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

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

Background How does a pulse oximeter work? Light to Frequency Converter CPU Digital Display LED Driver VR LED IR LED Photodiode 1. Source sends two wavelengths of light (red, nm, and infrared nm) 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 Townsend et al.

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.

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

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.

Adhesive Design Sketch Pulse oximeter

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

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

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

Updated Task List AudiaJamesAskarChristophel ResearcherModelerManufacturerPrototype Tester Research the potential hazards. Conceptual designCircuit 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)

Semester Goals 1.Research potential hazards Sensor designs Types of adhesives 2.Design an inexpensive reusable sensor that maintains accuracy of current competitors a disposable adhesive that maintains proper positioning on finger 3.Prototyping Construct prototype Preliminary testing versus current fully disposable models

Schedule (Gantt Chart)

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

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

Thank you Questions?