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Part 2: Human Factors Engineering Course ContentsDownload Handouts(Covered material that will be included in the exam are marked in Red color - other parts are not included)
General Considerations and Principles of Human Factors Engineering in Medical Device Design
4 General principles .............................................................................................................................................14 4.1 Introduction ................................................................................................................................................14 4.2 Seek user input..........................................................................................................................................14 4.2.1 Involve users early and often........................................................................................................14 4.2.2 Refine designs through usability testing .......................................................................................14 4.3 Establish design priorities ...........................................................................................................................14 4.3.1 Keep it simple ...............................................................................................................................14 4.3.2 Ensure safe use............................................................................................................................15 4.3.3 Ensure essential communication ..................................................................................................15 4.3.4 Anticipate device failures..............................................................................................................16 4.3.5 Facilitate workflow ........................................................................................................................16 4.4 Accommodate user characteristics and capabilities ...................................................................................16 4.4.1 Do not expect users to become masters ......................................................................................16 4.4.2 Expect user errors ........................................................................................................................17 4.4.3 Accommodate diverse users ........................................................................................................17 4.4.4 Maximize accessibility ..................................................................................................................18 4.4.5 Consider external factors that influence task performance...........................................................18 4.5 Accommodate users' needs and preferences.............................................................................................19 4.5.1 Prioritize user input.......................................................................................................................19 4.5.2 Do not rely exclusively on "thought leaders".................................................................................19 4.5.3 Let users set the pace ..................................................................................................................19 4.6 Establish realistic expectations of users .....................................................................................................19 4.6.1 Do not rely on training ..................................................................................................................19 4.6.2 Do not rely on instructions for use ................................................................................................19 4.6.3 Do not rely on warnings................................................................................................................20 4.6.4 Do not rely on users' memory.......................................................................................................20 4.6.5 Avoid information overload ...........................................................................................................20 4.6.6 Do not assign users tasks that are better suited to the device .....................................................20 4.7 Consider real-world demands .....................................................................................................................21 4.7.1 Consider the context of use..........................................................................................................21 4.7.2 Consider worst-case scenarios.....................................................................................................21 4.7.3 Make devices as rugged as necessary.........................................................................................22 4.7.4 Limit user workload.......................................................................................................................22 4.7.5 Consider the potential for device migration into other uses or use environments.........................22 4.8 Develop compatible designs .......................................................................................................................23 4.8.1 Accommodate mental models ......................................................................................................23 4.8.2 Establish natural or conventional mappings .................................................................................23 4.8.3 Follow industry conventions and consensus standards................................................................24 4.9 Optimize user interactions to enhance safety and effectiveness ................................................................24 4.9.1 Make devices error-tolerant and fail in a safe manner..................................................................24 4.9.2 Avoid physical strain, repetitive motions, and cumulative traumas...............................................24 4.9.3 Help users anticipate future events ..............................................................................................24 4.9.4 Confirm important actions.............................................................................................................24 4.9.5 Make critical controls robust and guard them...............................................................................25 4.9.6 Clarify operational modes.............................................................................................................25 4.9.7 Employ redundant coding.............................................................................................................25 4.9.8 Design to prevent user confusion .................................................................................................26 4.9.9 Don't neglect device appeal..........................................................................................................26 4.10 Summary...................................................................................................................................................26 4.11 References................................................................................................................................................27
5 Managing the risk of use error ...........................................................................................................................29 5.1 Introduction ................................................................................................................................................29 5.1.1 Overview .....................................................................................................................................29 5.1.2 Use-related hazards vs. traditional device-failure hazards ...........................................................29 5.1.3 Behavioral variability in human users ...........................................................................................30 5.1.4 Definition of use error ...................................................................................................................30 5.2 Types of use errors....................................................................................................................................30 5.3 General considerations for managing use-related hazards.........................................................................34 5.3.1 Use-error consequences in regulatory submissions .....................................................................34 5.3.2 General considerations for managing risk ....................................................................................34 5.4 Methods of managing the risk of use errors................................................................................................34 5.4.1 Overview .....................................................................................................................................34 5.4.2 Risk, risk management, and use safety........................................................................................34 5.4.3 Use-error risk management process ............................................................................................35 5.5 Definition of intended use, user, and the use environment .........................................................................36 5.6 Identification of use-related hazards ...........................................................................................................37 5.6.1 Overview .....................................................................................................................................37 5.6.2 Analysis of predecessor and similar devices ................................................................................37 5.6.3 Analysis of device use tasks.........................................................................................................37 5.6.4 Application of best practice for user-interface design ...................................................................38 5.6.5 Consideration of user workload in device use ..............................................................................38 5.7 Estimation and prioritization of risk of use-related hazards.........................................................................38 5.7.1 Overview .....................................................................................................................................38 5.7.2 Failure mode effects analysis .......................................................................................................38 5.7.3 Fault tree analysis ........................................................................................................................39 5.7.4 Usability testing ............................................................................................................................39 5.8 Implementation of risk controls ...................................................................................................................40 5.8.1 Overview .....................................................................................................................................40 5.8.2 Most preferred use-related hazard mitigation strategies...............................................................40 5.8.3 Less preferred use-related hazard mitigation strategies...............................................................40 5.9 Validation of safety of use (effectiveness of risk controls)...........................................................................41 5.10 Decision on whether risks are acceptable..................................................................................................41 5.11 Determination of whether new risks were introduced.................................................................................41 5.12 Documentation of the use-related risk management process ....................................................................41 5.13 Monitoring, identification, and control of use-related issues post-marketing ..............................................42 5.14 Summary...................................................................................................................................................42 5.15 References................................................................................................................................................42
6 Basic human skills and abilities.........................................................................................................................44 6.1 Introduction ................................................................................................................................................44 6.2 Design guidelines ......................................................................................................................................44 6.2.1 Overview .....................................................................................................................................44 6.2.2 Vision...........................................................................................................................................44 6.2.3 Audition and speech.....................................................................................................................55 6.2.4 Other sensory modalities..............................................................................................................58 6.2.5 Human information processing.....................................................................................................60 6.2.6 Human memory...........................................................................................................................62 6.2.7 Human response capabilities........................................................................................................65 6.2.8 Human vs. machine capabilities ...................................................................................................67 6.3 References ................................................................................................................................................68
7 Anthropometry and biomechanics.....................................................................................................................71 7.1 Introduction ................................................................................................................................................71 7.2 General considerations ...............................................................................................................................71 7.3 Anthropometric design guidance ................................................................................................................72 7.3.1 Overview .....................................................................................................................................72 7.3.2 Anthropometric data .....................................................................................................................72 7.3.3 One-dimensional measurements..................................................................................................73 7.3.4 Mobility and functional measurements .........................................................................................82 7.3.5 Strength.......................................................................................................................................87 7.3.6 Derivation of missing data ............................................................................................................95 7.4 Biomechanical design guidance .................................................................................................................96 7.4.1 Overview .....................................................................................................................................96 7.4.2 Critical design considerations .......................................................................................................96 7.4.3 Special considerations.................................................................................................................98 7.4.4 Design guidelines for tasks involving lifting ..................................................................................98 7.5 References ................................................................................................................................................102
8 Environmental considerations ............................................................................................................................105 8.1 Introduction ................................................................................................................................................105 8.2 General considerations ...............................................................................................................................105 8.3 Design guidelines ......................................................................................................................................106 8.3.1 Interruptions and distractions........................................................................................................106 8.3.2 Acoustic noise ..............................................................................................................................106 8.3.3 Lighting........................................................................................................................................109 8.3.4 Temperature and humidity............................................................................................................110 8.3.5 Vibration ......................................................................................................................................111 8.3.6 Slipperiness and friction ...............................................................................................................112 8.3.7 Atmospheric pressure...................................................................................................................112 8.3.8 Ease of maintenance....................................................................................................................112 8.3.9 Storage........................................................................................................................................113 8.3.10 Mounting of devices......................................................................................................................113 8.3.11 Radiant energy .............................................................................................................................113 8.3.12 Emergency environment...............................................................................................................113 8.3.13 Home environment .......................................................................................................................114 8.4 References ................................................................................................................................................114
