Clinical Engineering Engineers in the Modern Academic Medical Center Design Disasters Consequences of Blunders, Bad Luck, and Bias

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Clinical EngineeringEngineers in the Modern
Academic Medical CenterDesign
DisastersConsequences of Blunders, Bad Luck, and
Bias

• Patrick Norris, Ph.D.Assistant Professor of
  Surgery,Biomedical Engineeringpatrick.norris_at_va
  nderbilt.edu

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Clinical EngineeringWhy do hospitals need
engineers?

• Definition
• Past, Present, Future
• Examples
• Facility Design
• Biomedical Devices
• Information and Technology Management
• Clinical Research, Quality Improvement

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Definition
Biomedical Electronics
Clinical Technology Service
Biomedical Engineering
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DefinitionThe American College of Clinical
Engineering
A professional who supports and advances patient
care by applying engineering and management
skills to healthcare technology.
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Definition Hospitals need engineers when
technology requires

• Special (non-trade/craft skills) customization or
  maintenance
• Complex selection criteria
• Modification of existing facilities or systems,
  or special design of new ones
• Design and analytic skills, professional
  credentials, etc. differentiate engineers from
  technicians, craftspeople, clerical,
  administrators, etc

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Examples Past

• Einthoven EKG, early 1900s
• Other examples
• Day to day heat, AC, water, electricity, etc.

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Examples Present

• Infrastructure Design
• Typical Water, Electrical, HVAC, Telecom
• Special Medical Gas, Sample Handling
• Structural Imaging Systems
• Biomedical Devices
• Selection, integration, tracking
• Maintenance is becoming a sophisticated
  trade/craft skill
• Information

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Future

• Information
• Medical Informatics
• 6 VUSE PhDs
• Integration
• People
• IT Systems
• Medical Devices
• Regulation
• Privacy, Safety, Efficacy
• Across Multiple Healthcare Systems

Grimes SL, IEEE Engineering in Medicine and
Biology Magazine, March/April 2003 p.91-99
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Clinical Research

• SIMON Project
• (Signal Interpretation and Monitoring)
• Ongoing since 1994
• Seeks to Advance
• Medical Monitoring Technology
• Critical Care
• Scientific Knowledge
• Clinical Engineering Component

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Trauma

• 5th Leading Cause of Death (1st Under 45)
• 8 of Medical Expenditures (rank 3rd)
• All Age and Socioeconomic Groups
• VUMC
• Only Level 1 Facility, 65,000 Square Miles
• 3500 Annual Admissions
• 800 to Trauma ICU, 10 Mortality

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Patient Monitoring

• Cushing, early 1900s
• Importance of Monitoring and Recording Vital
  Signs
• Technology Has Advanced
• Fundamentally, Clinical Strategies Remain
  Unchanged
• Intermittent Recording
• Manual Interpretation

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Tools for Dense Physiologic Data Management
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Four Engineering Challenges

• Data Collection
• Interfaces to a Variety of Devices
• Remote Locations
• Storage
• Clinical Applications - Short-Term
• Research Applications - Forever
• Processing
• Time-Critical Tasks (Clinical Decision Support)
• Research Analysis
• Architecture
• Integration, Reliability, Scalability,
  Flexibility

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SIMON Data Capture

• Philips CareVue
• Routine, Automatic Vital Signs Capture
• HR, ABP, PAP, CVP, ICP, CPP, PAP, SaO2
• Episodic Waveform Capture
• Edwards Vigilance
• CI, EDVI, temp, SvO2, etc.
• Alaris IV Pump (near future?)

