AnesthesiaHub
TutorialsDrugsCalcsEmergencySubsQ-BankResourcesAIBookmarks
All cards
Crisis Card

Local Anesthetic Systemic Toxicity (LAST)

Lipid emulsion is the antidote. Modified ACLS — small epi doses, avoid vasopressin.

Lipid emulsion 20% — 1.5 mL/kg bolus → 0.25 mL/kg/min infusion

Recognize

  • Perioral numbness, tinnitus, metallic taste
  • Agitation → seizure (CNS excitation)
  • Drowsiness, coma (CNS depression)
  • Bradycardia, AV block, ventricular arrhythmia, refractory arrest
  • Onset typically within minutes of injection

Doses

Lipid emulsion 20% bolus
1.5 mL/kg over 1 min
~100 mL in a 70-kg adult
Lipid emulsion infusion
0.25 mL/kg/min
Double to 0.5 mL/kg/min if BP remains low
Epinephrine
≤ 1 mcg/kg per dose
NOT standard 1 mg ACLS doses
Midazolam (seizure)
1–2 mg IV

Sequenced Actions

  1. 1
    Get help — manage airway with 100% O₂
    • Hypoxemia and acidosis dramatically worsen toxicity
    • Intubate if needed for airway protection
  2. 2
    Stop seizures
    • Midazolam 1–2 mg IV (preferred)
    • Small doses of propofol acceptable, but avoid if CV unstable
    • Avoid large propofol doses (more myocardial depression)
  3. 3
    Lipid emulsion 20%
    • 1.5 mL/kg bolus over 1 min (~100 mL in an adult)
    • Infusion 0.25 mL/kg/min (~18 mL/min in 70 kg)
    • Continue at least 10 min after circulatory stability
    • Repeat bolus q3–5 min for persistent CV collapse
    • Maximum 10 mL/kg over first 30 min
  4. 4
    Modified ACLS
    • ↓ Epinephrine doses to ≤ 1 mcg/kg (NOT standard 1 mg)
    • AVOID: vasopressin, calcium channel blockers, β-blockers, local-anesthetic antiarrhythmics (lidocaine, procainamide)
    • Amiodarone preferred for ventricular arrhythmia
    • Continue CPR as long as needed — full recovery reported after > 1 h CPR
  5. 5
    If refractory
    • Activate cardiopulmonary bypass / ECMO early
    • Notify perfusion / cardiac surgery
    • Maintain CPR throughout
  6. 6
    Post-event
    • Continue monitoring at least 4–6 h after resolution
    • Report to LipidRescue registry (lipidrescue.org)
    • Refer to allergist if no clear dose explanation

Common Pitfalls

  • Giving full-dose epinephrine (1 mg) — worsens outcome in LAST.
  • Giving vasopressin, β-blocker, or CCB.
  • Stopping CPR too early — recovery after prolonged CPR is well-documented.
  • Forgetting that propofol is NOT a lipid emulsion substitute (lipid content too low).

References & Further Reading

  1. 1
    GuidelineOpen source

    Neal JM, Neal EJ, Weinberg GL. American Society of Regional Anesthesia and Pain Medicine Local Anesthetic Systemic Toxicity Checklist: 2020 Version. Reg Anesth Pain Med. 2021;46(1):81-82.

  2. 2
    Journal

    Weinberg GL. Treatment of local anesthetic systemic toxicity (LAST). Reg Anesth Pain Med. 2010;35(2):188-193.

  3. 3
    Textbook

    Flood P, Rathmell JP, Shafer S. Stoelting's Pharmacology and Physiology in Anesthetic Practice. 5th ed. Philadelphia: Wolters Kluwer; 2015.

  4. 4
    Textbook

    Gropper MA, Miller RD, Cohen NH, et al., eds. Miller's Anesthesia. 9th ed. Philadelphia: Elsevier; 2020.

Citations are provided to direct further study. Always check the most current edition of guidelines and society recommendations — the information in this chapter is a teaching summary, not primary source material.

Previous
Malignant Hyperthermia
Next
Anaphylaxis