Predictors of epinephrine autoinjector needle length inadequacy

Point-of-care ultrasonography in the allergy and immunology clinic

OBJECTIVE

To summarize evidence supporting the use of point-of-care ultrasonography as a clinical tool for allergists and immunologists.

DATA SOURCES

Cochrane Library, Medline, EMBASE, and Scopus databases were searched for articles published before December 18, 2018.

STUDY SELECTIONS

We included any retrospective or prospective study that evaluated ultrasonography in allergy and immunology and epinephrine autoinjector (EAI) needle length.

RESULTS

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.

CONCLUSION

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.

A narrative review of the success of intramuscular gluteal injections and its impact in psychiatry

There are 12 billion injections given worldwide every year. For many injections, the intramuscular route is favoured over the subcutaneous route due to the increased vascularity of muscle tissue and the corresponding increase in the bioavailability of drugs when administered intramuscularly. This paper is a review of the variables that affect the success of intramuscular injections and the implications that these success rates have in psychiatry and general medicine. Studies have shown that the success rates of intended intramuscular injections vary between 32 and 52%, with the rest potentially resulting in inadvertent subcutaneous drug deposition. These rates are found to be even lower for certain at-risk populations, such as obese patients and those on antipsychotic medications. The variables associated with an increased risk of injection failure include female sex, obesity, site of injection, and subcutaneous fat depth. New guidelines and methods are needed in order to address this challenge and ensure that patients receive optimum care. Looking forward, the best way to improve the delivery of intramuscular injections worldwide is to develop uniform algorithms or innovative medical devices to confirm or guarantee successful delivery at the bedside.

Epinephrine auto-injector needle lengths: Can both subcutaneous and periosteal/intraosseous injection be avoided?

BACKGROUND

Epinephrine should be administered intramuscularly in the anterolateral aspect of the thigh. The length of the epinephrine auto-injector (EAI) needle should ensure intramuscular injection.

OBJECTIVE

To discuss suitable EAI needle lengths based on ultrasound measurements related to weight.

METHODS

The skin-to-muscle distance (STMD) and skin-to-bone distance (STBD) were measured by ultrasound in the mid-third of the anterolateral area of the right thigh when applying high pressure (8 lb; high-pressure EAI [HPEAI]) or low pressure (low-pressure EAI [LPEAI]) on the ultrasound probe. The study included 302 children and adolescents and 99 adults. The maximum and minimum STMD and the maximum and minimum STBD were estimated.

RESULTS

Using HPEAIs, the risk of periosteal or intraosseous penetration was 32% in children weighing less than 15 kg. The risk of subcutaneous injection was 12% in adolescents and 33% in adults. With LPEAIs, there was no risk of periosteal or intraosseous injection and the risk of subcutaneous injections in adolescents and adults was lower at 2% and 10%, respectively. A new EAI for injection in small children would have no risk of periosteal or intraosseous injection but would have 71% chance of subcutaneous deposit of epinephrine.

CONCLUSION

Common HPEAIs have a high risk of periosteal or intraosseous penetration in children and subcutaneous injections in overweight and obese adults. LPEAIs have some risk of subcutaneous injection in adults. HPEAIs with 0.1 mg of epinephrine and shorter needles have no risk of periosteal or intraosseous injection but have a high risk of subcutaneous deposit. For adult or overweight or obese patients, HPEAIs and LPEAIs should have longer needles. Future studies should focus on triggering pressures and variations in needle length.

Bioavailability and Cardiovascular Effects of Adrenaline Administered by Anapen Autoinjector in Healthy Volunteers

BACKGROUND

The administration of adrenaline is a life-saving intervention for anaphylactic reactions. However, it has been questioned whether the needle length of the autoinjectors is sufficient to achieve genuine intramuscular delivery and optimal bioavailability.

OBJECTIVE

To assess the adequacy of Anapen, which has a relatively short needle length (10.5 mm), through a comparison of the depot localization, plasma pharmacokinetics, and cardiovascular responses of adrenaline delivered via Anapen versus a prefilled syringe with a 25.4-mm needle, which is generally used for intramuscular injections.

METHODS

This randomized, open-label, crossover study compared the impact of adrenaline administration at 2 sites in the thigh of 18 normal weight male volunteers, using either Anapen or the prefilled syringe; in addition, we studied the treatment of 12 overweight women with Anapen. The depot depth was measured by ultrasonography, plasma adrenaline level was evaluated by ultra performance liquid chromatography-mass spectrometry (UPLC-MS), and heart rates were measured using a Holter monitor.

RESULTS

Intramuscular injections were given with both devices at both thigh sites in nonobese men, but not in overweight women. Adrenaline levels showed a double peak, with parallel changes in the heart rate. The first peak, of potential vital importance in anaphylaxis treatment, occurred at approximately 10 minutes postinjection, with maximum concentration and area under the curve significantly higher with Anapen than with prefilled syringes; the magnitude of the second peak did not differ among the various conditions. Unexpectedly, in overweight women treated with Anapen, the magnitude of the first peak was similar to that observed in men, despite the injection being subcutaneous, and the overall bioavailability was enhanced.

CONCLUSIONS

Needle length and intramuscular injection are not absolute requirements for autoinjector efficacy, but the monitoring of injection location, biphasic adrenaline levels, and cardiovascular responses is important for the assessment of their therapeutic relevance in anaphylaxis.

Do epinephrine auto-injectors have an unsuitable needle length in children and adolescents at risk for anaphylaxis from food allergy?

Background

Food allergy is the most common cause of anaphylaxis in children. Intramuscular delivery of epinephrine auto-injectors (EAI) is the standard of care for the treatment of anaphylaxis. We examined if children and adolescents at risk of anaphylaxis weighing 15–30 kg and >30 kg would receive epinephrine into the intramuscular space with the currently available EAI in North America and Europe.

Methods

The distance from skin to muscle (STMD) and skin to bone (STBD) on the mid third anterolateral area of the right thigh was measured by ultrasound applying either high pressure (_max) or slight pressure (_min) in 102 children weighing 15–30 kg (group 1) and 100 children and adolescents, weighing more than 30 kg (group 2).

Results

Using a high pressure EAI (HPEAI), Epipen Jr^® and Auvi-Q^®/Allerject^® 0.15 mg, 11/102 (11 %) children in group 1 and 38/102 (38 %) using another HPEAI, Jext^®, had a STMD_max that showed a risk of intraosseous injection. There was a 1 % risk of subcutaneous injection with these devices. There was no risk of intraosseous injection using a low pressure EAI (LPEAI), Emerade^®. In group 2, the risk of intraosseous injection using a HPEAI was 3 % and no risk using a LPEAI. However, the risk of subcutaneous injection using HPEAI was 9 % and using LPEAI was 2 %.

Conclusion

There is a risk of intraosseous injection using HPEAI (Epipen^®/Epipen Jr^®, Auvi-Q^®/Allerject^® and especially Jext^®) in children at risk of anaphylaxis. There was also a risk of subcutaneous injection using the currently available HPEAI in children and adolescents.

Electronic supplementary material

The online version of this article (doi:10.1186/s13223-016-0110-8) contains supplementary material, which is available to authorized users.