When is lipid emulsion therapy indicated for treatment of local anesthetic toxicity?

Updated: Jan 09, 2019
  • Author: Raffi Kapitanyan, MD; Chief Editor: David Vearrier, MD, MPH  more...
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Intravenous infusion of a 20% lipid emulsion (eg, Intralipid 20%) has become an accepted part of treatment for systemic toxicity from local anesthetics, and particularly for cardiac arrest that is unresponsive to standard therapy. ASRA guidelines recommend considering the use of lipid emulsion therapy at the first signs of systemic toxicity from local anesthetics, after airway management. [2]

The proposed mechanism is that lipid infusion creates a lipid phase that extracts the lipid-soluble molecules of the local anesthetic from the aqueous plasma phase (lipid sink hypothesis). An in vitro study demonstrated high solubility of local anesthetics in lipid emulsions and high binding capacity of these emulsions. [13] Other possible mechanisms, which may work in concert with the lipid sink effect, include fatty acid supply, reversal of mitochondrial dysfunction, inotropic effect, glycogen synthase kinase–3β (GSK-3β) phosphorylation, inhibition of nitric oxide release, and reversal of cardiac sodium channel blockade. [9]

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