Antidote for Intra-arterial Bupivacaine or Lidocaine Injection During Brachial Block
The antidote for local anesthetic systemic toxicity (LAST) from intra-arterial injection of bupivacaine or lidocaine during brachial block is 20% intravenous lipid emulsion (ILE), which should be administered immediately upon recognition of toxicity. 1
Immediate Management Algorithm
Recognition of Toxicity
Local anesthetic systemic toxicity can present with:
- CNS symptoms first: perioral numbness, metallic taste, tinnitus, facial tingling, confusion, agitation, or seizures 1
- Cardiovascular collapse: profound bradycardia, junctional rhythms, asystole, or refractory hypotension—often occurring suddenly and may be the first manifestation with intra-arterial injection 2, 3, 4
- Bupivacaine is particularly cardiotoxic and can cause sudden cardiac arrest even at doses below the traditional maximum recommended dose 5, 4
Lipid Emulsion Therapy Protocol
The American Heart Association provides specific dosing recommendations 1:
Initial bolus: 1.5 mL/kg of 20% lipid emulsion over 1 minute (approximately 100 mL for a 70 kg patient) 1
Continuous infusion: 0.25 mL/kg/min for 30-60 minutes 1
Repeat bolus: May repeat the 1.5 mL/kg bolus once or twice for persistent cardiovascular collapse 1
Maximum total dose: 10 mL/kg over the first hour 1
Concurrent Resuscitation Measures
- Standard ACLS protocols should continue alongside lipid emulsion therapy 1
- Maintain adequate ventilation and oxygenation 6
- Control seizures with benzodiazepines or thiopental if they occur 6
- Avoid or use reduced doses of epinephrine (maximum 1 mcg/kg), as there are complex pharmacodynamic interactions between lipid emulsion and vasopressors 1
- Continue CPR if cardiac arrest has occurred 1
Critical Clinical Considerations
Why Lipid Emulsion Works
Lipid emulsion creates a lipid compartment in the serum that sequesters lipophilic local anesthetics (especially bupivacaine) away from cardiac tissue, and also increases cardiac inotropy through other mechanisms 1
Evidence Quality
- All 21 published cases of lipid emulsion use for bupivacaine-induced LAST demonstrated clinical improvement (return of spontaneous circulation, relief of hypotension, or resolution of dysrhythmia) 1
- Animal studies consistently show benefit of lipid emulsion in bupivacaine toxicity 1
- The 2023 American Heart Association guidelines give this a Class IIa recommendation (reasonable to use) 1
Bupivacaine-Specific Concerns
Bupivacaine is uniquely dangerous because 7, 5, 6:
- It causes more severe and refractory cardiac toxicity than other local anesthetics 6
- Cardiac arrest can occur suddenly without preceding CNS symptoms 5, 4
- Dysrhythmias may be refractory to standard ACLS medications 6
- Toxicity has been reported at doses as low as 1.1 mg/kg IV 5
- The FDA explicitly warns against using bupivacaine for IV regional anesthesia (Bier block) due to reports of cardiac arrest and death 7
Common Pitfalls and How to Avoid Them
Preparation is Essential
- Lipid emulsion 20% must be immediately available wherever regional anesthesia is performed 1, 8
- Staff should know the exact location of lipid emulsion storage 1
- Insufficient quantities may be problematic, as toxicity can recur 40+ minutes after initial lipid rescue, requiring additional doses 3
Recognition Delays
- Do not wait for confirmatory testing—treat immediately based on clinical presentation 1
- Intra-arterial injection can cause immediate cardiovascular collapse without the typical progression of CNS symptoms first 2, 4
- Bradycardia from bupivacaine toxicity is often refractory to atropine 4
Special Populations at Higher Risk
- Uremic patients are at increased risk of cardiotoxicity even at lower doses 2
- Patients with preexisting cardiac conduction abnormalities are more susceptible 2
- Those taking beta-blockers, calcium channel blockers, or digoxin have increased risk 6