Applied Human Factors in Medical Device Design

Mary Beth Privitera

• Publisher: Academic Press
• Year: 2019
• ISBN:
  9780128161647
• Topic: Biological Sciences
• Subtopic: Biotechnology
• Index: Biological Sciences

Applied Human Factors in Medical Device Design describes the contents of a human factors toolbox with in-depth descriptions of both empirical and analytical methodologies. The book begins with an overview of the design control process, integrating human factors as directed by AAMI TIR 59 and experienced practice. It then explains each method, describing why each method is important, its potential impact, when it's ideal to use, and related challenges. Also discussed are other barriers, such as communication breakdowns between users and design teams. This book is an excellent reference for professionals working in human factors, design, engineering, marketing and regulation.

• Focuses on meeting agency requirements as it pertains to the application of human factors in the medical device development process in both the US and the European Union (EU)
• Explains technology development and the application of human factors throughout the development process
• Covers FDA and MHRA regulations
• Includes case examples with each method

III

Human factors in design

Outline

Chapter 7. Applied human factors in design

Chapter 8. Combination devices

Chapter 9. Applying design principles to instructional materials

Chapter 7

Applied human factors in design

Mary Beth Privitera ^a , M. Robert Garfield ^b , and Daryle Gardner-Bonneau ^{c a}HS Design, Gladstone, NJ, United States ^bAbbot, St. Paul, MN, United States ^cBonneau and Associates, Portage, MI, United States

Abstract

The role of the human factors engineers is to assist the design team to produce designs that better meet the capabilities, limitations and needs of the user. This means that the device fits the user's mental and physical constraints (capabilities), that there are limitations in place which prevent injury and that individual needs are considered to improve the device's usability and efficiency based on context. This chapter discusses the importance of considering human factors in the product design for both the physical product embodiment as well as any controlling user interface or complimentary computer applications. It includes sections on how to know your users and the use environment, as well as specific elements of human factors in design, including affordances, touch points, color, materials and finish, along with a case example. It also includes a section about software design or user experience design with detailed descriptions on design intent, constraints and graphic design, including aspects of detection and discrimination. It concludes with the design of alarms, including highlights from recent changes in the standards as a result of advanced research into the perception of alarms.

Keywords

Device design; Anthropometry; Biomechanics; User interface design; Contextual design; Aesthetic beauty

1. 1. Introduction
2. 2. Understand your users
   1. 2.1 Using anthropometry and biomechanics to determine fit
      1. 2.1.1 Understanding percentiles
      2. 2.1.2 Deriving device form from anthropometry
   2. 2.2 Use related injury prevention
      1. 2.2.1 Nature of injuries
      2. 2.2.2 Using physiological measures to determine injury potential
3. 3. Know the use environment
4. 4. Device design
   1. 4.1 Affordances and design cues
   2. 4.2 Aesthetic beauty as it relates to usability
      1. 4.2.1 Simplicity
      2. 4.2.2 Diversity
      3. 4.2.3 Colorfulness
      4. 4.2.4 Craftsmanship
   3. 4.3 Use interaction touch points and control selection
      1. 4.3.1 Use interaction touch points
      2. 4.3.2 Control selection
      3. 4.3.3 Layout
   4. 4.4 Color, materials, and finish
      1. 4.4.1 Color
      2. 4.4.2 Materials
      3. 4.4.3 Finish
   5. 4.5 Case study: applied ergonomics for hand tool design
      1. 4.5.1 Step 1: handle shape selection
      2. 4.5.2 Step 2: control selection and placement
      3. 4.5.3 Step 3: handle and control size
      4. 4.5.4 Step 4: form language and surface refinement
5. 5. Software design: user experience (UX) design
   1. 5.1 User experience design
   2. 5.2 Describing the design intent and constraints
   3. 5.3 Communicating interactive conceptual design
   4. 5.4 Graphic design: detection and discrimination
      1. 5.4.1 Composition: grouping and organization – how does the mind group signals at a pre-attentive level?
      2. 5.4.2 Comprehension: meaning and working memory- can users find meaning at a cognitive level?
   5. 5.5 Learning and long-term memory - can users retain and recall knowledge at a metacognitive level?
6. 6. Alarms (Daryle Gardner-Bonneau)
   1. 6.1 Designing auditory alarms
7. 7. Summary
8. 8. Further reading
9. Acknowledgments
10. References

Do it by Design! Applied human factors is about designing systems that are resilient to the unanticipated event.

1. Introduction

Designing products for “everyone” is problematic as one person's experience will always be different than another's. This includes the fact that there is rarely a consensus of opinion and certainly a high degree of variability person to person. Each individual has a unique set of needs, perception and experience. In essence, environmental and human variability are perpetual. This reality must be considered when designing medical devices.

The role of the human factors engineers is to assist the design team to produce designs that better meet the capabilities, limitations, and needs of the user. In regards to capabilities, this means that the device fits the user's mental and physical constraints. That there is limitations in place which prevent injury; and that individual needs are considered to improve usability and efficiency based on context.

Human factors experts gather information regarding human characteristics and interactions with the work environment in order to design systems resilient to use error (Russ et al., 2013). The standard ANSI/AAMI HE75 (AAMI, 2009), is the most comprehensive resource in regards to human factors design guidance. This chapter provides examples of utilizing this guidance as well as providing further clarity of specific design processes for medical device design. For the purposes of design, key sections of ANSI/AAMI HE75 include:

1. • Human Skills and Abilities
2. • Anthropometry and Biomechanics
3. • Alarm Design
4. • Controls
5. • Visual Displays
7. • Software User Interfaces
8. • Medical Hand Tool and Instrument Design

This list is not exhaustive however represents the minimum references a design team should consider in their process. Other Sections such as Combination Products, Workstations and Packaging Design are examples of specific topics that are further detailed in the guidance however are not included in this chapter discussion.

This chapter discusses the importance of considering human factors in the product design for both the physical product embodiment as well as any controlling user interface or complimentary computer applications. This includes sections on how to know your users, know the use environment, specific elements of human factors in design including affordances, touch points, color, materials, and finishes with a case example. It also includes a section of software design or user experience design with detailed descriptions on design intent, constraints, graphic design including aspects of detection and discrimination. It concludes with the design of alarms with highlights from recent changes in the standards as a result of advanced research into the perception of alarms.

2. Understand your users

Applied human factors in design results in total solution for the user. It addresses human factors holistically including the physical interactions as well as the mental workload (perception and cognition) required. In order to do this an understanding of basic human skills and abilities, anthropometry and biomechanics, accessibility considerations as well as cross-cultural/cross-national design considerations must be explored in the context of the proposed medical device use (AAMI, 2009).

This includes exploring the “fit” of the device. Fit as defined by the overall shape and appearance of the device relative to the location of physical interaction. For example, the fit of a hand tool is the relationship of the tool itself to hand size and finger reach. Ultimately, fit is determined by the following:

1. • Anthropometry: determining the physical fit with the user/appropriate sizing
2. • Biomechanics: physical limitations for movement and control at a given joint which are required in order to use the device. It can be further broken down into:
3. 1. • Reach: access of a control
   2. • Operation: use of a control
   3. • Injury: reduction of pinch points, consideration toward repetitive use injury
   4. • Safety: inadvertent control activation

It also requires and understanding of the user's workload, stress, education and training. Specifically, the user's capacity for cognition and perce...