A 28-year-old parturient receives epidural bupivacaine 0.5% (20 mL) for labour analgesia. Thirty seconds after injection she becomes obtunded, develops generalised convulsions, followed by cardiovascular collapse with a wide QRS complex on ECG. Intralipid 20% is prepared. What is the recommended loading dose of Intralipid for local anaesthetic systemic toxicity (LAST)?

• A 0.5 mL/kg bolus
• B 3 mL/kg bolus
• C 5 mL/kg bolus over 30 minutes
• D 1.5 mL/kg IV bolus over 1 minute, followed by 0.25 mL/kg/min infusion ✓

Explanation

Local anaesthetic systemic toxicity (LAST) — especially from bupivacaine — causes CNS toxicity (seizures) followed by cardiotoxicity (prolonged QRS, ventricular arrhythmias, cardiovascular collapse) due to bupivacaine's high lipid solubility and sodium channel kinetics. Intralipid emulsion therapy acts as a lipid sink, extracting free bupivacaine from cardiac tissues. The AAGBI/ACRA protocol: 20% Intralipid 1.5 mL/kg bolus IV over 1 minute, then infusion at 0.25 mL/kg/min; bolus may be repeated twice. Max cumulative dose ~12 mL/kg. Concomitant ACLS, airway management, and avoidance of vasopressin/lignocaine/calcium channel blockers are essential.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.