International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 5 - October 2015
Evaluation of Abnormal Rate with Slew Parameters in Patient
Monitoring System using FPGA
K.Soundarya#1, N.Suresh*2
#
Pg Scholar, Applied Electronics, Prathyusha Institute of Technlogy and Management
*Assistant Professor, ECE, Prathyusha Institute of Technlogy and Management
Abstract—Heart disease has become a fatal
cause(ranking third)for over 20 years with the
mortality rate of approximately 3, 60,000 cases per
year or 987 cases per day. In an attempt to bring
down the numbers, patient monitoring systems have
been designed to continuously monitor the patient’s
physiological parameters such as ECG, Pulse Rate,
Body Temperature, RespiratoryRate through
Bluetooth with wearable antenna (Microstrip
antenna). However the efficiency of such a system
depends on the accuracy in data acquisition and data
analysis. This work aims to design a patient
monitoring system using FPGA which is found to
minimize the chip area thereby reducing power
consumption and increase efficiency using wearable
antenna.
Keywords-ECG,Blood Pressure, Body Temperature,
Respiratory Rate, FPGA, Threshold values,
Bluetooth, Wearable antenna (Microstrip).
I. INTRODUCTION
Heart disease is one of the most prevalent
and serious health problems in the world. According
to IANS, the disease kills 17.3 million people each
year. The numbers are rising. Over three quarters of
CVD, deaths take place in where the people are in the
low and middle income groups.Further,CVD claims
more lives than all forms of cancer. By 2030,it is
expected that 23 million people will die from CVDs
annually. Patient monitoring systems have been
designed in an effort to bring down the mortality rate.
A patient monitoring system monitors the patients
physiological parameters on a continuous basis and
alerts the physician and caretaker via SMS in the
event of an abnormality being detected.
The Patient Monitoring System currently in
use has been designed using aMicrocontroller. This
system has a few inherent drawbacks such as system
complexity, high power consumption and a large chip
area. This work aims to improvise the existing system
by implementing the patient monitoring system using
FPGA wherein the chip area is minimized thereby
reducing power consumption and improving
ISSN: 2231-5381
efficiency.
This
methodology
deals
with
measurement of the physiological parameters such as
ECG, Pulse Rate, Body Temperature and Respiratory
Rate on a continuous basis. An abnormality in any of
these parameters is intimated both to the physician as
well as to the care taker via SMS through Bluetooth
(2.4GHz) with wearable antennaso as to ensure
timely medical aid.
A patient monitoring system can be defined
as an analyzed collective data monitored
continuously providing better healthcare to the
patientsespecially thosein a critical condition. It helps
the physician to make informed decisions, thereby
getting timely attention for the patients.
II.RELATED STUDIES
Many works primarily on algorithms and software
based implementation for detection of abnormality
heart rates that have been measured already but we
have designed a FPGA with patient monitoring
system to detect any abnormal heart rate.
The current work is about an alert SMS sent
to the doctor through a microcontroller that has the
drawback of occupying large area and low power
consumption [1].An arrhythmias is detected through
GSM/GPRS module that are interfaced in ARM
processor to get an efficient output but it has
drawback of the whole system leads to
complexity[2].Telemetric system is interfaced by
software defined GSM baseband processor in FPGA
for real time healthcare monitoring system runs the
application on same board but delay is more through
GSM module[3]. A wearable ECG Transmitter is
placed on patients body that acquires continuously
ECG signal from high risk condition through ECG
analyzer in mobiles but delay is more if the signal is
not periodic [4].An algorithm is assessed by an
Electrocardiogram (ECG) signal that triggers alarm
for different types of arrhythmias but it has a smaller
accuracy of 95% and deficiency in noise quality [5].
An wavelet based transform is used for measuring the
heart beats by using Pan and Tompkins algorithm in
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International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 5 - October 2015
Lab View. But the process is complex to detect
abnormality and results in smaller accuracy [6]. The
presence of Linear Discriminate Analysis (LDA) is
used to detect abnormal depending on a database
classifier that leads to less accuracy range of 90.38%
[7].
The patient monitoring physiological parameters are
sent to a microcontroller in which average databases
are recorded such that it will alert the physician in
case of emergency through Zigbee. But it has the
drawback of a short range and a low data speed
[8].The patient is also monitored through a data
mining algorithm which compresses all the data in
multi-channel through different node processes.
However it requires long computation to solve the
processes which results in delay in sending the data
and complexity [9]. The patient‟s vital signs like
ECG, heart rate, breathing rate, temperature, SpO2
are sent to the doctor‟s phone using an Android.
There is an improper network failure during data
transmission [10]. The other details are also referred
from [11]-[15].
