Transcript CDR - EDGE

Pressure Sore Alleviation
Device
Senior Design Team P6203
Adam Hagerty
Elizabeth Hampton
Scott Keppel
Brian Phillips
Coordinator: Dr. Elizabeth DeBartolo
Sponsor: Kristen Quinlan, ARC of Monroe
Outline
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ARC of Monroe Overview
What is a Pressure Sore?
Project Needs
Concepts Developed
Design, Analysis, and Build
Budget
Final Product
ARC of Monroe Feedback (1 week of use)
ARC of Monroe Overview
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Organization that has provided care to
mentally/physically disabled patients for many
years
They are looking for a way to relieve pressure
sores on a single patient
Want device to function to eliminate need for
the nursing staff to constantly be disrupting
patient’s sleep for adjustment
Project Team Goals
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Create device to
alleviate pressure
spots on clients body
Make it affordable to
stay within budget
Make it safe and
reliable for all users
(i.e. – Nursing staff
and client)
Problems Discovered
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Client has pressure sores
Client has difficulty sleeping at night
Client is disabled and deaf
ARC doesn’t have effective device to
alleviate pressure sores without constant
supervision
What is a Pressure Sore??
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Develop due to constant pressure on an
area of skin
This reduces blood supply to the area
Causing
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Cell death
Breakdown of the skin
Development of an open sore
Picture Courtesy of www.WebMD.com
4 Stages of a Pressure Sore
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Stage 1 Pressure Sore
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Skin is red or discolored
Redness does not go away
30 minutes after pressure
is removed
Stage 2 Pressure Sore
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Upper layer of the skin is
broken
Creates a shallow, open
sore
Drainage may or may not
be present
Pictures Courtesy of www.WebMD.com
4 Stages of a Pressure Sore
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Stage 3 Pressure Sore
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Break in the skin extends
through the second skin
layer into fat tissue
Wound is deeper than in
Stage 2
Stage 4 Pressure Sore
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Breakdown extends into
the muscle and possibly
down to the bone
Usually lots of dead tissue
and drainage are present.
Pictures Courtesy of www.WebMD.com
1 Part of the Cure
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This device is only one part of the
pressure sore problem
Although this device will alleviate pressure
it will not cure a pressure sore, it is for
prevention only
Healing of a pressure sore is done by two
methods: Proper medical treatment and
proper nutrition
Needs of Project
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Safe for user
Alleviate long-term pressure areas
Stay in budget (<$1500)
Be waterproof
Rotate through position settings
Rotate at intervals
Comfortable to user
Simple user interface
Low/Easy Maintenance (repair)
Power source location
Operate quietly
Control interface location
Specifications
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Sales Price: $1500
Supportable Weight
(max): 300 lbs
Number of times patient
needs assistance during
sleep period due to an
issue with the device: <1
# of Cycle Patterns: 3-5
Duration of Each Cycle
Pattern: 30-60 min
# Of Buttons on User
Interface: 5 max
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Life of Product: 7 yrs
Selectable Duration for
Each Cycle Pattern: 1-3
Size of Mattress (in2):
54”x75”
# of Main Components:
10 max
Distance to User
Interface: 25 ft
Distance to Outlet: 10 ft
Concepts
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Concept # 1 – Air bladder system
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Concept # 2 – Cylinder mechanism
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Concept # 3 – Alternating track system
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Concept # 4 – Hinged mattress
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Concept # 5 – Water bladder system
CONCEPT # 1: AIR BLADDER
CONCEPT # 2: CYLINDER SYSTEM
CONCEPT # 3: ALTERNATING
TRACK SYSTEM
CONCEPT # 4: HINGED MATTRESS
CONCEPT # 5: WATER BLADDER
CONCEPT SELECTION
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CONCEPT # 1: AIR BLADDER
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Based on Pugh analyses
Determined to be best suited for needs
Design Guidelines
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MATTRESS
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3 cycles for alleviation
2 moving cycles
1 stationary cycle
Twin size section
Foam border to fill full
size bed of client
Water proof mattress
cover
Cycles of Alleviation
CYCLE 1
CYCLE 2
CYCLE 3
Air Cell Analysis
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 Worst Case:
Patient Statistics
(300lbs on 5 Tubes)
 W=115lbs.
300lbs.
 H=56in.
P max 
 .893 psi
2
336in.
 Assuming 18in.
wide patient
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Client Case:
300lbs.
P
 .278 psi
2
1008in.
Pump Analysis
Pump usage
 Inflate and deflate 10 air cells
7793.11in.3
in.3
Airflow 
 389.66
20 min .
min .
3
389.66
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3
3
in.
1 ft.
ft.


.
225
min . 12in.3
min .
Pressure (mm Hg)
Pump Pressure (mm Hg)
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45
40
35
30
25
20
15
10
5
0
Patient Weight = 115lbs.
0
50
100
150
200
250
300
350
400
Weight (lbs.)
The air pump must produce .23cfm to properly inflate
the mattress in 20 minutes.