9 Usability testing.................................................................................................................................................116 9.1 Introduction ................................................................................................................................................116 9.2 General considerations ...............................................................................................................................116 9.3 Design guidelines ......................................................................................................................................117 9.3.1 Types of usability tests .................................................................................................................117 9.3.2 Principles of good usability test design.........................................................................................117 9.3.3 Overview of usability testing .........................................................................................................118 9.3.4 Content of the usability test plan...................................................................................................121 9.3.5 Logistics ......................................................................................................................................129 9.3.6 Protocol-related activities .............................................................................................................132 9.3.7 Supplemental usability evaluation methods..................................................................................136 9.4 References ................................................................................................................................................137
10 Signs, symbols, and markings ...........................................................................................................................139 10.1 Introduction ...........................................................................................................................................139 10.2 General considerations ...........................................................................................................................139 10.3 Design guidelines ..................................................................................................................................140 10.3.1 Overview .....................................................................................................................................140 10.3.2 Labels for equipment identification ...............................................................................................140 10.3.3 Descriptions of equipment functions.............................................................................................140 10.3.4 Hazard labels...............................................................................................................................140 10.3.5 Electrical receptacle and connector labels ...................................................................................141 10.3.6 Fuse and circuit-breaker labels.....................................................................................................141 10.3.7 Labels on controls, keyboards, and keypads................................................................................143 10.3.8 Positioning and mounting of labels ...............................................................................................143 10.3.9 Label orientation..........................................................................................................................143 10.3.10 Indications of functional relationships ...........................................................................................143 10.3.11 Permanence and durability of labels.............................................................................................144 10.4 Specific design guidance ........................................................................................................................144 10.4.1 Consistency.................................................................................................................................144 10.4.2 Label content ...............................................................................................................................144 10.4.3 Use of symbols............................................................................................................................145 10.4.4 Legibility ......................................................................................................................................146 10.4.5 Coding .........................................................................................................................................147 10.4.6 Application of color to mimics and flow lines ................................................................................148 10.4.7 Flow lines ....................................................................................................................................148 10.4.8 Language ....................................................................................................................................148 10.4.9 Package labels .............................................................................................................................148 10.4.10 Hierarchical schemes ...................................................................................................................148 10.5 References.............................................................................................................................................149
11 User documentation..........................................................................................................................................151 11.1 Introduction ...........................................................................................................................................151 11.2 General considerations ...........................................................................................................................151 11.2.1 Overview .....................................................................................................................................151 11.2.2 Overall process for user documentation development..................................................................152 11.2.3 Basic design principles for layout, comprehension, and organization...........................................154 11.2.4 Control of user risks......................................................................................................................159 11.2.5 Documentation design for diverse environments..........................................................................160 11.3 Specific design guidelines for various types of user documentation .......................................................160 11.3.1 Overview .....................................................................................................................................160 11.3.2 User guides, operator manuals, and owner’s manuals.................................................................160 11.3.3 Quick-reference guides ................................................................................................................161 11.3.4 Electronic documentation .............................................................................................................162 11.4 References.............................................................................................................................................164
12 Packaging design..............................................................................................................................................166 12.1 Introduction ...........................................................................................................................................166 12.2 General considerations ...........................................................................................................................166 12.2.1 Overview .....................................................................................................................................166 12.2.2 The user ......................................................................................................................................166 12.2.3 The use environment....................................................................................................................167 12.3 Principles of good medical packaging design .........................................................................................168 12.3.1 Overview .....................................................................................................................................168 12.3.2 Opening packages.......................................................................................................................168 12.3.3 Assembling or sequentially using components.............................................................................170 12.3.4 Labeling packages.......................................................................................................................171 12.3.5 Identifying devices ........................................................................................................................172 12.3.6 Indicating sterilization status.........................................................................................................172 12.3.7 Storing packaged devices ............................................................................................................173 12.3.8 Handling packaged devices..........................................................................................................174 12.3.9 Disposing of packaging ................................................................................................................174 12.4 References.............................................................................................................................................174
