474 Correspondence / American Journal of Emergency Medicine 32 (2014) 466-485

(Mylan Inc, Canonsburg, PA) autoinjector, which showed that the SCTD was 2.78 +- 0.59 cm (range, 2-4 cm) with P = b.0001 (1 sample t test) [3,4]. Based on the data, all epinephrine injections in this study diffused through tissue beyond the autoinjector’s needle length of 1.43 cm. The SCTD delivery of epinephrine was 94.4% beyond the length of the autoinjector needle. The authors believe that compression or hand swing and propulsion by the spring loaded autoinjector have a role in delivery of epinephrine beyond the needle length. I think that needle length of 2.96 cm would be helpful in many female patients with high BMI but may be too long in some males with normal-to-Overweight BMI. Further studies assessing the ideal needle length need would be helpful considering compression and propulsion.

I am in agreement that “one size fits all” needle length for epinephrine autoinjector needs to be further evaluated. It may be helpful for clinicians if there was a BMI table for females and males with a suggested needle length for physician-directed use but may not be practical for epinephrine autoinjectors. We need to take into consideration, while making needle length recommendations, the intent and purpose of the use of epinephrine. In the emergency department setting or in physician-supervised setting, injecting epinephrine at a dose and route is best left to the judgment of the physician. Epinephrine drawn up in a general purpose syringe and administered IM may be appropriate for such a setting. Epinephrine autoinjectors are primarily for use by patients themselves in unsupervised setting in suspected (may not necessarily be proven) anaphylaxis. Simplicity of use and safety needs are to be considered in such a setting, so that patients can use the device correctly and are not overdosed or put at a safety risk. The currently marketed epinephrine autoinjectors may not necessarily fall short of such expectations.

T. Ted Song, DO Division of Allergy and Infectious Diseases University of Washington, School of Medicine

Seattle, WA E-mail address: [email protected]

http://dx.doi.org/10.1016/j.ajem.2014.01.025

References

1. Bhalla MC, Gable BD, Frey JA, Reichenbach MR, Wilber ST. Predictors of epinephrine autoinjector needle length inadequacy. Am J Emerg Med 2013;31(12):1671-6.
2. Song TT, Nelson MR, Chang JH, Engler RJM, Chowdhury BA. Adequacy of the epinephrine autoinjector needle length in delivering epinephrine to the intramus- cular tissues. Ann Allergy Asthma Immunol 2005;94:539-42.
3. pelvic digit anomaly in a patient wi”>Stecher D, Bulloch B, Sales J, Schaefer C, Keahey L. Epinephrine auto-injectors: is needle length adequate for delivery of epinephrine intramuscularly? Pediatrics 2009;124:65-70.
4. Song TT, Merrill NL, Cole JW. Delivery depth of epinephrine by auto-injector into the subcutaneous tissue of pig. Ann Allergy Asthma Immunol 2013;111(2):143-5.

   Response to comments on “Predictors of epinephrine autoinjector needle length inadequacy”?

   To the Editor,

   Dr Song, thank you for your interest in our article, “Predictors of epinephrine autoinjector needle length inadequacy.” [1] I also read with interest your study on delivery depth of epinephrine autoinjector into the subcutaneous tissue of pig [2]. The finding that the depth of the injected material was 2.78 cm or 94.4% beyond the depth of the 1.43-cm needle used in the study was helpful. I agree that further research needs to assess the depth of drug penetration at different pressures, and I also think more research needs to be done on drug absorption at different anatomic locations. In a study referenced on Pediatric News Digital

   ? I have no financial disclosures.

   Network presented at the 2013 Annual Meeting of the American Academy of Allergy, Asthma, and Immunology found that overweight and obese children had a shallower muscle depth in the distal thigh than the upper thigh. Weight, body mass index (BMI), and waist circumfer- ence were found to be associated with deeper muscles [3].

   From our Correlation analyses, we found significant associations between compressed muscle depth and BMI (r = 0.48; P b .001) and between compressed muscle depth and thigh circumference (r = 0.62; P b .001). Thus, thigh circumference and BMI account for 39% and 23%, respectively, of the variance in compressed muscle depth of emergency department patients in this sample. Moreover, both of these patient characteristics can be used as predictors for epinephrine autoinjector failure; however, we also found a large association between BMI and thigh circumference (r = 0.82; P b .001), which would likely lead to multicollinearity issues if both of these variables were included in the same regression model, so we would advise removing BMI and including thigh circumference along with height and weight in such models to reduce the risk of these types of issues.

