Epinephrine autoinjectors in order of patient preference: INT prototypes, then EpiPen followed by TwinJect

Prefilled epinephrine autoinjectors are sometimes improperly used by patients, caregivers, and physicians.

A user-centered design process led to the development of 2 prototype epinephrine autoinjectors (INT01 and INT02) that have:

- unidirectional perceived injection end

- self-retracting needle

- voice instructions to assist in guiding users through administration (INT02)

48 participants were divided equally among 3 age groups: 7 to 10, 11 to 15, and 16 to 55 years.

In each group, half had prior TwinJect or EpiPen training. In 1-hour sessions, without training, participants performed simulated-use testing under observation for all 4 epinephrine delivery systems.

More participants correctly followed all device instructions with INT02 (46%) than with INT01 (27%), EpiPen (12%), or TwinJect (0%). The youngest age group [those aged 7-10 years] performed significantly worse.

The first choice of overall preference was greater for INT02 (73%) vs. INT01 (15%), EpiPen (10%), and TwinJect (2%).

The user-centered device design may have a significant impact on correct epinephrine autoinjector use and patient preference.

Accidental Injection of Epinephrine Into Finger (click to enlarge the image).

References:
A comparison of 4 epinephrine autoinjector delivery systems: usability and patient preference.
Guerlain S, Hugine A, Wang L. Ann Allergy Asthma Immunol. 2010 Feb;104(2):172-7.

What are the ‘ideal’ features of an adrenaline (epinephrine) auto-injector in the treatment of anaphylaxis? http://goo.gl/lxCh

Figure: Design overview of currently available auto-injectors for emergency self-administration of adrenaline in the treatment of anaphylaxis.