13 Design for post-market issues...........................................................................................................................176 13.1 Introduction ...........................................................................................................................................176 13.2 General considerations ...........................................................................................................................178 13.2.1 Type of user: health care professional or home-use consumer....................................................178 13.2.2 Type of use environment: health care facility or home .................................................................178 13.2.3 Device longevity ...........................................................................................................................178 13.3 Design guidelines ..................................................................................................................................179 13.3.1 Overview .....................................................................................................................................179 13.3.2 Disposables .................................................................................................................................179 13.3.3 Single-use devices .......................................................................................................................179 13.3.4 Labeling.......................................................................................................................................180 13.3.5 Setup and installation ...................................................................................................................180 13.3.6 Routine maintenance....................................................................................................................181 13.3.7 Repair..........................................................................................................................................181 13.3.8 Upgrades.....................................................................................................................................183 13.3.9 Obsolescence..............................................................................................................................183 13.3.10 Disposal.......................................................................................................................................183 13.4 References.............................................................................................................................................184
14 Cross-cultural/cross-national design ..................................................................................................................185 14.1 Introduction ...........................................................................................................................................185 14.2 General considerations ...........................................................................................................................186 14.2.1 Differences among nations and cultures ......................................................................................186 14.2.2 National issues .............................................................................................................................187 14.2.3 Cultural issues .............................................................................................................................189 14.2.4 Culture-specific or nation-specific user profiles ............................................................................190 14.3 Guidelines for cross-cultural/cross-national design.................................................................................194 14.3.1 Overview .....................................................................................................................................194 14.3.2 Direct issues associated with the user–device interface...............................................................195 14.3.3 Indirect issues associated with the user–device interface ............................................................198 14.3.4 Cross-cultural/cross-national design process ...............................................................................200 14.4 Summary ...............................................................................................................................................201 14.5 References.............................................................................................................................................202
15 Alarm design .....................................................................................................................................................205 15.1 Introduction ...........................................................................................................................................205 15.2 General considerations ...........................................................................................................................205 15.2.1 Overview .....................................................................................................................................205 15.2.2 Goals...........................................................................................................................................206 15.2.3 Verifying that the alarm system works ..........................................................................................206 15.2.4 Initializing alarm monitoring ..........................................................................................................207 15.2.5 Avoiding false alarms ...................................................................................................................207 15.3 Considerations regarding specific requirements from IEC 60601-1-8.....................................................207 15.3.1 Attended-use model .....................................................................................................................207 15.3.2 Distributed alarm systems ............................................................................................................209 15.3.3 Alarm priority, urgency of response, and allowable latency..........................................................210 15.3.4 Distributed-alarm-system requirements of IEC 60601-1-8............................................................211 15.3.5 “Latching” alarm signals ...............................................................................................................212 15.3.6 Initiation and termination of alarm signals ....................................................................................212 15.3.7 Default alarm limits and alarm-limit adjustment ............................................................................213 15.3.8 Alarm-system inactivation states ..................................................................................................214 15.3.9 Simultaneous monitoring of multiple physiological states.............................................................215 15.4 Step-by-step guidelines for developing an alarm system........................................................................216 15.4.1 Developing an alarm system ........................................................................................................216 15.4.2 Gathering information ...................................................................................................................216 15.4.3 Generating a list of alarm conditions that require alarm signals ...................................................216 15.4.4 Creating signal-processing algorithms..........................................................................................216 15.4.5 Identifying the information to communicate about alarm conditions .............................................217 15.4.6 Allocating signaling modalities to alarm signals............................................................................217 15.4.7 Creating alarm signals for each signaling modality: visual alarm signals .....................................219 15.4.8 Creating alarm signals for each signaling modality: auditory alarm signals..................................220 15.4.9 Creating alarm signals for each signaling modality: other alarm signals ......................................223 15.4.10 Creating a simulated use environment .........................................................................................223 15.4.11 Testing prototype alarm systems with potential users ..................................................................225 15.4.12 Refining alarm systems on the basis of testing results .................................................................226 15.5 References ............................................................................................................................................226
