Intravenous lipid emulsion

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Related FACEM curriculum (2022) learning objectives:

• ME 3.8.1.6(e) Principles of management of toxicological presentations including: Indications for antidotes
• ME 3.8.2.4 Identify the appropriate antidote or antivenom.

Toxicological Indications

• Local anaesthetic-induced cardiovascular collapse resistant to standard resuscitation protocols.
• Rescue therapy for refractory cardiac instability or arrest caused by lipophilic agents (e.g., propranolol, tricyclic antidepressants, verapamil).

Contraindications

• Inadequate standard resuscitative efforts.
• Hypersensitivity to egg, soya, or peanut protein.

Mechanism of Action

• Introduces intravascular lipid phase to sequester lipophilic agents from tissue binding sites.
• Enhances myocardial ATP synthesis by reversing inhibition of fatty acid delivery to mitochondria.
• Restores myocyte function through calcium and potassium channel activation, increasing intracellular calcium.

Administration

Standard Protocol

• Continue standard resuscitation protocols during IVLE use.
• Bolus Administration:
  • 1–1.5 mL/kg of IVLE 20% over 1 minute.
  • Repeat bolus 1–2 times at 3–5-minute intervals if needed.
• Infusion:
  • Start at 0.25 mL/kg/min until haemodynamic stability is restored.
  • Increase to 0.5 mL/kg/min if hypotension persists.
• Total dose >8 mL/kg is unlikely to be beneficial.

Therapeutic Endpoints

• Return of spontaneous circulation with stable haemodynamics.
• Restart infusion if hypotension recurs upon cessation.

Adverse Drug Reactions and Management

Immediate

• Allergic reactions, including anaphylaxis.

Other Reactions

• Pulmonary hypertension, acute lung injury, haematuria, hypertriglyceridaemia, pancreatitis.
• Supportive management is required for adverse effects.

Specific Considerations

• Pregnancy: Safety not established but should not be withheld if indicated.
• Paediatrics: No reported use but should not be withheld if indicated.

Handy Tips

• For a 70-kg adult:
  • IV bolus of 100 mL followed by infusion of 400 mL over 20 minutes during advanced life support.
  • Repeat boluses up to twice more if no response.
  • If hypotension persists, increase infusion rate to 400 mL over 10 minutes.

Controversies

• Optimal dose and regimen for IVLE remain uncertain.
• Short- and long-term adverse effects require further study.
• Role of IVLE in non-local anaesthetic poisoning needs validation.
  • Benefits in cases of altered mental status from poisoning are doubtful.
  • May divert attention from resuscitation and airway priorities.