Mechanisms and Efficacy of Intravenous Lipid Emulsion Treatment for Systemic Toxicity From Local Anesthetics

Abstract

Local anesthetics are widely used clinically for perioperative analgesia to achieve comfort in medical treatment. However, when the concentration of local anesthetics in the blood exceeds the tolerance of the body, local anesthetic systemic toxicity (LAST) will occur. With the development and popularization of positioning technology under direct ultrasound, the risks and cases of LAST associated with direct entry of the anesthetic into the blood vessel have been reduced. Clinical occurrence of LAST usually presents as a series of severe toxic reactions such as myocardial depression, which is life-threatening. In addition to basic life support (airway management, advanced cardiac life support, etc.), intravenous lipid emulsion (ILE) has been introduced as a treatment option in recent years and has gradually become the first-line treatment for LAST. This review introduces the mechanisms of LAST and identifies the clinical symptoms displayed by the central nervous system and cardiovascular system. The paper features the multimodal mechanism of LAST reversal by ILE, describes research progress in the field, and identifies other anesthetics involved in the resuscitation process of LAST. Finally, the review presents key issues in lipid therapy. Although ILE has achieved notable success in the treatment of LAST, adverse reactions and contraindications also exist; therefore, ILE requires a high degree of attention during use. More in-depth research on the treatment mechanism of ILE, the resuscitation dosage and method of ILE, and the combined use with other resuscitation measures is needed to improve the efficacy and safety of clinical resuscitation after LAST in the future.

Case Report: Successful Intravenous Lipid Emulsion Therapy for Canine Amphetamine Toxicosis

“…This redirects the toxin-bound lipid to organs such as the liver, hastening its metabolism. Other proposed theories include the utilization of free fatty acids as an energy source by the myocardium, restoration of the mitochondrial function, an increase in intracellular calcium, and reduction of nitric oxide and vasodilatation ( 5 , 8 , 9 ).…”

“…The complete mechanism of how IVLE works with lipophilic agents is not fully understood and there are several theories describing the mechanism of action, with the primary two being the “lipid sink” and “lipid shuttle” theories. Both theories describe accelerated clearance of the lipid-bound toxin from the body and redirection of the toxin from sensitive organs such as the brain and heart ( 5 ). IVLE has a low incidence of adverse side effects when used according to recommended guidelines ( 6 , 7 ).…”

Intravenous lipid emulsion for the treatment of acute lipid-soluble anesthetic drug toxicity in pediatric patients

“…Patients are prone to clinical manifestations of intoxication in the form of a weakened heartbeat and coma. The shuttle process of lipid emulsions facilitates the binding of lipid molecules to lipid-soluble drugs and their redistribution to the liver and muscle, and the binding and redistribution process is much faster than the natural metabolism, thus accelerating the removal of drugs from organs metabolism of drugs by the liver [11]. In a study by Litonius et al on the therapeutic effects of lipid emulsions on the lipid-soluble drug bupivacaine, it was found that the half-life of bupivacaine in plasma concentration decreased from 45 minutes to 25 minutes after the use of intravenous lipid emulsions [12].…”

Combinatorial Therapy of Cancer: Possible Advantages of Involving Modulators of Ionic Mechanisms

“…Clinical aspects of this topic were analyzed subsequently in further detail in a series of articles published in 2021 and 2022 ( —accessed on 15 April 2022). The pre-clinical case seemed strong, with LAs suppressing the viability and migratory capacity of breast cancer cells, dependent on the concentration and duration of drug application [ 12 , 13 , 14 , 15 ]. At least a part of the suppressive effect of LAs could occur via VGSC inhibition [ 16 ].…”