Thursday Conference Content & EKG Review

Lidocaine Anesthetic Systemic Toxicity (LAST)

Dr. Carlos Cevallos, M.D.


Local anesthetics are a class of medications that includes esters and amides such as benzocaine/procaine and bupivacaine/lidocaine respectively

Local anesthetics MOA: Primarily through inhibition of voltage-gated sodium channels

Risk Factors for development of LAST:

  • High volume nerve blocks, lack of ultrasound guidance, prolonged high-dose lidocaine infusions, hepatic dysfunction, cardiac disease, renal disease, pregnancy

Clinical Presentation: Primarily affects the CNS and cardiovascular system

CNS: usually presents first

  • Sensory: tinnitus, perioral numbness, perioral numbness, metallic taste, blurred vision
  • Dizziness
  • Delirium
  • Tremors, lethargy
  • Dysarthria
  • Seizures
  • Respiratory depression

Cardiovascular symptoms:

  • Initial: Sympathetic activation (tachycardia, HTN, diaphoresis)
  • Late: Bradycardia, AV block, widened QRS, ventricular arrhythmias, PEA/Asystole


  • Immediately discontinue the anesthetic
  • Lipid Emulsion therapy:
    • Initial: 1.5ml/kg bolus of Intralipid 20% followed by infusion at 0.25ml/kg/min until 10 minutes after hemodynamic stability is obtained
    • If HD stability not obtained then you may re-dose the 1.5ml/kg bolus twice and increase the infusion to 0.5ml/kg/min