Patient Positioning Aid

1. Patient Positioning Aid Eduardo Vargas Emmanuel Kordieh Mikhail Britan October 28, 2005

2. Outline • Background • RERC 2005-2006 • Imaging technologies: MRIs • Essential in understanding our project • Current methods of approach • Our Design • Design Alternatives • Specifications • Protocol

3. Background • RERC 2005-2006: • Aim:Versatile, low-cost, easy-to-adjust patient positioning aid that works with a range of examination table…and meets the customer needs below. • Patients with disabilities • Do not necessarily lack access; however, current conditions make it very difficult for the user and therapist/clinician to perform proper examinations.

4. Patient Specifications • Bruce • Renal failure, manual wheelchair • Joan • Heart failure, old, weak, hard of hearing • Lloyd • Type II Diabetes, overweight • Sophia • On heparin, limited right arm function, uses a cane • Arnold • Parkinson’s, Diabetes, suffers from slight to moderate tremors • Dave • Limited use to right arm and leg, may use a scooter.

5. Imaging Technologies • Magnetic Resonance Imaging • Magnet • Measured in tesla or gauss (1 tesla = 10,000 gauss) • Common modern-day use: 0.5-2.0 tesla (5,000-20,000 gauss) • Comparison: Earth = 0.5 tesla • 3 major kinds of magnets are used: • Resistive • Very expensive to operate • Permanent • Weight to magnetism ratio is inefficient. • Superconducting (most common) • Wire through which current passes is bathed in liquid helium 452.4 degrees below zero. • Achieve the full range of 0.5-2.0 tesla • Gradient magnets (3) are used to maintain a variable magnetic field (18-27 millitesla) • Imaging is obtained through the variance in magnetic fields.

6. Imaging Technologies • No Metals – can become dangerous projectiles. • Paperclips, pens, stethoscopes, IV poles, etc. • Magnetism increases exponentially as distance decreases. • No metal internally! • Pacemakers • No metal in eyes • Dental implants • Aneurysm clips in the brain

7. Imaging Technologies • Magnetic Resonance Imaging • Resonance • Radio frequency (RF) • Comparable to that of many small radio stations (15-20kW) • Specific to hydrogen atoms, causing them to spin, thus creating ‘resonance’. • Imaging • Achieved by varying the magnetic fields in combination to shutting off the RF. • Hydrogen atoms return to their natural state, giving off a signal picked up by the coil. • This is sent to the computer and converted into an image via Fourier transform; thus, create the ‘imaging’ component.

8. Drawbacks to MRIs • Many people that cannot be scanned (i.e. pacemakers, too big) • Certain people (our patients) have extreme hardship for testing. • Claustrophobia comes into play. • Machine makes tremendous amounts of noise (earplugs, headphones) • Patients must remain very still for the entire duration (~ 20-90minutes) • Slight movements can/will distort the image and thus will have to be repeated. This is due from a patient merely swallowing during time of treatment. • Expensive equipment = expensive examinations!!!

9. What’s the purpose of MRIs? • Non-invasive • Patient is given the ability to be diagnosed and tested for: • Multiple sclerosis • Tumors (pituitary glands & brain) • Infections • Torn ligaments (wrist, knee, ankle) • Shoulder injuries • Tendonitis • Strokes in the early stages • Bone tumors, cysts, and bulging or herniated discs • Imaging can be done in any plane (achieved by the gradient magnets).

10. Are you claustrophobic?

11. X-Ray Machine Imaging Technologies Photons are emitted from tungsten Are absorbed by denser bone tissue

12. Imaging Technologies CAT-Scan • Uses the same technology as conventional X-ray machine • Soft tissue can be observe

13. Extremely basic Not patient specific. Often times this system fails = movement of patient = re-administrating of the MRI. Current Methods of Approach

14. Key to Success • Integration of old with the new

15. Our design • Bed-topper mattress • Initially filled with air • Patient lays down • Beads contour body • Deflation occurs • Contour stays as a solid entity • Clinician allows air back into the system • Ready for the next patient

16. Alternative designs – Air Flotation Device • Air flotation mattress with automatic sensor. • Determines body weight and position and molds mattress accordingly. • Firmness adjustable from ultra soft to super firm. • Internal computer continuously monitors firmness level. • Solid state sensor adjusts individual air tubes for degree of support at pressure points. Standard hospital bed sizes. • Damask or vinyl cover.

