Human Factors (HF) and Nocturnal Home Hemodialysis (NHD) Draft Michael Mendelson, D.D.S., M.S. Biomedical Engineer, Director Health Promotion Officer Human

Human Factors (HF) and Human Factors (HF) and Nocturnal Home Nocturnal Home Hemodialysis (NHD)Hemodialysis (NHD)

Human Factors (HF) and Human Factors (HF) and Nocturnal Home Nocturnal Home Hemodialysis (NHD)Hemodialysis (NHD)

DraftDraft

Michael Mendelson, D.D.S., M.S.Michael Mendelson, D.D.S., M.S.

Biomedical Engineer, Director Health Promotion Officer

Human Factors Science and Engineering Branch

Division of Device User Programs

Office of Communication, Education, and Radiation Control

Center for Devices and Radiological Health

June 8, 2005

TopicsTopics

Introduction to human factors (HF)Magnitude of medical error-caused adverse incidentsHF methodsNocturnal home hemodialysis challenges and observationsHuman Factors Branch Recommendations for premarket submissions

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General Definition of Human Factors (HF)General Definition of Human Factors (HF)

Human Factors discovers and applies information about human behavior, abilities, limitations, and other characteristics to the design of tools, machines, systems, tasks, jobs and environments for productive, safe, comfortable, and effective human use. *

-- Alphonse Chapanis 1985

*Sanders & McCormick, Human Factors in Engineering and Design., McGraw-Hill, Inc., 1987; page 5

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General Definition of ErrorGeneral Definition of Error

Human error is an inappropriate or undesirable human decision or behavior that reduces, or has the potential for reducing, effectiveness, safety, or system performance.*

*Sanders & McCormick, Human Factors in Engineering and Design., McGraw-Hill, Inc., 1987; page 607

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Magnitude of the Problem of Medical ErrorMagnitude of the Problem of Medical Error

Errors during hospital treatment result in 120,000 deaths each year – roughly equivalent to a jumbo jet’s crashing each day. (Leape, Harvard School of Public Health)

At least 44,000 people,and perhaps as many as 98,000 people,die in hospitals each year as a result of medical errors that could have been prevented…(To Err is Human: Building a Safer Health System; Institute of Medicine / National Academy of Sciences, 1999)

Photo courtesy of Boeing

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Safe & effective

Unsafe orineffective(Use Error)

Use Environment• Light, Noise• Distraction• Motion/Vibration

Device User• Knowledge• Abilities• Expectations• Limitations

Device• Operational requirements, procedures• Device complexity• Specific user interface characteristics

Use

HF Considerations

DeviceUse

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Increased Patient Safety through USABILITY (“User Friendliness”) of the Use Interface

Increased Patient Safety through USABILITY (“User Friendliness”) of the Use Interface

Intuitive operation Clear displays Safe and simple-to-use controls Positive and safe connections Effective alarms Clear and effective and labeling Safe and simple installation, repair,

maintenance, and disposal

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Two Key Human Factors (HF) MessagesTwo Key Human Factors (HF) Messages

A poorly designed device use interface can needlessly permit and even induce error.

Warnings and instructions in the operating manual (and even on the device) may help but they can’t OVERCOME a flawed design.

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Some Important Principles of Good Design (modified from The Design of Everyday Things, Donald Norman)


Make things visible Communicate clearly Provide correct and natural mappings Don’t be arbitrary, be consistent Simplify tasks Use appropriate constraints Design for error

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MAKE THINGS VISIBLE: This PCA pump fails.MAKE THINGS VISIBLE: This PCA pump fails.

Obradovich and Woods (1996)

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Obradovich and Woods (1996)

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Some Important Principles of Good Design (The Design of Everyday Things, Donald Norman)


Make things visible Communicate clearly (e.g., mode/system

status) Provide correct and natural mappings Don’t be arbitrary, be consistent Simplify tasks Use appropriate constraints Design for error

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Make things visible Communicate clearly Provide correct and natural mappings:

“What is this switch for?” Don’t be arbitrary, be consistent Simplify tasks Use appropriate constraints Design for error

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Make things visible Communicate clearly Provide correct and natural mappings Don’t be arbitrary, be consistent: e.g.,

valve conventions Simplify tasks Use appropriate constraints Design for error

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Make things visible Communicate clearly Provide correct and natural mappings Don’t be arbitrary, be consistent Simplify tasks (e.g., reduce programming

steps) Use appropriate constraints Design for error

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SAFE

Lead Wires with ProtectedPins and Correct Connections

UNSAFE

Lead Wires with UnprotectedPins and Incorrect Connections

Protected Pins

Protected Pins

ElectrodeLead Wires

PatientCable

PowerCord

Monitor

Use only lead wires that have protected pins. Protected pins can not accidentally be plugged into power cords or electrical outlets.

