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A Bier block is a pain management procedure carried out to prevent pain in the arms or legs. This anesthetic technique was pioneered by Auguste Bier, a German doctor who worked at the forefront of spinal anesthesia and other anesthetic techniques in the early 20th century. The Bier block involves blocking the nerves that feed the affected limb, and it often is used in surgical procedures carried out on the arms, legs, hands or feet, in cases where the patient is unsuitable for general anesthesia. In addition, this technique can be used to treat chronic pain caused by pain disorders such as chronic regional pain syndrome.
People with certain medical conditions, such as heart or lung diseases, are not good candidates for general anesthetic, because of the increased risks of the procedure. In these situations, a Bier block is a much safer alternative when anesthesia is needed for an operation on an arm or leg. A patient who has this technique performed as an alternative to general anesthesia typically will be given a sedative or relaxant to help them feel comfortable during the operation.
The Bier block works by blocking circulation to the limb before injecting anesthetic into the area. Circulation is blocked via the use of a tourniquet similar to the inflatable cuff used to measure blood pressure. The cuff is placed on the upper arm or leg and then inflated to cut circulation to the limb. Next, blood is drained from the limb by raising it over the level of the head or by gentle squeezing of the limb. The end result is that the limb is almost completely drained of blood, and fresh blood is prevented from entering the limb via the tourniquet.
Next, the anesthetic is administered to the limb by means of an intravenous injection into the hand or foot. The anesthetic numbs the entire limb below the tourniquet, and the tourniquet prevents anesthetic from entering into the circulatory system at the same time that it prevents blood entering the limb. Once the anesthetic takes effect, the limb is ready to be operated on.
When the operation is complete, the tourniquet is deflated and removed, allowing blood to enter the limb and the remaining anesthetic to enter the circulatory system and be metabolized by the body. The Bier Block pain management technique is suitable for short operations only, because preventing blood from entering the limb means oxygen is not being supplied to the tissues. To prevent oxygen starvation from damaging the limb, the block can stay in place no longer than 60 to 90 minutes.
Some people cannot undergo a Bier block because of factors that increase the risks of the procedure. These include allergies to local anesthetic medications, the use of blood thinning medications and certain illnesses such as sickle cell disease and kidney disease. In addition, someone who has previously had a blood clot in a limb might not be able to safely undergo this procedure. Because allergies, medications and illnesses can increase the risks, it is important that a patient tell his or her doctor about any and all of these factors, even if they seem minor.