Spirometry measures lung function by assessing the volume and speed of air inhaled and exhaled. It generates graphs of airflow and is used to diagnose respiratory conditions like asthma and detect obstructive and restrictive lung diseases. The test involves taking deep breaths into a mouthpiece and exhaling as forcefully as possible into the device multiple times. Results are analyzed to determine if values like forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) are within normal ranges, with abnormally low values indicating lung dysfunction.

1. By adnan qadir

2. Spirometry is the most common of the pulmonary
function test (PTF’s) . It measures lung function
specifically the amount (volume ) or speed of air
that can be inhaled or exhaled .
Spirometry ( pneumotachograhps )which
generates charts that plot volume (amount)
And flow (speed) of air coming in and out of the
lungs from one inhalation and exhalation
.

4. Spirometry is indicated for the following reasons :
 To diagnose asthama
 To detect respiratory disease in patients
presenting with the symptoms of breathlessness.
 To diagnose and differentiate between obstructive
and restrictive lung disease .
 To conduct pre operative risks assessment before
anaesthesia or cardiothoracic surgery.
 To diagnose the vocal cords dysfunction .

6.  The spirometry is performed by using a
device called SPIROMETER , which comes in
different varieties. Most spirometers display
the followings graphs called SPIROGRAMS .
 A “VOLUME –TIME GRAPH” showing volume
(lts) along y –axis and time (sec) along x – axis.
 A “FLOW –VOLUME LOOP” which graphically
depicts the rate of airflow on y –axis and total
volume inspired or expired on the x -axis

7.  Before starting test , keep following things in mind;
 Avoid alcohol before 4 hours
 Stop talking large meals before 2 hours
 Smoking should be stopped 1 hour before
performing test
 Avoid vigorous exercise before 30 minutes
 Wear loose and comfortable clothes
 Patient should be relexed
 On advice of doctor certain medications may be
avoided e.g inhalers

8. A spirometery test usually takes about 15 min ,
Here’s what happens during a spiromertry
procedure :
 A patient is seated on a chair in an
examination room. A doctor or nurse places a
clip on nose to keep both nostrils closed. A
cup like breathing mask is also placed around
the mouth.

9.  The doctor or nurse instructs patient to take
a deep breathe in hold the breath for a few
seconds and then exhale as hard as you can
into the breathing mask.
 The test can be repeated at least three times
to make sure that the results are constant.

10.  If lot of variations between the results occur
between the test than the highest value
among the three is considered as final result.
If there is any evidence of breathing disorder
,the doctor might give an inhaled medication
known as bronchodialators to open up the
lungs after the first round of test .
The is then asked to wait for 15 min after then
another set of measurement is done.

11. After doing another test the doctor than
compare the results of these two
measurements to known whether the
bronchodialators have helped to increase the
air flow or not.

12.  Some of the few complaints the patient experience
after the test are :
1. Dizziness
2. Shortness of breath immediately after the test .
3. The test requires some exertion so it is not
recommended if having HEART disease.

13.  Spirometry measures two key factors
EXPIRATORY FORCED VITAL CAPACITY
(FVC) and FORCED EXPIRATORY VOLUME
(FEV1).
 The doctor also looks at these as a combined
no known as FEV1/FVC ratio.

14. One of the primary spirometery measurements
is FVC, which is the greatest total amount of
air one can forcefully breathe out after
breathing in as deeply as possible. If FVC is
lower than normal, something is restricting
the breathing.
Normal and abnormal results are evaluated
differently between the adults and children

15.  For children aged 5 – 18 years
Percentage of predicted Result
FVC value
80% or greater Normal
Less than 80% Abnormal

16. For Adults
FVC Results
Is greater than or equal to Normal
The lower limit of normal
Is less than the lower limit Abnormal
of normal

17. An abnormal FVC could be due to restrictive or
obstructive lung disease.
An obstructive or restrictive lung disease could
be present by itself , but its possible to have
a mixture of these two types at same time.

18. The second key spirometry measurement is
forced expiratory volume (FEV1). This is
amount of air one can force out of lungs in
one second .
It helps the physician to know the severity of
breathing problems
A lower than normal FEV1 reading shows one
might have a significant breathing
obstruction.

19.  Normal and abnormal values according to
guidelines from the American Thoracic
Society.
Percentage of predicted Results
FEV1
80% or greater Normal
70-79% Mildly abnormal
60-69% Moderately abnormal
50-59% Moderate-severely abnormal
35-49% Severely abnormal
Less than 35% Very severely abnormal

20.  The FEV1/FVC ratio is a no that represents
the %age of lung capacity one is able to
exhale in one second
Higher %age represents normal or healthier
lungs while low ratio suggests something is
blocking airway

21. SMOKING IS HATE TO NOSE ,HARMFUL TO BRAIN AND DANGEROUS
TO THE LUNGS
DO U TAKE OR ...............