b) Intravenous Lipid Emulsion (ILE)
Intravenous lipid emulsion (ILE) will give the blood sample a lipemic appearance as shown. Initially used as a nutritional supplement, ILE has been studied and used as a rescue therapy for local anesthetic toxicity [1,2]. The mechanism of action is not fully understood, but the most common theory is the “lipid sink;” distributing the drugs away from the heart and brain and serving as a direct fuel source for cardiac muscle . Lipid emulsion has since been utilized in overdose cases involving several lipophilic cardiovascular and neurotoxic medications with varying results [3-6]. There are several formulations of lipid emulsions commercially available, with the most commonly reported being 20% Intralipid®, a sterile fat emulsion consisting of 20% soybean oil .
When would you use ILE for poisoning?
- The best evidence for the use of lipid emulsion is in severe local anesthetic systemic toxicity (LAST), predominantly with long acting anesthetics such as bupivacaine [3-6].
- LAST is characterized by seizures, CNS depression, cardiac conduction defects, arrhythmias, and cardiac arrest.
- Use of ILE in Non-LAST poisonings show inconsistent results [6,8].
- ILE can be considered with serious hemodynamic/CNS instability from non-LAST toxins with high lipid solubility such as tricyclic antidepressants, verapamil, propranolol, cocaine, buproprion, and others .
How do you administer ILE? 
- Using the 20% Intralipid® solution, a 1.5 mL/kg initial bolus is given over 2-3 minutes.
- The bolus may be repeated for persistent cardiovascular collapse.
- Maintenance rate is 0.25 mL/kg/min for 3-5 minutes with reassessment.
- If benefit, consider continuing rate at 0.025 mL/kg/min to limit cumulative dosing.
- If re-emergence of instability consider repeat bolus or increasing infusion rate up to a maximum of 0.5 mL/kg/min.
- Although there is no known maximal dose, 10mL/kg has been suggested.
What are complications of ILE? [9, 10]
- Due to lipemia, interference with laboratory assays such as bilirubin, glucose, potassium
- Acute pancreatitis
- Adult respiratory distress syndrome
- Possible interference with dialysis and ECMO
- Complications are worsened by prolonged or rapid infusion
- Unclear what the effects may be on other resuscitative medications
- Lipid emulsion is the antidote for severe CNS or cardiac effects after local anesthetic toxicity.
- It can be considered for life threatening toxicity of lipophilic cardiovascular and neurotoxic medications.
- Lipid emulsion interferes with some common labs and can cause multiple medical complications, particularly if rapidly infused or with prolonged infusions.