Local Anaesthetic Toxicity

Question 1

Categorise and describe the signs and symptoms of LA systemic toxicity

Answer 1

CNS
Initial
- Perioral paraesthesia
- Visual abnormalities
- Tinnitus
- Dizziness
- Metallic taste

Excitatory

• Muscle twitches
• Seizures

Depressive

• LOC
• Coma
• Apnoea

CVS
Initial
- HPT
- Tachycardia (excitatory phase)

Intermediary

• Hypotension
• Reduced CO
• Myocardial depression

Terminal

• Severe hypotension
• Bradycardia
• Arrythmia
• Cardiac Arrest

Question 2

Describe your approach to the treatment of local anaesthetic toxicity

Answer 2

Declare, get help, communicate
Stop injecting LA

SUPPORTIVE
A - Protect and maintain
B - Oxygenate and ventilate
C - IV access | Crystalloid bolus | Adrenalin 10 - 100ug bolus etc

SPECIFIC

1. INTRALIPID 20% lipid emulsion
   - Bolus: 1.5 mg/kg over 1 minute (100ml)
   - Infusion: 0.25 ml/kg/min (400 ml over 20 minutes)

Repeat bolus dose every 5 minutes x 2
Wait 5 minutes –> Inadequate tissue perfusion ongoing
- Bolus 1.5 ml/kg over 1 minute (100ml)
Increase infusion to 0.5 ml/kg/min (400 ml over 10 min)

Continue infusion until a stable adequate circulation has been restored.

2. SEIZURES
   - Midazolam 2 - 4 mg | Propofol 20 - 40 mg
3. ARRYTHMIAS
   - Amiodarone 300mg over 20 minutes than 1200 mg over 24 hours
   (Avoid CCB/BB/Vasopressin - may worsen cardiac depression)