What is the protocol for lidocaine (local anesthetic) injection infiltration for finger anesthesia?

From the Guidelines

Lidocaine infiltration is an effective method for achieving finger anesthesia prior to procedures, and the recommended dose should not exceed 7 mg/kg with adrenaline, as stated in the guidelines for postoperative pain management 1. To perform the infiltration, the following steps can be taken:

• Clean the injection site with antiseptic solution
• Insert a 27-30 gauge needle at the base of the finger on both sides (lateral and medial aspects) to block the digital nerves
• Inject slowly while advancing the needle, creating a ring of anesthesia around the base of the finger The typical dose is 3-5 mL per digit, and it is essential to avoid exceeding the maximal toxic doses of local anesthetics, as recommended in the guidelines 1. Some studies suggest that the addition of sodium bicarbonate to local anesthetic can decrease patient pain during drug delivery via subcutaneous or intradermal infiltration 1. However, the most recent and highest quality study on this topic is not directly applicable to finger anesthesia. It is crucial to watch for signs of lidocaine toxicity, including perioral numbness, dizziness, tinnitus, or seizures, and to have a plan in place for treatment, such as administering 1.5 mL/kg 20% lipid emulsion over ∼1 minute to trap unbound amide local anesthetics 1. The onset of action is typically within 5-10 minutes, and the anesthesia lasts 1-2 hours. Before beginning any painful procedure, it is essential to verify anesthesia by testing sensation.

From the FDA Drug Label

Lidocaine HCl Injections are indicated for production of local anesthesia by infiltration techniques such as percutaneous injection by peripheral nerve block techniques such as brachial plexus and intercostal, when the accepted procedures for these techniques as described in standard textbooks are observed.

• Infiltration anesthesia is a technique that can be used for local anesthesia.
• The drug label mentions infiltration techniques as an indication for lidocaine HCl injections.
• Percutaneous injection is mentioned as a method for infiltration techniques.
• There is no specific mention of finger infiltration, but peripheral nerve block techniques are mentioned, which could potentially include fingers.
• Given the information, lidocaine can be used for local anesthesia by infiltration, but the label does not explicitly state its use for finger infiltration 2.

From the Research

Lidocaine Anesthetic Injection Infiltration for Finger

• The use of lidocaine with epinephrine for digital anesthesia has been a topic of debate, with some studies suggesting that it may cause digital gangrene 3.
• However, a literature review found that the addition of epinephrine to lidocaine does not increase the risk of digital necrosis, and that proper injection technique and patient selection are crucial to minimize complications 3.
• The use of lidocaine with epinephrine has been shown to provide better and longer pain control during digital procedures, and reduces the need for tourniquets and large volumes of anesthetic 3, 4.
• A randomized controlled trial found that digital and local anesthesia with prior application of lidocaine-epinephrine-tetracaine (LET) resulted in similar pain scores for needle insertion, anesthetic infiltration, and suturing 5.
• A systematic review of local anesthetics for digital nerve blocks found that lidocaine with epinephrine provided a good short-term anesthesia with minimal pain on injection, while bupivacaine with epinephrine provided good long-term anesthesia 6.
• The use of lidocaine-adrenaline-tetracaine (LAT) gel has been shown to be effective in providing anesthesia for the repair of finger lacerations, with a success rate of 53.7% and no signs of digital ischemia 7.

Key Findings

• Lidocaine with epinephrine is a safe and effective combination for digital anesthesia 3, 4, 6.
• Proper injection technique and patient selection are crucial to minimize complications 3.
• The use of lidocaine with epinephrine reduces the need for tourniquets and large volumes of anesthetic 3, 4.
• LAT gel is a safe and effective means of providing anesthesia for the repair of simple finger lacerations in children 7.

Local Anesthetics for Digital Nerve Blocks

• Lidocaine with epinephrine provides a good short-term anesthesia with minimal pain on injection 6.
• Bupivacaine with epinephrine provides good long-term anesthesia 6.
• Ropivacaine provides the longest duration of anesthesia, but requires the use of a tourniquet to create a bloodless field 6.