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    Attention COACH STUDY participants:

    The principal investigators of the study request that you use the official version of the modified score here.

    Local Anesthetic Dosing Calculator

    Doses local anesthetics to help avoid toxic doses.

    IMPORTANT

    This calculator provides guidance for maximum dosing of local anesthetic and should not be used as the primary means of dosing. Always double check and err on the side of caution.

    INSTRUCTIONS

    Note: Previous versions of Goldfrank’s reported an increased maximum allowable dosage due to the vasoconstrictive effects of epinephrine when added to local anesthetics. The most recent version no longer includes this adjustment. While there likely is a higher safe dose when epinephrine is added, we no longer include that estimate on this calculator, and as always, dosages should be double-checked and reviewed using your local pharmacy and policies.

    When to Use
    Pearls/Pitfalls
    Why Use

    Patients undergoing nerve blocks or regional anesthesia.

    • Toxicity is based on ideal body weight.

    • Local anesthetic systemic toxicity (LAST) is rare but potentially life-threatening. Symptoms can be divided into two main categories: 

      • Neurotoxicity: perioral numbness, metallic taste, mental status changes or anxiety, visual changes, muscle twitching, and ultimately, seizures, coma, and respiratory depression.

      • Cardiovascular toxicity: tachycardia, hypertension, ventricular arrhythmias, and/or asystole.

    • Patient risk factors for LAST include:

      • Extremes of age.

      • Decreased muscle mass.

      • Renal, hepatic, or cardiac disease.

      • Metabolic disturbances (acidosis, hypoxia, hypercarbia).

      • Pregnancy.

    • Procedural risk factors for LAST include:

      • Injection into highly vascular areas (highest incidence in paravertebral injections, followed by upper and lower extremity peripheral nerve blocks).

      • Multiple injections or infusion.

    • Ways to reduce risk of LAST:

      • Calculate patient’s maximum dose.

      • Dilution of anesthetic with normal saline allows for large volume blocks to be performed without risking toxic doses. 

      • Vasoconstrictors such as epinephrine can be added to decrease rate of absorption and therefore decrease toxic dose.

      • Use ultrasound to confirm needle placement.

      • Aspirate prior to injecting.

      • Monitor for development of symptoms.

    LAST can occur with any local anesthetic through any route of administration. Calculating the maximum dose in advance may help reduce risk.

    Bupivacaine
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    Ropivacaine
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    Next Steps
    Evidence
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    About the Creator

    Other creator.

    Content Contributors
    • Paul Hausknecht, MD
    About the Creator
    OTHER
    Content Contributors
    • Paul Hausknecht, MD