What is the management of local anaesthetic overdose in a neonate or infant?

Management of Local Anaesthetic Overdose in Neonates and Infants

Immediately administer 20% lipid emulsion therapy while providing aggressive airway support and seizure control with benzodiazepines, as this is the definitive treatment for severe local anaesthetic systemic toxicity (LAST) in pediatric patients. 1

Immediate Recognition and Initial Response

Stop all local anaesthetic administration immediately when toxicity is suspected and call for help, alerting the nearest facility with cardiopulmonary bypass capability. 1

Early signs of toxicity in neonates and infants include:

• Changes in mental status or agitation 1
• Seizures (often the first manifestation) 1, 2
• Cardiovascular signs: arrhythmias, bradycardia, hypotension, or cardiac arrest 1, 2

Neonates and infants are at particularly high risk because they have delayed metabolism and elimination of local anaesthetics, decreased plasma concentrations of alpha-1-acid glycoprotein (leading to increased unbound drug), and procedures are typically performed under heavy sedation or general anaesthesia, making early detection difficult. 3

Airway Management and Oxygenation (First Priority)

Immediately secure the airway and ventilate with 100% oxygen. 1

• Provide bag-mask ventilation if needed 4
• Perform tracheal intubation and artificial respiration if respiratory arrest occurs 2
• Good basic life support with adequate oxygenation and ventilation is the foundation of successful resuscitation 4

Seizure Management (Second Priority)

Administer benzodiazepines as first-line therapy for seizures:

• Intravenous midazolam 0.1-0.2 mg/kg 1, 2
• Avoid propofol for seizure management in LAST, as it may worsen cardiovascular depression 1

Lipid Emulsion Therapy (Third Priority - Definitive Treatment)

Administer 20% lipid emulsion immediately for severe toxicity (cardiovascular collapse, refractory seizures, or arrhythmias). 1, 2, 4

The lipid emulsion protocol:

• Should be available immediately whenever long-acting local anaesthetics (bupivacaine, ropivacaine) are administered into vascular tissues 1
• Has been successfully used in multiple pediatric case reports 1
• Should be considered early in the treatment algorithm 4

Cardiovascular Support

Initiate standard resuscitation with chest compressions if cardiac arrest occurs. 1

Critical medication modifications for LAST:

• Avoid vasopressin entirely 1
• Reduce epinephrine dosages (use only small doses if needed) 1, 4
• Avoid calcium channel blockers and beta-blockers 1
• Do not administer additional local anaesthetic 1

Prolonged resuscitation efforts may be required as recovery can take considerable time. 1

Fluid Resuscitation

Administer isotonic fluid boluses (10 mL/kg each) of normal saline for hypotension. 1

Advanced Support

Contact the perfusion team early for possible cardiopulmonary bypass or ECMO if high-dose vasopressors fail to maintain blood pressure. 1, 4

Age-Specific Considerations for Neonates and Infants

Infants younger than 6 months require 30% dose reduction of all amide local anaesthetics to prevent toxicity in the first place. 1, 5, 6

Neonates are particularly vulnerable because:

• They have impaired hepatic metabolic function 3
• Delayed elimination of local anaesthetics 3
• Lower plasma protein binding, resulting in higher free drug concentrations 3

Prevention Strategies (Critical for High-Risk Pediatric Population)

Calculate maximum allowable dose before any procedure:

• Ropivacaine: 3 mg/kg with epinephrine, 2 mg/kg without 1, 5, 6
• Lidocaine: 7 mg/kg with epinephrine, 4.4 mg/kg without 1
• Bupivacaine: 3 mg/kg with epinephrine, 1.3 mg/kg without 1

Aspirate frequently before each injection to avoid intravascular administration. 5, 6, 2

Use lower doses in highly vascular areas due to increased systemic absorption. 1, 5, 6

Monitor vital signs every 5 minutes initially when administering amide local anaesthetics, then increase intervals to 10-15 minutes once stable. 1, 6

Never use long-acting local anaesthetics (bupivacaine, ropivacaine) for intravenous regional anaesthesia due to excessive cardiac toxicity risk. 1, 5, 6

Common Pitfalls to Avoid

• Failing to have 20% lipid emulsion immediately available when using long-acting local anaesthetics in vascular areas 1
• Not reducing doses by 30% in infants under 6 months 1, 5, 6
• Using propofol for seizure control (worsens cardiovascular depression) 1
• Administering full-dose vasopressin or high-dose epinephrine (exacerbates toxicity) 1, 4
• Performing procedures under heavy sedation without adequate monitoring, which delays recognition of early toxicity signs 3