Local anesthetic systemic toxicity

Background

• Complication of lidocaine injection (accidental into systemic circulation)
  • 0.2% of nerve blocks
• Occurs within minutes of injection
  • 75% occuring within 5 minutes

Specific Anesthetics

• Lidocaine - 5 mg/kg max, no more than 300 mg (1% soln contains 10 mg/ml)
• Lidocaine with epi - 7 mg/kg man
• Bupivacaine - 2.5 mg/kg, no more than 175 mg (0.5% soln contains 5 mg/ml)
• Ropivacaine - 3 mg/kg
• Prilocaine - 6 mg/kg

Diagnosis

• CNS symptoms
  • Agitation
  • Auditory changes
  • Metallic taste
  • Seizures or drowsiness
  • Coma
  • Respiratory arrest
• Cardiovascular
  • First excitation
    • Tachycardia
    • Ventricular dysrhythmia
    • Hypertension
  • Followed by depression
    • Bradycardia
    • Conduction block
    • Asystole

Management

• Lipid emulsion, 20% solution
  • 1.5 mL/kg bolus over 1 minute
  • Then, 15 mL/kg per hour x 20-minute infusion (0.25 mL/kg/min for 20 min or until hemodynamic stability)
• Manage seizures with benzodiazepines; propofol is an option but may worsen CV toxicity
• ACLS modifications per ASRA (Am Soc of Regional Anesthesia):
  • Small initial doses of 100 μg boluses in adults
  • No vasopressin
  • Avoid CCBs and BBs
  • Amiodarone preferred in ventricular dysrhythmias

See Also

• Lidocaine
• Nerve Blocks (Main)

References

Kapitanyan R, Su M, Tarabar A. Local Anesthetic Toxicity. [Internet]. 2014 Available from: http://emedicine.medscape.com/article/1844551-overview.