16 Accessibility considerations ...............................................................................................................................229 16.1 Introduction ...........................................................................................................................................229 16.2 General considerations ...........................................................................................................................229 16.2.1 User considerations.....................................................................................................................229 16.2.2 Design considerations ..................................................................................................................230 16.3 Design guidelines based on legislative guidance documents .................................................................232 16.3.1 Overview .....................................................................................................................................232 16.3.2 Users with lower-extremity disabilities ..........................................................................................232 16.3.3 Users with upper-extremity disabilities .........................................................................................234 16.3.4 Users who are deaf or hard of hearing .........................................................................................234 16.3.5 Users who are blind or have visual impairments ..........................................................................235 16.3.6 Users with limited tactile sensitivity...............................................................................................237 16.3.7 Users with cognitive or memory impairments ...............................................................................237 16.3.8 Users who could benefit from having more time for device operation ..........................................237 16.3.9 Users with speech impairments....................................................................................................237 16.4 Research-based design guidelines for patient-support surfaces ............................................................237 16.4.1 Overview .....................................................................................................................................237 16.4.2 Width of device base ....................................................................................................................237 16.4.3 Clearance for lift equipment..........................................................................................................238 16.4.4 Adjustability of surface height .......................................................................................................238 16.4.5 Transfer path ...............................................................................................................................238 16.4.6 Hand-holds ..................................................................................................................................238 16.4.7 Contact surfaces..........................................................................................................................239 16.4.8 Controls for support surfaces........................................................................................................240 16.5 Design guidelines for Web-based, mobile, and home-use health care products based on industry guidance documents...........................................................................................................................240 16.5.1 Overview .....................................................................................................................................240 16.5.2 Existing guidelines and standards ................................................................................................240 16.5.3 Built-in multimodal capabilities......................................................................................................241 16.5.4 Devices that use home-based technologies .................................................................................241 16.5.5 Existing laws related to use of hearing aids with telecommunication products.............................241 16.5.6 Training and informational materials.............................................................................................241 16.6 References.............................................................................................................................................241
Design Elements 17 Connectors and connections.............................................................................................................................244 17.1 Introduction ...........................................................................................................................................244 17.2 General considerations ...........................................................................................................................244 17.2.1 Overview .....................................................................................................................................244 17.2.2 Critical design considerations .......................................................................................................245 17.2.3 Key design criteria issues.............................................................................................................245 17.2.4 Types of connection failures .........................................................................................................245 17.3 Prioritizing types of connections .............................................................................................................246 17.3.1 Overview .....................................................................................................................................246 17.3.2 Direct patient connections for therapeutic purposes.....................................................................248 17.3.3 Direct patient connections for diagnostic purposes ......................................................................248 17.3.4 Connections between patient and device .....................................................................................249 17.3.5 Routinely connected non-patient connections ..............................................................................249 17.3.6 Permanent exterior device connections........................................................................................250 17.3.7 Permanent connections inside devices ........................................................................................250 17.4 Differentiating connectors .......................................................................................................................250 17.4.1 Overview .....................................................................................................................................250 17.4.2 Active differentiators .....................................................................................................................250 17.4.3 Passive differentiators ..................................................................................................................252 17.5 Preventing disconnections ......................................................................................................................253 17.5.1 Overview .....................................................................................................................................253 17.5.2 Rotating locking rings ...................................................................................................................253 17.5.3 Push–pull locking devices ............................................................................................................254 17.5.4 Locking levers..............................................................................................................................254 17.5.5 Screw-captive devices..................................................................................................................254 17.5.6 Capture clips................................................................................................................................254 17.5.7 Friction fit.....................................................................................................................................254 17.5.8 Positive feedback .........................................................................................................................255 17.5.9 Engagement of the locking mechanism........................................................................................255 17.5.10 Engagement indicators.................................................................................................................255 17.6 Facilitating connections..........................................................................................................................255 17.6.1 Connector design (shape, fit, feature) ..........................................................................................255 17.6.2 Receptacle design........................................................................................................................256 17.6.3 Connector use and testing and user training ................................................................................257 17.7 Preventing misconnections .....................................................................................................................257 17.8 Protecting connectors .............................................................................................................................257 17.9 User documentation...............................................................................................................................258 17.10 References...........................................................................................................................................258
