The Redesigning of a Pulse Oximeter

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

• Jeffrey James
• Sam Audia

Ted Askar Thomas Christophel
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Background

• What is a pulse oximeter?
• A simple non-invasive tool for monitoring the
  percentage of
• hemoglobin (Hb) which is saturated with oxygen.

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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
Monitor
Receiver
LEDs
98
95
93
90
88
85
81
76
70
70
Blood vessel
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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

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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.

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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

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Existing design problems

• No universal connectors
• Disposable pulse oximeter
• costly
• Clip/ Rubber slip
• unstable attachment
• only for the finger
• Alarm
• not discernable between situations

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Design Alternatives

• Removable adhesive
• Universal connectors
• Different alarm sounds for different situations

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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

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Professional Sketch
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Competitive Analysis

• Competitors
• Nellcor
• Disposable pulse oximeters
• Costly due to nonreusability
• Nonin, Minolta, BCI
• Finger tip pulse oximeter
• Portable
• Costly (300)

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Competitive Analysis (cont.)

• Redesign Strengths
• Inexpensive
• Reusable
• Multiple attachment sites (nose, ear, etc)
• Weaknesses
• Disposable adhesive (additional purchases)

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Modeling Strategy

• Modeling and Analysis
• Solidworks ANSYS
• LabView
  Pspice
• Matlab

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Team/Resources

• Four highly skilled undergrads
• Modeling and analysis software
• Electronic equipment (breadboard, voltmeter,
  oscilloscope, etc)
• Locations/Support
• St. Margarets Hospital (Mrs. Gartner)
• The University of Pittsburgh (BEH B69)

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Schedule (Gantt Chart)
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Task List
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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

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Acknowledgements

• Senior Design - BioE1160
• Dr. Gartner
• Mrs. Gartner
• Funding The University of Pittsburgh

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• Questions?
• Comments?
• Problems?