Intravenous regional anesthesia

Intravenous regional anesthesia
Intervention
Intravenous regional anesthesia (IVRA) using older tourniquet equipment. Modern electronic instruments include more safety features specifically for IVRA.
MeSH	D000771
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Intravenous regional anesthesia (IVRA) or Bier block anesthesia is an anesthetic technique for surgical procedures on the body's extremities where a local anesthetic is injected intravenously. The technique usually involves exsanguination, which forces blood out of the extremity, followed by the application of pneumatic tourniquets to safely stop blood flow. The anesthetic agent is introduced into the limb and allowed to set in while tourniquets retain the agent within the desired area.

The use of tourniquets and injected agents 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 quickly produce anesthetic and analgesic 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.

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 then applied to the limb and inflated 30mmHg above arterial pressure to occlude all blood vessels and then the elastic bandage is removed. The local anesthetic, typically lidocaine(DOC) or prilocaine without adrenaline, is slowly injected as distally as possible into the exsanguinated limb. The veins are filled with the anesthetic and sets in after approximately 6–8 minutes,after which the surgery may begin. Analgesic effect remains for upto 2 hours.The wait time is important for avoiding toxic levels of anesthetics in the systemic bloodstream which can lead to hypotension convulsions and even death in extreme cases so,cardiotoxic LA like bupivacaine and etidocaine are strictly contraindicated.