18 Controls ............................................................................................................................................................259 18.1 Introduction ...........................................................................................................................................259 18.2 General considerations ...........................................................................................................................259 18.2.1 Steps in specifying controls ..........................................................................................................259 18.2.2 Advantages and disadvantages of various types of controls ........................................................260 18.2.3 Control selection..........................................................................................................................260 18.2.4 Human factors principles that apply to all controls........................................................................262 18.2.5 Design considerations for medical device controls vs. controls for consumer products ...............263 18.3 Design guidelines ..................................................................................................................................264 18.3.1 Control-panel controls ..................................................................................................................264 18.3.2 Input devices ...............................................................................................................................273 18.3.3 Large mechanical controls............................................................................................................285 18.4 References.............................................................................................................................................288
19 Visual displays ..................................................................................................................................................290 19.1 Introduction ...........................................................................................................................................290 19.2 General considerations ...........................................................................................................................290 19.2.1 Overview .....................................................................................................................................290 19.2.2 Understanding and accommodating user population characteristics............................................290 19.2.3 Accommodating the range of user postures .................................................................................291 19.2.4 Determining typical mounting positions and variations in mounting positions ..............................291 19.2.5 Examining the physical environmental conditions ........................................................................291 19.2.6 Identifying the requirements for displayed information .................................................................291 19.2.7 Performing objective display measurements ................................................................................292 19.2.8 Conducting usability tests.............................................................................................................293 19.3 Guidelines for specifying visual-display performance .............................................................................293 19.3.1 Overview .....................................................................................................................................293 19.3.2 Visual-display viewing conditions .................................................................................................293 19.3.3 Spatial characteristics..................................................................................................................294 19.3.4 Temporal characteristics ..............................................................................................................295 19.3.5 Luminance and color characteristics ............................................................................................297 19.4 Guidelines for display formatting.............................................................................................................299 19.4.1 Size and spacing of displayed characters or symbols ..................................................................299 19.4.2 Font style.....................................................................................................................................300 19.4.3 Character, line, and word spacing ................................................................................................301 19.4.4 Size of color objects and alphanumeric strings.............................................................................301 19.5 Guidelines for displaying data .................................................................................................................301 19.5.1 Precision......................................................................................................................................301 19.5.2 Adequate signal duration..............................................................................................................301 19.6 Guidelines for selecting electronic visual displays ..................................................................................302 19.6.1 Comparison of major types of visual displays...............................................................................302 19.6.2 Liquid crystal displays...................................................................................................................303 19.6.3 Active-matrix vs. passive-matrix displays .....................................................................................303 19.6.4 Large-screen displays ..................................................................................................................303 19.6.5 Scale indicators ............................................................................................................................304 19.7 References.............................................................................................................................................307
20 Use of automation.............................................................................................................................................309 20.1 Introduction ...........................................................................................................................................309 20.2 General considerations ...........................................................................................................................309 20.2.1 Types of automated systems and common issues .......................................................................309 20.2.2 Automation vs. human tradeoffs in medical systems....................................................................311 20.2.3 Automation status.........................................................................................................................312 20.2.4 User understanding of the automation..........................................................................................312 20.3 Design guidelines ..................................................................................................................................313 20.3.1 Monitoring and alarm systems......................................................................................................313 20.3.2 Event-sequencing systems...........................................................................................................313 20.3.3 Decision-support systems ............................................................................................................313 20.3.4 Closed-loop physiological control systems ...................................................................................313 20.3.5 Hybrid or composite automation systems.....................................................................................313 20.4 References.............................................................................................................................................314
