Management of Local Anesthetic Systemic Toxicity

Immediate Management

The American Heart Association recommends the use of 20% intravenous lipid emulsion (ILE) as an antidote for local anesthetic systemic toxicity (LAST) from intra-arterial injection of bupivacaine or lidocaine during brachial block, which should be administered immediately upon recognition of toxicity 1, 2
Local anesthetic systemic toxicity can present with CNS symptoms first, including perioral numbness, metallic taste, tinnitus, facial tingling, confusion, agitation, or seizures 3, 4
The initial bolus of 20% lipid emulsion should be 1.5 mL/kg over 1 minute (approximately 100 mL for a 70 kg patient), followed by a continuous infusion of 0.25 mL/kg/min for 30-60 minutes 1, 2
Standard ACLS protocols should continue alongside lipid emulsion therapy, and epinephrine should be avoided or used in reduced doses (maximum 1 mcg/kg) due to complex pharmacodynamic interactions between lipid emulsion and vasopressors 1, 2

The American Heart Association provides specific dosing recommendations for lipid emulsion therapy, including a repeat bolus of 1.5 mL/kg once or twice for persistent cardiovascular collapse, and a maximum total dose of 10 mL/kg over the first hour 1, 2
Lipid emulsion creates a lipid compartment in the serum that sequesters lipophilic local anesthetics (especially bupivacaine) away from cardiac tissue, and also increases cardiac inotropy through other mechanisms 2

All 21 published cases of lipid emulsion use for bupivacaine-induced LAST demonstrated clinical improvement, and animal studies consistently show benefit of lipid emulsion in bupivacaine toxicity 2
The 2023 American Heart Association guidelines give this a Class IIa recommendation (reasonable to use) 1

Lipid emulsion 20% must be immediately available wherever regional anesthesia is performed, and staff should know the exact location of lipid emulsion storage 5