Patient Positioning Aid

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Patient Positioning Aid

• The Boss
• Matt Bruchas
• Matt Greulich
• Saira Mahmood
• Anna Rapp

December 9, 2005
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Background

• Patient Positioning Aids
• When imaging, specific limb orientations must be
  achieved and stabilized
• Who Benefits
• Elderly, Obese, Disabled
• Current Devices
• Foam wedges
• Wrap around coils
• Pillows
• Tape
• Velcro straps

CFI Medical Solutions. http//www.contourfab.com/N
PAs/MedVac20System.pdf
3
Problem Statement

• Current Problem
• Disabled patients lack access
• MRI, CT, X-Ray patient positioning
• Foam wedges and pillows fail to provide adequate
  positioning
• Static Positioning
• Proposed Solution
• A versatile, low-cost, easily adjusted, and
  stable positioning aid
• Applicable to a wide range of exam tables

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Objectives

• More effective patient positioning aids
• Stability
• Precision with respect to orientation
• Decrease interference in images
• Patient comfort
• Technician friendly
• Accommodate patients up to 500 lbs

5
Market

• Imaging market will rise 8 in the next 3 years
  in the U.S. alone
• Soon 10 billion a year
• Higher life expectancy
• Stability
• Limb control
• Evident need from improved static patient
  positioning

http//www.the-infoshop.com/study/fd20912_medical_
imaging_equip.html
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Social and Ethical Analysis

• Benefit consumer
• Comfort
• Allow disabled patients to have access to
  diagnostic imaging
• Static positioning
• Better diagnosis
• Benefits hospital staff
• Efficiency
• Less interference due to less motion
• Better defined images

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Design Criteria

• Compatibility
• Permeability to X-rays or other diagnostic
  vectors.
• Easily conforms to machine parameters
• Adjustability
• Large degree of freedom of positioning component
• Conforms to individual patients
• Stability
• Obese patients
• Storage
• One device vs. many (foam wedges, coils)
• Cost Effectiveness
• Single device
• Readily available materials
• Easily manufactured and assembled

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Competing Designs on Market

• Wrap around coils

Advantages -Closer Imaging -Homogenous
images -Ergonomically designed pads Disadvantages
-No Absolute Stability -Limited imaging
area -Not orientation specific
http//www.invivoresearch.com/
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Competing Design 1 CriteriaAugmented Transfer
Board

• Consolidation
• Single device
• Integration of parts
• Compatibility
• Diminish interference
• Adjustability
• Limb positioning
• Limit radiation exposure time
• Stability and Transportability
• Obesity
• Bed to bed transfer
• Storage
• Single device
• Cost Effectiveness

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Problems with Competing Design 1

• Board dimensions did not permit use on diagnostic
  tables
• Difficult to manufacture/ assemble
• Multiple parts
• Hinged design
• Interview with Dr. Matt Stadnyk
• Not radiologist recommended
• Dont re-invent to wheel

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Competing Design 2 CriteriaSingle Box-Bladder

• Consolidation
• Single device
• Approximately 3 feet long
• Compatibility
• Radiolucent
• Adjustability
• Velcro straps
• Cost Effectiveness

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Problems with Competing Design 2

• Difficult to adjust extremities
• No rotation
• Must deflate for each position adjustment
• Single big device
• Bulky
• Hard to store
• No reason for bottom bladder
• Time to inflate wasted
• Unnecessary space

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Proposed Design CriteriaAttachable
Boxes-Orientation Specific

• Stability
• Aids patient in maintaining static position
• Adjustability
• Accommodates a range of patients up to 500 lbs
• Compatibility
• Radiolucent for clear, homogenous images
• Cost Effectiveness
• Easy to manufacture
• Easy to assemble

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Specifications

• Design
• Inflatable Bladders- patient specific stability
• Rotating device- axis of limb
• Foam base- patient comfort

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Materials and Facilities

• Materials
• UHMWPE- box sides
• Radiolucent
• Sufficient mechanical properties
• Polyurethane/ Polyethylene- bladders
• Radiolucent
• Can withstand appropriate air pressures
• Pump Device
• Foam
• Facilities
• BME labs
• St. Josephs Hospital, Kirkwood
• Blow Torch
• Manufacturing Lab MDH

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Dimensions-Tolerances

• Lower extremity box 1 (Ankle)
• Length 12
• Width 12
• Height 10
• Thickness 0.25
• Lower extremity box 2
• (Knee)
• Length 12
• Width 12
• Height 10
• Thickness 0.25

• Upper extremity box
• Length 24
• Width 8
• Height 6
• Thickness 0.25

All PE wall tolerances are /- 0.05 PE wall
thickness /-0.025
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Dimensions-Tolerances

• Upper Extremity Swivel (UHMWPE)
• 9 diameter /- 0.05
• Upper Extremity Hand Support
• (UHMWPE)
• Length 5 /- 0.05
• Lower Extremity Swivel (UHMWPE)
• 6 diameter /-0.05
• Lower Extremity Foot Rest (UHMWPE)
• Length 3
• Width 3
• Height 3

• Bladders (Polyurethane-PE)
• Device width x length x height
• Knee Inflated to 6x12x10
• Ankle Inflated to 6x9x10
• Arm Inflated to 4x24x8
• Air Pressure
• Minimum pressure 10psi
• Maximum pressure 25psi

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Loading Tolerances

• Ankle and Hand support
• Segment weight of hand or foot
• Angular Swivel
• 180o (90 left of vertical and 90 right of
  vertical)

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Strategy

• Methods
• Material Purchase
• -Vinyl Technology- Air bladders
• -McMaster-Carr- UHMWPE Sheets
• Assembly
• -Cut sheets
• -Thermal Molding
• -Attach Bladders chemical- adhesive
• mechanical-
  slot lock
• thermal-
  melting
• Mechanical Testing
• Simulate injection molding
• Load testing (MTS Machine)
• Braces for hand/ ankle

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Vinyl Technology Air Bladders
http//www.vinyltechnology.com/face.php?Cmedical
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Ankle Design
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Knee Design
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Arm Design
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Concerns

• Damaged device
• Collapse
• Bladder explosion
• Possible reduction in image quality
• Material in path of imaging vector
• Engineering heuristics
• Conform to what is currently in service

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Cost Analysis Budget and Justification

• Materials
• Few materials required
• 3 UHMWPE sheets
• Polyethylene foam
• Polyurethane-nylon bags
• compressor
• Companies
• McMaster-Carr
• Campmor
• AC Delco

• Budget
• Approximately 300
• Testing Facilities
• BME student Lab
• Manufacturing Lab
• Resources
• Dr. Bledsoe
• Dr. Barnett
• Dr. Matt Stadnyk
• BME Department
• Saint Louis University

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Cost Analysis
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Timeline Plan of Action

• January 22nd
• Order materials
• February 19th
• Prototype assembly completed
• March 5th
• Begin MTS testing
• March 26th
• Collect results
• Adjust prototype if necessary

• April 9th
• Testing at St. Josephs with patient specs
• April 23rd
• Evaluate testing
• Begin writing final report
• May 5th
• Poster and report completed

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Timeline
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References

• 1. RERC National Design Competition.
  http//www.rerc-ami.org/rerc-ami/
• 2. Position Perfect. http//www.contourfab.com/
• 3. MEDTEC. http//www.medtec.com/products/immobili
  zation/
• 4. CFI Medical Solutions. http//www.contourfab.co
  m/NPAs/MedVac20System.pdf
•  
• 5. Wrap Around Coils. http//www.medical.toshiba.c
  om/clinical/radiology/15texcelart-125-130-411.htm

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Questions