peripheral edema sensor

1Peripheral Edema

SensorJovan Popovich

Mike MoellerBiomedical Engineering

2Project Goal

To develop a diagnostic method for testing peripheral edema using impedance analysis

methods

3Presentation Overview

• Background on Edema• Current Assessment Technique• Proposal of Impedance Analysis

• Background of Technique• Related Products/methods

• Overview of Current Project• Testing Methods and Considerations• Challenges• Future Work

4Edema

Edema: excess fluid build-up in the interstitial tissue from homeostatic imbalance

Affects 4.4 Million People in theUnited States

5Causes of Edema

• Congestive Heart Failure• Right Side

• Kidney disease/damage• Loss of protein• High salt concentration

• Liver disease• Drop in albumin level

• Blood Clots and Tumors

6Effects of Edema

• Poor blood circulation• Increased local pressure

• Loss of vessel elasticity

• Painful Swelling• Problems with Constricting Clothes/Shoes

• Difficulty in Walking

7Current Medical Assessment of Edema

• With no diagnostic device for tracking edema levels• Currently it is viewed only as an all-or-nothing symptom

Level

Pitting Edema – Measurement

Rebound Time

1 Barely detectable indentation

skin rebounds immediately

2 Noticeable Indentation 15 seconds for skin to

rebound

3 Deep Indentation 30 seconds for skin to rebound

4 Very Deep Indentation Greater than 30 seconds

8Project Goal: Continuous Physiological Monitor

Provides Physician with a better insight as to when and why a patient’s symptomsare occurring

• Need for a Chronic Edema Sensor• Indication of type of disorder

• Reveal severity of problem

• Reveal triggers and possible causes

• Show what effects medication hashttp://www.data-input.de/media/elektroden-anleitung-fuss.jpg

9Impedance Analysis

• Cell/Tissue have unique Dielectric properties

• Frequency dependent response

• Technique has been used for Biosensing Applications

• Potential for miniaturization and portable devices

10Body Composition Monitor• Determines:

• Total body fat• Skeletal muscle• Resting metabolism • Body mass index

• Uses full body analysis instead of localized tests

11Measurement Setup

• Two Electrode Technique• LCR Meter: integrates both characteristics

• Four Electrode Technique• Requires advanced measurement tool

12Impedance Analysis Equipment

• LCR Meter for preliminary testing• Measurements: 100Hz, 120Hz, 1kHz, 10kHz, 100kHz• Yields resistance values (ohms), and phase angle

• Impedance Analyzer• Measurement signals: up to MHz range• Yields tabulated impedance and phase values• Also can show temperature (ohmic heating)

13Electrodes

• Skin Impedance• Precise impedance characteristics: Zskin-electrode = Zelectr. + Zcont. + Zskin

• Location• Good Contact • Electrode Material

14Overall Testing Considerations

• Electrode Characteristics

• Tissue Analogue Testing• Efficacy/Reproducibility of data

• Trial Testing

15Anticipated Challenges

• Correct Estimation of skin contact impedance

• Interpreting and correlating data to Edema symptoms

• Sensitivity

• Finding participants for clinical trials

16Material Costs

Material PriceHandheld LCR Meter $575

ECG Monitor Electrodes $40

Wire $50

Connectors/clips $10

Gallium 99.99% Pure (40[g]) $100

Weight Scale (BMI capable) $50

Total Cost $825

17Research Schedule

October Further research on Bioelectrical Impedance Analysis methods

November Contact/lead Interface preliminary designDecember Mechanical design and reinforcement of sensors

January Determination of sensor placement for best resultsFebruary Data Acquisition and Interpretation of BIA

March Modifications to test and beginning of patient trials

April Compilation of results and conclusions about overall design

May Finish research report and present results

18Project Summary

• Bioimpedance analysis to measure peripheral edema

• Develop reliable, repeatable testing method• Electrode Design• Signal • Time Course

• Eventually Consideration: portable sensor • Data used for feedback on patient symptom severity and

patient/drug response

19Research Personnel

Advisors/ContactsProf. Mansoor Nasir

• Research Advisor

Prof. Kenneth Cook• Tech. consultant

ResearchersMichael Moeller

• Research mech. design & placement

• Data Collection• Report: background writing

Jovan Popovich• Research further in BIA• Data Interpretation• Report: data plotting, discussion

20References

• http://www-rohan.sdsu.edu/~ens304l/electrodes.jpg• http://www.medicalnewstoday.com/articles/159111.php• http://

www.med724.com/product-p/mmm-2231-pack.htm?site=google_base• http://www.medicinenet.com/edema/page5.htm• http://www.skintact.com/46.0.html

21Questions

22Questions

23Questions

24Questions

25Questions

26Consideration: Sensor Device

27Measurement Setup

Contact Electrodes

Human Subject

Impedance Meter/Analyzer Source Signal