Application of human factors engineering (HFE) to the design of a naloxone auto-injector for the treatment of opioid emergencies

Abstract

The increased use of opioids for chronic treatment of pain and the resulting epidemic of opioid overdoses have created a major public health challenge. Parenteral naloxone has been used since the 1970's to treat opioid overdose. Recently, a novel naloxone auto-injector device (EVZIO, kaleo, Inc., Richmond, VA) was approved by the Food and Drug Administration. In this article, we review the Human Factors Engineering (HFE) process used in the development and testing of this novel naloxone auto-injector currently used in nonmedical settings for the emergency treatment of known or suspected opioid overdose. HFE methods were employed throughout the product development process for the naloxone auto-injector including formative and summative studies in order to optimize the auto-injector's user interface, mitigate use-related hazards and increase reliability during an opioid emergency use scenario. HFE was also used to optimize the product's design and user interface in order to reduce or prevent user confusion and misuse. The naloxone auto-injector went through a rigorous HFE process that included perceptual, cognitive, and physical action analysis; formative usability evaluations; use error analysis and summative design validation studies. Applying HFE resulted in the development of a product that is safe, fast, easy and predictably reliable to deliver a potentially life-saving dose of naloxone during an opioid overdose emergency. The naloxone auto-injector may be considered as a universal precaution option for at-risk patients prescribed opioids or those who are at increased risk for an opioid overdose emergency.

Keywords: Auto-injector; Human factors engineering; Naloxone; Opioid overdose; Opioid-induced respiratory depression.

Fig. 1

EVZIO (naloxone hydrochloride injection) Auto-injector Human Factors Development Plan

Fig. 2

The naloxone auto-injector is provided in a removable outer case. To increase performance success and decrease cognitive demand, the motion to slide off the outer case is in the same direction as the motion needed to pull off the safety guard. Once the outer case is removed, a removable red plastic safety guard shields the needle. A tactile design allows the safety guard to be gripped and pulled off when needed during an emergency. The outer case and the auto-injector have a viewing window to inspect the naloxone and to assess if the auto-injector has been used. The auto-injector also includes an electronic prompt system that provides voice instructions from a speaker and visual cues from LEDs to assist in guiding the user through the injection