Local Anesthetic Systemic Toxicity (LAST) Management (ASRA 2020)

Algorithm Steps

1. ▶

   Start

   Suspect LAST

   Signs/symptoms during or after local anesthetic administration

   1. ◆

      Decision

      LAST Signs Present?

      CNS and/or cardiovascular toxicity

      • CNS EXCITATION: agitation, confusion, metallic taste, tinnitus, perioral numbness, seizures
      • CNS DEPRESSION: drowsiness, obtundation, coma, respiratory arrest
      • CV SIGNS: hypotension, bradycardia, arrhythmias, asystole
      • Atypical presentations common - maintain high index of suspicion
      1. ●

         Action

         Call for Help & Get Lipid Emulsion

         Immediate actions

         • Stop injection of local anesthetic immediately
         • Call for help
         • Get LAST rescue kit (lipid emulsion 20%)
         • Consider calling ACLS team
         • Designate team leader
         1. ●

            Action

            Airway Management

            Prevent hypoxia and acidosis which worsen toxicity

            • 100% oxygen via mask or secure airway
            • Ventilate if apneic
            • Prevent aspiration
            • Avoid hyperventilation (may worsen CNS toxicity)
            1. ◆

               Decision

               Seizure Activity?

               Treat seizures promptly to prevent acidosis

               1. ●

                  Action

                  Treat Seizures

                  Benzodiazepines preferred

                  • Midazolam 2-4 mg IV or
                  • Diazepam 5-10 mg IV or
                  • Lorazepam 2-4 mg IV
                  • Avoid large propofol doses (cardiac depression)
                  • If refractory: consider small propofol doses
                  • Succinylcholine stops motor activity but not CNS seizure
                  1. ◆

                     Decision

                     Cardiac Instability or Arrest?

                     Hypotension, arrhythmia, or cardiac arrest

                     1. ●

                        Action

                        Lipid Emulsion 20% Therapy

                        CRITICAL: Start lipid even if stable but symptomatic

                        • BOLUS: 1.5 mL/kg over 1 minute (~100 mL for 70 kg)
                        • INFUSION: 0.25 mL/kg/min
                        • If unstable: repeat bolus 1-2 times at 3-5 min intervals
                        • Double infusion to 0.5 mL/kg/min if unstable
                        • Continue infusion ≥15 min after hemodynamic stability
                        • Maximum ~10-12 mL/kg in first 30 minutes
                        1. ⚠

                           Warning

                           ⚠️ AVOID These Drugs

                           Contraindicated in LAST:

                           • Vasopressin
                           • Calcium channel blockers
                           • Beta-blockers
                           • Additional local anesthetics (e.g., lidocaine for arrhythmia)
                           • Large doses of propofol
                        2. ●

                           Action

                           Monitoring & Post-Event

                           Observe for recurrence

                           • Monitor ≥4-6 hours after treatment
                           • Watch for recurrence (may occur for up to 2 hours)
                           • Report event to www.lipidrescue.org
                           • Obtain serum LA levels if available
                           • Document carefully for future care
                           1. ✓

                              Outcome

                              Patient Stabilized

                              Continue monitoring, document event

                     2. ⚠

                        Warning

                        ⚠️ CARDIAC ARREST

                        Modified CPR + Lipid therapy

                        • Start CPR immediately
                        • Give lipid bolus AND infusion as above
                        • REDUCE epinephrine dose to <1 mcg/kg
                        • AVOID: vasopressin, calcium channel blockers, beta-blockers, lidocaine
                        • Consider prolonged resuscitation (>60 min) - lipid may delay recovery
                        • Consider ECMO/CPB if available