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

1. Human Factors (HF) and Nocturnal Home Hemodialysis (NHD) • Draft • 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

2. Topics Introduction to human factors (HF) Magnitude of medical error-caused adverse incidents HF methods Nocturnal home hemodialysis challenges and observations Human Factors Branch Recommendations for premarket submissions

3. 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

4. General 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

5. Magnitude 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

6. HF Considerations Use • Use Environment • Light, Noise • Distraction • Motion/Vibration Safe & effective • Device User • Knowledge • Abilities • Expectations • Limitations Device Use Unsafe or ineffective(Use Error) • Device • Operational requirements, procedures • Device complexity • Specific user interface characteristics

7. 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

8. Two 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.

9. 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

10. MAKE THINGS VISIBLE: This PCA pump fails. Obradovich and Woods (1996)

11. Obradovich and Woods (1996)

12. 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

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

14. 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: e.g., valve conventions • Simplify tasks • Use appropriate constraints • Design for error

15. 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 (e.g., reduce programming steps) • Use appropriate constraints • Design for error

16. Protected Pins SAFE Lead Wires with Protected Pins and Correct Connections Power Cord Protected Pins Monitor Electrode Lead Wires Patient Cable Use only lead wires that have protected pins. Protected pins can not accidentally be plugged into power cords or electrical outlets. UNSAFE Lead Wires with Unprotected Pins and Incorrect Connections From Patient From Patient Power Cord or Extension Cord Unprotected Pins Unprotected Pins APPROPRIATE CONSTRAINTS FDA, Dec. 28, 1993

17. Some Important Principles of Good Design (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: (e.g., require confirmation of critical actions)

18. 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 Human Factors (HF): Critical in Nocturnal Home Hemodialysis

19. 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

20. 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)

21. Nocturnal 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”)

22. 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

23. Nocturnal Home Hemodialysis User Needs (continued) • 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.

24. Nocturnal Home Hemodialysis User Needs (continued) • 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.

25. Nocturnal Home Hemodialysis User Needs (continued) • Consider tricky power-interruption scenarios (error-codes, default settings) • Design in virtual “guardrails”. • Allow for compromised nocturnal response to alarms

26. 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

27. 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.

28. Early Introduction of Human Factors to Medical Device Design c Product marketing Product development Cumulative savings Product release 0 Breakeven point Time b a

29. Applying HF is a Process:Human Factors Engineering Concept Phase Design Input Design Output Verification Validation Perform Studies & Analyses Develop Require- ments Develop Specs. Test Output Against Input Test Against Patient & User Needs Tasks Users Use Environment Standards & Guidelines Literature Complaints Observation Interviews Drawings Mockups Computer Prototypes Expert Evaluation Rapid Prototyping Usability/HF Testing Production Units Usability/HF Testing

30. Usability 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)

31. 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? ==>

32. 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

33. Human 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

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

35. 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.

36. ADDITIONAL SLIDES FOLLOW • ADDITIONAL SLIDES 

37. Sources 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”)

38. 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)

39. FDA 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

40. Guidance 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