This paper describes abnormal heart rate detection by
simultaneously monitoring patient's ECG that
includes other physiological parameters such as pulse
rate; respiratory rate and body temperature through
Bluetooth with microstrip antenna at a frequency
range of 2.4GHz. It is based on threshold based
classifier value which is meant to save the
patient‟slife. An alert is sent to the physician when an
abnormal rate is detected.
III. PROPOSED PROTOTYPE HARDWARE
DESCRIPTION
The proposed patient monitoring system uses Spartan
Kit for the said application.The architecture of the
system is shown in Fig.1.Here FPGA act as heart of
the system and stimulates the output signals with the
aid of smart bio signal sensors.
The following four analog input parameters are
described as below:
The Thermistor sensor is used to detect the patient‟s
body temperature. The analog signals from patient‟s
body are amplified and converted into digital values
which depend on resistance changes in response to
the patient‟s body temperature. The normal is given
as 45ºc.When the value is above the normal, it sends
an „SMS‟ as „T ABNORMAL‟ to the physician every
minute.
The ECG of the patient is measured by fixing three
electrodes potential that are placed in patient‟s body
ISSN: 2231-5381
i.e. on right arm, left arm, right or left leg. The
normal is given as 90-160 amplitude duration. When
the value is above the normal, it sends an „SMS‟ as
„E ABNORMAL‟ to the physician every minute.
Fig.1Block Diagram of Patient Monitoring System using Bluetooth
with Micro strip antenna
An infrared sensor is used to detect the pulse rate.
When the patient‟s finger is placed between the IR
transmitter and the IR receiver, blood flow density
increases simultaneously with intensity and received
at the IR receiver decreases and vice versa. The
normal is given as 80 beats per minute. When the
value is above the normal, it sends an „SMS‟ as „P
ABNORMAL‟ to the physician every minute.
There are two Thermistors are used for the
measurement of respiration. Here, one Thermistor is
used for the patient‟s respiration and the other is for
the indication of room temperature. The comparator
compares both values and gives the difference
between them. Details are shown in Figure 1.The
normal is given as 22 breaths per minute. When the
value is above the normal, it sends an „SMS‟ as „R
ABNORMAL‟ to the physician every minute.
A. BLUETOOTH WITH WEARABLE ANTENNA
The term wearable antenna means literally dedicated
antenna (or suitable) to wear. In simple terms it can
be concluded that the wearable antenna serves as
element of clothes, whose purpose is performing
tasks directly related to telecommunications.
Recently, body-centric communication (focused
around the human body) has become a very big
importance in the field of wireless communications.
Flexibility, nominal weight, resistant to shock and
vibrations are the main advantages of these body
wearable antennas. The technique used here is
resonance method and focused on the use of Micro
strip patch radiator which contains fabric material as
its substrate.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 5 - October 2015
In its most basic form, a Micro strip patch antenna
consists of a radiating patch on one side of a
dielectric substrate which has a ground plane on the
other side as shown in Fig. 2. The patch is generally
made of conducting material such as copper or gold
and can take any possible shape. The radiating patch
and the feed lines are usually photo etched on the
dielectric substrate.
Fig. 4 Back view of patch antenna
The front view and back view of Micro strip
antenna are shown in Fig 3 and 4.The design
considerations for a rectangular patch, the length L of
the patch is usually 0.3333 0 < L < 0.5λ0, where λ0 is
the free-space wavelength. The patch is selected to be
very thin such that ≪ λ0 (where t is the patch
thickness). The height h of the dielectric substrate is
usually 0.003λ0 ≤h ≤ 0.05λ0. The dielectric constant
of the substrate ( ) is typically in the range 2.2 ≤ ≤
12. In order to design a compact Micro strip patch
antenna, higher dielectric constants must be used
which are less efficient and result in narrower
bandwidth.
Fig.2 Micro strip patch Antenna
The radiating patch is the rectangle of width
45mm and height 50mm. A feeding point is etched,
which is used to provide input to the antenna. The
feeding point is at S distance of 10mm from the left
of the rectangular patch. The feeding point is placed
at a distance of 20mm from the bottom of the antenna
patch. The width of the feeding point is 25mm and
the length is 3mm. The radiating patch is made up of
copper which is a good conductor of electricity. The
port is placed at the edge of the feeding point to
provide the input to the antenna. This antenna design
is simple as well as favorable for Bluetooth
application shown in Fig.5.
