vii
TABLE OF CONTENTS
CHAPTER
TITLE
PAGE
DECLARATION
ii
DEDICATION
iii
ACKNOWLEDGEMENT
iv
ABSTRACT
1
v
ABSTRAK
vi
TABLE OF CONTENT
vii
LIST OF TABLES
xi
LIST OF FIGURES
xii
LIST OF SYMBOLS/ABBREVIATIONS
xvii
LIST OF APPENDICES
xviii
INTRODUCTION
1
1.1 Overview
1
1.2 Theory
2
1.2.1
Blood Pressure
1.2.2
Blood Pressure Instruments
2
4
1.2.3
Important of Blood Pressure
6
1.3 Methods of Blood Pressure Measurement
7
1.3.1
Direct Techniques
8
1.3.2
Indirect Techniques(Non-invasive)
10
viii
1.3.2.1 Auscultatory Method
11
1.3.2.2 Oscillatory Method
12
1.3.2.3 Automated Auscultatory Technique
13
1.3.2.4 Tonometry Technique
14
1.3.2.5 Infrasound and Ultrasound Technique
14
1.3.2.6 Ambulatory Blood Pressure Monitoring Technique 15
1.3.2.7 Finger Cuff Technique
16
1.3.2.8 Pulse Dynamic Technique
16
1.3.2.9 Plethysmography Technique
17
1.4 Problem Statements
17
1.5 Projects Objectives
18
1.6 Importance of Project
18
1.7 Thesis Structures
2
19
LITERATURE REVIEW
20
2.1 Blood Pressure Measurement Using Oscillometric Method
2.2 Blood Pressure Determination In The Oscillometric
20
25
2.3 Strategy For Determination of Systolic, Diastolic and Mean
30
2.4 Accuracy of Blood Pressure Measurement Devices
33
3
METHODOLOGY
36
3.1 Method
36
3.2 Instruments
38
3.2.1 Hardware
39
4
3.2.2 Software
40
3.2.3
42
System Assembling and Integration
HARDWARE DEVELOPMENT
44
4.1 E-BPMS Hardware
44
4.2 Hardware Parts
44
ix
4.2.1 Cuff & Bult
45
4.2.2 Integrated Pressure Sensor
46
4.2.3
Operational Amplifier
47
4.2.4
Differential Amplifier
48
4.2.5
Filter
50
4.2.6
Microcontroller
50
4.2.7
MAX 232
53
4.2.8
RS 232
55
4.3 Data Transmission and Receiving
5
57
4.3.1
Hardware Handshaking
58
4.3.2
Software Handshaking
59
4.4 Circuit Operation
59
4.5 Hardware Assembling
60
4.6 Hardware Testing
61
4.6.1 Alpha Testing
61
4.6.2 Beta Testing
62
4.6.3 System Testing
62
SOFTWARE DEVELOPMENT
63
5.1 Software Design
63
5.2 Interface Design
63
5.2.1 Database Menu
65
5.2.2 Measurement Interface
65
5.3 Microcontroller Initialization and Programming
6
RESULT AND DISCUSSION
6.1 Hardware Experiments
66
71
71
6.1.1 Pressure Sensor
71
6.1.2 Differential Amplifier
73
6.1.3 Filter
74
6.1.4 Microcontroller (PIC16F877)
75
6.1.5 MAX232-RS232 Interface
76
6.1.6 Blood Pressure Determination
77
x
7
6.2 Comparison of Result
81
6.3 Measurement Performance
82
CONCLUSION AND RECOMMENDATION
7.1 Conclusion
84
7.2 Project Limitation
85
7.3 Future Recommendations
85
REFERENCES
Appendices
84
A-D
87
91 - 122
xi
LIST OF TABLES
TABLE
TITLE
PAGE
1.1
Blood pressure range
3
2.1
Distribution values for the main parameter
30
2.2
Cross-relation Table between Measurement Values and
Parameters
30
2.3
Ratio Distribution for Systolic Pressure
31
2.4
Ratio Distribution for Diastolic Pressure
32
2.5
Summary of accuracy of blood pressure measurement
devices
35
5.1
Baud Rates for Asynchronous Mode (BRGH = 1)
6.1
Comparison of blood pressure measurement using Omron
Blood Pressure Meter and e-BPMS
68
82
xii
LIST OF FIGURES
FIGURE
TITLE
PAGE
1.1
Measurement of force applied to artery walls
2
1.2
Blood circulation in the heart
2
1.3
Electronic sphygmomanometer
4
1.4
Conventional sphygmomanometer
5
1.5
Aneroid sphygmomanometer
5
1.6
Blood pressure waveform, and systolic, diastolic, and mean
pressures, from an invasive monitor screen
9
1.7
Illustration of oscillometric method
10
1.8
Determination of blood pressure by using auscultatory
11
1.9
(a) Stepped deflation cuff pressure (upper trace)
12
(b) By zooming in on the cuff pressure, the small oscillations
generated by blood flow through the arteries, are visible
(lowertrace). The peak oscillation corresponds to the Mean
Arterial Pressure
12
1.10
Blood pressure waveform by using oscillometric method
13
1.11
Blood pressure instrument for ABPM
15
2.1
From top to bottom: IA blood pressure, increasing
cuff pressure, analogically hardware-filtered (HW)
and software-filtered (SW) cuff oscillation signal
(with bias) as a function of time. (VIII)
26
