LAST: local anesthetic systemic toxicity

LAST is a rare but life-threatening complication of local anesthetic use (ASRA). Say what you would look for: central nervous system signs such as agitation, altered mental status or seizures, and cardiovascular signs such as arrhythmias, hypotension or cardiac arrest, especially after a block or a large dose. Cardiac collapse can happen without warning signs first.

The ASRA 2020 checklist is a process flow. Talk through it in this order:

1. Stop the local anesthetic. Call for help, get the LAST rescue kit, and consider alerting a cardiopulmonary bypass team.
2. Airway: make sure the airway is adequate; oxygenate and ventilate.
3. Lipid emulsion: consider giving 20% lipid emulsion early, dosed per the checklist.
4. Seizures: benzodiazepine preferred.
5. Arrhythmia or hypotension: if you use epinephrine, use smaller-than-usual doses. Avoid local anesthetics, beta-blockers, calcium channel blockers and vasopressin.
6. Observe after you stabilize: the checklist gives longer observation after cardiovascular instability than after a seizure alone.

The key oral-boards point: the checklist says LAST resuscitation is different from standard ACLS, and the 2020 redesign highlights that difference because it was a common error in simulation (Neal et al.).

• Know your maximum dose for the patient and the drug.
• Use ultrasound guidance, incremental injection and aspiration.
• Consider a marker such as epinephrine in the test dose where appropriate.
• Monitor the patient during and after the block, with lipid emulsion available.

See malignant hyperthermia, the difficult airway, and how to structure SOE answers.