While local anesthesia is adequate for most lacerations, nerve blocks afford advantages in several situations. For wounds in cosmetic areas such as the face, local infusion may distort the wound, preventing optimal approximation of the wound margins. For wounds in distal areas such as fingertips, penis, and tip of the nose, local infusion can be extremely painful and may compromise blood flow. Nerve blocks can effectively anesthesize large areas where local infusion would require multiple injection sites and a prohibitive dose of anesthetic.

Before performing a nerve block, a neurological exam should be performed and documented. The patient should be informed that the nerve block may require injection of additional anesthetic and this is considered a par of the procedure and does not indicate failure of the nerve block. The goal of a nerve block is to infiltrate anesthetic around the nerve but not directly into it. Direct injection of the nerve can lead to neuritis through trauma to nerve, chemical irritation, and ischemia. If the patient experiences paresthesia (shooting pain, numbness or tingling) during injection, the needle should be withdrawn slightly.

General principles of local infiltration still apply to nerve blocks. The skin should be prepped n a sterile fashion. The smallest available needle (25- to 30 gauge) should be used. It is important to give the block adequate time to take maximum effect, often 20 to 30 minutes (5). Bupivicaine can be used for longer acting anesthesia.

 

Note that this chapter does not cover basic aspects of anesthetic agents, such as pharmacology, toxicity, and equipment used. This material is covered in detail in the Local Anesthesia Techniques section.

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Authors

Colin Devonshire , MD

Resident Physician in Emergency Medicine
Beth-Israel Deaconess Medical Center, Boston, Massachusetts

 

John E. Sullivan, MD

Instructor in Medicine, Harvard Medical School
Staff Physician, Department of Emergency Medicine
Mount Auburn Hospital, Cambridge, Massachusetts

  
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Gary Setnik, MD

Assistant Professor of Medicine, Harvard Medical School

Chair, Department of Emergency Medicine
Mount Auburn Hospital, Cambridge, Massachusetts

 
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Todd W. Thomsen, MD
Instructor in Medicine, Harvard Medical School
Staff Physician, Department of Emergency Medicine
Mount Auburn Hospital, Cambridge, Massachusetts
   

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