Stop injecting LA at the first symptoms. Call for help and get the 20% lipid emulsion early. Prolonged CPR may be needed; lipid is part of the resuscitation.
Early symptoms
- Perioral tingling, tinnitus, metallic taste
- Agitation, confusion, visual disturbance
- Seizures without hypoglycaemia
Late symptoms
- Arrhythmias, cardiovascular collapse
- May resemble other causes: still give lipid if LAST likely
- Maximum doses depend on agent, site, adrenaline use
Early CNS
- Perioral tingling, tinnitus, metallic taste
- Agitation, confusion
- Stop injecting, call for help
Seizures
- Seizures without hypoglycaemia
- Treat with a benzodiazepine
- Get 20% lipid emulsion now
Cardiovascular collapse
- Arrhythmia or arrest
- Lipid 1.5 mL/kg bolus then infusion
- Prolonged ALS, avoid vasopressin
LAST response
1
1. Stop LA
Airway support, high-flow oxygen. Treat seizures with benzodiazepine; avoid propofol if unstable.
Airway support, high-flow oxygen. Treat seizures with benzodiazepine; avoid propofol if unstable.
↓
2
2. Lipid emulsion
20% lipid: 1.5 mL/kg bolus over 1 min, then an infusion of 15 mL/kg/h. Repeat the bolus up to twice at 5-min intervals and double the infusion rate if the patient remains unstable (approximate maximum 12 mL/kg).
20% lipid: 1.5 mL/kg bolus over 1 min, then an infusion of 15 mL/kg/h. Repeat the bolus up to twice at 5-min intervals and double the infusion rate if the patient remains unstable (approximate maximum 12 mL/kg).
↓
3
3. CPR
Standard ALS if in arrest, but expect a prolonged resuscitation. Avoid vasopressin; use smaller adrenaline boluses and avoid calcium channel blockers and lidocaine (follow the LAST algorithm).
Standard ALS if in arrest, but expect a prolonged resuscitation. Avoid vasopressin; use smaller adrenaline boluses and avoid calcium channel blockers and lidocaine (follow the LAST algorithm).
↓
4
4. Aftercare
ITU monitoring. Report to national audit. Review total LA dose and technique.
ITU monitoring. Report to national audit. Review total LA dose and technique.
High-risk blocks
- Interscalene, supraclavicular, penile block
- Use ultrasound, aspirate, incremental doses
Pitfalls
- Confusing LAST with anaphylaxis (try both pathways if unsure)
- Under-dosing lipid
- Continuing block after mild CNS symptoms
MedPrep - www.medprep.uk - Educational revision aid only. Not clinical guidance. Doses are adult examples; check the BNF, current guidelines and local policy, and seek senior advice. Nov 2026