Lidocaine for Digital Block

Type and Concentration of Lidocaine

The American Academy of Dermatology recommends 1% lidocaine with epinephrine (1:100,000) as the preferred agent for digital blocks, providing adequate anesthesia with a duration of 90-200 minutes 1
Plain lidocaine (without epinephrine) can be used at 1-2% concentration but has a shorter duration of action (60-90 minutes), according to the American Academy of Pediatrics 3

The American Academy of Dermatology recommends a maximum safe dose of lidocaine with epinephrine: 7 mg/kg (not to exceed 500 mg total) 1
The American Academy of Dermatology recommends a maximum safe dose of plain lidocaine: 4.5 mg/kg (not to exceed 300 mg total) 1
For children, the American Academy of Dermatology and the American Academy of Pediatrics recommend 3.0-4.5 mg/kg with epinephrine; 1.5-2.0 mg/kg without epinephrine 1, 3

Aspirate before injection to avoid intravascular administration, as recommended by the American Academy of Dermatology 4
Use the lowest effective volume to minimize risk of compartment syndrome, according to the American Academy of Dermatology 1, 4
Buffering lidocaine with sodium bicarbonate (1:9 or 1:10 ratio) can reduce injection pain, as suggested by the American Academy of Dermatology 5

For longer procedures or extended postoperative analgesia, 0.5% bupivacaine provides longer duration (180-600 minutes) but has a similar onset time to lidocaine, according to the American Academy of Pediatrics 3
For patients with true lidocaine allergy, consider ester-type local anesthetics, as recommended by the American Academy of Dermatology 1, 2

Signs of local anesthetic systemic toxicity (LAST) include circumoral numbness, facial tingling, slurred speech, metallic taste, auditory changes, and hallucinations, as described by the American Academy of Dermatology 4
Advanced LAST can progress to seizures, CNS depression, and cardiac arrest, according to the American Academy of Dermatology 4
Reduce risk by using the lowest effective dose, aspirating before injection, and administering incremental injections, as recommended by the American Academy of Dermatology 4, 2

Exceeding maximum recommended doses can lead to systemic toxicity, as warned by the American Academy of Dermatology 1, 4
Using excessive volumes can cause compartment syndrome, according to the American Academy of Dermatology 4
Failing to aspirate before injection increases risk of intravascular administration, as cautioned by the American Academy of Dermatology 4
Using bupivacaine with sodium bicarbonate can cause precipitation and decreased efficacy, as noted by the American Academy of Dermatology 5