What lidocaine dose should be used to anesthetize the intra‑osseous insertion site in a pediatric patient (e.g., 5–10 kg) while staying within the maximum pediatric dosing limits?

Lidocaine Dosing for Intraosseous Insertion Site Anesthesia in Pediatric Patients

For a 5–10 kg pediatric patient requiring IO placement, administer 0.5 mg/kg of 1% lidocaine (without epinephrine) at the insertion site, which translates to 2.5–5 mg total (0.25–0.5 mL of 1% solution), staying well below the maximum safe dose of 4.5 mg/kg (22.5–45 mg for this weight range). 1

Weight-Based Dosing Algorithm

For children 5–10 kg:

• Standard dose: 0.5 mg/kg of 1% lidocaine = 2.5–5 mg total 1
• Volume to draw: 0.25–0.5 mL of 1% lidocaine solution 1
• Maximum allowable dose: 4.5 mg/kg without epinephrine = 22.5–45 mg 1
• With epinephrine (if appropriate): Maximum increases to 7.0 mg/kg = 35–70 mg 1

Critical Age-Related Dose Adjustment

If the child is under 6 months of age, reduce all amide local anesthetic doses by 30%. 1, 2 This means:

• For a 5 kg infant <6 months: Maximum dose drops from 22.5 mg to approximately 15.75 mg 1
• Practical dose would be 0.35 mg/kg instead of 0.5 mg/kg 1

Administration Technique for IO Sites

• Aspirate before injection to avoid intravascular administration, which dramatically increases toxicity risk 1, 3
• Use the smallest effective volume for local infiltration at the IO insertion site 1
• Avoid epinephrine at IO sites, as these are highly vascular areas where epinephrine may not be appropriate 3
• Administer slowly to minimize discomfort and allow for early detection of adverse reactions 1

Safety Considerations Specific to IO Access

The intraosseous route itself can be used for medication administration during resuscitation, and lidocaine can be given IO for arrhythmias at 1 mg/kg (maximum 100 mg). 4, 2 However, for local anesthesia at the IO insertion site, you are using infiltrative dosing, not systemic dosing. 1

Key distinction:

• Local infiltration at IO site: 0.5 mg/kg (2.5–5 mg for 5–10 kg child) 1
• Systemic IO administration for arrhythmias: 1 mg/kg (5–10 mg for 5–10 kg child) 2

Monitoring for Local Anesthetic Systemic Toxicity (LAST)

Early warning signs include: 1, 3

• Circumoral numbness
• Facial tingling
• Metallic taste
• These occur at plasma levels of 5–10 μg/mL 3

Severe toxicity signs: 1, 3

• Muscle twitching
• Seizures or CNS depression
• Loss of consciousness
• Occurs at plasma levels >10 μg/mL 3

Common Pitfalls and How to Avoid Them

Calculate the dose in milligrams before drawing up the solution to avoid volumetric errors—1% lidocaine = 10 mg/mL. 1, 3 For a 7 kg child:

• Maximum safe dose = 4.5 mg/kg × 7 kg = 31.5 mg
• Practical infiltrative dose = 0.5 mg/kg × 7 kg = 3.5 mg = 0.35 mL of 1% solution 1

Do not use lidocaine within 4 hours of other local anesthetic interventions to prevent cumulative toxicity. 3 If the child has received topical lidocaine for airway management (maximum 5–7 mg/kg), 4, 5 or regional anesthesia, account for this in your total dose calculation. 4

Track cumulative dosing carefully in emergency situations where multiple procedures may be performed. 1 The total dose from all sources (topical, infiltrative, regional) must not exceed 4.5 mg/kg without epinephrine. 1

Emergency Preparedness

• Resuscitation equipment and 20% lipid emulsion should be immediately available when administering local anesthetics. 3
• Have flumazenil and naloxone readily accessible if sedation is used concurrently. 4
• Enhanced sedative effects may occur when high doses of local anesthetics are combined with other sedatives or opioids. 1