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anesthesia.local-anesthetic-systemic-toxicity.core.v1PRODUCTION
anesthesia.local-anesthetic-systemic-toxicity.core.v1

Local Anesthetic Systemic Toxicity (LAST)

critical_careacuteadultpediatric
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Encounter flow

12/12 authored

Canonical 12-phase frame with authored status for this dossier.

Current phase

Frame

Detailed

Confirm LAST scope — systemic CNS + CV toxicity from intravascular or absorbed LA, especially after peripheral nerve / neuraxial / infiltrative block (ASRA 2020)

Inputs
1
Actions
0
Advance rule
Set
Advance when

plausible LA exposure with toxicity signs

Patient inputs (9)

Bupivacaine highest cardiotoxicity; document agent + dose + time of injection (ASRA 2020)

Dysrhythmia, bradycardia, or escalating tachycardia tracks toxicity progression (ASRA 2020)

Hypotension is a late CV sign that frequently precedes arrest (ASRA 2020)

Hypoxia worsens cardiotoxicity; 100% O2 is first action (ASRA 2020)

AMS / seizure marks CNS phase; airway protection (ASRA 2020)

Lipid emulsion 1.5 mL/kg lean body weight bolus; epinephrine dose-limited to <1 mcg/kg in LAST (ASRA 2020)

Acidosis worsens LA cardiotoxicity; corroborates resuscitation progress (ASRA 2020)

Pancreatitis is a documented late lipid-emulsion complication; baseline + serial (ASRA 2020)

Hypertriglyceridemia is a late lipid-emulsion complication (ASRA 2020)

* = hard-required. Engine cannot meaningfully run until these are filled.

Severity triggers (4)

4 need judgement
  • informationallife_threateninglast_cardiac_arrest
    Cardiac arrest with documented or strongly suspected LAST (ASRA 2020)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseverelast_seizure
    Seizure attributed to local anesthetic systemic toxicity (ASRA 2020)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseverebupivacaine_overdose_high_risk
    Documented bupivacaine dose >2 mg/kg in single shot (or >3 mg/kg ropivacaine, >7 mg/kg lidocaine with epi) (ASRA 2020)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalmoderatelast_prodrome
    CNS prodrome (perioral numbness, tinnitus, metallic taste, agitation) during or after LA injection (ASRA 2020)
    Trigger could not be auto-evaluated — needs clinician judgement.

Workflow calculators

This dossier does not reference any calculators.

Recommended regimen

Local Anesthetic Systemic Toxicity — ASRA 2020 checklist: STOP injection, airway/O2, benzodiazepine for seizure, 20% lipid emulsion, low-dose epinephrine, amiodarone
axis: last_resuscitation_pathwaystep 1 - Step 1 — Stop LA injection + airway management + call for help
Selected step "Step 1 — Stop LA injection + airway management + call for help" — LAST suspected (prodrome, seizure, dysrhythmia, or arrest after LA)
  • stop_local_anesthetic_injection
    first line
    trigger_discontinuation
    STOP all LA infusion / injection • IV • immediate
    triggers: LAST_suspected
    Halt ongoing exposure (ASRA 2020)
  • oxygen_100_percent_airway_support
    first line
    ventilation_supportive
    100% FiO2 via BVM; intubate if airway compromise / persistent seizure • inhaled • continuous
    triggers: LAST_suspected
    Hypoxia and acidosis worsen LA cardiotoxicity (ASRA 2020)
  • call_for_help_and_lipid_emulsion
    first line
    team_activation
    Activate LAST cart; request 20% lipid emulsion to bedside • team_call • once
    triggers: LAST_suspected
    LAST cart at every site administering LA (ASRA 2020)

inpatient playbook — drug actions (6)

  1. 1. STOP local anesthetic + 100% O2 + airway support
    discontinue + O2 • IV/airway • immediate
    trigger: LAST suspected (ASRA 2020)
    Halt exposure + correct hypoxia (ASRA 2020)
  2. 2. midazolam
    rxcui 6960
    2-5 mg IV (adult); 0.05-0.1 mg/kg IV (peds) • IV • PRN
    trigger: Seizure (ASRA 2020)
    First-line for LAST seizure (ASRA 2020)
  3. 3. 20% lipid emulsion bolus
    rxcui 227582
    1.5 mL/kg LBW IV bolus over ~1 min • IV • q3-5 min up to 3 boluses
    trigger: CV instability OR arrest (ASRA 2020)
    Cornerstone CV rescue (ASRA 2020)
  4. 4. 20% lipid emulsion infusion
    rxcui 227582
    0.25 mL/kg/min (double to 0.5 if BP not restored) • IV • continuous >=10 min beyond CV stability
    trigger: Post-bolus persistent CV signs (ASRA 2020)
    Sustained lipid concentration (ASRA 2020)
  5. 5. epinephrine LOW-dose
    rxcui 3992
    <1 mcg/kg IV (typical 10-100 mcg) • IV • q3-5 min titrated
    trigger: Hypotension OR arrest (ASRA 2020)
    High-dose impairs lipid rescue (ASRA 2020)
  6. 6. amiodarone
    rxcui 703
    150 mg IV bolus (adult); 5 mg/kg (peds) • IV • PRN VT/VF
    trigger: Ventricular dysrhythmia (ASRA 2020)
    Avoid lidocaine/procainamide (ASRA 2020)

