Which of the following describes the lipid emulsion dosing and general approach for LAST?

• A. Stop local anesthetic, call for help, secure airway, start 10% lipid emulsion bolus 1 mL/kg, then infusion 0.1 mL/kg/min.
• B. Stop local anesthetic, call for help, secure airway, start 20% lipid emulsion: bolus 1.5 mL/kg IV over 1 minute, then infusion 0.25–0.5 mL/kg/min; treat seizures with benzodiazepines and support.
• C. Continue local anesthetic and give methylene blue.
• D. Ignore lipid emulsion and manage with fluids only.

Answer: (B)

Lipid emulsion therapy works in LAST by acting as an intravascular lipid sink that binds the lipophilic local anesthetic, reducing its free concentration in plasma and tissues, while also providing an energy source to support cardiac and brain function. Because LAST can rapidly impair the heart and brain, prompt lipid rescue is a primary treatment alongside standard resuscitation measures.

The best approach is to give a 20% lipid emulsion as an initial bolus of 1.5 mL/kg IV over 1 minute, then start a continuous infusion of 0.25–0.5 mL/kg/min. If symptoms persist or recur, repeat boluses (up to a total of a few boluses depending on guidelines and clinical judgment) and consider increasing the infusion rate up to about 0.5 mL/kg/min. While administering lipid therapy, stop the local anesthetic and ensure airway support and hemodynamic stability. If seizures occur, treat with benzodiazepines and provide general supportive care.

This option is correct because it uses the standard 20% lipid emulsion dosing (bolus 1.5 mL/kg, then 0.25–0.5 mL/kg/min) and includes seizure management and overall supportive measures. The other choices use an incorrect lipid concentration or dosing, or omit lipid therapy entirely, or advocate inappropriate treatments.