LAST — recognize early, treat with lipid
Local anesthetic systemic toxicity
Mnemonic device
Tinnitus → Twitching → Tonic-clonic → Tachy/brady → flatline
Mapping
Early
Tinnitus, metallic taste, perioral tingling, lightheadedness — STOP injecting
Mid
Muscle twitching, dysarthria, agitation — escalating CNS
Late
Tonic-clonic seizure → coma → arrhythmia (wide-complex) → cardiac arrest
Tx
Airway + 100% O2; benzo for seizure; INTRALIPID 20% 1.5 mL/kg bolus then 0.25 mL/kg/min × 10 min minimum (or until stable + 10 min after)
Avoid
AVOID lidocaine, vasopressin, beta-blockers, CCBs. Use SMALL-dose epi (≤1 mcg/kg). Bupivacaine — most cardiotoxic; bind to lipid sink.
Clinical note: Ratio for lipid: 1.5 mL/kg lean body wt bolus, then 0.25 mL/kg/min infusion. Max ~12 mL/kg total. Have lipid available wherever neuraxial/peripheral blocks are performed.