17. A closer look 1) 2) 3) 4)

18. 220kg person = 1078Pa 127mbar = 12954Pa112mbar = 11424Pa ●Virtually maintenance-free operation in continuous duty service  ●Quiet operation; as low as 75 dB(A) ● Compact, lightweight design● Handles vacuum and/or pressure applications.

19. Foam – Alternative Design Foam Mattress Pad • Laminar 

20. Types of Foam • Open cellular • interconnected pores or cells and are suitable for filtration applications • Closed cellular • Closed cellular foams do not have interconnected pores or cells, but are useful for buoyancy or flotation applications • Flexible • Flexible foams can bend, flex or absorb impacts without cracking or delaminating • Rigid • Rigid foams feature a matrix with very little or no flexibility • Reticular • Reticular foams have a very open structure with a matrix consisting of an interconnecting network of thin material strands • Syntactic • Syntactic foams consist of rigid microspheres or glass micro-balloons held together by a plastic or resin matrix

21. Foam Specifications Average weight has 0.9-1.0 support pressure PSI

22. Flexible Foams • High-Resiliency (HR) • Mostly used commercial • Standard Urethanes • Natural Latex Foam • Visco-Elastic • Memory Foam • Creates a warmer sensation • Contours to the shape of anything

23. How do you determine foam density? • Density is just how much a piece of foam weighs per unit area. • What is the ILD? - The ILD stands for Indentation Load Deflection. - It's the number that really refers to the firmness of a piece of foam.

24. Mechanical properties that we should know • Bulk density • depends upon the theoretical density of the foam and its actual porosity after packaging • Tensile strength • of stress required to fail or break the foam under tension loading conditions. • Tensile modulus • is a material constant that indicates the variation in strain produced under an applied tensile load • Elongation • the percent deformation occurring during a tensile or other mechanical test • Thermal conductivity • Dielectric strength

25. Materials – Pros & Cons

26. Coverings • Naugahyde • A vinyl-coated, waterproof and durable fabric. • Nylon/Sailcloth • Also known as para-pak. A smooth, silky nylon material. • Knit • A stretchy woven materialóused. • Lycra/Neoprene • Similar to double-knit material; however, it has a laminated rubber backingósimilar to wetsuit material. • Shelterite • A vinyl-coated fabric, waterproof and durableósimilar to naugahyde except that it has a ridge texture. • Cordura • A woven-like nylon material with breathability. • Darlex/Dartex/Darflex • A four way stretch fabric that is water resistant and breathable.

27. Protocol – Where we’re headed Choosing our design • Meet with: • Dr. Wagshul, Head of Radiology Department – Stony Brook University • Mrs. Metzger, Head Nurse Stony Brook Hospital • Explore material properties under imaging environments.

28. References • http://electronics.howstuffworks.com/mri2.htm • http://www.magmedix.com/products/positioning/vertebral_positioning.html • Invest Radiol. 1992 Dec;27(12):1005-8.Related Articles, Links • Effect of prone versus supine patient positioning on pelvic magnetic resonance image quality. http://www.abledata.com/abledata.cfm?pageid=19327&top=13012&deep=2&trail=22,12999,13008 http://www.emedicine.com/pmr/topic179.htm http://electronics.howstuffworks.com/mri11.htm http://www.freedomdesigns.com/info_catalog_page114.html http://www.adaptivemall.com/versaformplus.html http://www.sunmatecushions.com/select.htm http://www.seatingdynamics.com.au

29. Any questions? Brainstorming Begins…