[Local anesthetic systemic toxicity-Part 1: recognizing and understanding : Pathophysiology, risk factors and...

Local anesthetic systemic toxicity (LAST) is a rare but potentially life-threatening complication of regional anesthesia. The increasing popularity of regional anesthesia of all kinds means that the risk of encountering LAST in clinical practice is nevertheless real.Part 1 of this CME-article focuses on the recognition and understanding of LAST, providing an up-to-date overview of its pathophysiology, risk factors, and clinical presentation.The pathophysiological processes underlying local anesthetic systemic toxicity (LAST) stem from the interplay of various complex molecular mechanisms involving ion channels within the central nervous system, the myocardium and peripheral vasculature. Furthermore, the cardiac toxicity associated with LAST can be partly explained by a pronounced dysregulation of mitochondrial energy metabolism. Clinically, LAST manifests as a broad and often atypical spectrum of neurological and cardiac symptoms, which do not necessarily occur in a defined sequence. Specific and important risk factors arise from extreme age groups, pre-existing medical conditions (particularly those affecting the cardiac and metabolic systems), the choice of regional anesthesia technique and the dosing of the local anesthetic. Building upon this foundation, part 2 of this article addresses the management and prevention of LAST and presents strategies for acute management (including lipid rescue) and prophylaxis.