International Journal of Engineering Trends and Technology (IJETT) - Volume4Issue5- May 2013
Diagnostic Spirometer
Reeva Prakash Chauhan
BTech, ME
Government Engineering college
Biomedical Department
Sector 28 Gandhinagar, Gujarat
Abstract: The Respiratory cycle include inhale and Exhale
lung volumes. From the lung volume the capacity of lung
will be defined. As per ATS (American Thoracic Society)
lung disease increased rapidly in the world. The detecting
of COPD, Asthma like is possible only by spirogram. To
measure respiratory capacity spirometer is good technique.
Using spirometer early detection of lung diseases is
possible. The present paper includes the methods for
diagnoses of lung diseases. This paper describes the perfect
technique to get precise result of respiratory capacity. The
hardware includes differential pressure and data
acquisition board. To get live patient data fuzzy system is
acquired. Using some ATS standards, deviations and
algorithm lung functions are diagnosed. Fuzzy system is
developed in the Lab view software. This software includes
comparative data of lung parameter and gives diagnosis as
per standards.
Keywords: Spirometer, Fuzzy Tool, Algorithm, standard
equation
Introduction
Spirometry is recommended for the diagnosis and
management of asthma and COPD in national and
international guidelines, and specialist respiratory groups
such as the American Thoracic and European Respiratory
Societies (ATS/ERS). Improved recognition and care of
patients with chronic obstructive pulmonary disease (COPD)
is underpinned by a need for high quality, reliable, diagnostic
spirometry. For diagnosis of COPD and Asthma mainly FVC
(Forced Vital capacity) , FEV1 (Forced Expiratory Volume
in 1 second) , and ratio of both the parameter. Spirometry
measures ventilation, the movement of air into and out of the
lungs. The spirogram will identify two different types of
abnormal ventilation patterns, obstructive and restrictive.
These parameters are measured from flow volume loop and
flow rate / time graph. Theses curves are getting into PC with
lab view software. In Lab view soft ware using fuzzy tool the
algorithm for spirometer were developed. Standardization of
equation and ratio of FVC/FEV1 is used to develop the
algorithm. To get the precise data of patient some
consideration should be taken.
FVC: FVC is the volume change of the lung between a full
inspiration to total lung capacity and a maximal expiration to
residual volume.
FEV1: Volume that has been exhaled at the end of the first
second of forced expiration.
VC: This is the amount of air (in liters) moved out of the
lung during normal breathing. The patient is instructed to
breathe in and out normally to attain full expiration.
TLC: Total lung capacity is full capacity of lung for exhaled
and inhaled air.
Above describe parameters and many more parameter are
displayed in Spirogram and floe volume curve.
Technique – How to do the spirometry test.
To ensure an acceptable result, the FVC man oeuvre must be
performed with maximum effort immediately following a
maximum inspiration; it should have a rapid start and the
spirogram and flow-volume curve should be a smooth
continuous curve.
To achieve good results, carefully explain the procedure to
the patient, ensuring that he/she is sitting erect with feet
firmly on the floor (the most comfortable position, though
standing gives a similar result in adults, but in children the
vital capacity is often greater in the standing position). Apply
a nose clip to the patient's nose (this is recommended but not
essential) and urge the patient to:
• Breathe in fully (must be absolutely full)
• Seal his/her lips around the mouthpiece
• Immediately blast air out as fast and as far as possible until
the lungs are completely empty
• Breathe in again as forcibly and fully as possible (if
inspiratory curve is required and the spirometer is able to
measure inspiration).
If only peak expiratory flow is being measured then the
patient need only exhale for a couple of seconds.
