How to administer local anesthesia with lidocaine?

How to Administer Local Anesthesia with Lidocaine

Infiltrative anesthesia with lidocaine is safe and effective for office-based dermatologic procedures when administered using proper technique, appropriate weight-based dosing, and safety precautions to prevent systemic toxicity. 1

Maximum Safe Dosing

Adults

• Do not exceed 4.5 mg/kg of lidocaine without epinephrine 1, 2
• Do not exceed 7.0 mg/kg of lidocaine with epinephrine 1, 2
• For multistage procedures (e.g., Mohs surgery), limit total dose to 500 mg of lidocaine delivered over several hours 1, 2
• Calculate dose using ideal body weight for patients with BMI > 30 kg/m² 2

Children

• Do not exceed 1.5-2.0 mg/kg of lidocaine without epinephrine 1, 2
• Do not exceed 3.0-4.5 mg/kg of lidocaine with epinephrine 1, 2

Tumescent Anesthesia (Special Case)

• For tumescent liposuction specifically, up to 55 mg/kg of lidocaine with epinephrine has been shown safe in patients weighing 43.6-81.8 kg 1
• This higher dosing applies ONLY to tumescent technique for liposuction, not standard infiltrative anesthesia 1

Administration Technique

Preparation

• Use lidocaine with epinephrine whenever possible, as it provides longer duration (90-200 minutes vs shorter without epinephrine), better hemostasis, and allows higher safe dosing 3
• Epinephrine is safe for use in digits, hands, and feet—the historical concern about digital necrosis has been thoroughly refuted 3
• Onset of action is 1-5 minutes 3

Injection Protocol

1. Aspirate before EVERY injection to avoid intravascular administration 1, 2, 4
2. Reposition the needle and aspirate again if any blood return is noted 4
3. Use incremental injections rather than bolus administration to minimize pain and toxicity risk 1, 2
4. Use the lowest effective dose of local anesthetic 1, 2

Pain Reduction Strategies

• Use warm anesthetic solution (40°C) to decrease patient discomfort during infiltration 1
• Inject slowly to reduce pain 1
• Consider buffering lidocaine with sodium bicarbonate (1:9 or 1:10 ratio) to decrease injection pain 3

Safety Monitoring

During Administration

• Continuously communicate with the patient to monitor for early signs of toxicity 1
• Watch for early toxicity signs: circumoral numbness, facial tingling, metallic taste, tinnitus, slurred speech 2, 3
• Watch for progressive toxicity: visual disturbances, confusion, muscle twitching, seizures, cardiovascular collapse 5, 4

Critical Safety Requirements

Only clinicians well-versed in diagnosis and management of dose-related toxicity should administer lidocaine injections, with immediate availability of oxygen, resuscitative drugs, cardiopulmonary equipment, and trained personnel. 4

Special Considerations

Timing with Other Lidocaine Use

• Do not use intravenous lidocaine within 4 hours of field block anesthesia 2, 3
• Do not perform field blocks until 4 hours after completion of intravenous lidocaine infusion 2, 3

Lidocaine Allergy

For patients with true lidocaine allergy, use alternatives: 1

• Ester-type local anesthetics 1
• 1% diphenhydramine 1
• Bacteriostatic normal saline 1

High-Risk Patients for Methemoglobinemia

Monitor closely in patients with: 4

• Glucose-6-phosphate dehydrogenase deficiency 4
• Congenital or idiopathic methemoglobinemia 4
• Cardiac or pulmonary compromise 4
• Infants under 6 months of age 4

Common Pitfalls to Avoid

• Never use lidocaine with preservatives (e.g., methylparaben) for epidural or spinal anesthesia 4
• Never assume absence of blood on aspiration guarantees avoidance of intravascular injection—always use incremental technique 4
• Never exceed weight-based dosing limits, even if the calculated volume seems small for the surgical field 1, 2
• Do not use intra-articular infusions of local anesthetics post-operatively, as this is an unapproved use associated with chondrolysis 4