Transcript No Slide Title

Instrumented Hand Exerciser to Promote Fistula Maturation
Brian Ginter, Patrick Kurkiewicz, Matt Hoffman, and David Leinweber
Client: Alexander S. Yevzlin, M.D.
Advisor: John Webster, Ph. D.
Early Testing
Abstract
Everyday, thousands of people undergo
dialysis treatment, an artificial filtering
of the blood.
In order to make
extracting a patient’s blood easier, a
fistula is formed by surgically attaching
two blood vessels in the arm. To help the
fistula mature, an ordinary stress ball is
used to exercise the hand and promote
blood flow. Our client has presented us
with the task of creating a device to
record data regarding a patient’s post
surgery exercise regimen. He will then
use that data to determine what the ideal
plan is for a dialysis patient.
The piezo-buzzer (shown at right) was obtained for
its piezoelectric element, which emits a voltage
signal proportional to applied pressure. One of our
preliminary designs involved the configuration of
piezoelectric devices inside of a ball. However, upon
attempting to harvest the piezoelectric element from
the buzzers, we found them to be extremely fragile
and therefore unsuitable for use in a device such as
ours.
Figure 1: The type of
fistula that the stress
ball can be used to
strengthen. (image from
a)
-Must withstand 30-60 minutes of squeezing every day
-Device should be accurate within 5% of actual pressure value
- Bulb must remain air tight for at least one month at a time
-Device should fit into a wide variety of people’s hands and be
squeezable for all hand strengths
Cost of Materials
Material
Cost
Voltage Pressure Transducer
$60
IOPI Bulb
$4.95
Polyurethane Stress Ball
$0.92
TOTAL
$65.87
b)
Upon receiving the pressure transducer, we found that it
interfaced perfectly with our air bladder and formed an airtight
seal necessary for accurate readings. We then set up a basic
experiment to obtain a calibration curve for the pressure
transducer. This was done by hooking up a blood pressure cuff
(and the attached pressure gauge) to the transducer with the use
of a T valve. By squeezing the blood pressure bulb we could
apply a measurable amount of pressure to the transducer and
read the voltage output from the digital multimeter.
Problem Definition
Design Criteria
b)
Figure 2: Piezoeletric buzzer, found to be unfit for
our project
seejanenurse.wordpress.co
m/2007/10/12/av-fistula/ )
Statement
-Develop a hand exerciser capable of recording the frequency and
intensity of squeezes exerted on it
Motivation
-To prove the concept of making a ball that is self contained and
provides the patient and physician with information regarding ball
use is possible
Why make more than just a stress ball?
-Patients are not going to log their own squeeze data.
-There is no strict quantitative information on how much
squeezing is necessary to mature a fistula
-A feedback system to tell patients if they are squeezing long/hard
enough would prove quite useful
a)
Figure 6: Prototype as currently assembled.
Conclusions
Through testing, it was shown that our prototype is capable of
recording the intensity and frequency of squeezes. With
additional funding and work, our prototype can be refined into a
product for use in researching an ideal exercise regimen for
dialysis patients.
Figure 3: Early testing of transducer in lab setting.
Final Design: Progress and Results
Final Design
-Made of Polyurethane foam
-Senses pressure with a voltage pressure
transducer
-Utilizes an IOPI bulb
-Runs on 5V DC current
-Costs $ 65.87
Figure 4: Output voltage vs. time while using the hand exerciser (graph
b)
a)
from LabVIEW).
Testing and Validation
•Runs off of LabView to create:
-Graph of voltage output vs. time
The pressure (mm Hg) of a given squeeze is
determined with the use of the equation
Voltage=.0005*(Pressure) + .5
-Graph of Amplitude vs. Frequency
The number of squeezes per given time
frame is determined by the integration of
the amplitude vs. frequency graph.
Future Work
-Make device self contained
-Printed circuit
-Battery
-Housing for circuitry
-Output data from device
-Output through USB cable
-Be able to output data in graphical form
-Tables
-Graphs
-Recording information
-How much memory is needed
-Test other programs besides LabVIEW
-On/Off switch
-Test other material
-Finalize shape and dimensions of device
Acknowledgments
The authors would like to thank John Webster, L. Burke
O'Neal, Alexander Yevzlin and Amit Nimunkar for their
continual help throughout the design process.
Figure 5: Corresponding frequency graph for Figure 2. Shows
frequency of squeezes during 10 second testing period (graph from
LabVIEW).