From Patient

UnprotectedPins

From Patient

UnprotectedPins

Power Cord orExtension Cord

APPROPRIATECONSTRAINTS

FDA, Dec. 28, 1993

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Make things visible Communicate clearly Provide correct and natural mappings Don’t be arbitrary, be consistent Simplify tasks Use appropriate constraints Design for error: (e.g., require

confirmation of critical actions)

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Human Factors (HF): Critical in Nocturnal Home HemodialysisHuman Factors (HF): Critical in Nocturnal Home Hemodialysis

Users Lack of on-site staff

and supplies Variable level of

education Medically

compromised: vision, touch, memory

Language and cultural diversity

Healthy-patient selection responsibile for home safety level*

Environment Family responsibilities,

children, pets Stress Physical (placement,

voltage/grounding, temperature, humidity, dust)

*D’Amico&Bazzi, Home Hemodialysis, in Replaplacement of Renal Function by Dialysis, 1989, page 694

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Clinical Incidents: Potential Nocturnal Home Issues?Clinical Incidents: Potential Nocturnal Home Issues?

Hazards always exist. Documented clinical post-market risks and adverse incidents (errors):

Midtreatment shutdown without warning =>clot/embolism risk

*ECRI Healthcare Product Comparison System, Sept. 2004; page 6

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Clinical Incidents: Potential Nocturnal Home Issues? (continued)

Clinical Incidents: Potential Nocturnal Home Issues? (continued)

For 3 fault codes which indicate need for manual adjustment of transmembrane pressure (TMP) => not actually controllable. Recall. Solution: labeling *

If unit plugged into receptacle without ground fault circuit interrupter (GFCI) – with certain other conditions => overheating. Recall. Solution: labeling *

*ECRI Healthcare Product Comparison System, Sept. 2004; page 10 (HDA A5092, A5624)

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Nocturnal Home Hemodialysis User NeedsNocturnal Home Hemodialysis User Needs

Simplify setup: minimize requirements for strict hygiene where possible.

Minimize burden on training. Consider periodic retraining.

Minimize dependence on bulky labeling. Use:– On-screen help/voice prompts (“Wizards”)– Quick Guides (laminated cards, “cheat

sheets”)

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Nocturnal Home Hemodialysis User Needs (continued)


Monitor supplies and preparation of prescribed dialysate

Ensure simple set up operation, and adjustment. Ensure safety of consumables: possible after-

market consumables lacking OEM safety features? (e.g., after-market infusion pump tubing sets – lethal outcome)

Need for priming blood lines, knowing symptoms of air embolism, how to respond

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Potential interrupted treatment: Ability to detect and respond?

Allow flexible installation – various viewing angles.

Allow for physical impairment (ESRD co-morbidities).

Consider touch screen and no cryptic error codes.

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Consider “progressive disclosure” of information– for range of user abilities and wants.

Facilitate detection of bleeding: enuresis pads, moisture detectors, effective needle dislodgement alarm (single needle?).

Patient abilities may be lowest at start of session.

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Consider tricky power-interruption scenarios (error-codes, default settings)

Design in virtual “guardrails”. Allow for compromised nocturnal

response to alarms

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Design of Hemodialysis Systems Requires Human Factors Engineering (HFE)

Design of Hemodialysis Systems Requires Human Factors Engineering (HFE)

The Quality System Regulation: HF implied in Design Controls Section (21 CFR 820.30)

Manufacturer: Must address the intended use Must address the needs of the user and

patient Shall include testing under actual or

simulated use conditions

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Introducing Human Factors (HF) Into Design: How Early?Introducing Human Factors (HF) Into Design: How Early?