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SIMON Data Storage

• Relational Database
• Time Constraints w/ Limited Resources
• Adaptive Sampling, 0.25-1Hz Storage
• 5500 TICU Patients
• Reliably Identified, Linked to Outcomes
• 450,000 Continuous Hours
• Grows by
• 2 Million Data Points/Day
• 70 Patients/Month

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Daily Reports
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Data Display
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Alerts

• Process
• Event
• Alert
• Notification
• Response

• Effective Alerting
• Right Information
• Right Person
• Right Time

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SIMON Architecture

• Modular, Simple Components
• Scalable
• Reliable
• Flexible
• Time-Constrained

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SIMONS1
SIMONT1
Devices
Digi Driver
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Research Hypotheses
New measurements, available through techniques
of dense data capture and analysis, will

• Identify failure of communication pathways
  (uncoupling)
• Linking systems, organs, cells, proteins, and
  genes
• Illuminate underlying control mechanisms
• especially in the critically ill

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Short-Term HRV - Survival
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Short-Term HRV - Death
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Short-Term HRV - Combined
Time normalizedwithin outcome group
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Design DisastersConsequences of Blunders, Bad
Luck Bias

• What is a Design Failure?
• Why Do They Happen?
• Examples
• Recipes for Design Disasters
• Space Program
• Transportation
• Medical

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What is a Design Failure?

• Elements of Establishing Defect
• Identify the design defect
• Establish a causal link to harm or cost
• Identify alternate designs (correctable)
• Compare to similar products
• A product does not have a design defect when it
  is safe for any reasonably foreseeable use and
  meets all applicable functional specifications.

Geddes, Medical Device Accidents With
Illustrative Cases
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Example Design Defect(probably from urban legend)
Nurses in Pelonomi Hospital, South African
hospital were baffled that every Friday morning
the patient in one particular bed would be found
dead! Investigation revealed that the cleaning
person would unplug that beds life support
equipment, in order to plug in her floor polisher
when she did the floors each Friday. When
finished, she would plug the equipment back in
unaware that the patient was now dead.
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Example Design Defect

• Definition

• Pelonomi Hospital Legend

• Identify defect
• Causal link
• Alternate designs
• Comparison

• Life support equipment could be unknowingly
  unplugged
• Staff were not alerted when machine unplugged,
  patient died
• Alarms and batteries
• All life-critical equipment offered by vendors
  X,Y,Z have alarm battery backup

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What is a Design Failure?

• There are plenty of definitions
• Numerous example cases
• In the end, failures are debatable
• Ultimately, court may have to decide
• With testimony from experts
• Sometimes difficult to separate liability from
  design flaw
• Negligence is a legal, not technical, term

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Why Do Designs Fail?At least three types of
factors

• Blunders (Human Error)
• Everyone makes mistakes
• Bad Luck (Random Effects)
• S happens
• Bias
• People sometimes believe what they want to,
  irrespective of facts
• Especially when money, power, relationships are
  involved

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Example 125M Blunder

• 1999 Mars Orbiter
• JPL, Lockheed
• Metric vs. English units
• Erroneous orbital entry calculation engine burn
  time

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Example Bad Luck (?)

• Weather A random effect
• Dense fog on I-75
• 99 vehicle pile-up in TN
• Killing 12, injuring 56
• Initially weather blamed
• Then local paper mill
• 13.5M settlement
• Once bad luck
• Many times negligence?

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Example Bad Luck

• Tacoma-Narrows bridge
• Unforeseeable consequence of lightweight design,
  wind profile
• No human deaths
• 5.2M in 1940, 70M today
• (Insurance paid)

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Types of Bias

• Statistical
• Sampling
• Multiple comparisons
• Repeated measurements
• Psycho-Social
• Groupthink
• Corpthink

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Examples Statistical Bias

• More people die in hospitals than anywhere else,
  therefore dont go to the hospital! (unfair
  sampling)
• Similar situation A medical device designed only
  for the critically ill
• Randomized, controlled trials are part of the
  answer

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Examples Statistical Bias

• Suppose you design a device that will roll a six
  every time how many times do you need to test
  it?
• Which results do you report?
• Increasingly an issue in medical drug and device
  trials
• 95 significance (plt.05) means that 1 in 20
  studies is a false-positive

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Psycho-Social Biases

• Individual
• Primacy The first option mentioned seems best
• Recency The last option seems best
• Group
• Groupthink Consensus rules
• Corpthink Desire to please those higher in the
  chain of command

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NASA Ripe for Disaster?

