Process Book - Team Hydra

O2Go: Portable Pressurized Oxygen Therapy Device

Jacqueline Bidlack, Megan Hollowell, Madison Lewis and Rachel Little

BMED 2300 Spring 2015

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

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 withstands up 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.


http://206.252.132.81/patients/pediatrics.asp

http://kempmd.squarespace.com/pin-site-infection/

http://lymphedema-pump.com/hyperbaric-chambers-new-york-specialists.php

http://www.healinggrapevine.com/recover-now/understanding-your-health/how-oxygen-therapy-works.html

http://www.healinggrapevine.com/recover-now/understanding-your-health/how-oxygen-therapy-works.html

http://galleryhip.com/kid-full-body.html

https://www.youtube.com/watch?v=J3DtFbax40Y

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Process Book - Team Hydra