Auto-drafted A&P note

inpatient

Subjective

- Possible entry pathways: CNS excitation (perioral numbness, tinnitus, metallic taste, agitation, seizure) after local anesthetic block (ASRA 2020); Cardiovascular collapse (dysrhythmia, hypotension, arrest) after local anesthetic injection or infusion (ASRA 2020); Local anesthetic dose at or above maximum (bupivacaine >2 mg/kg, ropivacaine >3 mg/kg, lidocaine >7 mg/kg with epi) (ASRA 2020).

Objective

- No vitals, labs, or imaging entered for this encounter.

Assessment

**Local Anesthetic Systemic Toxicity (LAST)** (anesthesia.local-anesthetic-systemic-toxicity.core.v1).
Phenotype framing: Differentiate from vasovagal syncope, post-block hypotension (sympathectomy), allergic reaction, pre-existing seizure disorder, hyperventilation (ASRA 2020)
Scope: Confirm LAST scope — systemic CNS + CV toxicity from intravascular or absorbed LA, especially after peripheral nerve / neuraxial / infiltrative block (ASRA 2020)

No severity triggers fired against current inputs.

Plan

Regimen axis: **Local Anesthetic Systemic Toxicity — ASRA 2020 checklist: STOP injection, airway/O2, benzodiazepine for seizure, 20% lipid emulsion, low-dose epinephrine, amiodarone** — step "Step 1 — Stop LA injection + airway management + call for help".
1. stop_local_anesthetic_injection STOP all LA infusion / injection IV immediate (trigger_discontinuation, first line) — Halt ongoing exposure (ASRA 2020)
2. oxygen_100_percent_airway_support 100% FiO2 via BVM; intubate if airway compromise / persistent seizure inhaled continuous (ventilation_supportive, first line) — Hypoxia and acidosis worsen LA cardiotoxicity (ASRA 2020)
3. call_for_help_and_lipid_emulsion Activate LAST cart; request 20% lipid emulsion to bedside team_call once (team_activation, first line) — LAST cart at every site administering LA (ASRA 2020)

Setting playbook (inpatient) — Recognize LAST early prodrome; STOP LA; airway + O2; treat seizure with midazolam; lipid emulsion bolus + infusion; low-dose epinephrine + amiodarone for CV; ICU disposition (ASRA 2020)
4. STOP local anesthetic + 100% O2 + airway support discontinue + O2 IV/airway immediate — LAST suspected (ASRA 2020) (Halt exposure + correct hypoxia (ASRA 2020))
5. midazolam 2-5 mg IV (adult); 0.05-0.1 mg/kg IV (peds) IV PRN — Seizure (ASRA 2020) (First-line for LAST seizure (ASRA 2020))
6. 20% lipid emulsion bolus 1.5 mL/kg LBW IV bolus over ~1 min IV q3-5 min up to 3 boluses — CV instability OR arrest (ASRA 2020) (Cornerstone CV rescue (ASRA 2020))
7. 20% lipid emulsion infusion 0.25 mL/kg/min (double to 0.5 if BP not restored) IV continuous >=10 min beyond CV stability — Post-bolus persistent CV signs (ASRA 2020) (Sustained lipid concentration (ASRA 2020))
8. epinephrine LOW-dose <1 mcg/kg IV (typical 10-100 mcg) IV q3-5 min titrated — Hypotension OR arrest (ASRA 2020) (High-dose impairs lipid rescue (ASRA 2020))
9. amiodarone 150 mg IV bolus (adult); 5 mg/kg (peds) IV PRN VT/VF — Ventricular dysrhythmia (ASRA 2020) (Avoid lidocaine/procainamide (ASRA 2020))

