From the Guidelines
The correct technique for administering local infiltration anesthesia is subepidermal "pushpin" and subcutaneous infiltration, as this method allows for effective anesthesia with minimal discomfort and risk of complications. When administering local infiltration anesthesia, it is essential to follow several key steps to ensure patient safety and comfort. First, select an appropriate anesthetic agent such as lidocaine (1-2%), bupivacaine (0.25-0.5%), or mepivacaine (1-2%), with epinephrine (typically 1:100,000 or 1:200,000) often added to prolong duration and reduce bleeding, except in end-arterial areas like fingers or toes 1. Before injection, clean the area with an antiseptic solution such as chlorhexidine or povidone-iodine. Use a small-gauge needle (25-30G) to minimize pain, and aspirate before injecting to avoid intravascular administration 1. Inject slowly (approximately 1 mL per 10 seconds) to reduce pain and tissue distortion, starting at the periphery of the area and working inward using a fan-like pattern. The total volume depends on the size of the area but typically ranges from 3-10 mL. Allow 5-10 minutes for full effect before beginning the procedure. To minimize pain during injection, consider using a slow rate of infiltration, vibration of the skin, use of a warm solution, or cold air skin cooling 1. Potential complications include pain during injection, hematoma formation, infection, allergic reactions, and systemic toxicity, so always verify maximum safe dosage based on patient weight and monitor for adverse reactions.
Some key considerations when administering local infiltration anesthesia include:
- Using the lowest effective dose of local anesthetic to minimize the risk of systemic toxicity 1
- Adding epinephrine to the anesthetic to prolong duration and reduce bleeding, except in end-arterial areas 1
- Using incremental injections of anesthetic and continually assessing the patient for signs of early toxicity 1
- Considering the use of additives such as hyaluronidase or buffering with sodium bicarbonate to ease diffusion and reduce contour distortion 1
- Minimizing pain during injection through the use of slow infiltration rates, vibration, or cold air skin cooling 1