What are the South African guidelines for dosing local anesthetics in pediatric patients, including maximum milligram limits and volume per kilogram?

South African Guidelines for Local Anaesthetic Doses in Children

While no specific South African national guideline was identified in the evidence, international pediatric guidelines provide clear maximum dosing recommendations that are widely applicable, including in South African practice settings.

Maximum Dose Recommendations

The most relevant and recent guidelines for pediatric local anaesthetic dosing come from the American Academy of Pediatrics (AAP) Pediatrics guidelines 1, 2. These provide comprehensive dosing tables that should guide practice:

Amide Local Anaesthetics (Most Commonly Used)

With Epinephrine:

• Lidocaine: 7.0 mg/kg maximum (medical use) or 4.4 mg/kg (dental use)
• Bupivacaine: 3.0 mg/kg maximum (medical use) or 1.3 mg/kg (dental use)
• Ropivacaine: 3.0 mg/kg maximum (medical use) or 2.0 mg/kg (dental use)
• Levobupivacaine: 3.0 mg/kg maximum (medical use) or 2.0 mg/kg (dental use)
• Mepivacaine: 7.0 mg/kg maximum (medical use) or 4.4 mg/kg (dental use)

Without Epinephrine (lower doses required):

• Lidocaine: 4.0-4.4 mg/kg maximum
• Bupivacaine: 2.5 mg/kg maximum (medical use) or 1.3 mg/kg (dental use)
• Ropivacaine: 2.0 mg/kg maximum
• Levobupivacaine: 2.0 mg/kg maximum
• Mepivacaine: 4.4-5.0 mg/kg maximum

1, 2, 3

Critical Age-Specific Modifications

For infants younger than 6 months:

• Reduce amide local anaesthetic doses by 30% due to immature hepatic enzymes and prolonged drug half-life 1, 2, 3
• For topical lidocaine specifically, use maximum of 4 mg/kg (ideal body weight) instead of 5 mg/kg 4

Practical Volume Calculations

To convert concentrations to volumes, use this conversion:

• 1% solution = 10 mg/mL
• 0.5% solution = 5 mg/mL
• 0.25% solution = 2.5 mg/mL
• 0.2% solution = 2 mg/mL

1, 2

Example: For a 20 kg child receiving bupivacaine 0.25% with epinephrine:

• Maximum dose = 3.0 mg/kg × 20 kg = 60 mg
• 0.25% = 2.5 mg/mL
• Maximum volume = 60 mg ÷ 2.5 mg/mL = 24 mL

Specific Regional Technique Dosing

The European Society for Paediatric Anaesthesiology (ESPA) 2024 guidelines provide technique-specific volumes 5:

Wound infiltration/peripheral nerve blocks:

• Bupivacaine 0.25%: maximum 1 mL/kg (= 2.5 mg/kg)
• Ropivacaine 0.2%: maximum 1.5 mL/kg (= 3 mg/kg)

Caudal blocks:

• 1.0 mL/kg of bupivacaine 0.25%, levobupivacaine 0.25%, or ropivacaine 0.2%

Epidural blocks (lumbar):

• 0.5 mL/kg initially (maximum 15 mL)

Epidural blocks (thoracic):

• 0.2-0.3 mL/kg initially (maximum 10 mL)

5

Essential Safety Considerations

Always Calculate Before Administration

Calculate the maximum allowable dose in mg/kg before administering any local anaesthetic to prevent overdosing, particularly in small children 1, 2, 3. Use ideal body weight for dosing calculations 4.

Avoid High Concentrations in Small Children

• In children weighing <10 kg, use 1% or 2% lidocaine solutions (not higher concentrations) 4
• Lidocaine solutions >4% should not be used in children 4
• Lower doses should be used when injecting into highly vascular tissues 1, 2

Contraindications

• Do not use lidocaine solutions with adrenaline for airway topicalisation due to risk of hypertensive crises and cardiac arrest 4
• Aspirate frequently before injection to avoid intravascular administration 1, 2

Monitoring Requirements

When high doses or amide local anaesthetics are administered, document vital signs at least every 5 minutes initially, then may increase intervals to 10-15 minutes once stable 1

Combined Drug Effects

Enhanced sedative effects may occur when maximum recommended doses of local anaesthetics are combined with other sedatives or opioids 1, 2, 3

Local Anaesthetic Systemic Toxicity (LAST) Management

Have 20% lipid emulsion immediately available when administering long-acting local anaesthetics (bupivacaine, ropivacaine) 1, 2, 6:

Treatment protocol:

1. 1.5 mL/kg of 20% lipid emulsion over ~1 minute
2. Repeat bolus once or twice for persistent cardiovascular collapse
3. Initiate infusion at 0.25 mL/kg/min until circulation restored
4. Recommended upper limit: ~10 mL/kg total

1, 2, 6

Documentation Requirements

Clearly document in the patient record:

• Total dose of local anaesthetic used (in mg and mg/kg)
• Concentration and volume administered
• Time(s) of administration
• Route and site of administration

4, 1

Context from South African Practice

A 2024 survey of anesthetists in South Africa (and three other sub-Saharan African countries) found good availability of simple analgesia, opioids, ketamine, and local anaesthetics, with positive pain prescription practices reported 7. However, two-thirds lacked institutional pediatric pain management guidelines, emphasizing the importance of following established international recommendations like those outlined above.