   Doing a study with a bigger sample size would be needed to develop a regression model to predict muscle depth with other measurements and may overcome current autoinjector design problems. We did find that no patient with a thigh circumference greater than 80 cm or a BMI greater than 40 kg/m² had a muscle depth less than 15.9 mm, but this only applied to a handful of patients in our study sample. Emergency department and Prehospital providers typically use a 1.5 in (3.81 cm) or a 1 in (2.54 cm) needle for Intramuscular injections, so a subcutaneous injection is unlikely. It may be unrealistic to use such a long needle in an autoinjector given the need for needle retraction and ease of use. For now, I will continue to advise my patients to use the available autoinjectors. There was recently a new autoinjector introduced in Europe with a 25-mm needle that may be more appropriate for some patients, but it is not currently available in the United States [4].

   Mary Colleen Bhalla, MD Department of Emergency Medicine Summa Akron City Hospital

   Akron, OH 44304 Northeast Ohio Medical University (NEOMED)

   Akron, OH 44304

   http://dx.doi.org/10.1016/j.ajem.2014.01.030

   References

   Bhalla MC, Gable BD, Frey JA, Reichenbach MR, Wilber ST. Predictors of epinephrine autoinjector needle length inadequacy. Am J Emerg Med 2013;31(12):1671-6.

5. Song TT, Merrill NL, Cole JW. Delivery depth of epinephrine by auto-injector into the subcutaneous tissue of pig. Ann Allergy Asthma Immunol 2013;111(2):143-5.
6. Worchester S. For overweight children, inject epinephrine in lower thigh: Pediatric News [Internet]. [cited 2014 Jan 16]. Available from: http://www.pediatricnews. com/top-news/single-article/for-overweight-children-inject-epinephrine-in- lower-thigh/42febcdd9aa45db553217e756756fcee.html.
7. Anonymous. Emerade adrenaline auto-injector: overview [Internet]. [cited 2014 Jan 17]. Available from: http://www.emerade.com/hcp/.

   The pelvic digit anomaly in a patient with multiple fractures: does it mimic the fracture??

   To the Editor,

   I read an interesting article by Ogul et al [1] entitled “The pelvic digit anomaly in a patient with multiple fractures: does it mimic the

   ? The English in this document has been checked by at least 2 professional editors, both native speakers of English. For a certificate, please see: http://www.textcheck. com/certificate/CYnmm8.

   Correspondence / American Journal of Emergency Medicine 32 (2014) 466-485 475

   

   Fig. A. Routine radiography shows a digit like bony (arrows) at near the right Iliac crest. Coronal reformatted computed tomography (B) and axial sequential computed tomography slices (C,D,E,F) show an anomaly digit like free bone without joint or pseudo articulation arising from the upper part of the right iliac wing, extending downwards toward the greater trochanter of the femur).

   fracture?” in your journal published on 2013 Oct; 31(10):1537. The patient in this report had a successful outcome. Nevertheless, I want to share more information about this rare anomaly. I treated a patient with a pelvic digit with no joint nor pseudo-articulation.

   A 29-year-old man was brought to the emergency department following a motor vehicle accident. Routine radiography and computed tomography (CT) showed an anomaly arising from the upper part of the right iliac wing, extending downwards toward the greater trochanter of the femur (Fig. A-F). This was accepted as consistent with a pelvic digit, since it had the typical radiographic appearance of a rib or phalanx-like bone on plain radiographs. CT helped to identify the cortex and medulla of the free bone tissue and to show that no joint nor pseudo-articulation was present.

   Pelvic digits are most common on the ilium. The importance of recognizing a pelvic digit is in distinguishing it from post-traumatic ossification and avulsion injuries of the pelvis. If there is no pseudo- articulation or joint, it is difficult to distinguish one from a post-traumatic bone fragment or ossification. The literature contains an important paper on pelvic digits by Gayen et al [2] that reviews 27 cases in addition to their case. They reported only five cases without a joint or pseudo- articulation, like my case. Radiologists who work in emergency de- partments must be aware of this and check the morphology of free bone pieces without a pseudo-articulation or joint to decide if they are pelvic digits. A pelvic digit is usually an incidental finding that does not need further evaluation or invasive intervention.

   Serife Ulusan, MD

   Department of Radiology Baskent University, Faculty of Medicine Yuregir, Adana, Turkey 01250

   E-mail address: [email protected] http://dx.doi.org/10.1016/j.ajem.2014.01.031

   References

   Ogul H, Pirimoglu B, Genc B, Bayraktutan U, Kantarci M. The pelvic digit anomaly in a patient with multiple fractures: does it mimic the fracture? Am J Emerg Med 2013;31(10):1537.

8. Goyen MG, Barkhausen JB, Markschies NA, Debatin JF. The pelvic digit-a rare developmental anomaly. A case report with CT correlation and a review of literature. Acta Radiol 2000;41:317-9.

   The author responds

   To the Editor,

   We thank Dr Sabour for his comments about “The accuracy of bedside ultrasonography as a diagnostic tool for the Fifth metatarsal fractures.” The aim of our research, as stated in the full text of the article, was to determine the diagnostic reliability of ultrasonography