Safe dosing of nebulized lidocaine

Safe dosing of nebulized lidocaine

2016-11-11T19:02:35+00:00

NebulizersmSerum lidocaine levels correlate well with observed clinical effects. As the concentration increases, lightheadedness, tremors, hallucinations, seizures, and cardiac arrest can occur. Levels > 5 mcg/mL are associated with serious toxicity. With so many concentrations (1%, 2%, 4%) and routes of administration available, the total dose of lidocaine is always a concern.

This graph from Goldfrank’s Toxicologic Emergencies textbook depicts the relationship between rising lidocaine serum concentrations and expected clinical decompensation. [1]

Lidocaine - goldfrank's

The nebulized form of lidocaine is one option in our armamentarium prior to inserting an NG tube or performing a non-emergent nasotracheal intubation. Generally a 4% (40 mg/mL) solution is used.

So, what is a safe dose of nebulized lidocaine?

  • Lidocaine plasma levels were evaluated after nebulized administration. A dose of 400 mg (5.7 mg/kg in a 70 kg patient) produced a peak of 1.1 mcg/mL, far below the 5 mcg/ml level associated with toxicity. [2]
  • Application to real-life: Using 5-mL of 4% topical lidocaine solution via nebulizer will provide a total dose of 200 mg. This is within the range of safe, studied doses, and may provide the anesthetic effect you (and the patient) desires. Even if a second or third neb is needed, lidocaine serum concentrations should remain in the safe range.

Safe Lidocaine Dosing Thresholds by Other Routes

  • Intradermal/Subcutaneous: Max dose is 4.5 mg/kg. When used in combination with epinephrine, this value is increased to 7 mg/kg.
  • Intravenous: The generally recognized maximum dose of IV lidocaine is 3 mg/kg (or 300 mg). However, some references estimate up to 6.4 mg/kg as an acceptable minimum IV toxic dose in humans. [1]

Product Selection

There isn’t a standard product for this indication. Many hospitals use 4% topical solution. The other option is 4% injectable lidocaine, if your hospital carries it. While the injectable form theoretically reduces risk of pyrogen inroduction, filter needles must be used to draw up the medication to limit potential glass particle contamination from the ampule.

References

  1. Schwartz DR, Kaufman B. Chapter 66. Local Anesthetics. In: Schwartz DR, Kaufman B, eds. Goldfrank’s Toxicologic Emergencies. 9th ed. New York: McGraw-Hill; 2011.
  2. Chinn WM, Zavala DC, Ambre J. Plasma levels of lidocaine following nebulized aerosol administration. Chest 1977;71(3):346-8. [PMID 319962]
Bryan D. Hayes, PharmD, FAACT, FASHP

Bryan D. Hayes, PharmD, FAACT, FASHP

Chief Science Officer, ALiEM
Creator and Lead Editor, CAPSULES series, ALiEMU
Clinical Pharmacist, EM and Toxicology, MGH
Assistant Professor of EM, Harvard Medical School
Bryan D. Hayes, PharmD, FAACT, FASHP

Latest posts by Bryan D. Hayes, PharmD, FAACT, FASHP (see all)

  • Silmonster

    I’ve always wondered how nebulized lido compares with the SC doses. This is great, and also reassuring! Thanks.

  • Jason Oh

    Great article Bryan. How about via mucosal atomizer device? Or just plain old direct application of the 4% straight onto the mucosa?

    Hope things are going well in B-more!

    Jason Oh

    • Bryan D. Hayes

      Jason, thanks for the question. We certainly miss you here in Baltimore. While I don’t have a specific answer for your question, here is a link to some useful references: http://intranasal.net/TopicalAnesthetics/topicalanestheticabstracts.htm. It covers various studied routes of lidocaine administration for ENT and airway-related procedures.

  • njoshi8

    I love nebulized lidocaine especially prior to NGT placement, and I never knew how much to put into the cannister. Good to know how much to actually use! Also, LOVE the Goldfrank reference! 🙂

  • Pete, MI

    are ther any ill effects or even any benefits of using buffered lido in a neb?

    • Bryan D. Hayes

      Thank you for the question. I have not seen any data utilizing buffered lidocaine in a nebulizer. The purpose of buffering the lidocaine for injection is to reduce pain from the lidocaine. This should not be an issue in a nebulizer preparation.

      • Thankyou for your response. I understand that buffered lido is used for injection but was wondering if given by neb accidentaly ther would be anything to be conserned with or would the buffering agent (sodium bicarb) just disipatewith the nebulization?

  • evelyn

    I’ve done the math on total lidocaine you might use for awake intubation – nebulized 4% + 5% lidocaine paste +/- 2% lidocaine gel. The gel is 20mg/mL, the paste is 40mg/inch. If you use all three, I’ve calculated 200 mg neb (5mL) +100mg gel (5mL) + 80mg paste (2 inches). That brings you to 380 mg total. So even if you use all 3, you are still in the safe range.
    I’ve read that up to 9mg/kg topically is safe.

  • Travis Sewell

    I am finding this article 2 years late but it is the best article I have found on the topic. Is injectable lidocaine also appropriate for nebulization? Thanks.

    • Bryan D. Hayes

      Travis, thank you for the feedback. We utilize the 4% topical solution at my institution, but I don’t know of any reason you couldn’t use the injectable product.

  • dileepkumar g

    Thanks Bryan for the brilliant article. Does it needs further mixing with saline before using in nebulizer?

    • Bryan D. Hayes

      Thanks for your question. The lidocaine is ok to administer by itself. It could also be mixed with saline for nebulization, if needed.