Will use pump from Sentech (110V)
Data Courtesy of www.sentechmedical.com
User Box
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Contains 4 lighted
switches for cycle control
Holds microcontroller,
solid state relays, and
other electrical
components
Enclosure is safe for
electrical devices
Mounts to wall with ease
Pump Box
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Contains switch and power
connection for pump
Holds pump, 2 valves, 2
pressure sensors, and other
electrical components
Again, safe for electrical
devices and easy mounting
capability
Foam Containment
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Foam used to surround and contain air
cells
Foam purchased from
www.efoamstore.com
 Can be made in any shape for any
specific application (aka bedding)
Yellow foam is medium grade
bedding foam
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Medium foam will compress
approximately .75”
Blue foam is firm grade bedding
foam
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Firm foam will compress
approximately .25”
FINAL ASSEMBLY-MATTRESS
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Consists of 4 foam sides, 4
foam inserts, 1 foam base,
and 10 air cells
Electrical Analysis
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The controls are outside of the bedroom
due to customer requirement
4 lighted switches used to control the
cycles
Sense pressure in air tubes
Open valves when the pressure is above
the set level (discussed later)
Sensing Pressure
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Need to sense pressure around
20mmHg (up to 50 mmHg)
This pressure sensor ranges from 0 to
51 mmHg which is perfect for this
application
Controller input needs to switch to high
when at proper pressure
VO-1.5=.09*R (Used this to determine
resistor necessary for proper pressure
switching point)
www.honeywell.com
Comfort Analysis
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Used 20 mmHg as base point for analysis
Adjusted Resistor from 6 ohms to 18 ohms where
maximum comfort was experienced
An 18 ohm resistor gave a voltage of 3.12 volts and an
approximate pressure of 33 mmHg
Voltage vs Pressure Interpolation
V  I * R  2.048V  1.5V  .09 A * R
R  6.09 ohms
60.00
Pressure (mmHg)
50.00
Start
40.00
•Used this calculation to determine
resistor needed to meet comfort
level
End
30.00
20.00
10.00
0.00
0
0.5
1
1.5
2
2.5
Voltage (V)
3
3.5
4
4.5
5
•1.5 V is the high/low trip point for
the controller and .09A is the
current of the controller
Opening Valves
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A solid state relay was used
to open the valves with the
5VDC, 30mA signal the
controller outputs
Relay, when signaled would
allow a 12VDC signal to
travel to the valve
Two relays were used to
control each valve separately
•When 12 VDC is passed
across valve, exhaust port is
opened
•Valve closes when 12 VDC is
removed
•Mattress pressure is regulated
through these valves
Figure Courtesy of www.norgren.com
Electrical Schematic
User Control Box
9V DC
30 min
SW1
45 min
SW2
60 min
SW3
Full Inf late
SW4
12V DC
Microcontroller Interf ace
R4
RL2
0
1
3
5
7
9
11
13
15
17
19
1
2
120
4
3
Solid State Relay
Vss
P0
P2
P4
P6
P8
P10
P12
P14
Vdd
Vss
P1
P3
P5
P7
P9
P11
P13
P15
Vin
2
4
6
8
10
12
14
16
18
20
RL1
R3
1
2
120
4
3
Solid State Relay
Valv e
V2
+
-
+
-
5V DC
Valv e
V1
U2
U1
C1
220nF
R1
18
1
2
3
4
+Vs
Vout
GND
N/C
N/C
N/C
N/C
N/C
5
6
7
8
0
R2
18
+Vs
Vout
GND
N/C
N/C
N/C
N/C
N/C
5
6
7
8
Pressure Sensor
Pressure Sensor
Pump/Valve Box
C2
220nF
1
2
3
4
System Control
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BASIC stamp
microcontroller
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Excellent for small
control applications
Simple programming
language
16 I/O ports for
connections
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This project used 8
ports
System Control
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Pin Assignments
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Pins 0 and 1 were used for pressure sensors
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Pins 3 and 4 were used for valve control
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Pins 10-13 were used for lighted switch
control
System Control
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Depending on switch selected
program will select proper cycle
time (30, 45, 60 minute cycles,
or Full Inflate)
If no switch is selected mattress
will automatically full inflate
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If multiple switches are selected
mattress will choose first switch
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These times are based on count
commands within the program
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To determine the proper count
testing was performed on the
system for each required time.
Cycle Tim e Reliability
Time (minutes)
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61
59
57
55
53
51
49
47
45
43
41
39
37
35
33
31
29
30 Minutes
45 Minutes
60 Minutes
0
2
4
6
Test Run #
8
10
System Control
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Air pump is always on
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System pressure is controlled by valves and pressure sensors
as seen earlier
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When pressure in either cell cycle exceeds 33 mmHg, stamp
input 0 or 1 is signaled to switch to high
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This switch signals input 3 or 4 to switch high, opening the
valve associated with it
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This valve remains open for 5 seconds and then closes
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If cycle calls for valve to be open, input 3 or 4 is left high to
release pressure from the required set of air cells
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Cycles rotate between the 3 patterns until new switch is
selected and old switch is shut off
Budget Overview
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Budget Available = $1500
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Total Cost of Project = $920
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This project was under budget by $580
Final Product
Arc of Monroe Feedback
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Patient is sleeping uninterrupted throughout the
night (4 Nights since installation)
Nursing staff says patient looks comfortable in
mattress system
No problems with mattress system recorded, all
positive feedback!
Recommendations for Future Work
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This device is made specifically for a 115
lb client leaving available the variable user
side of this project
This device is only a prototype, making it
for mass production would be another
area to investigate
Special Thanks
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This material is based upon work
supported by the National Science
Foundation under Award No. BES0527358.
The electrical enclosure for our pump,
valves, and pressure sensors was provided
courtesy of Fibox.
Disclaimer
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Any opinions, findings, and conclusions or
recommendations expressed in this
material are those of the author and do
not necessarily reflect the views of the
National Science Foundation.
References
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[1] www.sentechmedical.com
[2] www.parallax.com
[3] www.efoamstore.com
[4] www.neurocare.com
[5] www.caregiverproducts.com
[6] www.medicalharmony.com
[7] www.medicalproductsdirect.com
[8] www.therohogroup.com
[9] www.sunrisemedical.com
[10] www.invacare-ccg.com
[11] www.medicalsupplis4all.com
[12] www.webMD.com
[13] www.foamorder.com
[14] www.airdimensions.com
[15] www.norgren.com
[16] www.fibox.com
Questions