FINGER PLETHSYMOGRAPH TO MEASURE BLOOD RESISTIVITY-BIOMEDICAL PROJECTS

SUMMARY ABOUT THE PROJECT

Impedance plethysmography can be used to measure arterial volume change that occurs with propagation of the blood pressure pulse in a limb segment. For this measurement, we assume a constant value of blood resistivity.

However, blood resistivity may change under both physiological and pathological conditions. Use of an impedance plethysmograph on a finger immersed in a saline filled beaker may yield a method for determining this change in blood resistivity.

This may develop into a method that diabetics can use to measure glucose levels non-
invasively.  The goal of our project is to design a finger plethysmograph to measure blood resistivity.

PROBLEM STATEMENT
Our goal is to design a finger plethysmograph to measure blood resistivity.  In order to
accomplish this, we will need to design and build a data acquisition device to acquire the signal
from the finger.

The device should mechanically immobilize the test subjects’ finger such that motion artifacts are kept to a minimum.

This device should be able to detect the electrical potential (voltage) change across the finger so that the change in resistance may be determined.
It should be able to detect the velocity-dependent change in blood resistivity due to arterial blood pulsations.
In addition, we will need to build an electrical circuit to perform signal processing and
analysis.  This circuit should be capable of rectifying the alternating current (AC) signal from the finger data acquisition device and modulate it into a direct current (DC) signal to be analyzed.  The circuit should be capable of discerning or visually displaying the voltage changes caused by correlated changes in blood resistivity.

As an added feature, this circuit may contain an automatic reset function capable of adjusting one of the differential amplifier inputs to that of the output from the data acquisition (finger holder) device.

This will allow the device to easily accommodate fingers having different electrical resistances and will prevent having to manually adjust voltages using a potentiometer to match independences with each new test subject or finger position.

DOWNLOAD THE COMPLETE PROJECT REPORT FROM HERE

LINK 1

Related articles by Zemanta

• Biopotentials (slideshare.net)