From the Guidelines
For a patient on warfarin with a finger laceration, it is generally safe to use lidocaine with epinephrine at a maximum dose of 7 mg/kg without epinephrine or 4.5 mg/kg with epinephrine (1:100,000 or 1:200,000 concentration).
Key Considerations
- The old adage of avoiding epinephrine in digits has been disproven by modern evidence, and it can be safely used in fingers when appropriate doses are observed 1.
- The benefit of adding epinephrine is reduced bleeding during the procedure and prolonged anesthesia.
- However, caution should be exercised in patients with severe peripheral vascular disease.
- Warfarin itself is not a contraindication to using lidocaine with epinephrine, though these patients may experience more bleeding during the procedure, so good hemostasis techniques should be employed.
- Always aspirate before injecting to avoid intravascular administration, and monitor the total dose to prevent lidocaine toxicity.
Recommended Dosage
- For most finger lacerations, 1-5 mL of 1% or 2% lidocaine with epinephrine is typically sufficient.
- The maximum recommended doses and duration of action are shown in the guidelines, with lower doses recommended for very vascular areas 1.
Important Notes
- The use of epinephrine in small amounts is safe for dermatologic surgery, including in patients with stable cardiovascular disease 1.
- The addition of epinephrine to local anesthesia can result in less need for tourniquet, faster onset, and longer duration of anesthesia 1.
- The most commonly used concentrations of epinephrine in dermatologic surgery are 1:100,000 and 1:200,000, with the authors recommending the use of the lowest effective concentration of epinephrine for dermatologic procedures 1.
From the Research
Laceration Repair and Anesthesia
- The goal of laceration repair is to achieve hemostasis and optimal cosmetic results without increasing the risk of infection 2.
- Local anesthetic with epinephrine in a concentration of up to 1:100,000 is safe for use on digits, including fingers 2.
Epinephrine and Lidocaine Concentration
- A study found that the use of lidocaine with epinephrine 1:100,000 resulted in an immediate decrease in cutaneous blood flow, which was maximal at 10 min in the forearm and 8 min in the face 3.
- Another study used lidocaine 1% with epinephrine 1:200,000 for a field block in cutaneous surgery, but noted a potential complication of postoperative hemorrhage due to the wearing-off effect of epinephrine 4.
Digital Anesthesia for Finger Lacerations
- A randomized controlled trial compared digital anesthesia with local anesthesia for finger lacerations and found no significant difference in pain scores between the two groups 5.
- The study used 1% lidocaine for digital infiltration and found that only one patient required rescue anesthesia 5.
Recommendations for Epinephrine with Lidocaine
- Based on the available evidence, it is recommended to use a concentration of up to 1:100,000 epinephrine with lidocaine for digital anesthesia in finger lacerations 2, 3.
- However, the amount of epinephrine with lidocaine that can be safely used in a patient on warfarin with a finger laceration is not explicitly stated in the provided studies, and caution should be exercised due to the potential risk of bleeding complications 4.