Non-pharmacologic actions:
- Bring LAST cart with 20% lipid emulsion to bedside (ASRA 2020)
- Intubate if airway compromise or persistent seizure (ASRA 2020)
- Transfer to bypass-capable facility for refractory arrest (ASRA 2020)
- Report event to LipidRescue.org / ASRA registry (ASRA 2020)

AVOID / contraindication checks:
- Avoid_high_dose_epinephrine_in_LAST_use_low_dose_under_1mcg_per_kg (ASRA 2020)
- Avoid_vasopressin_in_LAST (ASRA 2020)
- Avoid_calcium_channel_blockers_and_beta_blockers_in_LAST (ASRA 2020)
- Avoid_lidocaine_and_procainamide_for_LAST_dysrhythmia (ASRA 2020)
- Avoid_propofol_for_LAST_seizure_if_hemodynamic_compromise (ASRA 2020)
- Lipid_emulsion_via_dedicated_or_central_line_when_possible (ASRA 2020)

Monitoring

Regimen monitoring:
- continuous etco2 (ASRA 2020)
- continuous telemetry (ASRA 2020)
- ABG q30 to 60 min during resuscitation (ASRA 2020)
- lipase triglycerides post lipid emulsion (ASRA 2020)
- monitor for recurrence x minimum 2 4h (ASRA 2020)
- lipid cumulative dose tracker max 12 mL per kg (ASRA 2020)

Setting (inpatient) monitoring:
- Continuous telemetry + EtCO2 (ASRA 2020)
- ABG + lactate q30-60 min during resuscitation (ASRA 2020)
- Lipid cumulative dose tracker - max 12 mL/kg (ASRA 2020)
- Lipase + triglycerides post-lipid (Rosenblatt 2006, ASRA 2020)

Follow-up plan: Report event to LipidRescue registry; investigate dose/technique cause; consider plain ropivacaine over bupivacaine for high-dose blocks; counsel patient (ASRA 2020)
- Close-out criterion: case reported + corrective plan

Monitoring phase: Telemetry, ABG, lactate, lipase + triglycerides post-lipid; recurrence within hours possible due to LA redistribution (ASRA 2020)

Disposition

Current setting: inpatient — Recognize LAST early prodrome; STOP LA; airway + O2; treat seizure with midazolam; lipid emulsion bolus + infusion; low-dose epinephrine + amiodarone for CV; ICU disposition (ASRA 2020)

Disposition criteria:
- ICU >=2h CNS-only resolution / >=4h CV-only resolution / cardiac arrest >=24h ICU (ASRA 2020)

Escalation triggers (move to higher acuity):
- Refractory CV collapse despite 3 lipid boluses + low-dose epi -> CPB/ECMO (ASRA 2020)
- Persistent seizure -> RSI + benzodiazepine + non-depolarizing NMB (ASRA 2020)

Earlier-Return Triggers

Return-precaution thresholds (watch for):
- [LIFE_THREATENING] Cardiac arrest with documented or strongly suspected LAST (ASRA 2020)
- [SEVERE] Seizure attributed to local anesthetic systemic toxicity (ASRA 2020)
- [SEVERE] Documented bupivacaine dose >2 mg/kg in single shot (or >3 mg/kg ropivacaine, >7 mg/kg lidocaine with epi) (ASRA 2020)

Citations

- ASRA 2020 Local Anesthetic Systemic Toxicity Checklist (Neal, Neal, Weinberg — Reg Anesth Pain Med 2020) — current ASRA practice advisory; complemented by Weinberg 1998 (Anesthesiology — lipid emulsion rat model) and Rosenblatt 2006 (Anesthesiology — first successful human lipid rescue case) [PMID:33148630](https://pubmed.ncbi.nlm.nih.gov/33148630/)
- Cited evidence (PMID 16810015) [PMID:16810015](https://pubmed.ncbi.nlm.nih.gov/16810015/)
- Cited evidence (PMID 9579517) [PMID:9579517](https://pubmed.ncbi.nlm.nih.gov/9579517/)

Last reconciled with current guidelines: 2026-05-26.
References
  • ASRA 2020 Local Anesthetic Systemic Toxicity Checklist (Neal, Neal, Weinberg — Reg Anesth Pain Med 2020) — current ASRA practice advisory; complemented by Weinberg 1998 (Anesthesiology — lipid emulsion rat model) and Rosenblatt 2006 (Anesthesiology — first successful human lipid rescue case) — PMID:33148630
  • Cited evidence (PMID 16810015) — PMID:16810015
  • Cited evidence (PMID 9579517) — PMID:9579517