21 Software–user interfaces ..................................................................................................................................315 21.1 Introduction ...........................................................................................................................................315 21.1.1 Overview .....................................................................................................................................315 21.1.2 Sample software–user interfaces .................................................................................................315 21.1.3 Factors influencing software–user interface design......................................................................316 21.2 General considerations ...........................................................................................................................317 21.2.1 Overview .....................................................................................................................................317 21.2.2 Make the software–user interface easy to use .............................................................................318 21.2.3 Focus on user tasks .....................................................................................................................318 21.2.4 Provide user guidance..................................................................................................................318 21.2.5 Safeguard against use error .........................................................................................................318 21.2.6 Optimize interaction requirements................................................................................................319 21.2.7 Improve software and hardware integration .................................................................................319 21.2.8 Select the interaction style............................................................................................................320 21.2.9 Support product evolution............................................................................................................320 21.3 Special considerations ............................................................................................................................321 21.3.1 Overview .....................................................................................................................................321 21.3.2 Screen size..................................................................................................................................321 21.3.3 Compatibility................................................................................................................................321 21.3.4 Information priority.......................................................................................................................321 21.3.5 Information legibility.....................................................................................................................321 21.3.6 User population ............................................................................................................................321 21.3.7 Standardization............................................................................................................................322 21.3.8 System integration.......................................................................................................................322 21.4 Design guidelines ..................................................................................................................................322 21.4.1 Categories ...................................................................................................................................322 21.4.2 Conceptual model.........................................................................................................................323 21.4.3 User-interface structure ................................................................................................................323 21.4.4 Interaction style ............................................................................................................................324 21.4.5 Screen layout...............................................................................................................................325 21.4.6 Legibility ......................................................................................................................................326 21.4.7 Aesthetics ....................................................................................................................................328 21.4.8 Data entry....................................................................................................................................329 21.4.9 Color............................................................................................................................................331 21.4.10 Dynamic displays.........................................................................................................................333 21.4.11 Special interactive mechanisms ...................................................................................................335 21.4.12 User support ................................................................................................................................341 21.4.13 Consistency.................................................................................................................................343 21.5 References.............................................................................................................................................343
Integrated Solutions 22 Hand tool design ...............................................................................................................................................344 22.1 Introduction ...........................................................................................................................................344 22.2 General considerations ...........................................................................................................................346 22.2.1 Overview .....................................................................................................................................346 22.2.2 Biomechanics ...............................................................................................................................346 22.2.3 Hand grips and positions associated with tool use .......................................................................346 22.2.4 Forces associated with the use of hand tools...............................................................................347 22.2.5 Injuries and discomfort associated with tool use...........................................................................348 22.2.6 Risk factors..................................................................................................................................349 22.2.7 Compensatory strategies and tradeoffs........................................................................................350 22.3 Special considerations ............................................................................................................................351 22.3.1 Laparoscopic surgery ...................................................................................................................351 22.3.2 Catheter-based procedures..........................................................................................................353 22.3.3 What to do if design data are not available...................................................................................354 22.4 Design guidelines ..................................................................................................................................355 22.4.1 Overview .....................................................................................................................................355 22.4.2 Context of use ..............................................................................................................................355 22.4.3 Location and environmental factors..............................................................................................355 22.4.4 The end-effector (tool interactions with anatomy).........................................................................357 22.4.5 Characteristics of the tool .............................................................................................................358 22.4.6 Safety ..........................................................................................................................................364 22.4.7 User characteristics and related design considerations................................................................364 22.4.8 Controls for hand tools .................................................................................................................370 22.4.9 Sensory feedback........................................................................................................................372 22.4.10 Guidelines specifically for laparoscopic instrument design...........................................................372 22.5 References.............................................................................................................................................373