Fig. 3 Front view of patch antenna
Fig.5 Design of Micro strip antenna
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International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 5 - October 2015
Bluetooth is a wireless transferring technology that
enables short-range wireless connections upto 10100metres. Here AUBTM-23 Bluetooth are used to
transmit and receive the data in serial communication
with the UART connected signal parameters of
(Body Temperature, Electrocardiogram, Pulse Rate,
Respiratory Rate) threshold values from wearable
antenna and send the message to physician. This
works based on the principle of radio wave
connection between two devices is used to send and
receive data between two Bluetooth devices. There
are 79 frequency channels of a frequency 2.45 GHz
through which the devices send and receive threshold
values with each other.
B. FPGA IMPLEMENTATION
The patient monitoring system is designed using
FPGA via Bluetooth with wearable antenna as shown
in Fig.6. The process in FPGA kit are converted by
external analog inputs of patient‟s ECG, Body
temperature, Respiratory rate and Pulse rate into
digital threshold values. This system monitors
patient‟s healthcare continuously and gives output by
receiving the SMS via Bluetooth with antenna to
physician at critical stage. The patient‟s condition
comes to the physician‟s knowledge depending on
the values of the FPGA output. All the above
parameters are monitored continuously, if any of
these parameters occur as abnormal that immediately
it sends a „SMS‟ to physician. An abnormal message
(SMS) is send to doctor through Bluetooth frequency
(2.4GHz) with micro strip antenna (cotton material)
that are attached in patients body for long distance
communication and high efficiency in terms of
receiving abnormal message. The patient‟s life can be
saved in case of emergency by giving proper medical
aid especially for aged persons and ICU patients.
IV. SOFTWRAE IMPLEMENTATION
The inputs that are taken from patient monitoring are
diagnosed by assigning a value to each parameter and
then converted into crisp decision values given to the
FPGA kit. These parameters such as body
temperature, ECG, pulse rate, respiratory rate are
monitored continuously. Based on output commands,
a doctor receives an abnormal „SMS‟.
Let us consider the set X as the number of
four parameters = {Body Temperature, ECG, Pulse
rate, Respiratory rate} => {S1, S2, S3, S4} and Y as
the patient‟s condition= {Normal, Abnormal} => {N,
AN}.Specification of the patient‟s condition depends
on these four parameters which are expressed in (1)
values as F selected from the set
F= {Low, Normal, High} ……..(1)
For example, <Body temperature, low> means it
indicates that value given in a set P as: P= {<S1, V1>,
<S2, V2,><S3, V3><S4, V4>……<Sn, Vn>} Vn is the
threshold value that is applied to each parameter Sn.
Where n=1, 2, 3, 4......
The set of rules are considered as parameters X
captured in a set of tables P, heart disease. The set of
Y is identified through an SMS. The value P is
obtained from the patient‟s condition as P(X, Y). The
inference rules are written as syntax in the form as:
IF<Threshold values> then < Threshold values > as,
IF (Body temperature is low) AND (Pulse rate is low)
AND (Respiratory Rate is low) AND (ECG is low)
THEN ABNORMAL.IF (Body temperature is high)
AND (Pulse rate is high) AND (Respiratory Rate is
high) AND (ECG is high) THEN ABNORMAL.IF
(Body temperature is normal) AND (Pulse rate is
normal) AND (Respiratory Rate is normal) AND
(ECG is normal) THEN NORMAL.
The four parameters of equations (2), (3), (4), (5) are
given below:
ECG
Body Temperature
Respiratory Rate
….(2)
…….. (3)
……. (4)
Fig.6 Circuit Description of FPGA
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International Journal of Engineering Trends and Technology (IJETT) – Volume 28 Number 5 - October 2015
VI. CONCLUSION
……. (5)
Pulse Rate
The above equation shows the method of
implication based on commands S1, S2, S3, and S4 as
low, high and normal. They are interfaced in FPGA
and send an “ABNORMAL” message at each minute
with the monitored values.
V. EXPERIMENTAL RESULT
The analyzed input parameters obtained from
patient‟s body are processed under FPGA in Fig.7
and give output as digitalized values are shown in
Fig.8.The output of each parameter is displayed
under LCD and when it goes beyond the normal
range values, it sends an „ABNORMAL‟ SMS to the
physician every minute.
Fig.7 Prototype Model
Fig.8 Abnormal SMS via Bluetooth with wearable antenna
ISSN: 2231-5381
The results got from vital parameters of the patient
monitoring system implemented with FPGA are
promising compared to other conventional methods.
The parameters that are measured using FPGA are
sent as „SMS‟ to the physician in the case of
emergency through Bluetooth with wearable antenna.
Due to this, patients get timely help and hence are
saved from high risk conditions. The main advantage
of FPGA kit lies in, its flexibility to all field
applications; power consumption and minimal chip
area. The architecture is purely based on commands
that are executed in a programmable chip. In future,
the entire process would be implemented using SOPC
of neural networks with different algorithms.
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