Adequacy of the epinephrine autoinjector needle length in delivering epinephrine to the intramuscular tissues

doi:10.1016/S1081-1206(10)61130-1

Annals of Allergy, Asthma & Immunology

Volume 94, Issue 5, May 2005, Pages 539-542

https://doi.org/10.1016/S1081-1206(10)61130-1 Get rights and content

Background

Epinephrine injected by an autoinjector in the anterolateral aspect of the thigh is the standard of care in the emergency self-treatment of anaphylaxis. In the United States, the autoinjector EpiPen is widely used for the self-treatment of anaphylaxis.

Objective

To investigate whether EpiPen autoinjector, with a needle length of 1.43 cm, is sufficient for intramuscular delivery of epinephrine in men and women.

Methods

The distance from skin to muscle in the anterolateral aspect of the thigh was measured in 50 men and 50 women who had undergone computed tomography of the thighs for other medical reasons. For each individual, body mass index (BMI; a measure of weight in kilograms divided by the square of height in meters) was also calculated, and the individuals were classified as underweight (BMI, <18.5), normal (BMI, 18.5-24.9), overweight (BMI, 25.0-29.9), and obese (BMI, ≥30.0) using standard definition.

Results

In the study participants the mean ± SD distance from skin to muscle was 0.66 ± 0.47 cm for men and 1.48 ± 0.72 cm for women (P < .001). One man (obese at a BMI of 42.2) and 21 women (11 obese with a mean BMI of 35.2, 6 overweight with a mean BMI of 30.1, and 4 normal with a mean BMI of 24.5) had a greater distance from skin to muscle than the EpiPen needle length of 1.43 cm.

Conclusion

The distance from skin to muscle for the anterolateral aspect of the thigh is higher in women compared with men. This difference suggests that EpiPen may not deliver epinephrine to the intramuscular tissue in many women.

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Citation Excerpt :
The needle length of the 0.3-mg device is appropriate for most children and adults weighing 30 kg and more.90 Ultrasound studies indicate that the needle tip will not reach muscle in approximately 28% of adult women, even after accounting for the tissue compression needed for device activation.91-93 Propulsion may deliver the device past the needle tip into the IM space.94,95
Epinephrine is life-saving and the only first-line medication in the management of anaphylaxis. At therapeutic doses, it acts rapidly to reverse nearly all symptoms of anaphylaxis, and stabilize mast cells. The standard approved doses administered intramuscularly in the lateral thigh have a long track record for safe and effective use, but more information is needed on epinephrine pharmacokinetics and pharmacodynamics to ensure that current dosing strategies are optimal. Epinephrine should be administered promptly once anaphylaxis is suspected, to minimize morbidity and mortality. Providers on the front-line for managing patients with life-threatening allergic reactions need clear parameters and tools to guide the appropriate use of epinephrine, which take into account the potential evolution of symptoms and signs over time. All patients at risk for anaphylaxis should carry 2 epinephrine autoinjectors and be taught and able to demonstrate how to use them. Epinephrine autoinjectors need to be affordable, readily available, and easy for patients with allergies to carry and use. Furthermore, these devices should be available to meet the needs of all patients, from small infants through large or obese adults. The ideal means for storing and delivering epinephrine in prehospital and hospital environments warrants further study, to determine how to best balance efficiency, safety, and costs.
Point-of-care ultrasonography in the allergy and immunology clinic
2019, Annals of Allergy, Asthma and Immunology
To summarize evidence supporting the use of point-of-care ultrasonography as a clinical tool for allergists and immunologists.
Cochrane Library, Medline, EMBASE, and Scopus databases were searched for articles published before December 18, 2018.
We included any retrospective or prospective study that evaluated ultrasonography in allergy and immunology and epinephrine autoinjector (EAI) needle length.
The standard EAI needle length may be inadequate for intramuscular delivery of epinephrine, particularly for women, at risk of anaphylaxis. In patients who weigh less than 15 kg, the lengths of commercially available EAIs may be too long, risking inadvertent intraosseous injection and resultant complications. Ultrasonography can be routinely used in the allergy clinic to guide needle length and angle for subcutaneous allergen immunotherapy injections to minimize systemic adverse effects.
Point-of-care ultrasonography can be a useful tool to enhance patient care and safety in an allergy clinic. Ideally, all patients prescribed EAIs should have ultrasonographic measurement of the skin to muscle distance and skin to bone distance to assist in identifying patients at risk of subcutaneous or intraosseous injection in anaphylaxis and those at risk of intramuscular injection during subcutaneous allergen immunotherapy injections.

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: The opinions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of the Defense. The work was funded by the US Army. No external financial support was provided.

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ORIGINAL ARTICLESAdequacy of the epinephrine autoinjector needle length in delivering epinephrine to the intramuscular tissues

Background

Objective

Methods

Results

Conclusion

J Allergy Clin Immunol

J Allergy Clin Immunol

J Allergy Clin Immunol

J Allergy Clin Immunol

Catecholamine, sympathomimetic drugs, and ad-renergic receptor antagonist

Anaphylaxis and emergency treatment

Pediatrics

Adrenaline in the treatment of anaphylaxis: what is the evidence

BMJ

Use of epinephrine in the treatment of anaphylaxis

Curr Opin Allergy Clin Immunol

ORIGINAL ARTICLES
Adequacy of the epinephrine autoinjector needle length in delivering epinephrine to the intramuscular tissues