What is Local Anesthetic Systemic Toxicity (LAST) and its initial management?

• A. A non-life-threatening reaction; continue injection.
• B. A potentially life-threatening reaction; stop injection, secure airway, provide oxygen, monitor; lipid emulsion therapy for severe cases.
• C. A skin rash at the injection site.
• D. Anaphylaxis requiring epinephrine.

Answer: (B)

Local Anesthetic Systemic Toxicity is a systemic emergency that can follow local anesthetic administration when enough drug enters the bloodstream to disrupt the central nervous system and cardiovascular function. It is potentially life-threatening, so the priorities are to stop the source, protect the airway, and support circulation. Immediately discontinue the local anesthetic, ensure an open airway, provide 100% oxygen, and monitor the patient. In more severe cases, lipid emulsion therapy is given because it helps to bind circulating anesthetic molecules and provides an energy source to stressed tissues, improving outcomes. This sequence—halt the drug, secure the airway, oxygen and monitoring, with lipid emulsion therapy for severe toxicity—best reflects the urgent, lifesaving approach to LAST.

The other options don’t fit LAST: a non-life-threatening reaction that prompts continuing the injection would worsen toxicity; a skin rash at the injection site is not systemic toxicity; and LAST differs from anaphylaxis, which has a different pathophysiology and management, with epinephrine not being the initial targeted treatment for LAST.