Intravenous regional anesthesia (IVRA) or Bier's block anesthesia is an anesthetic technique on the body's extremities where a

local anesthetic A local anesthetic (LA) is a medication that causes absence of all sensation (including pain) in a specific body part without loss of consciousness, providing local anesthesia, as opposed to a general anesthetic, which eliminates all sensati ...

is injected intravenously and isolated from circulation in a target area. The technique usually involves

exsanguination Exsanguination is the loss of blood from the circulatory system of a vertebrate, usually leading to death. The word comes from the Latin 'sanguis', meaning blood, and the prefix 'ex-', meaning 'out of'. Exsanguination has long been used as a met ...

of the target region, which forces blood out of the extremity, followed by the application of

pneumatic Pneumatics (from Greek 'wind, breath') is the use of gas or pressurized air in mechanical systems. Pneumatic systems used in Industrial sector, industry are commonly powered by compressed air or compressed inert gases. A centrally located a ...

tourniquets to safely stop blood flow. The anesthetic agent is intravenously introduced into the limb and allowed to diffuse into the surrounding tissue while tourniquets retain the agent within the desired area.

History

The use of tourniquets and injected anesthesia to induce localized anesthesia was first introduced by August Bier in 1908. He used an Esmarch bandage to exsanguinate the arm and injected procaine between two tourniquets to rapidly induce anesthetic and

analgesic An analgesic drug, also called simply an analgesic, antalgic, pain reliever, or painkiller, is any member of the group of drugs used for pain management. Analgesics are conceptually distinct from anesthetics, which temporarily reduce, and in s ...

effects in the site. Though it proved effective, IVRA remained relatively unpopular until C. McK. Holmes reintroduced it in 1963. Today, the technique is common due to its economy, rapid recovery, reliability, and simplicity.

Methods

Protocols vary depending on local standard procedures and the extremity being operated on. A vast majority of practitioners begin by exsanguinating the limb as Bier did with an elastic bandage ( Esmarch bandage), squeezing blood proximally toward the heart, then pneumatic tourniquets are applied to the limb and inflated 30mmHg above arterial pressure to occlude all blood vessels and then the elastic bandage is removed. A high dose of local anesthetic, typically

lidocaine Lidocaine, also known as lignocaine and sold under the brand name Xylocaine among others, is a local anesthetic of the amino amide type. It is also used to treat ventricular tachycardia and ventricular fibrillation. When used for local anae ...

or prilocaine without adrenaline, is slowly injected as distally as possible into the exsanguinated limb. The veins are filled with the anesthetic, with the anesthetic setting into local tissue after approximately 6–8 minutes, after which the surgery, reduction, or manipulation of the region may begin. It is important that the region is isolated from active blood flow at this time. Analgesic effect typically remains for up to two hours depending on the dosage and type of anesthetic agent being used. The wait time and isolation of blood flow from the region is important for avoiding an overdose of the anesthetic agent in the blood which can lead to hypotension, convulsions, arrhythmia, and death. Cardiotoxic local anesthetic agents like bupivacaine and etidocaine are strictly contraindicated.

Safety

The safety and effectiveness of IVRA is well established in clinical literature. However, cardiotoxic local anesthetic agents like bupivacaine and etidocaine are contraindicated. Shorter procedure times (for up to 2 hours) are preferred when IVRA is applied on the distal limb, especially on the forearm, except when the patient has contraindications to tourniquet use (such as in

sickle cell anemia Sickle cell disease (SCD), also simply called sickle cell, is a group of inherited haemoglobin-related blood disorders. The most common type is known as sickle cell anemia. Sickle cell anemia results in an abnormality in the oxygen-carrying ...

, where there is a risk of massive hemolysis due to low oxygen tension or hemolytic crisis due to restricted blood flow). A systematic review of IVRA-related complications found 64 cases reported between 1964 and 2005, which compares favorably against other techniques. The type of anesthetic agent, improper equipment use or selection, and technical error are prominent factors in most cases of

morbidity A disease is a particular abnormal condition that adversely affects the structure or function of all or part of an organism and is not immediately due to any external injury. Diseases are often known to be medical conditions that are asso ...

related to IVRA. Modern practice now includes various safeguards to improve patient safety.

Equipment

Reports from anesthesiologists and surgeons cite proper selection, inspection, and maintenance of equipment as important safety measures. The safest tourniquet equipment should have IVRA-specific features such as independent limb occlusion pressure measurements for each channel, as well as dual-bladder tourniquet cuffs combined with dedicated safety lockouts that reduce

human error Human error is an action that has been done but that was "not intended by the actor; not desired by a set of rules or an external observer; or that led the task or system outside its acceptable limits".Senders, J.W. and Moray, N.P. (1991) Human Er ...

. Additionally, IVRA protocols should include procedures for regular preventative maintenance of the equipment and performance testing, whether manual or automated, prior to surgery.

Drug additives

Adjuvants improve the safety of IVRA by promoting anesthetic action and minimizing side effects. For example, a

benzodiazepine Benzodiazepines (BZD, BDZ, BZs), colloquially known as "benzos", are a class of central nervous system (CNS) depressant, depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed t ...

and fentanyl are often added to prevent seizures and to improve nerve blockage, respectively. One survey of anesthesiologists who practice intravenous regional anesthesia found that 98% used adjuvant benzodiazepines and/or opioids, with benzodiazepines always being given systemically (to the whole body and brain), whereas opioids can be given either systemically or locally (only into the limb being anesthetized). Most providers use drugs from both classes, a benzodiazepine and an opioid, along with the local anesthetic.

Procedural safeguards

Improved protocols, including adherence to standardized practice, may also help ameliorate the chance and the effect of complications. For example, limb protection padding and a snug tourniquet application prevents tissue damage, while sufficient but not excessive tourniquet pressure ensures that anesthetics remain within the limb without risking injury. Care should be taken to avoid the premature release or a lack of inflation in the cuff. Should complications occur, constant physiological monitoring and ready access to resuscitative drugs and equipment facilitates a speedy recuperative response.

References

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External links

Advances in IVRA Instrumentation
Regional anesthesia