Transcript Document

School of Biomedical Engineering, Science & Health Systems
BIOMEDICAL SIGNALS & SYSTEMS RESEARCH
Impedance Cardiography for Non-invasive Monitoring of Hemodynamics
Impedance cardiography (ICG) is a safe, affordable, non-intrusive, and
non-invasive technology that has special significance in its application to
monitoring of the heart. As a cardiac diagnostic tool, this technology
measures continuously any electrical impedance changes that occur
throughout the thorax in response to changes in blood flow resulting
from each and every heartbeat.
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Gastroscope Non-invasive Monitoring of Gastric Contractility
The Gastroscope is proposed as the only non-invasive
system for measuring and monitoring the myoelectrical
activity of the stomach. This will be achieved by placing
electrodes on the abdominal surface and recording the
signals preceding gastric activity. The Gastroscope is
designed specific to this task and will incorporate electronic
components for extracting and manipulating pre-determined
frequency components of importance. The system will be
programmed for signal processing techniques and
mathematical computations for revealing specific information
visually to a medical professional operating the device.
3.3 cpm
12 dB
fEGG= 27 dB
POWER
MENU
E
Faculty: Dr. Hun H. Sun, Ph.D., Drexel University; Dr. Han C. Ryoo, Ph.D., Drexel University.
Collaborating Researchers: Dr. Ata Akin, Ph.D., Drexel University.
WWW.BIOMED.DREXEL.EDU/ResearchPortfolio/
V 2.0 SD [020204]
School of Biomedical Engineering, Science & Health Systems
IMPEDANCE CARDIOGRAPHY FOR NON-INVASIVE
MONITORING OF HEMODYNAMICS
Impedance cardiography (ICG) is a safe, affordable, non-intrusive, and non-invasive technology that has special
significance in its application to monitoring of the heart. As a cardiac diagnostic tool, this technology measures
continuously any electrical impedance changes that occur throughout the thorax in response to changes in blood
flow resulting from each and every heartbeat.
Figure 1 shows two pairs of disposable impedance electrodes
positioned on a patient’s neck and thorax , as well as to an ECG
lead array. The other end of the electrodes are connected to a monitor,
which displays the heartbeat-induced impedance signals, as seen
in Figure 2.
Continuous measurement of these impedance signals makes it possible
to measure, calculate, and monitor the complete cardiac cycle, including
stroke volume, cardiac output, contractility parameters, and total thoracic
fluid status.
Figure 1 - Electrode configuration
Clinical Applications
Out Patient
Chronic Heart Failure
Hypertension
Pacemaker
Dialysis
In Patient
Critical Care
Surgery / Anesthesia
Emergency Care
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Figure 2 - Monitor-displayed impedance
signals
An ICG measures the heart’s mechanical activity in a way similar
to how an ECG measures the heart’s electrical activity. Measurement
of the heart’s mechanical activity is indicated by a change in
impedance over time that results from the heartbeat-induced changes
in blood flow.
The change in impedance over time is indicated as dZ/dt in Figure 3.
Cardiac events are marked as points A, B, C, X, and O on the
impedance
signals in Figure 3. By using advanced signal processing techniques,
these points are localized and integrated into system models (such as
Kubicek or Sramek) to obtain hemodynamic information that can be
used to show cardiac performance.
Figure 3 - ECG phonocardiograph and
impedance signals showing cardiac events
The phonocardiograph signal in Figure 3 indicates the opening and closing of the heart valve, but is not used in the signal
processing.
Faculty/Contact: Dr. Hun H. Sun, Ph.D., Drexel University; Dr. Han C. Ryoo, Ph.D., Drexel University.
E-mail: [email protected]; [email protected]
Collaborating Researchers: Dr. Ata Akin, Ph.D., Drexel University.
Funding: Wantagh, Inc.
Laboratorie: Biomedical Information Technology Laboratory (BITLab).
WWW.BIOMED.DREXEL.EDU/ResearchPortfolio/
V 2.0 SD [020204]
School of Biomedical Engineering, Science & Health Systems
GASTROSCOPE NON-INVASIVE MONITORING
OF GASTRIC CONTRACTILITY
The Gastroscope is proposed as the only non-invasive system for measuring and monitoring the myoelectrical
activity of the stomach. This will be achieved by placing electrodes on the abdominal surface and recording the
signals preceding gastric activity. The Gastroscope is designed specific to this task and will incorporate electronic
components for extracting and
Problem Statement:
manipulating pre-determined
A need for non-invasive monitoring of stomach activity
frequency components of
Ambulatory recording is required
importance. The system will be
Cost of diagnosing gastric motility disorders is high
programmed for signal processing
Follow-up tests are uncomfortable to patients
techniques and mathematical
computations for revealing specific
information visually to a medical
professional operating the device.
Solution = Gastroscope
Components of Gastroscope:
High gain low noise amplifier
Low pass filter
Analog Digital Converter
Digital Signal Processor
Memory
Display
Ports for data transfer
Biomedical
Sensors
Amplifier
Fiter
Memory
DSP
Data Transfer
(PC)
A
D
C
Signal Processing of fEGG:
The acquisition of myoelectrical signals of the stomach are called the
Electrogastrogram (EGG). EGG signals have a dynamic range of 0.01
Hz to 2 Hz (1-120 cycles per minute, cpm). The frequency component
within 2-5 cpm is called the primary/dominant signal while the high
frequency components at the 50-80 cpm are called the fast EGG (fEGG)
fEGG signals are correlated with the peristaltic contractions; hence the
motility.
fEGG signals can be extracted by using a bandpass filter with
appropriate bandwidth
Design of a portable handheld NIR
Breast Cancer Imager
Touchscreen
LCD
3.3 cpm
12 dB
fEGG= 27 dB
POWER MENU
EGG Signal
Primary Signal
3 cpm
Fast Fourier
Transform
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Secondary Signal
50 - 80 cpm
Data Windowing
(1 minute)
Peak Detection
and
Corresponding
Frequency
Butterworth
Filter
Power
Average Power
Display and
Memory
Faculty/Contact: Dr. Ata Akin, Ph.D., Drexel University.
E-mail: [email protected]
Funding: Drexel University, Sanhill, Inc.
Laboratorie: Biomedical Information Technology Laboratory (BITLab).
WWW.BIOMED.DREXEL.EDU/ResearchPortfolio/
V 2.0 SD [020204]
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