Peak Inspiratory and Expiratory Flow Meter Team Andrew Eley Sarah Offutt Darshan Patel Eric Bader BME 200 300 December 2 2005 Client Christopher G Green MD Pediatric Pulmonology UW Hospital Advisor John Webster Ph D Dept of Biomedical Engineering University of Wisconsin Abstract A device for measuring both peak inspiratory and expiratory air flow in a single device is desired It will help prevent the misdiagnosis of vocal chord dysfunction as asthma A prototype was built to measure these air flows The design is a clear plastic tube that contains a plunger which pushes the indicator arrows depending on the air flow The device was calibrated and tested with a rotameter Future work includes manufacturing of better parts obtaining a patent and marketing for use Problem Statement The goal of this project was to create a peak inspiratory and expiratory flow meter in a single device Peak expiratory flow meters are used to monitor asthma and measure flows of about 700 liters per minute Vocal chord dysfunction which causes stenosis of air passages during inspiration is often misdiagnosed as asthma Having a peak inspiratory and expiratory flow meter in one device can help prevent a misdiagnosis of a patient s condition Background Asthma Exhaling air restrictions in the lower airways Caused by external triggers Treated with medications Vocal Chord Dysfunction Inhaling air restrictions caused by vocal chords Possible causes exercise nervousness Treated with speech therapy Background Current Methods Expiratory Flow Meters use to monitor asthma Exhaling force moves plunger Portable Measured in Liters Minute Breathing Zones Inspiratory Flow Meter Inhaling force moves plunger Portable Proposed Design Design Criteria Combination expiratory inspiratory flow meter Measure peak flow rates 700 L min expiratory 400L min inspiratory Simple device using springs and disks No use of electricity Safe clear plastic Altered Design Prototype Design How it works Dual Action Inhaling Exhaling Plunger pushes Indicator Arrows Springs balance the force on the plunger caused by the pressure difference Scale on the side for reading measurement Testing and Calibration Used a rotameter to calibrate and test the inspiratory and expiratory flows Results Results Cont Project Expenses Our Device Materials Clear plastic tube 1 97 End caps plunger 1 96 Solid metal rod 0 82 Connecting rod 0 30 5 05 Springs 0 00 Estimated Cost with Manufactured parts 4 50 Future Work Device made from machined parts with higher quality materials Indicators plastic covering removable mouthpiece Replacement with a new set of springs to obtain a sufficient range with a linear relationship Add breathing zone indicators to show acceptable values for peak inspiratory and expiratory flow Future Work Cont Calibrate device with a more accurate method and with multiple trials Rotameter proved to be insufficient Possibly apply for a patent and find a company to manufacture this device for commercial use References Allen James MD 2002 Vocal Cord Dysfunction Retrieved October 2 2005 from http home columbus rr com allen vocal cord dysfunction htm American Lung Association 2005 July Asthma in Adults Fact Sheet Retrieved October 2 2005 from http www lungusa org site pp asp c dvLUK9O0E b 22596 Framingham School 2005 June Framingham School Health Services Asthma Retrieved October 2 2005 from http www framingham k12 ma us schoolhealth health info Asthma htm
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