Difference between revisions of "Local anesthetic systemic toxicity"

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==Background==
 
==Background==
*Complication of lidocaine injection (accidental into systemic circulation)
+
*Life-threatening adverse reaction to local anesthetic toxicity.
**0.2% of nerve blocks
+
*Cases<ref name="Fencl">Fencl JL. Local anesthetic systemic toxicity: perioperative implications. AORN J. 2015 Jun;101(6):697-700.</ref>
*Occurs within minutes of injection
+
**Injection of local anesthetic into systemic circulation
**75% occuring within 5 minutes
+
**Exceeding the maximum dose of local anesthetic (see table below)
 +
**Absorption of anesthetic into systemic circulation by injection into extremely vascular area.
 +
*Incidence = ~0.2% of nerve blocks
 +
*Generally occurs within minutes of injection
  
 
{{Maximum doses of anesthetic agents}}
 
{{Maximum doses of anesthetic agents}}
  
 
==Clinical Features==
 
==Clinical Features==
*CNS symptoms
+
*CNS symptoms (typically occur before CVS symptoms<ref name="Fencl" />)
 
**Agitation
 
**Agitation
 
**Auditory changes
 
**Auditory changes
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**Coma
 
**Coma
 
**Respiratory arrest
 
**Respiratory arrest
*Cardiovascular
+
*Cardiovascular<ref name="Fencl" />
**First excitation
+
**Early signs
 
***Tachycardia
 
***Tachycardia
 
***Ventricular dysrhythmia
 
***Ventricular dysrhythmia
 
***Hypertension
 
***Hypertension
**Followed by depression
+
**Late signs
 
***Bradycardia
 
***Bradycardia
 
***Conduction block
 
***Conduction block
 +
***Cardiovascular collapse
 
***[[Asystole]]
 
***[[Asystole]]
  

Revision as of 07:54, 16 July 2015

Background

  • Life-threatening adverse reaction to local anesthetic toxicity.
  • Cases[1]
    • Injection of local anesthetic into systemic circulation
    • Exceeding the maximum dose of local anesthetic (see table below)
    • Absorption of anesthetic into systemic circulation by injection into extremely vascular area.
  • Incidence = ~0.2% of nerve blocks
  • Generally occurs within minutes of injection

Maximum Doses of Anesthetic Agents

Agent Without Epinephrine With Epinephrine Duration Notes
Lidocaine 5 mg/kg (max 300mg) 7 mg/kg (max 500mg) 30-90 min
  • 1% soln contains 10 mg/ml
  • 2% soln contains 20 mg/ml
Mepivicaine 7 mg/kg 8 mg/kg
Bupivicaine 2.5 mg/kg (max 175mg) 3 mg/kg (max 225mg) 6-8 hr
  • 0.5% soln contains 5 mg/ml
  • May cause cardiac arrest if injected intravascularly
  • Do not buffer with bicarbonate
Ropivacaine 3 mg/kg
Prilocaine 6 mg/kg
Tetracaine 1 mg/kg 1.5 mg/kg 3hrs (10hrs with epi)
Procaine 7 mg/kg 10 mg/kg 30min (90min with epi)

Clinical Features

  • CNS symptoms (typically occur before CVS symptoms[1])
    • Agitation
    • Auditory changes
    • Metallic taste
    • Seizures or drowsiness
    • Coma
    • Respiratory arrest
  • Cardiovascular[1]
    • Early signs
      • Tachycardia
      • Ventricular dysrhythmia
      • Hypertension
    • Late signs
      • Bradycardia
      • Conduction block
      • Cardiovascular collapse
      • Asystole

Differential Diagnosis

  • Anaphylaxis
  • Anxiety

Diagnosis

  • Clinical diagnosis

Workup

  • Directed by clinical picture
  • Blood levels of anesthetic are available, but not clinically useful.

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

External Links

Medscape:Local Anesthetic Toxicity

References

  1. 1.0 1.1 1.2 Fencl JL. Local anesthetic systemic toxicity: perioperative implications. AORN J. 2015 Jun;101(6):697-700.