discomfort due to the pressure from the
proximal cuff. This maneuver will provide an additional 15-30 minutes of
comfort. When tourniquet pain is first reported by the patient, the surgeon
should be consulted for information on the expected time required to complete
the surgery. The proximal tourniquet should not be released prematurely. The
proper procedure for changing the tourniquet from the proximal to the distal
cuff is as follows:
TIP: It is important to
properly label the proximal and distal cuffs and their respective valves to avoid
deflation of the wrong cuff and the abrupt loss of anesthesia that would ensue
or risk of local anesthetic toxicity.
Proper procedure of deflating the tourniquet at
the end of surgery is also important to avoid the risk of local anesthetic
toxicity when the procedure is completed within 45 minutes after the injection
of local anesthetic. A two-stage deflation is suggested whereby the cuff is
deflated for 10 seconds and reinflated for 1 minute
before the final release. This practice allows for a more gradual
"washout" of local anesthetic.
TIP: The release of the tourniquet will result in a
rapid resolution of anesthesia and analgesia. The surgeon should be instructed
to infiltrate local anesthetic before the release of the tourniquet to prevent
a sudden, oncoming pain. When this is not possible, judicious doses of
analgesic should be administered preemptively in anticipation of postoperative
pain
Complications and How to
Avoid Them
Complications
of intravenous regional blocks are few and are mostly limited to systemic
toxicity from the local anesthetic that is related to problems with the
tourniquet.
|
Systemic toxicity of local anesthetic |
-The risk mainly comes from an inadequate tourniquet application
or equipment failure at the beginning of the procedure |
|
Hematoma |
-Use a small gauge IV catheter |
|
Systemic toxicity of Clonidine |
-The risk mainly comes from an inadequate tourniquet application
or equipment failure at the beginning of the procedure |
|
Engorgement of the extremity |
-Ensure that the tourniquet is fully functional and that the
arterial pulse is absent |
|
Exchomoses and subcutaneous
hemorrhage |
-The above principle applies. |
Bibliography