Before the availability of local anesthetics, local pain control for lacerations, fractures, and minor surgery was achieved by minimizing the pain response centrally, typically with opiates or alcohol. Procaine, which entered clinical use in 1904, was the only local anesthetic available for almost 40 years, but the short duration of action and high rate of allergic reactions limited its effectiveness. Lidocaine was introduced in 1943 and continues to be the local anesthetic most commonly used in the ED.1,2 Additional local anesthetics are available for both topical and injectable use (Tables 34-1 and 34-2). Emergency physicians commonly use local and regional anesthetic techniques for potentially painful procedures performed in the ED.3 Regional anesthesia can also be used to control the pain of acute injuries and reduce the utilization of systemic analgesics.4,5
Table 34-1 Topical Anesthetic Agents |Favorite Table|Download (.pdf)
Table 34-1 Topical Anesthetic Agents
|Agent||Active Ingredients||Application||Time to Effectiveness|
|Eutectic mixture of local anesthetic agents (EMLA®)|
Apply thick layer, 5–10 grams (maximum 20 grams), to area to be anesthetized; cover with semiocclusive dressing.
|Tetracaine (amethocaine) gel (Ametop®)||Tetracaine 4%||Apply 1 gram (one tube) to area to be anesthetized; cover with occlusive dressing.||30 min|
|Liposome encapsulated tetracaine||Tetracaine 5%||Apply 0.5 gram to area to be anesthetized.||60 min|
|Liposome encapsulated lidocaine (LMX4® and LMX5®)||Lidocaine 4% or 5%||Apply 2.5 grams to area to be anesthetized.||30–60 min|
|Lidocaine, epinephrine, tetracaine (LET)|
|Apply 5 mL to gauze pad placed into wound; cover with semiocclusive dressing.|
|Topical anesthetic gel (ZAP®)|
Apply 0.2 mL (one dispenser application) with cotton swab to area to be anesthetized.
|Benzocaine spray (Hurricaine®)||Benzocaine 20%||Apply 1-s spray to area to be anesthetized; volume delivered is highly dependent on canister orientation and residual volume.||15–30 s|
|Viscous lidocaine||Lidocaine 2%||Apply 10–15 mL to area (e.g., topical anesthesia before upper airway procedures).||2–5 min|
Table 34-2 Local Anesthetic Agents |Favorite Table|Download (.pdf)
Table 34-2 Local Anesthetic Agents
|Agent||Lipid Solubility*||Protein Binding||Duration† (min)||Onset‡ (min)||Maximum Dose (milligrams/kg, with epinephrine)||Concentration (subdermal use)||Concentration (regional anesthesia use)|
|Alternatives for patients with reactions to amides ...|
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