Practical guide for the management of systemic toxicity caused by local anesthetics

Abstract

Systemic toxicity from local anesthetics can occur in any of the wide range of situations in which these agents are used. This practical guide is created to generate a shared awareness of the prevention, diagnosis, and treatment of local anesthetic systemic toxicity among all medical professionals who perform nerve blocks. Systemic toxicity of local anesthetic is induced by an increase of its protein-unbound plasma concentration. Initial symptoms are characterized by central nervous system signs such as excitation, convulsions, followed by loss of consciousness and respiratory arrest. These symptoms are often accompanied with cardiovascular signs such as hypertension, tachycardia and premature ventricular contractions. Further increase of plasma concentration of local anesthetic induces bradycardia, conduction disturbances, circulatory collapse and asystole. The incidence of local anesthetic systemic toxicity is 1–11 cases per 10,000. Infants, patients with decreased liver function and low cardiac output are vulnerable to systemic toxicity. When performing regional anesthesia, the guideline-directed monitoring, securing a venous line, preparation of medication to treat convulsions and lipid emulsions are required. For prevention of local anesthetic systemic toxicity, small-dose, divided administration, using agents with low toxicity such as ropivacaine and levobupivacaine, performing an aspiration test are recommended. If systemic toxicity is suspected, halt administration of local anesthetic, request assistance, secure venous line, airway, administration of 100% oxygen and if necessary tracheal intubation and artificial respiration should be immediately performed. Benzodiazepines are recommended to treat convulsions. Administration of 20% lipid emulsion according to the protocol is recommended to treat severe hypotension and arrhythmia.

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