Maximum Lidocaine Dose for a 13kg Child
For a 13kg child, the maximum safe dose of local infiltrative lidocaine is 58.5mg (5.85mL of 1% lidocaine) without epinephrine, or 91mg (9.1mL of 1% lidocaine) with epinephrine.
Weight-Based Dosing Guidelines
The maximum safe doses for local infiltrative lidocaine in children are clearly defined by pediatric emergency medicine guidelines:
Without epinephrine: 4.5 mg/kg 1
- For 13kg child: 4.5 × 13 = 58.5mg maximum
With epinephrine: 7.0 mg/kg 1
- For 13kg child: 7.0 × 13 = 91mg maximum
These doses are specifically recommended for local infiltration and peripheral nerve blocks in children 1. The American Academy of Dermatology supports similar ranges, recommending 3.0-4.5 mg/kg with epinephrine for children 1, 2.
Practical Volume Calculations
To make this clinically useful, here are the maximum volumes for common lidocaine concentrations:
Without epinephrine (58.5mg max):
- 1% lidocaine (10mg/mL): 5.85mL maximum
- 0.5% lidocaine (5mg/mL): 11.7mL maximum
With epinephrine (91mg max):
- 1% lidocaine (10mg/mL): 9.1mL maximum
- 0.5% lidocaine (5mg/mL): 18.2mL maximum
Critical Safety Considerations
Age-specific dose reduction: If this child is under 6 months of age, reduce all amide local anesthetic doses by 30% 1. This would lower the maximum to approximately 40.9mg without epinephrine or 63.7mg with epinephrine.
Aspiration technique: Always aspirate frequently before injection to avoid intravascular administration, which dramatically increases toxicity risk 1.
Lower doses in vascular areas: Use reduced doses when injecting into highly vascular tissues (face, scalp, genitals) due to increased systemic absorption 1.
Avoid intravenous use: These doses apply only to local infiltration. For intravenous regional anesthesia (Bier block), the maximum dose drops dramatically to 3-5 mg/kg, and long-acting agents should never be used intravenously 1, 3.
Monitoring for Toxicity
Early signs of local anesthetic systemic toxicity (LAST) include 1, 4:
- Circumoral numbness and facial tingling
- Metallic taste
- Slurred or pressured speech
- Auditory changes or tinnitus
Progressive toxicity manifests as 1:
- Seizures or CNS depression
- Cardiac arrhythmias
- Cardiovascular collapse
Monitoring frequency: When using high doses of local anesthetics, document vital signs at least every 5 minutes initially, then every 10-15 minutes once stable 1.
Common Pitfalls to Avoid
Cumulative dosing errors: Calculate the maximum allowable dose before starting the procedure 1. This is especially important during lengthy procedures where multiple injections occur over time.
Concentration confusion: A common error is confusing percentage concentration with mg/mL. Remember that 1% = 10mg/mL, 0.5% = 5mg/mL 5.
Combination with sedatives: Enhanced sedative effects occur when maximum recommended doses of local anesthetics are combined with opioids or other sedatives 1. Use caution and consider dose reduction.
Repeat dosing intervals: Do not administer additional local anesthetic within 4 hours of the initial dose to avoid cumulative toxicity 3, 4.