What are the recommendations for local anesthesia administration?

Local Anesthesia Administration: Evidence-Based Recommendations

Maximum Dosing Guidelines

For adults, use lidocaine with epinephrine at a maximum dose of 7.0 mg/kg (or 4.5 mg/kg without epinephrine), and calculate the maximum allowable dose before administration to prevent systemic toxicity. 1

Adult Dosing by Agent

• Lidocaine with epinephrine: Maximum 7.0 mg/kg (4.4 mg/kg for dental procedures) 1
• Lidocaine without epinephrine: Maximum 4.5 mg/kg (4.4 mg/kg for dental procedures) 1
• Bupivacaine with epinephrine: Maximum 3.0 mg/kg (1.3 mg/kg for dental procedures) 1
• Mepivacaine with epinephrine: Maximum 7.0 mg/kg 1
• Procaine with epinephrine: Maximum 10.0 mg/kg 1

Pediatric Dosing

In children, reduce amide local anesthetic doses by 30% in infants younger than 6 months due to immature hepatic metabolism. 1

• Lidocaine with epinephrine: Maximum 7.0 mg/kg for medical use, 4.4 mg/kg for dental 1
• Lidocaine without epinephrine: Maximum 4.4 mg/kg 1
• Bupivacaine with epinephrine: Maximum 3.0 mg/kg for medical use, 1.3 mg/kg for dental 1

Administration Technique to Minimize Toxicity Risk

Always aspirate before each injection to avoid intravascular administration, which is the most common cause of systemic toxicity. 1, 2

Key Safety Steps

• Calculate maximum dose in mg/kg before starting the procedure 1
• Use incremental injections rather than rapid boluses 2, 3
• Aspirate frequently during injection to detect vascular placement 1, 2
• Monitor vital signs every 5 minutes when using high doses or amide anesthetics 1
• Continuously communicate with the patient to detect early toxicity signs 2

Specific Technique Modifications

• Lower doses in highly vascular areas to reduce systemic absorption 1
• Add sodium bicarbonate to lidocaine with epinephrine to decrease injection pain (Level A recommendation) 1
• Warm tumescent solutions to 40°C before administration to reduce discomfort 2
• Use slow infiltration rates for tumescent anesthesia to minimize patient discomfort 2

Epinephrine Use: Dispelling Historical Myths

Epinephrine can be safely added to local anesthesia for use on digits, nose, ears, hands, and feet—the historical contraindication has been definitively refuted by multiple systematic reviews and randomized trials. 1

Evidence-Based Epinephrine Guidelines

• Digital blocks with epinephrine: Level A recommendation based on Level I and II evidence showing no cases of necrosis, with benefits including longer duration and reduced need for tourniquets 1
• Ear and nose procedures: Safe with no anesthesia-related complications and decreased operative time 1
• Penile procedures: Level B recommendation based on retrospective data showing safety 1
• Lowest effective concentration: Use the minimum epinephrine concentration needed for vasoconstriction (Level B recommendation) 1

Special Populations for Epinephrine Use

• Pregnancy: May be used in small amounts, but postpone elective procedures until after delivery; urgent procedures should be delayed until second trimester when possible 1
• Stable cardiac disease: Safe to administer; consult cardiology if uncertain about patient tolerance 1

Managing Lidocaine Allergy

For patients with true lidocaine allergy (representing only 1% of adverse reactions), switch to an ester-type anesthetic such as procaine, as cross-reaction between amide and ester classes is rare. 1

Alternative Agents for Lidocaine Allergy

• Ester anesthetics (procaine, chloroprocaine): First-line alternative due to rare cross-reactivity 1
• 1% diphenhydramine: Alternative option but has longer onset (5 minutes vs 1 minute) and limited efficacy 1
• Bacteriostatic saline (0.9% benzyl alcohol): May be less painful than diphenhydramine when combined with epinephrine 1

Recognizing and Treating Local Anesthetic Systemic Toxicity (LAST)

Early CNS toxicity signs include restlessness, metallic taste, tinnitus, perioral numbness, and lightheadedness; progression leads to seizures, cardiovascular depression, and potential death if untreated. 3

LAST Treatment Protocol

Have 20% lipid emulsion immediately available when using long-acting agents (bupivacaine, ropivacaine) in vascular tissues. 1

1. Get help immediately and ventilate with 100% oxygen 1
2. Manage seizures with benzodiazepines (midazolam 0.1-0.2 mg/kg IV); avoid propofol 1
3. Initiate CPR if needed; avoid vasopressin, calcium channel blockers, and beta-blockers 1
4. Reduce epinephrine doses during resuscitation 1
5. Alert nearest facility with cardiopulmonary bypass capability 1

Monitoring Requirements

When administering high doses or amide local anesthetics, document vital signs at least every 5 minutes initially, then increase intervals to 10-15 minutes once the patient begins to awaken. 1

Essential Monitoring Parameters

• Continuous pulse oximetry 1
• Heart rate and blood pressure every 5 minutes during high-dose administration 1
• Capnography to detect apnea or airway obstruction, especially with supplemental oxygen 1
• Patient communication for early toxicity detection 2

Procedure-Specific Recommendations

Tumescent Anesthesia for Liposuction

The maximum dose of lidocaine with epinephrine for liposuction is 55 mg/kg, validated only for patients weighing 43.6-81.8 kg. 2

• This higher dose applies exclusively to liposuction procedures 2
• For non-liposuction dermatologic procedures, standard 7.0 mg/kg maximum applies 2
• Prilocaine may be combined with lidocaine to reduce toxicity risk when large volumes are needed 2

Office-Based Dermatologic Surgery

Local infiltrative anesthesia is safe and effective for skin biopsy, excision, wound closure, tissue rearrangement, skin grafting, cauterization, and laser procedures. 1

• Combining methods (infiltrative, topical, nerve block) is helpful for complex procedures like full-face ablative laser or Mohs surgery 1
• Maximum 500 mg lidocaine for multistage Mohs micrographic surgery (Level B recommendation) 1

Critical Pitfalls to Avoid

• Never exceed calculated maximum dose based on patient weight 1
• Never use intra-articular continuous infusions of local anesthetics due to chondrolysis risk 3
• Never combine IV lidocaine with regional blocks within 4 hours to prevent additive toxicity 1
• Never use articaine in children under 4 years of age 1
• Never apply excessive topical anesthetics to mucosal surfaces due to rapid systemic uptake and methemoglobinemia risk 1