Transcript The Redesigning of a Pulse Oximeter University of Pittsburgh Senior Design - BioE1160

University of Pittsburgh
Senior Design - BioE1160
The Redesigning of a
Pulse Oximeter
Jeffrey James
Ted Askar
Sam Audia
Thomas Christophel
Background
What is a pulse oximeter?
• A simple non-invasive tool for monitoring the percentage of
hemoglobin (Hb) which is saturated with oxygen.
Processor/ Monitor
Pulse Oximeter
Background (cont)
How does an oximeter work?
• Light source originates from a LED at two wavelengths (650nm
and 805nm).
• The light is partly absorbed by hemoglobin.
• A processor calculates the absorption at the two wavelengths
and determines O2 concentration.
Finger
LED’s
Monitor
Receiver
98%
70%
76%
81%
85%
88%
90%
93%
95%
Blood vessel
Background (cont)
General Limitations
• The oximeter is dependant on pulsatile flow and would
be unable to function when flow is sluggish (i.e.
during vasoconstriction)
• Oximeters give no information about the level of CO2
• Accurate at oxygen saturations of 70 to 100% (+/-2%),
but less accurate under 70%…. Under 70% is fatal.
et, al. Fearnley
Overview
Product
• A pulse oximeter with replaceable adhesive.
• Alleviates problems involved with maintaining proper positioning of
the device.
Intended solution
• Design will be based upon current disposable pulse oximeters, but
will incorporate a reusable sensor and replaceable adhesive.
Audience
• Intended for patients using current pulse oximetry devices,
specifically those who experience difficulties keeping the device
positioned properly.
Project Goals
• Design cost effective pulse oximeter that
maintains accuracy of current designs
• Design universal adapter to integrate
replaceable device into current electronic
monitoring systems
• High level timing goals
• Research
• Design
• Prototyping
Existing design problems
• No universal connectors
• Disposable pulse oximeter
• costly
• Clip/ Rubber slip
• unstable attachment
• only for the finger
• Alarm
• not discernable between situations
Design Alternatives
• Removable adhesive
• Universal connectors
• Different alarm sounds for different situations
Features & Benefits
• Replaceable Adhesive
• Cost effective alternative to current disposable models
• Maintains ability of disposable adhesive models to stay in
place
• Can be used on a variety of body parts
• i.e. finger, toe, nose, forehead, or earlobe
• Increased versatility
• Universal Adapter
• Can be integrated into electronics already in use
Professional Sketch
Adhesive
Pulse oximeter
Universal Connecter
Competitive Analysis
• Competitors
• Nellcor
• Disposable pulse oximeters
• Costly due to nonreusability
• Nonin, Minolta, BCI
• Finger tip pulse oximeter
• Portable
• Costly ($300+)
Competitive Analysis (cont.)
• Redesign Strengths
• Inexpensive
• Reusable
• Multiple attachment sites (nose, ear, etc…)
• Weaknesses
• Disposable adhesive (additional purchases)
Modeling Strategy
• Modeling and Analysis
• Solidworks
ANSYS
• LabView
Pspice
Matlab
Team/Resources
• Four highly skilled undergrads
• Modeling and analysis software
• Electronic equipment (breadboard, voltmeter,
oscilloscope, etc…)
• Locations/Support
• St. Margaret’s Hospital (Mrs. Gartner)
• The University of Pittsburgh (BEH B69)
Schedule (Gantt Chart)
Task List
Group Members
Jeffrey James
Tasks
Subtasks
Design/
Modeling
Ted Askar
Sam Audia Tom Christophel
Circuitry/
Prototype Testing
Research
Virtual Testing
Conceptual Design
Acquire parts
Current Devices/
Components
ANSYS
Modeling Device/ Adhesive
Assembly
Costs
Lab View
Hazards
Pspice
Finished Model/ Rapid Prototype Pilot Testing
Current Completions
• Design History File
• Product Design Specification
• Objective Tree/ Functions-Means
Analysis
• Initial Hazard Analysis
• Fault Tree Analysis
• FMEA
• Meeting with Mrs. Gartner
• Obtained 2 pulse oximeters
• Gantt Chart
Acknowledgements
Senior Design - BioE1160
Dr. Gartner
Mrs. Gartner
Funding: The University of Pittsburgh
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