Early Versus Late Deflation of Distal Tourniquet in Intravenous Regional Anesthesia With and Without Ketorolac in Hand & Forearm Surgery

Bier block , or intravenous regional anesthesia (IVRA), is a method of anesthesia for upper extremity surgeries. IVRA was first described by August Bier in 1908, and after a period of latency, it began to gain widespread use after Holmes reemphasized its use in 1963. Bier blocks are technically easy to perform, and the rates for successful anesthesia approach 98%. Furthermore, when compared with brachial plexus blocks for outpatient hand and upper extremity surgery, IVRA may realize lower costs and faster postanesthesia recovery.

Although a reliable source of anesthesia, IVRA has been associated with some disadvantages. Some patients cannot tolerate the tourniquet-mediated arm pain, and there are also reports of neurologic injury and compartment syndrome caused by the tourniquet. Perhaps the most serious complications associated with IVRA relate to the potential systemic toxicity of the local anesthetics used. If the local anesthetic gains access to a patient's systemic circulation, the central nervous system (CNS) and cardiovascular system can be affected. The CNS is usually affected first, with symptoms including dizziness, tinnitus, perioral paresthesia, and seizures. Anesthetic-induced toxicity of the cardiovascular system may manifest as hypotension, bradycardia, arrhythmias, or cardiac arrest.

Historically, the tourniquet used in IVRA is left inflated for a minimum of 20 minutes. Theoretically, this allows time for the local anesthetic to bind to the tissues and, consequently, prevent a large bolus of drug from entering the systemic circulation. However, this tourniquet time appears to be arbitrary, and no safe time interval between anesthetic drug injection and tourniquet deflation has been established.