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Local and regional anesthesia

Last updated: July 15, 2021

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Local and regional anesthesia, in contrast to systemic, general anesthesia, involves the reversible numbing of a specific region of the body to prevent any sensation of pain. Pain may be blocked on different levels of its signal transduction pathway, e.g., at the site of origin, along the nerves, or in the brain. Accordingly, local and regional anesthesia can be divided into local topical and infiltration anesthesia, regional peripheral nerve blocks (PNB), and neuraxial anesthesia (e.g., spinal and epidural). Local anesthesia can be combined with general anesthesia, allowing the doses of anesthetic and analgesic drugs to be reduced during surgery, and may eliminate the need for other measures to achieve sufficient anesthesia (depending on the timeframe of surgery, risk profile, patient's consent). In general, local anesthesia carries less risk than general anesthesia, as essential body functions (e.g., respiration) are not affected. However, specific complications (e.g., bleeding, infection) and contraindications (e.g., patient's refusal, allergies) to local anesthesia must be considered. The drugs used for anesthesia can be found in the article local anesthetic agents.

Local and regional anesthesia are used prior to certain medical procedures to reduce pain; see “Indications” in local anesthetic agents.

  • Definition: : Local anesthesia reversibly blocks nerve endings and pain conduction near the site of administration (limited area).
  • Indications: See “Local anesthetic agents.”
  • Procedure
    • Topical anesthesia: application of gels, ointments, sprays, or patches → anesthetic agent gets absorbed through the skin or mucosa
    • Infiltration anesthesia: injection of local anesthetic directly into a painful area or one to be operated on
      • Technique
        • Hygiene is crucial and depends on the specific intervention!
        • Sufficient infiltration of the target area (e.g., wound margins of a cut) by injecting the local anesthetic drug from all sides with as few punctures as possible (avoid vascular infiltration by aspirating before injecting!)
      • Injection site: injected locally subcutaneously and/or submucosally wherever required (e.g., wound margins of a cut)

The effect of local anesthetic drugs is very limited in inflamed tissues (e.g., abscess)! The acidic environment of inflamed tissues leads to protonation of the anesthetic drug, which in turn reduces its lipophilicity and prevents the spread of the drug to the site of action.

  • Definition: Local anesthetic is injected near a specific nerve or nerve bundle.
  • Indications
    • Surgery of the upper extremities
      • Interscalene block
      • Supraclavicular plexus block
      • Vertical infraclavicular plexus block
      • Axillary brachial plexus block
    • Surgery of the lower extremities
    • Surgery of the scalp, neck, and trunk
    • Block of selected peripheral nerves (e.g., digital nerve block): technique to anesthetize the digits to perform surgery on the fingers or toes.
  • Relative contraindication: coagulopathy
  • Procedure
    • Injection site: depends on the nerves that need to be blocked
    • Technique
      • The patient is placed in a position that is tolerable for him or her and allows the practitioner to access the relevant nerve easily (e.g., to apply an axillary plexus block, the hand is placed underneath the head with the arm abducted and bent.)
      • Hygiene: hand disinfection, sterile gloves, sterile face mask, utensils for wipe disinfection of the puncture site afterward, (if catheter is inserted, also sterile gown and sterile fenestrated drape)
      • Identification of the relevant nerve guided by specific landmarks and/or:
      • Two approaches to inject the local anesthetic drugs are available:

Peripheral nerve blocks are preferred over general anesthesia in patients with respiratory problems and preferred over epidural/spinal anesthesia in patients who are at high risk for urinary retention or other side effects of these procedures.

References:[1]

All procedures

Epidural/spinal anesthesia

References:[2][3]

We list the most important complications. The selection is not exhaustive.

  1. Turnbull DK, Shepherd DB. Post-dural puncture headache: pathogenesis, prevention and treatment. Br J Anaesth. 2003; 91 (5): p.718-729. doi: 10.1093/bja/aeg231 . | Open in Read by QxMD
  2. Clinical Relevance of the Bezold–Jarisch Reflex. http://anesthesiology.pubs.asahq.org/article.aspx?articleid=1943118. Updated: May 1, 2003. Accessed: February 20, 2017.
  3. Gimeno AM, Errando CL. Neuraxial regional anaesthesia in patients with active infection and sepsis: a clinical narrative review. Turk J Anaesthesiol Reanim. 2018; 46 (1): p.8-14. doi: 10.5152/TJAR.2018.12979 . | Open in Read by QxMD
  4. Agabegi SS, Agabegi ED. Step-Up To Medicine. Wolters Kluwer Health ; 2015