Recent Modalities of Intravenous Regional Anaesthesia

Abstract

Intravenous regional anesthesia (IVRA) was first described by August Bier in 1908 for anesthesia of the hand and forearm, it is simple, easy, safe with success rate reaching 98%, but of short duration and is not suitable for many surgery, tourniquet pain and the lack of post operative analgesia. Latter on it became used in the lower limb surgery although it is less efficient. Local anesthesia is defined as the temporary or permanent loss of sensation in localized areas of the body by either chemical or physical modalities.The chemical modalities include the use of local anesthetic agents, which reversibly inhibit the generation and propagation ofimpulses in electrically excitable tissues producing a transient loss of autonomic, sensory and motor functions. Commonly used amino amides include lidocaine, mepivacaine, prilocaine, bupivacaine, etidocaine, and ropivacaine. Commonly used amino esters include cocaine, procaine, tetracaine, chloroprocaine, and benzocaine. Local anaesthetic action is dependent on blockade of the voltage activated Na+ channel (VASC). VASCs provide selective permeability to Na+ when the cell becomes depolarized from the resting potential (approximately −70 mV), which is maintained in quiescent neurons by the tonic activity of potassium ion (K+) channels. The complications of IVRA are mainly due to either local anaesthetic systemic toxicity, so the local anaesthetic used should be safe (can be injected intravenously), and of wide safety margin, or the tourniquet pain, pressure complications....etc