Importance of Human Factors Engineering in Medical Device Domain

Human Factors Engineering is the application of knowledge about human behaviour, abilities, limitations, and other characteristics of medical device users to the design of medical devices including mechanical and software driven user interfaces, systems, tasks, user documentation, and user training to enhance and demonstrate safe and effective use.

The terms Human factors engineering (HFE) and usability engineering (UE) can be considered to be synonymous.

Human Factors Engineering = “Integrating human factors requirements into design”

Introduction

The usability engineering process aims to deliver products that are user-friendly and safe when used according to their intended purpose, by intended users, and in the intended use environment. Ideally, users should not have to struggle with complex instructions for use or adapt to the device's requirements, nor should they use it incorrectly or in a potentially dangerous manner. Therefore, a well-designed product should be easy to use and have a user interface that aligns with user experiences and expectations.

This article provides a concise overview of the Usability Engineering/ Human Factors Engineering process, emphasizes the crucial role of Human Factors Engineering in the medical device domain and its profound implications for patient safety, and delves into the regulatory framework associated with these aspects.

History

The term "Human Factors" came into prominence during World War II, marking a significant transformation in the approach to design thinking. It took the experiences of two world wars for designers to recognize the critical role of the Human Factor. Before World War I, the prevailing objective was to adapt humans to machines. However, the advent of aircraft in warfare introduced the concept of aviation psychology, which aimed to tailor machines to fit human capabilities.

Many practitioners who served in World War II witnessed numerous system designs that were challenging to operate and posed safety risks. This realization led to a shift in focus, emphasizing user-friendly designs rather than excessive reliance on training, with the expectation that users would become more capable over time. Although initially applied in the aviation and aerospace industry, human factors principles have now permeated various sectors, including healthcare, software, oil and gas, chemicals, and automobile manufacturing.

Human factors: why they matter for patient safety

The increased utilization of medical devices for diagnostic, monitoring, and therapeutic purposes has resulted in a rise in usage errors that can harm patients. Such errors often stem from inadequate device design, particularly in devices with complex user interfaces. Examples of medical devices prone to potential design issues include ventilators, infusion pumps, automatic electronic defibrillators (AEDs), and auto-injectors. These design issues can lead to problems such as medication overdoses, incorrect therapy, and challenges in delivering medication.

As medical devices continue to advance in their capabilities and are used in increasingly busy environments with new distractions and specialized training requirements, the likelihood of usage errors also escalates. Moreover, with the evolving healthcare landscape, including the transfer of patient care to home settings, there is a need to ensure that even less skilled or unskilled users, such as patients and caregivers, can safely operate complex medical devices.

Regulatory framework

The absence of human factors considerations in the design of medical devices can result in counter-intuitive interfaces that are difficult to learn, comprehend, interpret, and use. Consequently, this can lead to errors and have adverse effects on patient safety. Over the past two decades, medical errors of this nature have caused adverse events, including severe injuries and patient fatalities. There has been an alarming upward trend in post-market events associated with user interface (UI) design issues.

In response to the increasing occurrence of adverse events caused by UI-related factors, the US Food and Drug Administration (FDA) now mandates human factors and usability engineering reviews as a routine part of their pre-market approval process. This review process is conducted by the Office of Device Evaluation within the Centre for Devices and Radiological Health (CDRH). In December 2022, FDA. released a draft guidance document titled "Content of Human Factors Information in Medical Device Marketing Submissions." This guidance serves as a complement to the previous one and specifically focuses on the type of human factors data that manufacturers should include in their marketing submissions.

In a similar vein, the International Electrotechnical Commission (IEC) has incorporated IEC 62366-1, which replaces IEC 62366 and pertains to the application of usability engineering in medical devices. Both the FDA guidance and IEC 62366-1 outline a process that encompasses activities throughout device development, including validation testing of the final user interface (UI) design in simulated use environments.

Overview of the HFE/UE process

According to the FDA guidance [4], human factors engineering (HFE), and usability engineering (UE) primarily focus on understanding how people interact with technology and studying the impact of UI design on those interactions.

The development of medical devices with HFE/UE considerations involves three main components:

• device users,
• device use environments, and
• device user interfaces.

The interactions among these components are illustrated in Figure 1, where human factors influence the outcomes of using medical devices.

Figure 1 Human factors affect outcomes of using medical devices (MHRA guidance)