Local Anesthetic Systemic Toxicity

About this case

A 52-year-old receives a high-volume interscalene block before shoulder arthroplasty, reports perioral tingling, seizes, and arrests within about 90 seconds. The case turns on recognising that this is not a routine arrest and that standard resuscitation needs modification.

Key clinical features

• LAST — Bupivacaine

  High-volume interscalene block, perioral tingling → seizure → V-fib within 90 seconds

• Refractory V-Fib

  2 defibrillations failed — bupivacaine stabilizes Na channels, standard ACLS may fail

• Intralipid Rescue

  20% Intralipid emulsion is definitive treatment — must be given early and in high doses

• ACLS Modifications

  No epinephrine boluses (worsens lipid delivery to heart), no vasopressin, no amiodarone

What the examiner is testing

• Whether you identify LAST from the prodrome and the timing relative to the block, rather than treating an undifferentiated arrest.
• Your knowledge that bupivacaine cardiac toxicity can be refractory to defibrillation, and what that implies for persistence of effort.
• How you prioritise lipid emulsion rescue relative to the rest of the resuscitation.
• Your awareness that several standard ACLS drugs are modified or withheld in this specific arrest — and your ability to say why.

Where candidates lose points

• Running unmodified ACLS because the rhythm looks familiar, without acknowledging the toxicological cause.
• Mentioning lipid emulsion late, or as an afterthought once other measures have failed.
• Being unable to justify the ACLS modifications when the examiner presses on the reasoning.

How it is scored

Every BoardSim case is scored across the same five phases — pre-operative evaluation, anaesthetic plan, intra-operative management, crisis management, and emergence — for a total of 100 points, with a pass set at 70 and no missed critical action. You receive a written report against each phase rather than a single number. Read the scoring methodology.