Essentials are:
• To breathe in fully (must be absolutely full)
• A good seal on the mouthpiece
• Very vigorous effort right from the start of the maneuver
and continuing until absolutely no more air can be exhaled
• No leaning forward during the test
• obtain at least 3 acceptable tests that meet repeatability
criteria
Lung Capacity measurement parameter:
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International Journal of Engineering Trends and Technology (IJETT) - Volume4Issue5- May 2013
obstructed lung (below), how FVC is smaller than normal,
but also that FEV1 is much smaller than normal. This is
because it is very difficult for a person with an obstructive
disease (e.g. asthma) to exhale quickly due to the increase in
airway resistance. As a result, the FEV1/FVC ratio will be
much lower than normal, for example 40% as opposed to
80%.
The time taken for total volume expulsion generally does not
exceed 3 s. The volume expelled during first 1 second
(FEV1) and the total air expelled (FEV) are calculated. From
that information, the ratio of FEV1/ FEV is obtained. This
ratio is very important for diagnosis. The relationship
between the flow and volume provides useful information
about pulmonary function.
Reference figure 1
Technique for PFT test.
Fuzzy rules:
Table 1
Severity of obstruction
Positioning of the patient:
FEV1
% of predicted
Mild
>80
Moderate
50 to 79
Severe
30 to
Very severe
<30
Table 2
Getting the patient comfortable and in the proper position is
important step. Have the patient loosen any tight clothing,
such as neckties, belts. Denture should be left in place unless
they are loose and interfere with performance of test.
Measurements curves:
Figure 2
Severity of restriction
FVC
% of predicted
Mild
>65 to 80
Moderate
>50 to 65
Severe
<50
Table 1 and table 2 describe the rules for obstructive and
restrictive disease. The value of FVC and FEV1 is decided
from the flow rate /second graph. The % of FVC and FEV1
is mark up on the graph. Decrement and increment/normal %
of FVC and FEV1 graph divide in 25% to 75%.
Figure 3
Figure 4 FVC report
Liter
25%
50%
(Reference figure)
75%
The figure 2 and figure 3 describes the volume/ time (flow
rate) curve. From the flow rate curve % of the FVC and
FEV1 can be measured. The FVC test allows one to clearly
distinguish between the two disease types. Notice in the
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Second
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International Journal of Engineering Trends and Technology (IJETT) - Volume4Issue5- May 2013
Figure 4 shows the flow rate graph of spirometer. The marks
on the graph define the % of FVC. For diagnosis of diseases
algorithm is prepared in fuzzy tool.
Figure 5 diagnosis algorithm for spirometer.
6)
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The algorithm prepared in fuzzy tool. For making the system
easy and reliable lab view is good option. In lab view we can
prepared the soft ware system which can take data from the
hardware. In the lab view fuzzy system designer was used
for making the rules for spirometer.
18)
Different methods are used for diagnosis of lung diseases.
Nitrogen wash out, Helium dilution, DLCO etc. for different
methods more standards were described by researcher. Here
we define method using flow graph of spirometer. From the
severity of obstruction and restriction the lung diseases are
measured. The soft ware method for diagnosis gives more
precise and easy to use. Also patient feels comfort while give
test.
Figure 6 block diagram of spirometer in Fuzzy system
designer
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AUTHOR:
Reeva Prakash Chauhan received B.TECH degree in Bio
Medical Engineering from U V Patel College of Engineering,
Ganpat University Mehsana, in 2008. After completion during
2008 to 2011 worked as an Assistant Manager of Operation
Theatre in Shalby Hospitals, Ahmedabad, Gujarat. From March
2011 joined the Maharani Medicare Pvt. Ltd as a project
biomedical Engineer. Research work carried out on US probe
revision HIP surgery. Right now continue in ME in Bio medical
Engineering from Government College of Engineering
Gandhinagar Sec 28, Gujarat. Now as part of research study
working on Digital Spirometer.
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Testing” ch.8 page 77-117.
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Measurement, Instrumentation, and Sensors “Handbook.
EUA:CRC 1999
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testing”. J. 6(Suppl 16), 3–52 (1993)
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http://www.ijettjournal.org
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