Local Anaesthetic Toxicity

Question 1

What are the classic signs and symptoms of local anaesthetic toxicity?

Answer 1

1. Tingling in lips and tongue
2. Metallic taste
3. Dysphoria
4. Blurred vision
5. Tinnitus
6. Restlessness
7. Confusion
8. Loss of consciousness
9. Seizures
10. Hypotension
11. Cardiovascular collapse

Question 2

What would be some common differential diagnoses for LA toxicity?

Answer 2

1. Vasovagal episode
2. Anxiety
3. Anaphylaxis
4. Total spinal
5. Epilepsy

Question 3

Outline an immediate management strategy for local anaesthetic toxicity

Answer 3

• Cease administration of local anaesthetic
• Call for help
• ABC approach
• Intubate if dec LOC
• Hyperventilate if possible as acidosis increases cardiotoxicity of local anaesthetics
• Manage hypotension with pressors and IV fluids
• Give atropine for bradycardia
• If presents in cardiac arrest - commence CPR and give Intralipid
• Manage tachyarrythmias with Amiodarone and Intralipid

Question 4

What is the dose for IV 20% lipid emulsion?

Answer 4

1.5mL/kg over 1 min as a bolus

Commence infusion at 15mLs/kg/hr

Repeat bolus after 5 mins if CVS stability has not been achieved

Maximum of 3 boluses (including initial)

If still not stable after 3 boluses - increase infusion rate to 30mLs/kg/hr

DO NOT exceed maxiumum cumulative dose of 12mLs/kg

Question 5

What options are available for management of seizures associated with LA toxicity?

Answer 5

As per management of refractory seizures in epilepsy - IV Midazolam 5mg IV, Propofol 50mg increments, Thiopentone 50mg increments