Abstract Problem Definition Final Design: Progress and Results Conclusions Acknowledgments 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. 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. 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 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. 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. Final Design -Made of Polyurethane foam -Senses pressure with a voltage pressure transducer -Utilizes an IOPI bulb -Runs on 5V DC current -Costs $ 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. a) b) a) b) a) b) Cost of Materials Early Testing Figure 4: Output voltage vs. time while using the hand exerciser (graph from LabVIEW). Figure 5: Corresponding frequency graph for Figure 2. Shows frequency of squeezes during 10 second testing period (graph from LabVIEW). 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 Figure 6: Prototype as currently assembled. Design Criteria -Must withstand 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 Figure 1: The type of fistula that the stress ball can be used to strengthen. (image from seejanenurse.wordpress.co m/2007/10/12/av-fistula/ ) MaterialCost Voltage Pressure Transducer$60 IOPI Bulb$4.95 Polyurethane Stress Ball$0.92 TOTAL$65.87 Figure 3: Early testing of transducer in lab setting. 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. Figure 2: Piezoeletric buzzer, found to be unfit for our project 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.