The Redesigning of a Pulse Oximeter

1. University of Pittsburgh Senior Design - BioE1160 The Redesigning of a Pulse Oximeter Jeffrey James Sam Audia Ted Askar Thomas Christophel

2. Pulse Oximeter Processor/ Monitor Background • What is a pulse oximeter? • Non-invasive tool for monitoring the percent concentration of • hemoglobin (Hb) saturated with oxygen.

3. Light to Frequency Converter CPU Digital Display Background How does a pulse oximeter work? • Source sends two wavelengths of light (red, 600-700nm, and infrared 850-1000nm) through an appendage • The Hb absorbs red light while O2Hb absorbs infrared light • Photodiode measures LED intensities • A processor calculates the absorbance ratio which is then used to determine oxygen saturation 3 Photodiode 2 IR LED VR LED 4 1 LED Driver Townsend et al.

4. Specific Aims • 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. • Test ability of prototype to adhere to surfaces under different conditions via volunteer based testing.

5. 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

6. 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.

7. Pulse oximeter Design Sketch Adhesive

8. 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

9. 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

10. 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

11. Updated Task List

12. 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

13. Schedule (Gantt Chart)

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

15. Recent Successes • Background research • Conceptual model adopted • SBIR rough draft • Experimental design protocol • Some parts acquired

16. Thank you Questions?