Local Anesthetics and Regional Anesthesia

Abstract

With cocaine first isolated from the coca leaves in Germany during the 1860s, local anesthetics are one of the oldest forms of anesthesia. Since that time, numerous local anesthetics have been developed, and much has been learned about their potential role in the perioperative period. Today, local anesthetics are widely utilized to provide anesthesia and analgesia by disrupting nerve conduction in the central nervous system (CNS) or peripheral nervous system (PNS). In order to understand the implications for local anesthetic utilization in the geriatric patient, this chapter reviews nerve anatomy and physiology before exploring local anesthetic pharmacology. Various local anesthetic types are examined with a corresponding review of mechanism of action, onset, metabolism, and potency. Factors prolonging duration are also considered, including local anesthetic type, perineural additives, and emerging local anesthetic formulations. The focus then shifts to local anesthetic utilization through regional anesthesia, including the benefits of regional techniques for the geriatric patient. Basic regional anesthesia techniques are discussed, including the role of ultrasound and indications for common peripheral nerve blocks. Finally, other important considerations are reviewed, including systemic toxicity, concerns with anticoagulant and antiplatelet medications, and the potential for postoperative falls, which are relevant to the geriatric population.