Determination of the scaling multiplier and characteristic
ratios (CR values) for diastolic, mean and systolic
blood pressure from the normalized cuff oscillation
curve in the oscillometric method. (VIII)
28
Flowchart diagram depicting the oscillometric method
29
2.2
2.3
xiii
3.1
Comparison between oscillometric and auscultatory
37
3.2
Basic principle of oscillometric
38
3.3
Block diagram of e-BPMS
38
3.4
Hardware development of e-BPMS
40
3.5
Software development
42
4.1
Cuff and Bult
45
4.2
Integrated pressure sensor MPX5050G
46
4.3
Expected output of pressure sensor
47
4.4
Power supply decoupling and filtering circuit
47
4.5
LM324N Operational Amplifier
48
4.6
Differential Amplifier Circuit
49
4.7
Output signal of differential amplifier
49
4.8
Frequency response of the filter
50
4.9
Pin assignment of PIC16F877
51
4.10
Test set up for MAX232
54
4.11
Expected output from MAX232
54
4.12
Pin assignment and internal configuration of MAX232
54
4.13
Pin assignment of RS232
56
4.14
Timing diagram for data transmission by using handshaking
58
4.15
PCB layout for e-BPMS
60
4.16
Schematic diagram of e-BPMS
60
4.17
E-BPMS circuit after soldering
61
5.1
Main interface e-BPMS
64
5.2
Patient database
65
5.3
Measurement value of blood pressure
66
5.4
Initialization of register ADCON1 and all ports used
67
5.5
Setting of transmission mode and baud rate
68
5.6
PC detection of START/STOP data transfer
69
5.7
Starting the Analog-to-Digital Conversion Operation
69
5.8
ADRESL and ADRESH setting for data transfer
69
5.9
Detect the end of Capture Duration
70
6.1
Differential pressure obtained from sensor
72
6.2
Differential amplifier circuit
73
xiv
6.3
Filter frequency response
75
6.4
Input / output of analog to digital converter (ADC)
76
6.5
Output of both pin T2IN and T2OUT
77
6.6
Blood pressure measurement using oscilloscope
78
6.7
Real time blood pressure measurement using e-BPMS
79
6.8
Blood pressure oscillations envelope
81
6.9
Waveform comparison of oscillation signal between theory
and e- BPMS
82
6.10
Performance measure of e-BPMS
83
7.1
Inconsistent reading when pressure > 150mmHg is applied
85
LIST OF SYMBOLS/ ABBREVIATIONS
xv
A/D - Analog-Digital
AAMI - Association of Advancement Medical Instrumentation
ABPM - Ambulatory Blood Pressure Monitoring
ADC - Analog to digital Converter
AHA - American Health Association
Ap - Attenuation
ASCII - American Standard Code for Information Interchange
atm - Atmospheric unit (pressure measurement)
CMOS - Complementary MOSFET
COM - Component Object Model
CP - Cuff Pressure signal
CPU - Central Processing Unit
CTS - Clear To Send
DIY - Do It Yourself
DSR - Data Set Ready
DTR - Data Terminal Ready
e-BPMS - Electronic Blood Pressure Measurement System
EIA/TIA-232E Serial Communication Standard
EMI - Electromagnetic Induced Voltage
FET - Field Effect Transistor
GND - Ground
GPIB - General Purpose Interface Bus
GUI - Graphical User Interface
Hz - Hertz (unit of frequency)
LCD - Liquid Crystal Display
MAP - Mean Arterial Pressure
mmHg - Unit millimeter mercury
MOSFET - Metal Oxide Semiconductor FET
MS Chart - Microsoft Chart (ActiveX function)
MS Comm. - Microsoft Communication (ActiveX function)
xvi
MSC - Multimedia Super Corridor
NIBP - Non Invasive Blood Pressure
Pa - Pascal unit (pressure measurement)
PC - Personal Computer
PIC - Peripheral Interface Controller
RC - Resistor-Capacitor
RS-232 - Serial Communication Protocol
RTS - Request to Send
RXD - Received data
SI - International System (unit of measurement)
SPBRG - Baud rate generator
TTL - Transistor-Transistor Logic
TXD - Transmit data
UART - Universal Asynchronous Receiver/Transmitter
V - Volt (unit of voltage)
VB6 - Visual Basic 6.0
VDC - Direct current Voltage
Vout - Voltage output
Vs - Voltage Supply
WHO - World Health Organization
LIST OF APPENDICES
APPENDIX
TITLE
PAGE
A
PIC Programming
91
B
Interface Program Using VB
96
xvii
C
E-BPMS Hardware Setup
109
D
Standard Blood Pressure Issued by WHO
112
E
Data Sheet
113