Local Anesthetic Systemic Toxicity (LAST) Pathway

Step-by-step decision

Choose step by step as prompted; reaching an endpoint gives the management recommendation. You can go back a step or restart anytime.

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Full pathway

1. [Decision] Severity of toxicity
   CNS/cardiovascular toxicity after local anesthetic? (Excessive plasma local anesthetic (often inadvertent intravascular injection during a nerve block; bupivacaine is the most cardiotoxic). Progressive biphasic course: first CNS excitation (perioral numbness, tinnitus, metallic taste, agitation, seizures) → depression; cardiovascular from hypertension → hypotension/bradycardia/conduction block/ventricular arrhythmia/arrest, can arrest suddenly (delayed from absorption).)
   • Severe: seizures/arrhythmia/hypotension/arrest → Severe → lipid emulsion rescue
   • Early mild signs (perioral numbness/tinnitus/dizziness) → Early mild signs · stop and monitor
2. [End] Early mild signs · stop and monitor
   Early mild signs (perioral numbness/tinnitus/metallic taste/dizziness/agitation): immediately stop injecting the local anesthetic, call for help, oxygen/airway monitoring, continuous monitoring (symptoms can progress or be delayed); have 20% lipid emulsion and resuscitation ready. Escalate at any seizure/cardiovascular instability.
3. [End] Severe → lipid emulsion rescue
   Severe (seizures/arrhythmia/hypotension/arrest): immediately stop injecting, oxygen/airway; treat seizures with a benzodiazepine (avoid large-dose propofol which worsens cardiac depression); 20% lipid emulsion (ILE) at the first sign: 1.5 mL/kg bolus (~100 mL) then 0.25 mL/kg/min infusion, repeat boluses/double the rate if unstable. Manage arrest by modified ACLS — reduce epinephrine dose, avoid vasopressin/calcium channel blockers/beta-blockers/further local anesthetic, amiodarone preferred for arrhythmia; consider ECMO if refractory.

Source guidelines & references

• Local anesthetic systemic toxicity (ASRA 2020 practice advisory; NYSORA)

This pathway is our own synthesis of the decision logic in the guidelines above (not the guideline verbatim); thresholds and workflows change as guidelines update — in practice follow the latest guideline, your institution's protocol and the individual patient.

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