Process Book - Team Hydra

O2Go: Portable Pressurized Oxygen Therapy Device
Jacqueline Bidlack, Megan Hollowell, Madison Lewis and Rachel Little
BMED 2300 Spring 2015

Background ……………………………………………….PG 3
Problem and Goal Identification………………...PG 4
Initial Concepts and Oxygen Therapy………….PG 5
Initial Designs……………………………………………..PG 6
Prototyping…………………………….…………………..PG 7
Final Device……………………….……………………....PG 8
Usability………………………….……………………..…..PG 9
Engineering Analysis……………….…………………..PG 10
Market Analysis…………………………………………..PG 11
References…………………………………..……………..PG 12
Table of Contents

Fixation devices have evolved greatly in the
last 50 years, stemming from the original
external fixation frame designed by Dr.
Gavril Ilizarov in the 1950’s. These external
fixation devices are used on patients who
are undergoing leg lengthening, correction
of bone deformities, or have severe leg
trauma. This procedure has entered the
modern age with digital pin movement
prescriptions given by an orthopedist.
Background
Example of the pin adjustment prescription given to patient [2]
[3]
Leg healing process with the Taylor Spatial Frame [1]

The frame we were given access to was a
pediatric Taylor Spatial Frame, so the main
user we focused on was a young child using
the frame to correct a bone deformity. In
speaking with an orthopedic surgeon, we
found that infections were extremely common
among wearers of this device. This not only
endangers the user’s health and could lead to
hospital stay, but also lengthens the already
long healing process. Our main goals were
chosen to help these children by designing a
device that would reduce the infection rate
and speed the healing time while in the TSF.
Problem and Goal
Identification
Child in pediatric TSF, the frame is
typically worn for 9-12 months [4]
Child born with upper leg bone deformity [5]
Pin site infection [6]
Infections occur in 52% of
patients wearing the device

Our initial ideas focused on improving
the device itself, but we found that
adjustments to the frame alone were
not going to be useful in fighting
infection. We began researching
external infection prevention and
discovered a relatively new treatment
procedure: pressurized oxygen
therapy. This inspired many ideas on
how we could use such a procedure in
conjuction with the TSF.
Initial Concepts
A topical pressurized oxygen tank [7]
Oxygen therapy is a procedure that
uses pressurized oxygen to help
maintain the cleanliness of open
wound sites. With red blood cells being
able to carry 15-20 times the normal
amount of oxygen, white blood cells
are more active and able to keep areas
clean and new blood vessel
connections can be built faster which
increases circulation. It also reduces
swelling, pressure and pain. While this
is a helpful treatment, patients often
have to go to a separate facility to have
it done.
Pressurized Oxygen
Therapy
[8]

We wanted to design a device that could be
worn around the frame that was portable
and sterile. Initial designs were of a two-
banded bubble-like device that would
encircle the leg. Feedback from an
orthopedic surgeon led us to a larger,
stocking shaped device that could also be
used with the TSF foot attachments. This one
-banded concept reduces the air loss and
helps maintain the air pressure within the
device. With this design, the device can be
used with other traumatic open wounds
such as skin grafts and burns.
Initial Designs
Initial concept drawings [9]

The first prototype is made of a canvas
fabric, elastic band with non slip grips
interwoven into the band, hook and eye
closures, plastic tubing (from a pen), and a
zipper. The canvas fabric did keep air within
the device, proving to be windproof, however,
it was very stiff to inflate and uncomfortable.
Although the hook and eyes were adjustable
along the band like a bra strap, it still allowed
for some air to slip in because it was not
completely adjustable to form to the user’s
leg. Furthermore, the elastic did not have
enough stretch, so we searched for a more
elastically resistant band in our next
prototype. The nozzle was represented with a
plastic tube and taped to the device after
cutting a small hole. We were able to blow in
air through this to see how strong the seals
were and how the device would inflate. The
zipper worked well for not allowing a release
in air pressure but also for opening and
closing the device so the user could put it on.
Prototyping
Prototypes and models of
the device and the seal [10]

Our final device prototype consisted of
a stocking made of a windbreaker
material, an elastic band with hook and
loop closures sewn on, a Schrader
valve to input air, and two washers to
anchor the valve onto the sock. The
stocking is pulled on and closed with a
zipper in the back.
In real life production, the stocking
would be made of a 3-layer windproof,
waterproof softshell fabric that is
machine washable to comply with CDC
reusable device guidelines and
maintain cleanliness. The valve is made
of various metals, plastics and a rubber
base. The band is non-roll elastic with
plastic and fabric hook and loop
closures (Velcro). The washers are
nylon.
Final Prototype
Our proto-
type being
inflated [11]
Final SolidWorks rendering [13]
Device in use [12]

Use of the device by the patient would
consist of daily pin cleaning followed
by a timed oxygen treatment in our
device. The time spent in the device
would be prescribed by their
orthopedist according to the severity
of injury and stage of the treatment
process the patient is in.
Usability
Step 1: Patient cleans wound sites daily
with disinfectant and inspects scabs [14]
Step 2: Patient puts on the O2Go device [15]
Step 3: Patient attaches pressurized oxy-
gen tank and fills the device [16]
Step 4: Patient relaxes as the treatment
occurs for the time prescribed [12]
Step 5: Patient cleans the device by
washing it and applying a disinfecting
germicide. [16]