• Huge shift in corporate culture
• Space race Do it at any cost
• Increasing cost concerns, cuts, downsizing,
  resource pressure, etc.
• Feynman, Challenger Disaster Report
• Engineer estimate of catastrophic failure 1 in
  100
• Management 1 in 100,000
• What is the cause of managements fantastic
  faith in the machinery?

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More Design Failures

• Recipes for Disaster
• Ignition Source Flammable Material
• More Examples
• Transportation
• Space Program
• Software

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Hindenburg

• German airship
• Caught fire while landing in 1937
• Design defect
• Hydrogen?
• Skin?

http//www.youtube.com/watch?vF54rqDh2mWA
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Apollo 1

• Pad fire during test
• Killed 3 astronauts
• Design defects
• 31 miles of electrical wire
• Pressurized pure oxygenenvironment
• Flammable materials
• Substandard wiring

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Medical Devices Fire

• Ignition Source

• Flammable Materials

• Electrocautery
• Nerve stimulators
• Short-circuit
• Electrostatic discharge
• Cigarettes

• Anesthetic gas
• not so much today, ex. O2
• Gases in the body, especially GI system
• Geddes reports 10 cases of GI explosions during
  procedures, some lethal!
• Bedding, clothing
• Bandages
• Cleaning solutions, solvents, etc.

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Medical Software Design

• What type of medical technology is least
  regulated?
• Software
• There is no professional-level (i.e. PE)
  certification for software engineering
• Less regulation than devices/drugs

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Medical Software Design

• Design failures are being publicized
• Computerized Physician Order Entry
• Cedars-Sinai software rollout
• Multi-million dollar project scrapped
• Software endangered patient safety
• This story is not unique
• Privacy issues
• Will software design failures increase?

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Summary Clinical Engineering

• Definition of clinical engineering
• Engineers role in the hospital?
• Technology design, management
• Increasingly, information management
• Clinical research, i.e. VUMC Trauma
• Differences between engineering and trade/craft
  skills (design analysis)

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Summary Design Disasters

• Geddes definition of design failure
• Identified defect
• Causal link to harm
• Available alternative
• Deficiency w/ respect to other products
• 3 factors in design disasters
• Human error (blunder)
• Random effects (bad luck)
• Bias

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Sample Questions

• Which is not an aspect of establishing design
  failure (according to Geddes)?

• What factor best differentiates engineers from
  trades/craftspeople?

1. Identified defect
2. Causal link to harm
3. Negligence
4. Feasible alternative design

1. Design and analytic skillset
2. Professional ethics
3. Ability to work in highly regulated fields
4. Salary

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Sample Questions

• What kinds of bias is most likely encountered by
  an individual doing statistical analysis of
  complex data?

1. Unfair sampling
2. Groupthink
3. Recency
4. All of the above

• According to Feynmans appendix to the Challenger
  disaster report, NASA engineers estimate
  probability of failure at about 1 in ________,
  compared to managements 1 in ________ .

1. 10, 10000
2. 1000, 1000
3. 100, 100000
4. 10000, 100

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References/Sources

• clinicalengineering.duhs.duke.edu/
• cms.clevelandclinic.org/anesthesia/body.cfm?id124
  
• www.healthsystem.virginia.edu/internet/clinical-en
  g/
• www.wikipedia.org
• www.ceasa-national.org.za/
• www.mc.uky.edu/clinicalengineering/
• cms.clevelandclinic.org/anesthesia/body.cfm?id156
  
• www.uams.edu/ClinEng/default.aspx
• simon.project.vanderbilt.edu/
• tafkac.org/medical/hospital_cleaning_lady.html
• www.cnn.com/TECH/space/9909/30/mars.metric.02/
• mars.jpl.nasa.gov/msp98/orbiter/
• www.douglasjfeeslaw.com/achievements.jsp
• gtresearchnews.gatech.edu/reshor/rh-ss01/fog.html
• www.ralentz.com/old/space/feynman-report.html
• youtube.com

patrick.norris_at_vanderbilt.edu