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?
• Non-invasive tool for monitoring the percent
  concentration of
• hemoglobin (Hb) saturated with oxygen.

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Background
How does a pulse oximeter work?

1. Source sends two wavelengths of light (red,
   600-700nm, and infrared 850-1000nm) through an
   appendage
2. The Hb absorbs red light while O2Hb absorbs
   infrared light
3. Photodiode measures LED intensities
4. A processor calculates the absorbance ratio
   which is then used to determine oxygen saturation

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Photodiode
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IR LED
VR LED
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1
LED Driver
Townsend et al.
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Specific Aims

1. Develop a design and a prototype pulse oximeter
   sensor with disposable hypoallergenic adhesive(s)
   that can be shown to be more cost effective than
   current fully disposable models.
2. Test ability of prototype to adhere to surfaces
   under different conditions via volunteer based
   testing.

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Existing design problems

• Current competitor disposable pulse oximeters
• are too costly
• Current competitor reusable pulse oximeters
• have a clip or rubber slip which are very
  unstable attachments
• require repair labor costs
• are very expensive

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Overview

• Product
• A pulse oximeter with replaceable adhesive.
• Alleviate 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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Design Sketch
Adhesive
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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
• Reusable sensor
• Low cost replaceable sensor

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SBIR Experimental Design

• 1. Prototype Development
• develop reusable sensor design
• develop hypoallergenic adhesive to be
  incorporated with reusable sensor
• preliminary testing
• 2. Testing
• Volunteers will test two models
• prototype
• current disposable model
• The following dexterity tasks will be performed
  by both groups
• eating
• walking while attached to monitor
• writing
• Different tasks will be performed in different
  conditions to evaluate effect of perspiration on
  adhesion
• wet
• dry
• Analyze data to determine correlation between
  different factors
• subsequent testing will be developed according to
  results

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Modeling Strategy

• Modeling and Analysis
• Solidworks
• Adhesive modeling
• Reusable pulse oximeter modeling
• LabView
• Create a virtual pulse oximeter processor station
• Matlab and MS Excel
• Data analysis

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Updated Task List
Audia James Askar Christophel
Researcher Modeler Manufacturer Prototype Tester
Research the potential hazards. Conceptual design Circuit design of pulse oximeter Pilot test the new adhesive with pulse oximeter
Research current pulse oximeters (competitors) Model the adhesive with Solidworks Purchase adhesives and pulse oximeters Test new adhesive design verses current models.
Research possible size, type, and shape of adhesives. Model the pulse oximeter with Solidworks Assemble prototype device Perform data analyses of the results
Specific aims (SBIR) Relevant Experience (SBIR) Significance (SBIR) Experimental Design and Methods (SBIR)
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Semester Goals

• Research
• potential hazards
• Sensor designs
• Types of adhesives
• Design
• an inexpensive reusable sensor that maintains
  accuracy of current competitors
• a disposable adhesive that maintains proper
  positioning on finger
• Prototyping
• Construct prototype
• Preliminary testing versus current fully
  disposable models

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Schedule (Gantt Chart)
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Problems

• Research
• Circuit designs not public property
• Final model and virtual testing
• Parts needed
• Fixed budget
• Monitors/sensors expensive

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Recent Successes

• Background research
• Conceptual model adopted
• SBIR rough draft
• Experimental design protocol
• Some parts acquired

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Thank you

• Questions?