From the Guidelines
Local anesthetic toxicity should be treated immediately with lipid emulsion therapy, as recommended by the 2023 American Heart Association guidelines 1. The treatment of local anesthetic toxicity (LAST) involves several key steps to ensure the best possible outcome in terms of morbidity, mortality, and quality of life.
Initial Management
- Stop the local anesthetic administration and call for help.
- Secure the airway, provide oxygen, and establish intravenous access.
Seizure Management
- Administer benzodiazepines such as midazolam 2-5mg IV or diazepam 5-10mg IV to treat seizures associated with local anesthetic systemic toxicity, as recommended by the 2023 American Heart Association guidelines 1.
Cardiovascular Collapse
- Start CPR if needed.
- Give a 20% lipid emulsion as a 1.5 mL/kg bolus over 1 minute, followed by an infusion at 0.25 mL/kg/min for at least 10 minutes after hemodynamic stability, as recommended by the 2023 American Heart Association guidelines 1.
- The maximum recommended dose is 12 mL/kg.
Arrhythmia Management
- Treat arrhythmias with amiodarone rather than lidocaine or other local anesthetic-like antiarrhythmics.
Hypotension Management
- Use vasopressors like epinephrine (10-100 mcg boluses) or norepinephrine (0.05-0.1 mcg/kg/min) for hypotension.
- Avoid propofol in severe cardiovascular instability.
Monitoring
- Monitor the patient closely in an intensive care setting for at least 12 hours after stabilization, as toxicity can recur. The use of lipid emulsion therapy is based on the principle of creating a "lipid sink" that extracts lipophilic local anesthetics from tissue and provides a substrate for cardiac metabolism.
Additional Considerations
- Sodium bicarbonate may be administered for life-threatening wide-complex tachycardia associated with local anesthetic toxicity, as suggested by the 2023 American Heart Association guidelines 1.
- Atropine may be administered for life-threatening bradycardia associated with local anesthetic systemic toxicity, as suggested by the 2023 American Heart Association guidelines 1.
- Extracorporeal life support techniques such as VA-ECMO may be utilized in local anesthetic toxicity with refractory cardiogenic shock, as suggested by the 2023 American Heart Association guidelines 1.
From the Research
Treatment for Local Anesthetic Systemic Toxicity (LAST)
The treatment for Local Anesthetic Systemic Toxicity (LAST) involves several steps to manage the condition effectively.
- Halt administration of local anesthetic immediately if systemic toxicity is suspected 2
- Request assistance and secure the patient's airway, breathing, and circulation (ABCs) 2, 3
- Administer 100% oxygen and consider tracheal intubation and artificial respiration if necessary 2
- Use benzodiazepines to treat convulsions 2
- Administer lipid emulsion therapy to treat severe hypotension and arrhythmia 2, 4, 5, 6
Lipid Emulsion Therapy
Lipid emulsion therapy is a recommended treatment for LAST, with a suggested initial bolus dose of 1.5 mL/kg followed by an infusion of 10 mL/min 4.
- The mechanism of effect is unclear, but it is thought to involve increasing metabolism, distribution, or partitioning of the local anesthetic away from receptors into lipid within tissues 4
- Lipid emulsion has been reported to be useful in the treatment of systemic toxicity caused by local anesthetics, with a high survival rate and minimal sequelae 5
Prevention of LAST
Prevention of LAST is crucial and can be achieved through: