peak inspiratory and expiratory flow meter team: andrew eley, sarah offutt, darshan patel, eric...
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Peak Inspiratory and Peak Inspiratory and Expiratory Flow Meter Expiratory Flow Meter
Team:Team:
Andrew Eley, Sarah Offutt, Darshan Patel,Andrew Eley, Sarah Offutt, Darshan Patel,
Eric BaderEric Bader
BME 200/300BME 200/300
December 2, 2005December 2, 2005
Client:Client:Christopher G. Green, MDChristopher G. Green, MD
Pediatric Pulmonology Pediatric Pulmonology UW HospitalUW Hospital
Advisor:Advisor:John Webster, Ph.D.John Webster, Ph.D.
Dept. of Biomedical EngineeringDept. of Biomedical EngineeringUniversity of WisconsinUniversity of Wisconsin
AbstractAbstract A device for measuring both peak inspiratory A device for measuring both peak inspiratory
and expiratory air flow in a single device is and expiratory air flow in a single device is desired. It will help prevent the misdiagnosis desired. It will help prevent the misdiagnosis of vocal chord dysfunction as asthma. A of vocal chord dysfunction as asthma. A prototype was built to measure these air prototype was built to measure these air flows. The design is a clear plastic tube that flows. The design is a clear plastic tube that contains a plunger which pushes the indicator contains a plunger which pushes the indicator arrows depending on the air flow. The device arrows depending on the air flow. The device was calibrated and tested with a rotameter. was calibrated and tested with a rotameter. Future work includes manufacturing of better Future work includes manufacturing of better parts, obtaining a patent, and marketing for parts, obtaining a patent, and marketing for use. use.
Problem StatementProblem Statement The goal of this project was to create a The goal of this project was to create a
peak inspiratory and expiratory flow meter peak inspiratory and expiratory flow meter in a single device. Peak expiratory flow in a single device. Peak expiratory flow meters are used to monitor asthma and meters are used to monitor asthma and measure flows of about 700 liters per measure flows of about 700 liters per minute. Vocal chord dysfunction, which minute. Vocal chord dysfunction, which causes stenosis of air passages during causes stenosis of air passages during inspiration, is often misdiagnosed as inspiration, is often misdiagnosed as asthma. Having a peak inspiratory and asthma. Having a peak inspiratory and expiratory flow meter in one device can expiratory flow meter in one device can help prevent a misdiagnosis of a patient’s help prevent a misdiagnosis of a patient’s condition. condition.
BackgroundBackground
Asthma Asthma – Exhaling, air restrictions in Exhaling, air restrictions in
the lower airwaysthe lower airways– Caused by external triggersCaused by external triggers– Treated with medicationsTreated with medications
Vocal Chord DysfunctionVocal Chord Dysfunction– Inhaling, air restrictions Inhaling, air restrictions
caused by vocal chordscaused by vocal chords– Possible causes, exercise, Possible causes, exercise,
nervousnessnervousness– Treated with speech Treated with speech
therapytherapy
Background/Current MethodsBackground/Current Methods
Expiratory Flow Meters, Expiratory Flow Meters, use to monitor asthmause to monitor asthma– Exhaling force moves Exhaling force moves
plungerplunger– PortablePortable– Measured in Measured in
Liters/MinuteLiters/Minute– Breathing ZonesBreathing Zones
Inspiratory Flow MeterInspiratory Flow Meter– Inhaling force moves Inhaling force moves
plungerplunger– PortablePortable
Proposed DesignProposed Design
Design CriteriaDesign Criteria– Combination Combination
expiratory-inspiratory expiratory-inspiratory flow meterflow meter
– Measure peak flow rates, 700 L/min expiratory, 400L/min inspiratory
– Simple device using Simple device using springs and diskssprings and disks
– No use of electricityNo use of electricity– Safe – clear plasticSafe – clear plastic
Altered DesignAltered Design
Prototype DesignPrototype Design
How it worksHow it works– Dual ActionDual Action
Inhaling/ExhalingInhaling/Exhaling
– Plunger pushes Plunger pushes Indicator ArrowsIndicator Arrows
– Springs balance the Springs balance the force on the plunger force on the plunger caused by the caused by the pressure differencepressure difference
– Scale on the side for Scale on the side for reading reading measurementmeasurement
Testing and CalibrationTesting and Calibration
Used a rotameter Used a rotameter to calibrate and to calibrate and test the inspiratory test the inspiratory and expiratory and expiratory flows.flows.
ResultsResults
Peak Inspiratory Flow Calibration Curve
y = 0.1708e0.009x
R2 = 0.996
0
1
2
3
4
5
6
7
0 100 200 300 400 500
Flow (L/min)
Dis
tan
ce T
rave
rsed
(cm
)
Results Cont.Results Cont.Peak Expiratory Flow Calibration Curve
y = 0.5213e0.0093x
R2 = 0.9782
0
1
2
3
4
5
6
7
0 50 100 150 200 250 300
Flow (L/min)
Dis
tan
ce
Tra
ve
rse
d (
cm
)
Project ExpensesProject Expenses
Our Device --- Our Device --- MaterialsMaterials– Clear plastic tube Clear plastic tube
$1.97$1.97– End caps - plunger End caps - plunger
$1.96$1.96– Solid metal rod Solid metal rod $0.82$0.82– Connecting rodConnecting rod $0.30$0.30– Springs Springs $0.00$0.00
$5.05
Estimated Cost with
Manufactured parts
$4.50
Future WorkFuture Work Device made from machined parts with Device made from machined parts with
higher quality materialshigher quality materials– Indicators, plastic covering, Indicators, plastic covering,
removable mouthpieceremovable mouthpiece
Replacement with a new set of springs Replacement with a new set of springs to obtain a sufficient range with a linear to obtain a sufficient range with a linear relationship.relationship.
Add breathing zone indicators to show Add breathing zone indicators to show acceptable values for peak inspiratory acceptable values for peak inspiratory and expiratory flow.and expiratory flow.
Future Work Cont.Future Work Cont.
Calibrate device with a more accurate Calibrate device with a more accurate method and with multiple trials.method and with multiple trials.– Rotameter proved to be insufficient.Rotameter proved to be insufficient.
Possibly apply for a patent and find a Possibly apply for a patent and find a company to manufacture this device company to manufacture this device for commercial use.for commercial use.
ReferencesReferences Allen, James MD. (2002). Allen, James MD. (2002). Vocal Cord DysfunctionVocal Cord Dysfunction. Retrieved . Retrieved
October October 2, 2005, from2, 2005, fromhttp://home.columbus.rr.com/allen/http://home.columbus.rr.com/allen/
vocal_cord_dysfunction.vocal_cord_dysfunction.htm.htm.
American Lung Association. (2005, July). American Lung Association. (2005, July). Asthma in Adults Asthma in Adults Fact Fact SheetSheet. Retrieved October 2, 2005, from. Retrieved October 2, 2005, from
http://www.lungusa.org/site/pp.asp?http://www.lungusa.org/site/pp.asp?c=dvLUK9O0E&b=22596.c=dvLUK9O0E&b=22596.
Framingham School. (2005, June). Framingham School. (2005, June). Framingham School Health Framingham School Health Services: Asthma. Services: Asthma. Retrieved October 2, 2005. fromRetrieved October 2, 2005. fromhttp://www.framingham.k12.ma.us/schoolhealth/http://www.framingham.k12.ma.us/schoolhealth/
health_info/health_info/Asthma.htm.Asthma.htm.