What is the management for a patient with suspected local anesthetic toxicity?

Management of Local Anesthetic Systemic Toxicity (LAST)

Immediately stop local anesthetic administration, call for help, secure the airway with 100% oxygen, and administer 20% intravenous lipid emulsion (1.5 mL/kg bolus over 1 minute followed by 0.25 mL/kg/min infusion) while providing standard resuscitation—this is the definitive life-saving intervention for LAST. 1, 2

Immediate Recognition and Initial Actions

Stop the local anesthetic immediately upon suspecting LAST and call for help—do not delay treatment while confirming the diagnosis. 2, 3

Airway and Breathing Management

• Secure the airway and administer 100% oxygen via non-rebreather mask, high-flow nasal cannula, or endotracheal intubation if necessary. 1, 2
• Intubate the trachea if the patient cannot protect their airway or has severe respiratory compromise. 1
• Ventilate with 100% oxygen to maximize oxygenation, as hypoxia and acidosis worsen local anesthetic toxicity. 1

Seizure Management

• Administer benzodiazepines immediately for seizures—this is the first-line treatment for LAST-induced seizures. 1
• Avoid propofol in large doses as it can worsen cardiovascular depression in LAST. 4
• Seizure suppression is critical because seizures increase oxygen consumption and worsen acidosis, which potentiates local anesthetic toxicity. 4

Lipid Emulsion Therapy: The Definitive Treatment

Administer 20% intravenous lipid emulsion immediately for cardiovascular collapse or severe symptoms:

• Initial bolus: 1.5 mL/kg over 1 minute (approximately 100 mL for a 70 kg adult). 1, 2
• Continuous infusion: 0.25 mL/kg/min immediately after the bolus. 1, 2
• Repeat bolus: If cardiovascular stability is not restored, repeat the 1.5 mL/kg bolus and increase infusion to 0.5 mL/kg/min. 1
• Maximum cumulative dose: Approximately 10 mL/kg over the first 30 minutes. 1

Lipid emulsion creates a lipid compartment in serum that sequesters lipophilic local anesthetics away from cardiac tissue and increases cardiac inotropy. 1

Cardiovascular Management

For Wide-Complex Tachycardia

• Administer sodium bicarbonate (1-2 mEq/kg IV) for life-threatening wide-complex tachycardia associated with local anesthetic toxicity. 1
• Sodium bicarbonate helps reverse sodium channel blockade caused by local anesthetics. 1

For Bradycardia

• Administer atropine (0.5-1 mg IV for adults) for life-threatening bradycardia. 1
• Repeat every 3-5 minutes as needed up to maximum 3 mg. 1

For Hypotension and Cardiovascular Collapse

• Start CPR immediately if cardiac arrest occurs, following Advanced Life Support guidelines. 1
• Use small doses of epinephrine (<1 mcg/kg) if needed—avoid standard ACLS doses as large doses of epinephrine may worsen outcomes in LAST. 4
• Avoid vasopressin as it may impair the effectiveness of lipid emulsion therapy. 4
• Administer rapid IV crystalloid bolus (1-2 liters normal saline or lactated Ringer's solution) for hypotension. 1

Refractory Cardiovascular Collapse

• Consider VA-ECMO (veno-arterial extracorporeal membrane oxygenation) for refractory cardiogenic shock unresponsive to lipid emulsion and standard resuscitation. 1, 2
• Communicate early with perfusion team for possible cardiopulmonary bypass if cardiovascular collapse persists. 4

Monitoring During Resuscitation

• Continuous ECG monitoring is essential as cardiovascular signs represent late manifestations of toxicity, especially in anesthetized patients. 2
• Monitor for resedation or recurrent symptoms, as local anesthetics have prolonged effects. 3
• Continue monitoring vital signs until complete resolution of symptoms. 5

Critical Pitfalls to Avoid

Do not use propofol for seizure control in large doses—it worsens cardiovascular depression in LAST. 4

Do not use standard ACLS epinephrine doses—use small doses (<1 mcg/kg) as large doses may impair lipid emulsion effectiveness and worsen outcomes. 4

Do not delay lipid emulsion therapy—administer as soon as LAST is suspected with cardiovascular symptoms, not after failed standard resuscitation. 1, 2

Do not assume the diagnosis is wrong if initial lipid therapy fails—repeat boluses and increase infusion rate may be needed. 1

Post-Resuscitation Care

• Transfer to ICU or appropriate critical care area for continued monitoring, even if symptoms resolve. 1
• Observe for at least 4-6 hours after symptom resolution, as recurrent toxicity can occur with long-acting local anesthetics. 3
• Document exact timing of local anesthetic administration, dose, route, symptom onset, all treatments administered, and patient response. 5, 6

Prevention Strategies

• Use ultrasound guidance for regional anesthesia to reduce risk of intravascular injection. 3
• Aspirate before injection to check for blood return. 3
• Use the minimal effective dose of local anesthetic. 2, 3
• Administer local anesthetics in fractionated doses rather than single large boluses. 1
• Monitor continuously during and after local anesthetic administration. 2