Introduction

Pediatric obesity threatens the efficacy of life-saving medications given intramuscularly to anaphylactic patients. Epinephrine auto-injector needle lengths are potentially too short to reach the muscle compartment in patients with elevated body habitus. The objective of the study was to determine needle length requirements for intramuscular injections in pediatric patients.

Methods

Ultrasound was used to measure the distance from skin to muscle compartment of the thigh in 200 pediatric patients of various weight and body mass index who presented to the Emergency Department.

Results

Patients with higher body mass index had an increased distance to muscle and bone. If current auto-injector recommendations were followed, 12% of patients weighing less than 30 kilograms and 9% of patients weighing more than 30 kilograms would have potentially used an auto-injector inadequate in needle length.

Conclusion

With the increase in childhood obesity, auto-injector needle lengths may be too short to effectively deliver medications. Needle length should be evaluated to accommodate pediatric patients with increased skin to muscle distance.