Human Factors Engineering Validation Study for a Novel 0.1 mg Epinephrine Auto-Injector

RATIONALE: Anaphylaxis in infants and young children is increasing. Currently available epinephrine auto-injectors (EAIs) are not FDA approved for patients weighing <15 kg, and therefore, EAIs are prescribed off-label for these patients. Ultrasound studies suggest currently marketed 0.15 mg EAIs have needle lengths that may strike bone in ~29-43% of patients weighing <15 kg, resulting in possible intraosseous injection. An EAI with a shorter needle length has been developed to help potentially minimize the risk of striking bone during epinephrine injection in patients weighing 7.5 to 15 kg. A human factors usability study was completed to validate the 0.1 mg EAI user interface.

METHODS: This study was conducted with parents of severely allergic children to evaluate simulated use of the 0.1 mg EAI by the intended user group. Fifteen participants were enrolled and received training on the 0.1 mg EAI. Approximately 24-hours later, participants completed a simulated emergency-use scenario using the 0.1 mg EAI with an infant mannequin. The primary endpoint was successful simulated administration of a meaningful epinephrine dose.

RESULTS: All participants simulated administration of a meaningful epinephrine dose. Fourteen participants successfully used the 0.1 mg EAI per the instructions for use in the simulated emergency-use scenario. One participant did not press the device against the thigh for the length of time defined for this critical task; however, the device was pressed long enough for complete delivery of the 0.1 mg dose.

CONCLUSIONS: This study validated the user interface of the 0.1 mg EAI for the intended users, uses, and use environments.