We chose a 3-layer fabric in order to
maintain air pressure and for its
durable qualities. We performed a
failure mode and effects analysis
(FMEA) on this component of the
device because its malfunction was
thought to lead to the most critical
failure of the device and least harm to
the user. [19]
We found the greatest
pressure the device would experience
(2.5x atmospheric pressure at sea
level) and also found the psi strength
of our material. These numbers give us
a very high safety factor, which shows
that there is little chance of failure and
thus harm to the patient.
Engineering Analysis
Greatest Internal Pressure will be 36.74 psi
3 Layer Polyester Windproof and Waterproof
Fabric withstandsup to 217556.55 psi [17]
Safety Factor is 10216.59 (> 2)
[18]

The cost per unit of our device was found to
be $22.14. We predict it would be sold at
$120. The Market Analysis of our device
combines the cost analysis of the
manufacturing process, cost of patent
application and FDA 510(k) premarket
notification, labor, and takes into account a
profit margin.
Because our device falls under the ‘bone
stimulator’ category of devices, cost of the
device to the patient and the oxygen needed
would be covered by insurance. We also
created this device to be reused, and
imagined hospitals lending it our to in or
outpatients who needed it, which reduces
both waste and cost overall. The orthopedic
device market is a growing field, and is
expected to be a hot market in the coming
years, so we believe there is definitely a
market for our device.
Market Analysis
Zipper by bulk of 50 is 11.50 = $0.23 per person
Hook by bulk of 50 yd is 15.50 = $0.31 per person
Loop by bulk of 50 yd is 15.50 = $0.31 per person
Valve by bulk of 50 is 11 = $0.22 per person
Valve head by bulk of 50 is 13.93 = $0.28 per person
Fabric by bulk of 50 yd is 639.50 = $12.79
Total cost when getting in bulk: $14.14
CNC Laser Machine: $3500
Sewing Machines: 3 machines x 50 = $150
FDA: $4960
Patent: $1500
Cost of labor: 8$/hr
5 workers
total cost labor: $320
Make 40/day-> cost of materials -> $565.6
Cost per unit: $22.14
[20]

1. Manner HM, Huebl M, Radler C, Ganger R, Petje G, Grill F. Accuracy of complex lower-limb deformity correction with external fixation: a comparison of the
Taylor Spatial Frame with the Ilizarov ring fixator. Journal of Children’s Orthopaedics. 2007;1(1):55-61. doi:10.1007/s11832-006-0005-1.
2. Smith & Nephew. TSF Nomenclature; 2004. Available at: http://www.smith-nephew.com/documents/nl-tsf-surgicaltechnique. Accessed April 25, 2015.
3. Rubin Institute. Taylor Spatial Frame. image http://www.lifebridgehealth.org/RIAO/TheConcept.aspx. Accessed April 25, 2015.
4. Child in Taylor Spatial Frame. https://lifewithpseudoachondroplasia.files.wordpress.com/2013/03/general-pictures-211.jpg. Accessed April 25, 2015.
5. Orthofix. Pediatrics: Childhood Limb Deformities. http://206.252.132.81/patients/pediatrics.asp. Accessed April 25, 2015.
6. Travis J. Kemp, M.D. Signs and Symptoms of Pin Site Infection. http://kempmd.squarespace.com/pin-site-infection/. Accessed April 25, 2015.
7. OJ Medtech. Topical Hyperbaric Oxygen. http://lymphedema-pump.com/hyperbaric-chambers-new-york-specialists.php. Accessed April 25, 2015.
8. Healing GrapeVine How Oxygen Therapy Works http://www.healinggrapevine.com/recover-now/understanding-your-health/how-oxygen-therapy-
works.html. Accessed April 25, 2015.
9. Team Hydra. Initial Conccept Drawings; 2015.
10. Team Hydra. Prototyping Photos; 2015.
11. Team Hydra. Inflated prototype photo; 2015.
12. Team Hydra and Gallery Images. Child in Device Mock-Up; 2015 http://galleryhip.com/kid-full-body.html. Accessed April 25, 2015.
13. Team Hydra. Final Solidworks Rendering; 2015.
14. Purpledserex. Daily pin site cleaning and Taylor Spatial Frame care; 2011. https://www.youtube.com/watch?v=J3DtFbax40Y. Accessed April 25, 2015.
15. Team Hydra. Device Photo; 2015.
16. Team Hydra. Device in Use; 2015.
17. REI. How Rainwear Works; 2014. http://www.rei.com/learn/expert-advice/rainwear-how-it-works.html. Accessed April 25, 2015.
18. Team Hydra. Final Assembly exploded view SolidWorks; 2015.
19. Roger C. Jensen. Risk Reduction Methods for Occupational Safety and Health Chapter 6.1. Accessed April 25, 2015.
20. BCC Research. Global Market For Advanced Orthopedic Technology.; 2015. Available at: http://www.pddnet.com/news/2014/09/global-market-advanced-
orthopedic-technology-reach-422b-2019. Accessed April 25, 2015.

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