What is the safe dose of bupivacaine (local anesthetic) 0.25% for local infiltration in a 10kg, 1-year-old child undergoing foreign body extraction?

Safe Bupivacaine 0.25% Dose for Local Infiltration in a 10kg, 1-Year-Old Child

For local wound infiltration in this 10kg child, use a maximum of 10 mL of bupivacaine 0.25% (total dose 25 mg or 2.5 mg/kg), which is the established safe upper limit for this age and weight. 1

Maximum Safe Dosing

• The European Society for Paediatric Anaesthesiology (ESPA) 2024 guidelines establish 2.5 mg/kg as the maximum safe dose of bupivacaine 0.25% for wound infiltration and peripheral nerve blocks in pediatric patients 1
• For bupivacaine 0.25%, this translates to a maximum volume of 1 mL/kg 1, 2
• In your 10kg patient, this equals 10 mL maximum volume or 25 mg total dose 1, 2

Critical Safety Considerations for Small Children

Children under 15kg require special caution with bupivacaine dosing due to altered pharmacokinetics:

• Smaller children (10-15kg) achieve significantly higher plasma bupivacaine concentrations than larger children when given the same mg/kg dose 3
• Peak plasma levels in the 10-15kg group averaged 1.5 mg/L but ranged up to 4.0 mg/L (near toxic threshold) with doses of only 1.25 mg/kg 3
• The toxic plasma concentration threshold in small children is approximately 4 mg/L 3
• Plasma concentrations often remained elevated (>2 mg/L) at 60 minutes post-injection in smaller children 3

Dosing Algorithm for This Case

For local infiltration in exploratory laparotomy for foreign body removal:

1. Calculate maximum allowable dose: 10kg × 2.5 mg/kg = 25 mg total 1, 2
2. Convert to volume: 25 mg ÷ 2.5 mg/mL = 10 mL of 0.25% bupivacaine 1
3. Do not exceed this dose - the 2.5 mg/kg limit is specifically designed to prevent systemic toxicity 1, 2
4. Consider using less than the maximum if adequate analgesia can be achieved with smaller volumes 3

Common Pitfalls to Avoid

• Never exceed 2.5 mg/kg in children, especially those under 15kg - this population demonstrates unpredictable and potentially dangerous plasma concentrations 3
• Always calculate total dose in mg/kg, not just volume, as this is the critical safety parameter 2
• Be aware that even doses of 1.25 mg/kg have produced near-toxic plasma levels in some children under 15kg 3
• Ensure adequate monitoring for signs of local anesthetic systemic toxicity (LAST) for at least 60 minutes post-injection, as plasma levels may remain elevated 3

Alternative Considerations

• If larger volumes are needed for adequate infiltration, consider using ropivacaine 0.2% instead, which allows up to 3 mg/kg (1.5 mL/kg or 15 mL in this patient) 1, 4
• Levobupivacaine 0.25% offers similar efficacy with potentially improved safety profile and can be used at the same 2.5 mg/kg maximum dose 1, 5