23 Workstations .....................................................................................................................................................378 23.1 Introduction ...........................................................................................................................................378 23.2 General considerations ...........................................................................................................................380 23.2.1 Adaptation of design to user needs ..............................................................................................380 23.2.2 Safety ..........................................................................................................................................381 23.2.3 Usability.......................................................................................................................................381 23.2.4 User satisfaction ...........................................................................................................................383 23.3 Special considerations ............................................................................................................................383 23.3.1 Overview .....................................................................................................................................383 23.3.2 Serve life-critical purposes............................................................................................................383 23.3.3 Accommodate evolving clinical practices .....................................................................................383 23.3.4 Accommodate a variety of user positions .....................................................................................383 23.3.5 Accommodate users with varying degrees of skill, training, and experience ................................384 23.3.6 Accommodate workstation use by individuals with disabilities .....................................................384 23.3.7 Accommodate patients who might be under stress ......................................................................384 23.3.8 Accommodate caregivers who might be under stress ..................................................................384 23.3.9 Anticipate potential migration from hospital to home use .............................................................384 23.3.10 Anticipate frequent or infrequent cleaning ....................................................................................384 23.3.11 Design for compactness ...............................................................................................................385 23.4 Design guidelines ..................................................................................................................................385 23.4.1 Overview .....................................................................................................................................385 23.4.2 Operational factors .......................................................................................................................385 23.4.3 Power supply...............................................................................................................................388 23.4.4 Readiness ...................................................................................................................................389 23.4.5 Security .......................................................................................................................................389 23.4.6 Privacy.........................................................................................................................................390 23.4.7 Communication............................................................................................................................390 23.4.8 Component configuration .............................................................................................................392 23.4.9 Physical interaction......................................................................................................................400 23.4.10 User accommodations.................................................................................................................405 23.4.11 Environmental factors...................................................................................................................415 23.5 References.............................................................................................................................................415
24 Design of mobile medical devices......................................................................................................................417 24.1 Introduction ...........................................................................................................................................417 24.2 General considerations ...........................................................................................................................417 24.2.1 Overview .....................................................................................................................................417 24.2.2 User considerations.....................................................................................................................417 24.2.3 Use-environment considerations ..................................................................................................417 24.3 Design guidelines ..................................................................................................................................418 24.3.1 General design guidance..............................................................................................................418 24.3.2 Mechanical design........................................................................................................................418 24.3.3 Electrical design ...........................................................................................................................421 24.3.4 Display of information on computer-based medical devices.........................................................421 24.3.5 Controls and input devices ...........................................................................................................425 24.3.6 Connectors and cables.................................................................................................................426 24.3.7 Security .......................................................................................................................................427 24.3.8 Instruction manuals and other forms of device documentation.....................................................427 24.4 References ............................................................................................................................................427
25 Home health care..............................................................................................................................................428 25.1 Introduction ...........................................................................................................................................428 25.1.1 Trends in medical device use .......................................................................................................428 25.1.2 The home user .............................................................................................................................428 25.1.3 The home environment.................................................................................................................428 25.2 General considerations ...........................................................................................................................429 25.2.1 Overview .....................................................................................................................................429 25.2.2 Adjustability .................................................................................................................................429 25.2.3 Durability .....................................................................................................................................429 25.2.4 Learnability and intuitiveness........................................................................................................429 25.2.5 Freedom from calibration, maintenance, and repair .....................................................................429 25.2.6 Protection from unintended misuse and/or tampering ..................................................................429 25.2.7 Portability and maneuverability.....................................................................................................430 25.2.8 Power requirements .....................................................................................................................430 25.2.9 Aesthetics and unobtrusiveness...................................................................................................430 25.2.10 User guidance and training...........................................................................................................430 25.3 Design guidelines ..................................................................................................................................430 25.3.1 Overview .....................................................................................................................................430 25.3.2 Design guidance related to sensory capabilities and limitations ...................................................431 25.3.3 Design guidance related to cognitive capabilities and limitations .................................................434 25.3.4 Design guidance related to physical capabilities and limitations ..................................................436 25.3.5 Design guidance related to the use environment..........................................................................437 25.3.6 Medical device training materials and documentation for home users .........................................438 |
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