What is the best anesthesia for simple suture wounds?

Best Anesthesia for Simple Suture Wounds

For simple laceration repair, infiltrated lidocaine remains the gold standard, though topical anesthetics (particularly non-cocaine formulations) are equally effective for facial and scalp wounds and should be considered first-line to avoid injection pain. 1

Topical Anesthetics as First-Line for Select Wounds

Topical anesthetics are recommended as first-line anesthesia for repair of dermal lacerations, particularly in facial and scalp wounds where absorption is highest. 1 Multiple studies demonstrate equivalent efficacy between topical agents and infiltrated anesthetics for minor laceration repair, with the significant advantage of avoiding injection pain. 1

Preferred Topical Formulations

• Non-cocaine formulations are strongly preferred over cocaine-containing preparations due to lower cost and reduced potential for adverse effects, with no difference in efficacy. 1
• Lidocaine 2% provides 30-45 minutes of anesthesia and is safe for use in pregnant or nursing women. 1
• EMLA cream (lidocaine/prilocaine eutectic mixture) requires 60-120 minutes after occlusive dressing application but is effective for intact skin. 1
• LET solution (lidocaine, epinephrine, tetracaine) produces wound blanching in 73% of cases and provides adequate needlestick anesthesia, though injection pain reduction is similar to EMLA. 2

Application Considerations

• Apply topical anesthetics at the time of patient presentation (triage) to allow adequate time for effect before the procedure begins. 2
• Ensure adequate lighting and patient analgesia before repair. 3
• The area must be dry for proper adhesion if tissue adhesive will be used subsequently. 3

Infiltrated Local Anesthetics

When topical anesthesia alone is insufficient or for wounds in locations with lower absorption (trunk, extremities), infiltrated anesthetics are necessary. 1

Agent Selection

Lidocaine 1% is the standard infiltrative agent for most emergency department laceration repairs. 4, 5

• For wounds requiring prolonged analgesia beyond the immediate post-repair period, bupivacaine 0.25% significantly reduces pain for up to 5 hours compared to lidocaine's 2-hour duration. 4 This is particularly relevant as patients experience pain after wound closure when lidocaine wears off. 4
• Bupivacaine and levobupivacaine may negatively affect wound healing at 21 days, showing lower tensile strength and collagen maturation scores compared to controls. 6
• Lidocaine and prilocaine do not affect wound healing adversely. 6

Alternative Agents

• Diphenhydramine 0.5% is a viable alternative when lidocaine allergy exists, providing comparable anesthesia for non-facial lacerations with mild injection pain, though lidocaine remains superior for facial wounds. 5

Combined Approach for Optimal Pain Control

Topical anesthetics should be used adjunctively to lessen the pain of infiltration and reduce the dose of infiltrative anesthetic needed for larger procedures. 1

• Apply topical agent first at triage
• Perform infiltration through wound edges after topical effect achieved
• This combination reduces overall pain perception compared to infiltration alone 1

Pediatric Considerations

Topical agents are specifically recommended as first-line for laceration repair in children, with adjunctive topical anesthesia to reduce infiltration discomfort when topical alone is insufficient. 1

• Maximum doses must be weight-based to avoid systemic toxicity 7
• For infants under 12 months receiving methemoglobin-inducing agents, avoid lidocaine/prilocaine cream 7
• Neonates with gestational age less than 37 weeks should not receive lidocaine/prilocaine cream 7

Critical Safety Considerations

• When using multiple local anesthetic sources (topical plus infiltration), calculate total absorbed dose to avoid systemic toxicity. 1
• Use ideal body weight for dose calculations: (height in cm - 100) for men; (height in cm - 105) for women 1
• Monitor for signs of local anesthetic toxicity: tingling tongue/lips, tinnitus, light-headedness, slurred speech, muscle twitching 1
• Do not use intravenous lidocaine within 4 hours of nerve blocks or wound infiltration to prevent cumulative toxicity 1

Practical Algorithm

1. Facial/scalp lacerations: Apply topical non-cocaine anesthetic (LET or lidocaine 2%) at triage, wait 15-45 minutes, assess adequacy before suturing 1, 2
2. If topical inadequate or non-facial location: Infiltrate with lidocaine 1% through wound edges 1, 5
3. If prolonged post-repair analgesia needed: Consider bupivacaine 0.25% instead of lidocaine, accepting potential minor wound healing effects 4, 6
4. Lidocaine allergy: Use diphenhydramine 0.5% for non-facial wounds 5
5. Children: Prioritize topical first, add minimal infiltration only if needed 1