Signal Processing Techniques used for Analysis of Acoustic Signals from Heart and Lungs to

129 Pages·2017·2.57 MB·English

University of Colorado, Boulder
CU Scholar
Electrical, Computer & Energy Engineering
Electrical, Computer & Energy Engineering
Graduate Theses & Dissertations
Spring 4-1-2015
Signal Processing Techniques used for Analysis of
Acoustic Signals from Heart and Lungs to Detect
Pulmonary Edema in 2015
Pratibha Sharma
University of Colorado at Boulder, [email protected]
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Recommended Citation
Sharma, Pratibha, "Signal Processing Techniques used for Analysis of Acoustic Signals from Heart and Lungs to Detect Pulmonary
Edema in 2015" (2015).Electrical, Computer & Energy Engineering Graduate Theses & Dissertations. 108.
https://scholar.colorado.edu/ecen_gradetds/108
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SIGNAL PROCESSING TECHNIQUES USED FOR THE ANALYSIS OF
ACOUSTIC SIGNALS FROM HEART AND LUNGS TO DETECT
PULMONARY EDEMA IN 2015
by
Pratibha Sharma
Bachelor of Engineering., Maharishi Dayanand University, 2001
Master of Engineering., University of Delhi, 2006

A thesis submitted to the
Faculty of the Graduate School of the
University of Colorado in partial fulfillment
of the requirement for the degree of
Doctor of Philosophy
Department of Electrical, Computer and Energy Engineering
2015
This thesis entitled:
Signal processing techniques used for analysis of acoustic signals from heart and
lungs to detect Pulmonary Edema in 2015
written by Pratibha Sharma
has been approved for the Department of Electrical, Computer and Energy
Engineering

____________________________________________________________
Professor Frank S. Barnes

____________________________________________________________
Professor Kimberly Newman Frey

Date___________

The final copy of this thesis has been examined by the signatories, and we
Find that both the content and the form meet acceptable presentation standards
Of scholarly work in the above mentioned discipline.
IRB protocol # _11- 0204
iii

Abstract
Sharma, Pratibha (Ph.D. Electrical, computer and Energy Engineering)
Signal processing techniques used for analysis of acoustic signals from heart and
lungs to detect Pulmonary Edema
2015
Thesis directed by Professor Frank S. Barnes and Professor Kimberly Newman

This thesis uses signal processing techniques on acoustic signals of the heart and
lung that help measure the changes in the Congestive heart failure patient’s
pulmonary edema from decompensated to compensated and vice versa. CHF is one
of the leading causes of death worldwide leading to nearly 287,000 deaths annually
[1].

This thesis investigates various signal processing techniques with the potential to
remotely monitor congestive heart failure. Measurements are taken on diagnosed
CHF patients who are compensated and decompensated to further monitor their
progress in the management of their disease. The long term goal is to create an
algorithm that can be used to determine when a person changes classification from
healthy to heart failure as well as from compensated to decompensated so that
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readings may be taken in a home setting to improve health care and reduce the
occurrence of emergency hospitalization. This thesis focuses on three signals:
acoustic signals of the heart due to opening and closing of heart valves, acoustic
signals of the lungs due to respiration and the electrocardiogram (ECG) signals.

The research is based on the application of Fourier transform, short time
Fourier transform and wavelet analysis to acoustic signals of the heart and lungs.
The power spectra obtained through Fourier transform produced results that
differentiated signals from healthy people and CHF patients, while, the short time
Fourier transform (STFT) technique didn’t give envisaged results. The most
promising results were derived through the wavelet analysis method. Wavelet
transforms gives better resolution in time for higher frequencies and better
resolution in frequencies for lower frequencies. Using wavelets, a difference between
decompensated and compensated conditions are shown in the wavelet coefficients
for the same patient that appears correlated with the weight of the patient.
Dedication

I want to dedicate my dissertation to my whole family who stood there as my
backbone during my PhD study. This thesis is especially dedicated to my soul mate,
Pankaj Sharma, cutest son, Shubh Sharma and my lovely mom, Vijay Sharma.
Further, I would like to dedicated this thesis to my father, Mr. R.B. Sharma, My
father-in-law, Mr. R.D. Sharma, my mother-in law, Mr. Indira Sharma, My brother,
Mr. Dinesh, his wife, Upasana Sharma and two nieces, Dishita Sharma and Anisha
Sharma
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Acknowledgment

First, I would like to give special thanks to my esteemed advisors, Professor
Frank S. Barnes and Professor Kimberly Newman Frey. Without the constant
support and guidance provided to me by Professor Frank S Barnes, this thesis
would not have been possible. Professor Kimberly Newman Frey’s criticism and
appreciation at times helped me a lot to complete my thesis.

I would like to give special thanks to my whole family. Without my brother
initiative, I might not have thought of doing PhD from U.S. My mother and
husband motivated me throughout my 3.9 years of PhD. My son’s incredible love
and his patience pushed me to always do better. He was the only one who was with
me throughout these years without a miss.

Also, my committee members were very helpful at times. They opened
different solutions to my research problem with their knowledge and experience
during my research. I would like to thank Dr. Carlin Long with his medical
expertise who gave me valuable advises in my research and helped us in recruiting
CHF patients from Denver Health center. I would like to thank Professor
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A.J.Gasiewski who guided me about the signal to noise ratio of the equipment and
digital signal processing techniques that improved the success of my research.

Finally, I would like to thank all my healthy and CHF subjects who
volunteered to participate in my research. Special thanks to Nurse Inez at Denver
health center who helped in coordinating with the CHF patients for my research
and Mr. Clive who was kind enough to donate Thinklabs stethoscope for our
research.
viii

CONTENTS
CHAPTER

1. INTRODUCTION ....................................................................... 1
1.1 Objective ......................................................................... 3

2. REVIEW OF THE LITERATURE………………………………. 5
2.1 Background ................................................................... 5

3. HEART SOUNDS AND LUNG SOUNDS ................................. 9
3.1 Heart sounds ................................................................. 9
3.2 Lung sounds ................................................................. 14
3.3 Congestive heart failure ............................................. 15
3.3.1 Types of heart failure .................................... 16
3.3.2 Main causes and symptoms of congestive
heart failure ........................................................................................ 17
3.4 Diagnosis of CHF ........................................................ 18

4 . EQUIPMENT USED ............................................................ 19
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4.1 Digital stethoscope ...................................................... 19
4.1.1Sensor used-The electromagnetic
diaphragm (Emd)……………………………...19
4.1.2 Frequency…………………………………… 21
4.1.3 Ambient noise reduction .................. ... ……..21
4.1.4 Experiments…………………………………..22
4.2 Alivecor heart monitoring machine ............................ 26

5. EXPERIMENTAL METHODOLOGY ............................................ 31
5.1 About the study ........................................................... 31
5.2 Recruitment methods .................................................. 32
5.3 Procedures for measurement ...................................... 33
5.4 Measurement of lung acoustics .................................. 34
5.5 Measurement of heart acoustics ................................. 35
5.6 Data management ....................................................... 36

6. RESULTS AND DISCUSSION ...................................................... 38

7. FUTURE SUGGESTION ............................................................... 85
BIBLIOGRAPHY……………………..………………………………………….86