Pulse OximeterPulse Oximeter Measuring Oxygen Saturation LevelsMeasuring Oxygen Saturation Levels

Final PresentationFinal PresentationMay 14, 2008May 14, 2008

Tony Succar & Mustapha Tony Succar & Mustapha OkaddiOkaddi

Table of ContentsTable of Contents ObjectivesObjectives BackgroundBackground ProgressProgress ResultsResults ResponsibilitiesResponsibilities TimelineTimeline ConclusionConclusion

ObjectivesObjectives To build a pulse oximeterTo build a pulse oximeter

– To achieve the Oxygen Saturation Level in To achieve the Oxygen Saturation Level in blood by using two LED’s as transmitters blood by using two LED’s as transmitters and a Photodetector as the receiver.and a Photodetector as the receiver.

An algorithm is developed through An algorithm is developed through LabViewLabView

BackgroundBackground The theory of measuring OThe theory of measuring O22 levels in levels in

blood began in the 1930’s.blood began in the 1930’s.– Observe the skin tonesObserve the skin tones

Bluish skin color = Low Oxygen level = Bluish skin color = Low Oxygen level = BADBAD

The Modern Pulse Oximeter was The Modern Pulse Oximeter was invented in 1978 by Dr. William New at invented in 1978 by Dr. William New at Stanford University.Stanford University.– It was a breakthrough that paved the way for It was a breakthrough that paved the way for

medical advances in the years to come.medical advances in the years to come.– Huge impact on prevention of diseases & illnesses.Huge impact on prevention of diseases & illnesses.

Engineering ApproachEngineering Approach

Photodiode

PrinciplePrinciple

By calculating the light absorption of the two By calculating the light absorption of the two wavelengths, the processor can compute the wavelengths, the processor can compute the proportion of oxygenated hemoglobin.proportion of oxygenated hemoglobin.

PrinciplePrinciple

Oxygen saturation level is a direct Oxygen saturation level is a direct function of the following ratio:function of the following ratio:

Stage 1: The beginning…Stage 1: The beginning…

Stage 1 resultsStage 1 results

This setup was not effectiveThis setup was not effective– Numbers were inaccurateNumbers were inaccurate– Data was not stableData was not stable– SpO2 was very low, SpO2 was very low, less than 50%less than 50%

SolutionSolution– Stabilize the Photo DetectorStabilize the Photo Detector

Mount the Photo Detector and LED’s Mount the Photo Detector and LED’s onto the table or onto the same plate.onto the table or onto the same plate.

Stage 2: Improvements Stage 2: Improvements AppliedApplied

Stage 2 resultsStage 2 results New Plastic FixtureNew Plastic Fixture

Numbers were greatly improvedNumbers were greatly improved Much more accurateMuch more accurate Much more stableMuch more stable

However, problems persisted…However, problems persisted… Although much more stable and closer to the expected Although much more stable and closer to the expected

value, still it was not stable enough:value, still it was not stable enough: 60% < SpO2 < 95%60% < SpO2 < 95%

Ambient light would creep in and effect the photosensorAmbient light would creep in and effect the photosensor The pressure on the finger was not stableThe pressure on the finger was not stable

This effects the accuracy of the data.This effects the accuracy of the data.

Stage 2Stage 2 Possible SolutionsPossible Solutions

– Apply constant pressure to the Apply constant pressure to the fingerfinger

– Block all external light sources from Block all external light sources from effecting the photosensor.effecting the photosensor.

Stage 3: Final DesignStage 3: Final Design

Stage 3: Final DesignStage 3: Final Design

LabView Data from Final LabView Data from Final DesignDesign

Results and DataResults and Data Our final design was the best design.Our final design was the best design.

– Data is accurateData is accurate– Numbers are relatively stableNumbers are relatively stable– SpO2 is consistentSpO2 is consistent

90% < SpO2 < 97% 90% < SpO2 < 97%

New clip fixtureNew clip fixture– Applied constant pressure to fingerApplied constant pressure to finger– Blocked all ambient light from effecting Blocked all ambient light from effecting

photosensorphotosensor

Overall, our project was a success!Overall, our project was a success!

ResponsibilitiesResponsibilities Both of us met at the lab many Both of us met at the lab many

times the past several months to times the past several months to build and test the oximeter.build and test the oximeter.

Both of us worked together on the Both of us worked together on the LabView program and simulated it LabView program and simulated it with the oximeter.with the oximeter.

Time LineTime LineID Task Name Start Finish

Feb 2008 Mar 2008 Apr 2008 May 2008

2/17 2/24 3/2 3/9 3/16 3/23 3/30 4/6 4/13 4/20 4/27 5/4 5/11

1 3/5/20082/20/2008Research theory and project background and prepare Report 1

2 3/5/20083/5/2008Report 1 Due

3 3/14/20083/6/2008Develop Labview program

4 4/1/20083/17/2008Carry out experiment

5 4/8/20084/2/2008Prepare oral Presentation 2

6 4/9/20084/9/2008Present Presenation 2 to class(progress, results…)

7 4/15/20084/10/2008Prepare Written Report 2

8 4/16/20084/16/2008Report 2 Due

9 4/25/20084/17/2008Complete experiment, compile data

10 5/6/20084/28/2008Prepare Final Presenation

11 5/14/20085/14/2008Present Final Presentation to classAnd hand in Final Report

12 5/27/20085/15/2008RELAX!

5/18

Any Any Questions Questions

or or Comments?? Comments??