510(k)/PMA submission is too late Pre IDE/IDE submission is late The concept stage is ideal.

– User needs designed in.– Early HF design changes fast and economical.– Fewer “slapped-on” warnings and bulky

manuals.– User acceptance and product life increased.– Industry estimate: $3 return on $1 HF

investment.

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Productdevelopment

Productmarketing

Productrelease

Breakevenpoint

Time

Cu

mu

lati

ve s

av

ing

s

0

a b

c

Early Introduction of Human Factors to Medical Device Design

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ConceptPhase

DesignInput

DesignOutput Verification Validation

Literature

Complaints

Observation

Interviews

Tasks

Users

UseEnvironment

Standards &Guidelines

Drawings

Mockups

ComputerPrototypes

ExpertEvaluation

RapidPrototyping

Usability/HF Testing

ProductionUnits

Usability/HF Testing

PerformStudies &Analyses

DevelopRequire-

ments

DevelopSpecs.

Test OutputAgainst

Input

Test AgainstPatient &

UserNeeds

Applying HF is a Process:Human Factors Engineering Applying HF is a Process:Human Factors Engineering

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Usability Study: Validation of Use InterfaceUsability Study: Validation of Use Interface

Most visible human factors step Actual production units Prospective users Realistic environment Test user in critical functions (from hazard

analysis, literature, other reports) Objective measures – not preferences –

(e.g., time, error rate, physiological stress)

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Clinical Trials and Usability Studies: Complementary

Clinical Trials and Usability Studies: Complementary

Usability Studies demonstrate: low risk of dangerous use error where, when, and how device is used by typical users. (usually a simulation)

Clinical trials demonstrate: safety and effectiveness where, when, and how used exactly as directed.

Demonstrate usability before clinical trials! Why? ==>

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Clinical Trials and Usability Studies: Complementary (continued)Clinical Trials and Usability Studies: Complementary (continued)

Clinical trials: not usually representative users Clinical trials: cannot impose hazardous

scenarios Clinical trials: usability measurement can be

intrusive Clinical trials: too late for HF design

improvements

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Human Factors Interaction:Manufacturer <==> FDAHuman Factors Interaction:Manufacturer <==> FDA

FDA HF Branch emphasizes PROCESS, not specific design features (usually).

Submit comprehensive description of HFE process early to FDA: ODE ==> Human Factors Branch

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– Concepts– Design input

sources– Describe testing– Include hazard

analysis– Standards and

guidance used

– Submit all labeling– Describe training– Include usability

study and report– Identify discovered

usability problems and describe solution

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Human Factors Recommendations/Conclusion

Human Factors Recommendations/Conclusion

Begin comprehensive Human Factors Engineering (HFE) process at concept stage.

Assume significant patient/user and environmental compromises.

Minimize burden on training and paper instructions.

Ensure comprehensive patient/user support from manufacturer or value-added retailer.

Encourage postmarket feedback from users. Engage FDA early.

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ADDITIONAL SLIDES FOLLOWADDITIONAL SLIDES FOLLOW

ADDITIONAL SLIDES

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Sources of Design InputSources of Design Input

User input, other devices, environment General HF design conventions,

knowledge (“heuristics”) Standards (including HF, risk, alarms) FDA HF Guidance documents (Web:

www.fda.gov/cdrh; “Topic Index”; “Human Factors”)

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Design Controls: HF implied in the design controls portionof the Quality System Regulation

Design Controls: HF implied in the design controls portionof the Quality System Regulation

Design input Paragraph 820.30 (c)

Design verification Paragraph 820.30 (f) Design validation Paragraph 820.30

(g)

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FDA Recognized StandardsFDA Recognized Standards

ANSI/AAMI HE74:2001, HF process standard (FDA-recognized)

ISO 14971:2004, Risk Management ISO/IEC alarm standard 60601-1-8,

1st edition

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Guidance DocumentsGuidance Documents

Device Use Safety: Incorporating Human Factors in Risk Management

Do It By Design: an Introduction to Human Factors in Medical Devices

Guidance on Medical Device Labeling

(Web: www.fda.gov/cdrh; “Topic Index”; “Human Factors”).

HF guidance integrated into FDA software guidance documents and specific device guidance