Local Anesthetic Systemic Toxicity
LAST:
• Central nervous system or cardiovasicular collapse following the use of local anesthetics
• May occur if high dose enters vascular or systemic circulation
• A variety of symptoms may be present (tinnitus, agitation, confusion)
• Primary concern is for central nervous system or cardiovascular collapse instability
• Often occurs within minutes but may be delayed
Risk Factors:
• Large doses
• Elderly and pediatric populations
• Pre-existing comorbidities (heart failure, liver or renal impairment)
Recommendations:
• Know where the crash cart is kept
• Know where lipid emulsion is kept
• Have LAST checklist available
• Monitor for 30-60 minutes
• Monitor for central nervous system and cardiovascular instability
Amount of Anesthetic:
• Depends on the location and type of block
• Use weight-based calculation (mg/kg)
• Avoid high doses
• For a helpful chart on max doses, see the Highland EM ultrasound page