How long after applying Lidocaine (LET) (lidocaine epi topical) should sutures be started for optimal analgesia?

Optimal Timing for Suturing After LET Application

For optimal analgesia, sutures should be started 10-20 minutes after applying LET (lidocaine, epinephrine, tetracaine) topical solution, or when wound edges appear blanched. 1

Evidence-Based Timing for LET Application

The American Academy of Pediatrics provides clear guidelines on the use of LET for wound anesthesia:

• LET requires 10-20 minutes to achieve optimal anesthetic effect
• Visual indicator: wound edges should appear blanched before beginning suturing
• This timing provides excellent wound anesthesia for laceration repair 1

Application Protocol for LET

1. Application method:

   • Apply 3 mL for children >17 kg (0.175 mL/kg for children <17 kg)
   • Place LET directly on open wound and cover with occlusive dressing, or
   • Place cotton ball soaked with LET solution into the wound 1

2. Contraindications:

   • Allergy to amide anesthetics
   • Gross contamination of wound 1

Considerations for Optimal Analgesia

Efficacy Considerations

• Research shows that a single 30-minute application provides similar analgesia to multiple applications
• A study comparing triple application (every 10 minutes) versus single 30-minute application found no significant difference in pain scores (mean VAS 16 for both groups) 2
• Only about 19% of patients require additional anesthesia regardless of application method 2

Timing Considerations

• The 10-20 minute timeframe balances the need for adequate anesthesia with clinical workflow
• Waiting longer (30 minutes) may provide slightly better anesthesia but studies show the difference is not clinically significant 3
• The blanching of wound edges serves as a visual indicator that vasoconstriction from epinephrine has occurred and anesthesia is likely adequate 1

Common Pitfalls to Avoid

1. Insufficient waiting time:

   • Starting suturing too early (before 10 minutes) may result in inadequate anesthesia
   • Patient discomfort may lead to movement and compromise procedural success

2. Excessive waiting time:

   • Waiting beyond 30 minutes provides minimal additional benefit
   • Unnecessarily prolongs emergency department stay 3

3. Timing with other anesthetics:

   • If supplemental injectable lidocaine is needed, LET still reduces the pain of injection
   • When using LET with other local anesthetics, maintain appropriate intervals between applications 1

Special Populations

For neonates and infants:

• LET can be used safely with appropriate weight-based dosing
• Consider supplementing with non-pharmacological methods (pacifier, sucrose) for enhanced comfort 1

For facial lacerations:

• The 10-20 minute timeframe is particularly important as these areas are highly vascular
• Blanching is an especially useful indicator in these areas 1

By following these evidence-based guidelines for timing LET application, clinicians can provide optimal analgesia while maintaining efficient patient care in the emergency setting.